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my boat battery

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Category: Saltwater Fishing
Forum Name: The Captain Morgan Briny Bar
Forum Description: The place for general chat on saltwater fishing!
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=136028
Printed Date: 08 Dec 2021 at 1:14am


Topic: my boat battery
Posted By: letsgetem
Subject: my boat battery
Date Posted: 02 Oct 2021 at 11:05am
THis is old hat thats no doubt been discussed before.

My boat battery failed after 2 and a half years. Thats pretty short time.Ive bought a new one, ok.  

Im not very knowledgable re batteries. Im thinking that, the battery doesnt like dropping to low charge. Ive got a anchor winch. It drains heaps of charge out of the battery. Then I run, mostly very short trips, to other places and back home. Possibly not enough to fully charge the battery. So, is it likely, the battery has dropped (and stayed) too low, and thats caused it to fail. 

With the new battery, when I raised the anchor, I saw (on my sonar voltage readout), the voltage dropped from about 12v to 10.7v; that seems pretty low?
Its a 1000w anchor winch, thats a high drain on the battery.

I will fully charge the battery (with a charger), and the see how much the voltage drops on anchor raising.

I would appreciate any words of wisdom on this.



Replies:
Posted By: Mr Moritz
Date Posted: 02 Oct 2021 at 11:34am
Maybe a bigger battery if it will fit..

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If you always do, what you've always done. You will always get, what you have always got
Henry Ford


Posted By: bazza
Date Posted: 02 Oct 2021 at 12:15pm
Rex ... I have been there but now have the comfort of knowing
am not likely to get caught out whilst out on the water since having a couple of backup features installed ... you are welcome to check them out once L2 is announced & restrictions are lowered.Text Colour

Until it happens to us we seldom think about how vulnerable we are to battery failure particularly as modern day batteries seem to be much more prone to dying with little or no warning compared to their predecessors.

Of course firstly motor should be running before & during the winch being implemented as it is the major draw on any battery power, not that it will totally compensate but at least if motor is kept running you should be assured of being able to return to launching/retrieving place ... however am certain with your wealth  of experience you will be well aware of all that so will move on to other pitfalls that can be encountered due to a flat battery.

AlanL is the only person I know that has been able to rope start my 90hp Merc & that was when still on the trailer ... I certainly cannot manage to do so.

Next GPS/chart plotter possibly dead along with installed VHF, bilge pump & motor tilt ... mob ph could also be out of cover.

A small portable jump start may manage to start motor but have to take care cable clamps don't short out on anything particularly on ali hulls but seem to recall your new boat is FGlass.

On two occasions my main emergency backup system has come to the rescue ... would not be without it. 


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Scored a much needed hair cut this morning so now on the way to Mitre 10 to take back the hedge trimmer !!


Posted By: Big -Dave
Date Posted: 02 Oct 2021 at 12:36pm
Put any significant load on a battery and the terminal voltage will drop. 100 is quite small for an anchor winch, I'd expect it to be drawing more than 10 amps.

Think in amp hours. If it takes 2 minutes to pull an anchor up using 480 w winch. Assume it is drawing that. P=vxa, 480 divided by 12 volts is 40 amps.

You used that current for 2 minutes.
If your motor can charge at 5 amps, that is one eighth of what you were drawing, so you need to charge for 8 times the time...16 minutes to replace that charge.

So, if you up pick and move lots, short distances, you might be slowly draining your battery. If this is only day trips, then a good charge overnight when you get home, will top the battery up. No real harm done.
You then need to use a maintenance charger if you don't use the boat at least every month..

No battery likes to sit even in a partially discharged state for long. It will die.
Anything over 50% discharge at any time will cause damage.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Kandrew
Date Posted: 02 Oct 2021 at 1:06pm
Originally posted by letsgetem letsgetem wrote:

THis is old hat thats no doubt been discussed before.

My boat battery failed after 2 and a half years. Thats pretty short time.Ive bought a new one, ok.  

Im not very knowledgable re batteries. Im thinking that, the battery doesnt like dropping to low charge. Ive got a anchor winch. It drains heaps of charge out of the battery. Then I run, mostly very short trips, to other places and back home. Possibly not enough to fully charge the battery. So, is it likely, the battery has dropped (and stayed) too low, and thats caused it to fail. 

With the new battery, when I raised the anchor, I saw (on my sonar voltage readout), the voltage dropped from about 12v to 10.7v; that seems pretty low?
Its a 100w anchor winch, thats a high drain on the battery.

I will fully charge the battery (with a charger), and the see how much the voltage drops on anchor raising.

I would appreciate any words of wisdom on this.
Gidday can you tell us what motor and battery size you have.


Posted By: letsgetem
Date Posted: 02 Oct 2021 at 2:07pm
Its a 90hp Mercury 4 stroke. The battery is 530cca 52AH.


Posted By: v8-coupe
Date Posted: 02 Oct 2021 at 2:13pm
Originally posted by letsgetem letsgetem wrote:

THis is old hat thats no doubt been discussed before.

My boat battery failed after 2 and a half years. Thats pretty short time.Ive bought a new one, ok.  

Im not very knowledgable re batteries. Im thinking that, the battery doesnt like dropping to low charge. Ive got a anchor winch. It drains heaps of charge out of the battery. Then I run, mostly very short trips, to other places and back home. Possibly not enough to fully charge the battery. So, is it likely, the battery has dropped (and stayed) too low, and thats caused it to fail. 

With the new battery, when I raised the anchor, I saw (on my sonar voltage readout), the voltage dropped from about 12v to 10.7v; that seems pretty low?
Its a 100w anchor winch, thats a high drain on the battery.

I will fully charge the battery (with a charger), and the see how much the voltage drops on anchor raising.

I would appreciate any words of wisdom on this.

A friend of mine has had the same/similar problems.
Seemed to have solved it with a permanent trickle charger when not using the boat.
Batteries lasting ages now.
Also as Bazza says, always advisable to have the motor running when raising the anchor. 


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Legasea Legend Member


Posted By: Pcj
Date Posted: 02 Oct 2021 at 2:21pm
Maybe check the output from engine charging system?


Posted By: Kandrew
Date Posted: 02 Oct 2021 at 2:28pm
Originally posted by letsgetem letsgetem wrote:

Its a 90hp Mercury 4 stroke. The battery is 530cca 52AH.
90 4s has a good output alternator 35amp and the battery size looks to be ok. As Bazza says you should always start your engine first before using the winch. I like the new smart chargers I’ve got a 8 cycle charger and just leave it connected all the time. I would suggest checking all your electric connections to make sure there’s voltage drop because seeing your fish finder drops down to 10.7v seems really low lucky it even starts at that. So it makes me think you might have a bad connection somewhere between the battery and the fish finder. Perhaps put a voltmeter across the battery terminals and see what the voltage drops to there when you run the winch. The engine and the winch would run off a different battery feed so maybe that’s why your only seeing the low voltage reading at you finder.

How did you know your last battery was stuffed, did you take it in and get it load tested.


Posted By: letsgetem
Date Posted: 02 Oct 2021 at 3:41pm
Three points -

Oh my mistake - its 1000w anchor winch (not 100).

The battery voltage drops from 12v to 10.7v when the anchor winch is pulling up - not when starting the motor.

The previous battery, wouldnt start the motor - not a peep out of it. I took it to a garage and they load tested and said its stuffed.


Posted By: Kandrew
Date Posted: 02 Oct 2021 at 4:20pm
Ok that makes more sense, what does the voltage return to. The winch should have a working load about 80 amps. Which shouldn’t take to much out of your battery if it’s fully charged. As above maybe look at a small ctek smart charger or something similar.


Posted By: Steps
Date Posted: 02 Oct 2021 at 4:59pm
The concept of starting the outboard and having running while using a winch/ capstain, is not about charging.
 Alternators have next to no charge till hit around 1200 to 1800 rpms.
 The reason is that if you have a dud battery, and/ or charging circuit , at least the engine is fired up to get home.

As per others above.. batteries , any type dont like being discharged and stored partly charged, espec modern batteries... In saying that I maintained they actually have a far longer life.

About a 530 cca is ok for just your engine spec, and gps, sounder few other low current items... A larger battery with greater storage would certainly help longevity using high current winches. Something the battery ppl should advise on.

Even so getting home and throw on a smart charge (ctek) 8 stage charger...an maintain that charge between trips.

 This is all assuming that your battery connections, isolating switch connections etc, the battery top is kept clean and that the charging system is actually working.
These will not only cause extra current draw to items but also effect the rate the alternator re charges.

In general a fully charged battery will give you 1 1/2 good days trips out fishing before you notice that when you trim the engine it sounds different and weak.

Check  and clean, re grease connections, then check its charging...


Posted By: letsgetem
Date Posted: 02 Oct 2021 at 5:57pm
According to the manual (for the Mercury 90hp), the alternator charges at 50amps.

When its charging, the voltage rises from 12v to 14v. 

And I can confirm the motor alternator does not charge until over 1000rpm, ie not at idle. 


Posted By: Kandrew
Date Posted: 02 Oct 2021 at 6:44pm
Originally posted by letsgetem letsgetem wrote:

According to the manual (for the Mercury 90hp), the alternator charges at 50amps.

When its charging, the voltage rises from 12v to 14v. 

And I can confirm the motor alternator does not charge until over 1000rpm, ie not at idle. 
Mate the reason for starting the motor first is if the battery get to flat to start the engine while your running the winch.


Posted By: Alan L
Date Posted: 02 Oct 2021 at 7:46pm
You should be charging at 1000 rpm. My Merc 2S has about 10A at 1000 rpm or there-abouts - and the manual specs say so too. You will have pretty much the same charging system. If the motor is turning, it is charging. Just at the low end of output.
But as Steps said, and you have deduced. The battery does not like being left half charged.
If you are only short running and potentially short charging , a trickle chargewhile the boat is stored is the answer. I leave all my boat and car batteries on trickle - for up to 6 mths. In the boat I am using right now a $100 battery (not even Marine) ), 3 yrs old - and still holding 12.8 V. It had been on trickle for 6 mths and had 12.8V after standing for a day or two. And still does. And cranks the engine no problem.
Also most batteries don't like rapid deep drain - but you can't avoid that with a winch. Is it Deep Cycle? Should be - for that job.
Alan



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Legasea Legend member


Posted By: Alan L
Date Posted: 02 Oct 2021 at 8:03pm
approximate
amperes:
RPM AMPERES (9A charger)
Idle 4.0
1000 8.0
(14 Ampere Stator) 2000 11.0
3000 13.0
4000 14.0
5000 14.0
RPM AMPERES
Idle 5.0
1000 10.0
16 Ampere Stator 2000 16.0
3000 17.0
4000 18.0
5000 18.0

The copy /paste got messed up. This is early Merc 2S around 90HP. Somewhere I have more recent specs but can't find right now. There are usually 3 charge options - small/med/large. But at 1000 rpm you should be charging around 10A. If not - you have a problem.
Alan


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Legasea Legend member


Posted By: Bounty Hunter
Date Posted: 02 Oct 2021 at 9:15pm

assume you have the now standard AGm chemistry battery - you, like many people are finding they dont seem to last as long as the old FLA batteries.

there are two issues you need to be aware of that are hurting your battery;

the anchor winch is drawing at least 80amps - possibly more if your wiring or terminals arent ideal - and whilst as mentioned above, the total A/hrs removed from the battery arent that many because of the short winching duration - the RATE of current is getting quite high - 80+ AMps is approaching double thew capacity of your batt and many manufacturers recommend against very high charge/discharge rates - often only 100% of capacity. this is where lithium is a big improvement - 500+% charge/discharge rates are no issue

secondly - AGM do not like being left at anything less than 'full voltage' for very long - best practice is to bring them up to full once a week. even with everything disconnected, they will often have a self discharge rate of 1 - 3% per month -  so they need regular attention.

basically you should consider getting a larger battery next time so your winch isnt asking too much from it in terms of 'rate of current draw' and get a decent multi-stage smart charger that can be left plugged in permanently when the boat is stored on the trailer between outings


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Death - Our community's #1 killer


Posted By: letsgetem
Date Posted: 03 Oct 2021 at 9:21am
Good stuff, thanks.

According to the motor specs (2018 90hp 4 stroke) - the alternator output is 50amps. THat appears a lot higher than the 2 stroke amps mentioned. 

One thing Im bothered by. THere doesnt appear to be a way of measuring the % charged of the battery. If there was, I would know whether the battery needs charging - and put the charger on it. Has anyone figured a way of measuring this? 


Posted By: Kandrew
Date Posted: 03 Oct 2021 at 9:29am
Originally posted by letsgetem letsgetem wrote:

Good stuff, thanks.

According to the motor specs (2018 90hp 4 stroke) - the alternator output is 50amps. THat appears a lot higher than the 2 stroke amps mentioned. 

One thing Im bothered by. THere doesnt appear to be a way of measuring the % charged of the battery. If there was, I would know whether the battery needs charging - and put the charger on it. Has anyone figured a way of measuring this? 
I use one of these, simple easy to install and read, I just hang mine of the side of the battery box where I can see it any time and my ctek smart charger plugs straight into it.

https://www.marine-deals.co.nz/smart-battery-chargers/ctek-comfort-indicator-eyelet-m8-8-4mm?gclid=EAIaIQobChMIpNvcrces8wIVgiQrCh2RBQDFEAQYASABEgJXePD_BwE" rel="nofollow - https://www.marine-deals.co.nz/smart-battery-chargers/ctek-comfort-indicator-eyelet-m8-8-4mm?gclid=EAIaIQobChMIpNvcrces8wIVgiQrCh2RBQDFEAQYASABEgJXePD_BwE


Posted By: Steps
Date Posted: 03 Oct 2021 at 9:45am
BH covers that above...
just put it on a maintenance charger once a week or simply leave on the smart charger.
 And make sure your chargers are the correct charger for the type of the battery, otherwise you will over charging a little or undercharging and either of these also drops the battery life dramatically.

 Also that 50 amp rating is not 50 amp at 1000 rpms. The 1000 rpms is where it starts to charge.
 
There is also another long term issue with a battery too small for the engine , and or too small for the engine and other large loads at the same time... If your voltage drops too low, you CDI / ignitions sealed regulators  have to draw more current to maintain their required power draw.
 More current means they then heat up, and they do not like running too warm or hot.
 And they are expensive to replace...

Never run the engine disconnected from the battery either.. that kills the sealed regulator/ tach unit, and they are not cheap either.

From memory my manual says run a min 630cca battery
I have a 760 or 780..because running high pressure wash down pump or the capstan from 50/ 60m.
 The Local auto electrician only has 2 rather 'oversized ' marine batteries in stock. Reason being he doesnt get ppl coming back because of early battery failure.


Posted By: Mr Moritz
Date Posted: 03 Oct 2021 at 10:22am
Originally posted by letsgetem letsgetem wrote:

Good stuff, thanks.

According to the motor specs (2018 90hp 4 stroke) - the alternator output is 50amps. THat appears a lot higher than the 2 stroke amps mentioned. 

One thing Im bothered by. THere doesnt appear to be a way of measuring the % charged of the battery. If there was, I would know whether the battery needs charging - and put the charger on it. Has anyone figured a way of measuring this? 


Just put a voltmeter across your battery terminals 12 Volts =flat 12.5 volts = Half charge   12.8 volts = Good fully charged battery.
Do this test when battery is at rest and at least 24 hours after charging cause charging pushes voltage up (14V )and takes about a day or so to settle down... 


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If you always do, what you've always done. You will always get, what you have always got
Henry Ford


Posted By: letsgetem
Date Posted: 03 Oct 2021 at 10:27am
Oh damn I made another error - the 90hp motor charges at 35amps (not 50). 

The winch draws 83 amps. 
Anchor retrieval max rate is 41m/min. 
Anchor drop rate is 45m/min. (not free fall)

I havent measured the exact time the winch operates - next time Im out I will keep a record of this.

I have calculated roughly how much power should be used to drop and retrieve anchor - for my maximum anchoring, say 3 times at 25m depth (with twice the depth out). Its about 7.8AH.

Charging at 35Amps, 7.8AH would take 17.8mins to recharge. 

I would always run for longer than 17.8 mins (at high speed) coming back in - so, theoretically, the battery should have always been fully charged when returned to the ramp.

Whether the old battery failed because it was left not fully charged, or there was something wrong with it, I will never know. Interestingly, manufacturers warranty appears to be max 2 years ONLY! THats pathetic.

But, maybe things dont always work according to plan.
So, I will buy a Battery Comfort Indicator to ascertain when the battery needs charging; and a Ctek MXS 5.0 charger to charge it up fully. 
Can anyone comment on how this performs, or if any other battery charger would be better. 

THanks for all the points raised.




Posted By: SaltyC
Date Posted: 03 Oct 2021 at 11:10am
The amps actually going into your battery are not controlled or set by what the charging output of your motor is. That is just the maximum that the motor can output.

The actual amps going into the battery is a function of the level of charge of the battery (the internal resistance of the battery increases as its state of charge goes up).

If your battery is above about 85% State of Charge (SoC) then the amps it will accept to charge are way lower than the theoretical max output of your charging device and usually this drops to about 10% of the battery capacity at 90% charge and keeps dropping as the SoC increases, so you may only be charging at 5.2 amps once the battery reaches 90 %. Ie it will take hours of running to get those last amps replaced and the battery back to full charge.

So, the net effect is that it is practically impossible to recharge your battery to 100% unless you spend hours trolling. As you do multiple trips you gradually decrease the level of chrge in a semi-cummulative manner. 

First trip starting at say, 100% you might end up at 92%. Next trip pulls the battery down further than the first because of the lower starting point and so is likely to end at lower recharge as well, say 90% etc etc etc as each trip gradually lowers the finishing SoC until the battery is more likely to fail, or you go trolling for 8 hours!

So, get a good battery charger, like the Ctek you mentioned and use it every time you return home. I don't personally like battery chargers left connected all the time as they can cause catastrophic damage if you get a dead short in the battery from a dead cell or thermal runaway in some AGM batteries. But a couple of days is all it needs each time.



Posted By: Steps
Date Posted: 03 Oct 2021 at 11:15am
Interestingly, manufacturers warranty appears to be max 2 years ONLY! THats pathetic.

 That has been the case, even way back into the 60s.
 I meanted this above...


The Local auto electrician only has 2 rather 'oversized ' marine batteries in stock. Reason being he doesnt get ppl coming back because of early battery failure.

If batteries are treated right they last way beyond their warrantee periods.
Im thinking way back to my 1st car.. 63 triumph herald...and boat.. near 50yrs ago... I can not rem a battery ever failing under 6 to 10 yrs... Camaro went thru 3 batteries over near 40 yrs and 300,000 miles.. Bradford 1 over about 7 yrs and sold it with it still in. Big horn replaced the one we brought it with after about 4yrs, and the new one still fine 3/4yrs on. Even my jumper batteries last 10yrs plus.
 Tops always clean.. little over size to allow for extra loads, and always kept charged.


Posted By: Sufishent
Date Posted: 03 Oct 2021 at 11:34am
Originally posted by Kandrew Kandrew wrote:

Originally posted by letsgetem letsgetem wrote:

Good stuff, thanks.

According to the motor specs (2018 90hp 4 stroke) - the alternator output is 50amps. THat appears a lot higher than the 2 stroke amps mentioned. 

One thing Im bothered by. THere doesnt appear to be a way of measuring the % charged of the battery. If there was, I would know whether the battery needs charging - and put the charger on it. Has anyone figured a way of measuring this? 
I use one of these, simple easy to install and read, I just hang mine of the side of the battery box where I can see it any time and my ctek smart charger plugs straight into it.

https://www.marine-deals.co.nz/smart-battery-chargers/ctek-comfort-indicator-eyelet-m8-8-4mm?gclid=EAIaIQobChMIpNvcrces8wIVgiQrCh2RBQDFEAQYASABEgJXePD_BwE" rel="nofollow - https://www.marine-deals.co.nz/smart-battery-chargers/ctek-comfort-indicator-eyelet-m8-8-4mm?gclid=EAIaIQobChMIpNvcrces8wIVgiQrCh2RBQDFEAQYASABEgJXePD_BwE

Although a great idea these are not foolproof. I have a multistage charger and always recharge the battery before a trip out. I also fitted one of these battery level indicators to my battery as extra awareness on battery charge. 

However I'm now having to change my battery as although the indicator is still showing green, the battery voltage has dropped to 11.6V and the battery won't hold a charge as I think a cell has gone. 


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You can never have enough fishing tackle


Posted By: Bounty Hunter
Date Posted: 03 Oct 2021 at 11:48am
Originally posted by letsgetem letsgetem wrote:

Oh damn I made another error - the 90hp motor charges at 35amps (not 50). 

The winch draws 83 amps. 
Anchor retrieval max rate is 41m/min. 
Anchor drop rate is 45m/min. (not free fall)

I havent measured the exact time the winch operates - next time Im out I will keep a record of this.

I have calculated roughly how much power should be used to drop and retrieve anchor - for my maximum anchoring, say 3 times at 25m depth (with twice the depth out). Its about 7.8AH.

Charging at 35Amps, 7.8AH would take 17.8mins to recharge. 

I would always run for longer than 17.8 mins (at high speed) coming back in - so, theoretically, the battery should have always been fully charged when returned to the ramp.

Whether the old battery failed because it was left not fully charged, or there was something wrong with it, I will never know. Interestingly, manufacturers warranty appears to be max 2 years ONLY! THats pathetic.

But, maybe things dont always work according to plan.
So, I will buy a Battery Comfort Indicator to ascertain when the battery needs charging; and a Ctek MXS 5.0 charger to charge it up fully. 
Can anyone comment on how this performs, or if any other battery charger would be better. 

THanks for all the points raised.



your calculation on recharge time is flawed unfortunately

read SaltyC s post about declining acceptance rates as the battery comes up to full 


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Death - Our community's #1 killer


Posted By: Kandrew
Date Posted: 03 Oct 2021 at 2:34pm
Originally posted by letsgetem letsgetem wrote:

Oh damn I made another error - the 90hp motor charges at 35amps (not 50). 

The winch draws 83 amps. 
Anchor retrieval max rate is 41m/min. 
Anchor drop rate is 45m/min. (not free fall)

I havent measured the exact time the winch operates - next time Im out I will keep a record of this.

I have calculated roughly how much power should be used to drop and retrieve anchor - for my maximum anchoring, say 3 times at 25m depth (with twice the depth out). Its about 7.8AH.

Charging at 35Amps, 7.8AH would take 17.8mins to recharge. 

I would always run for longer than 17.8 mins (at high speed) coming back in - so, theoretically, the battery should have always been fully charged when returned to the ramp.

Whether the old battery failed because it was left not fully charged, or there was something wrong with it, I will never know. Interestingly, manufacturers warranty appears to be max 2 years ONLY! THats pathetic.

But, maybe things dont always work according to plan.
So, I will buy a Battery Comfort Indicator to ascertain when the battery needs charging; and a Ctek MXS 5.0 charger to charge it up fully. 
Can anyone comment on how this performs, or if any other battery charger would be better. 

THanks for all the points raised.


Yep as I said mate 35 amp and about 400 plus watts of output, also has a water cooled regulator so I don’t know where this regulator overheating comes from. The Mercury 4S also run digital inductive ECM ignition not CDI. Some of the stuff posted on here can really confuse the solution.

Go to a larger battery if you want to but I would spend my money on a good smart charger. I have the same ctek charger pretty foolproof and I like the way the charger plugs straight into the comfort plug with out having to take the top of the battery box all the time and at a glance I can see where the battery at.

But there’s plenty of other chargers and voltmeters to look at depends on how much money you want to spend and how complicated system you want.


Posted By: Steps
Date Posted: 04 Oct 2021 at 8:31am
. I have a multistage charger and always recharge the battery before a trip out. I also fitted one of these battery level indicators to my battery as extra awareness on battery charge. 

However I'm now having to change my battery as although the indicator is still showing green, the battery voltage has dropped to 11.6V and the battery won't hold a charge as I think a cell has gone.


Chances are you may have , or have a voltage leak, maybe anything from salt/ dirt on the battery top between the terminals or in the isolation switch etc. A case of battery not being full charge when stored , and huge effect on battery life.

Quick test if battery going down/ cell dropping, and dont have a load tester...
Charge it up...leave 5 mins, note voltage. Then get an old incandescent car head lamp or something that pulls a lot current .. 12v pump, capstan/winch etc..run for 3 or 4 mins turn off wait couple minutes then check voltage... if good voltage will be same or very close to what was before loaded.


Posted By: Mr Moritz
Date Posted: 04 Oct 2021 at 9:45am
Just a thought, I guess your battery is well secured in your boat. If there is any up or down movement the slamming could be damaging battery cells..

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If you always do, what you've always done. You will always get, what you have always got
Henry Ford


Posted By: RockCrashing
Date Posted: 04 Oct 2021 at 10:19am
Hi, I've charger with a temperature sensor and sometimes i forget to connect it. Do the sensor make big diferance to the charging time?  


Posted By: SaltyC
Date Posted: 04 Oct 2021 at 10:30am
The temp sensor is only there so the charger can stop charging if the battery temperature gets to high. Doesn't effect the charge rate, that is purely down to the batteries resistance.


Posted By: Sufishent
Date Posted: 04 Oct 2021 at 11:30am
Originally posted by Steps Steps wrote:

. I have a multistage charger and always recharge the battery before a trip out. I also fitted one of these battery level indicators to my battery as extra awareness on battery charge. 

However I'm now having to change my battery as although the indicator is still showing green, the battery voltage has dropped to 11.6V and the battery won't hold a charge as I think a cell has gone.


Chances are you may have , or have a voltage leak, maybe anything from salt/ dirt on the battery top between the terminals or in the isolation switch etc. A case of battery not being full charge when stored , and huge effect on battery life.

Quick test if battery going down/ cell dropping, and dont have a load tester...
Charge it up...leave 5 mins, note voltage. Then get an old incandescent car head lamp or something that pulls a lot current .. 12v pump, capstan/winch etc..run for 3 or 4 mins turn off wait couple minutes then check voltage... if good voltage will be same or very close to what was before loaded.

Chances are you may have , or have a voltage leak, maybe anything from salt/ dirt on the battery top between the terminals or in the isolation switch - battery is disconnected after each trip so no stray currents and no salt/dirt on connections

battery not being full charge when stored - I have always charged before a trip and I will now charge after each trip

I used to check the battery voltage occasionally with a volt meter but used the CTEK led battery monitor system as my routine go to for monitoring battery level - after this issue it is now in the rubbish bin.




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You can never have enough fishing tackle


Posted By: Big -Dave
Date Posted: 04 Oct 2021 at 2:12pm
Problem with charging a battery before a trip, is it can prop up a dying battery, long enough to get you out there and then go t*ts up..best to maintain if you are worried.

I admit i havent for years, use winches stereo etc, up to 3 months gaps between use as well, never had a flat battery unless the isolator was left on and the stereo or something.
I even switch to the house battery for a start up occasionally to see if it will still do the job.


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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: letsgetem
Date Posted: 06 Oct 2021 at 11:39am
For the record -

I bought a charger Ctek MXS 5.0 (5 amps max) - $159 from Repco.
My boat battery started at 12v - thats pretty low, although it us still enough to start the motor. 12v has been called "flat", but its not really, ive read that 12v is about 25% charged.. 
THe Ctek charger, went thru 4 stages (of analysis stuff), then at stage 5, charged at higher amps until 80% charged - took 16 hours. Then went on stage 6, charging at lower amps until fully charged (12.8v) - took 10 hours. 

Ive permanently installed the Ctek input cable onto the battery - its plug (to connect the charger) hangs outside the battery box, that easy to use.

So - took 26 hours in total. THats quite a long time, presumably the 5amps is relatively low. Fine if you have plenty of time, but not if you want to get out soon.
I thought of getting a Ctek Comfort Connect Indicator, that shows voltage in 3 bands (red <12v, needs charging (although its not totally flat), orange 12.4-12.65v, partially charged, green >12.65v fully charged. But as I have battery voltage shown on my FF screen, thats easy and more precise, so I probably wont use the comfort Indicator.
NOw Im happy to get out there - now Covid regs allow boating - but Ive got a doctors appointment - BUGG.R.

Oh, and Im  charging my ute battery, only 12v after sitting doing nothing for 10 weeks.



Posted By: Steps
Date Posted: 06 Oct 2021 at 6:05pm

So - took 26 hours in total. THats quite a long time, presumably the 5amps is relatively low. Fine if you have plenty of time, but not if you want to get out soon.

 Modern agm batteries are NOT like our old school Pb car batteries... hence the new 'smart chargers'
They must be charged low and slow...
And as mentioned above.. must be tied down to reduce thumping.. they dont like that either.


Posted By: letsgetem
Date Posted: 22 Nov 2021 at 11:43am
Ive been studying how the battery charge changes between trips (ie motor charging).
At the end of the trip - 12.7v, thats about 100% charged.
Next day - 12.6v - interesting drop
then the voltage drops every day
after 5 days 12.5 about 90%
after 5 days 12.4 about 80%
etc - it appears to go down faster than I expect.

I have tried turning off the battery isolation switch, doesnt make any difference, so assume the drop is at the battery.

The battery is near new, 4 months old; and I cant see any dirt or salt buildup on the top of the battery.

So, I normally have the boat out of the water for around 14-21 days. The voltage should be about 12.4v when it goes for a spin and is recharged. I would prefer it to be fully charged.

So - two options - 

(a) I have a Ctek 5a charger, which if kept going all the time will keep the battery fully charged. 

(b) I could checking the voltage after each trip, and then leave it; and checking voltage around once a week, and fully charge before going fishing.

Im leaning towards option (a). Anyone see anything I should consider?

I imagine Covid lockdown has been bad for batteries, as they will have gone down too much and failed.




Posted By: tjm
Date Posted: 22 Nov 2021 at 1:08pm
I agree with Salty, Lead acid batteries in particular do not take kindly to being left in a low charge state or no charge / discharge for any length of time. Smart trickle chargers that slowly charge and discharge are the go. ( must get one for mine soon)If you have bad luck a battery can last two years, while many last 5 or more. In the old days every winter the automotive techs used to have phone calls from client with dead batteries, another issue is that batteries are at their worst when the weather is cold.

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Cant beat hunting and Fishing in N.Z


Posted By: SaltyC
Date Posted: 22 Nov 2021 at 3:50pm
Letsgetem, the discharge rate rate you are reporting over just a couple of weeks is not typical of a battery sitting unconnected, it is way too high.

I would suggest there is still something draining amps at low but steady rate even with the battery isolation switch off.

If you can, get your hands on a mutimeter with an amp clamp and check the actual amps being discharged with the isolation switch off.

If you can't find one locally somewhere, give me a yell and let me know where you are (Whangaparaoa?) and I will drop in with mine when up there next.




Posted By: Pcj
Date Posted: 22 Nov 2021 at 4:43pm
Totally disconnect battery then check in 2 days as to what the discharge rate is,if nil,then isolator will be faulty,may need a clean as salt crystals making contact..
If battery is discharging when disconnect find receipt and take back.


Posted By: MATTOO
Date Posted: 22 Nov 2021 at 4:46pm
Salty has lead you to a very good area of watch.

There are others often not picked up.
One is when you have two batteries, house and start with a dvs link.
Start can drain the house because of evs priority.

However, one of the most unrecognised battery drain is heat. And I mean heat in the battery cabinet. Heat destroys batteries pretty fast.
You can check your environment by placing a thermoter to measure those temps. If it your boat sits in the driveway cooking in the sun, it may well be cooking your batteries to certain early death.

As salty said good regular maintenance s a key.
Your c-tek may do the job but not all chargers are equal in there ability to maintain batteries.
Some reading maybe helpful.

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Just cruising in my now sweetas pimped out Southern 755 HT0!


Posted By: Steps
Date Posted: 23 Nov 2021 at 1:08pm
Totally disconnect battery then check in 2 days as to what the discharge rate is,if nil,then isolator will be faulty,may need a clean as salt crystals making contact..
If battery is discharging when disconnect find receipt and take back.

Yep..
Dont rely on isolating switch.. mine 'broke ' a few months back.. so dismantled it while new on was coming..
They are sealed, but still get a vertigrease (think its called) build up inside ...
Combine that with something in the boat conducting and you have discharge.
Can use ammeter to find out where etc...
But end of the day, disconnect both terminals at the battery, way to go for 100% sure.

PS once the isolation switch was cleaned , seals plus silicone, back working  so have the new spare anyway.


Posted By: Pcj
Date Posted: 23 Nov 2021 at 3:08pm


Posted By: Pcj
Date Posted: 23 Nov 2021 at 3:09pm
ended up with the above from jaycar,cheap but works.


Posted By: Pcj
Date Posted: 23 Nov 2021 at 3:45pm
Do not think batteries are made in NZ anymore,so they are imported and sit on a ship in a container for 3+months.Go to store etc and retailer certainly doesnt test charge or trickle them. So if a batterary can travel/sit on a shelf/container.
Why are we all determanded that we plug them in to a trickle charger??Surely if under 24 months old they should hold charge unless damaged,isolator failure,engine not charging full capacity?
Mine is at least 4yrs and did have a issue with slight discharge hence why I went to above,Can sit for a month put on cheap warehouse charger and its full within 30 minutes.
This is sealed flooded battery.
What type of batteries are people having issues with??flood/gel particular brand??


Posted By: SaltyC
Date Posted: 23 Nov 2021 at 5:23pm
from Battery Dynamics website:

The rate of self-discharge for lead acid batteries depends on the storage or operating temperature. At a temperature of 80 degrees F. a lead acid battery will self-discharge at a rate of approximately 4% a week. A battery with a 125-amp hour rating would self-discharge at a rate of approximately five amps per week. Keeping this in mind if a 125 AH battery is stored for four months (16 weeks) winter without being charged, it will loose 80 amps of its 125-amp capacity.


Posted By: Dagwood
Date Posted: 24 Nov 2021 at 8:03am
Originally posted by letsgetem letsgetem wrote:

Its a 90hp Mercury 4 stroke. The battery is 530cca 52AH.

Not sure if it's related but I've just installed a 100 Merc 4 Stroke. The installer was adamant that the battery needed to be upgraded as they are very sensitive to it. 

The manual (which covers the range from 75 - 115hp) states the min is 1000 Marine cranking amps (MCA), 800 cold cranking amps (CCA) or 65 amp hour (Ah)


Posted By: Steps
Date Posted: 24 Nov 2021 at 8:38am
Not sure if it's related but I've just installed a 100 Merc 4 Stroke. The installer was adamant that the battery needed to be upgraded as they are very sensitive to it. 

The manual (which covers the range from 75 - 115hp) states the min is 1000 Marine cranking amps (MCA), 800 cold cranking amps (CCA) or 65 amp hour (Ah)

Yes. As described in several previous posts..

The manual spec is for bare engine... that doesnt put out much charge/current at low rpms.
Now throw in a current draw from a winch, or capstan plus gps and few other bits in pieces.. the engine alternator doesnt keep up with the load if battery is min. spec.
So engine running, high draw on say a winch, current/ voltage to things like seal alternator regulator, ignition CD! unit/ coils. They get hot and eventually intermittent loading like this over time they die.



Posted By: letsgetem
Date Posted: 24 Nov 2021 at 9:02am
OH! For my 90hp mercury 4S, battery needs to be at least 1000 Marine cranking amps (MCA), 800 cold cranking amps (CCA) or 65 amp hour (Ah). 
The new battery I got is only 530cca, not enough. 
Ill get another battery big enough.


Posted By: Steps
Date Posted: 24 Nov 2021 at 4:54pm
I replaced my battery few months back for the 2S V6 150 Johnson..
 Factory  Installation and Repair Manual for the 150 and 175 hp
 12V  500cca (620 MCA) with 90 mins reserve capacity or 50 AHr
I replaced with a 720 (or 780 cant rem) CCA.
Alternator rated at 35 amp fully regulated
 Out Put
[email protected] 1000 rpms
33A @ 2000 rpms
38A @4000 rpms


Same Manual for the
 V4 90 and 115 hp
12V  360 CCA (465 MCA) with 90 min reserve capacity  or 50AHr
Alternator is  rated 20 amp fully regulated.
Out Put :
10A @ 1000 rpms
18A @ 2000 rpms
20A @ 4000 rpms


Posted By: Bounty Hunter
Date Posted: 24 Nov 2021 at 7:54pm
dont place too much weight on the published alternator output - it does give an indication but i wouldnt base calcs on these values.

usually the published output is the 'marketing dept' figures.

you should be looking for the 'hot rated' output values - which are usually 15-20% or so lower 


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Death - Our community's #1 killer


Posted By: Steps
Date Posted: 25 Nov 2021 at 7:42am
As stated, Those are not the 'marketing' BS numbers.. they are from the page in the BRP Installation and Repair Manual...for technicians.
Battery spec from the specs pages and the alternator specs from the testing /specs pages


Posted By: Pcj
Date Posted: 25 Nov 2021 at 7:50am
Steps. You may know the answer .I have no idea But why do we have so much trouble with marine batteries.suppose to have plates closer together to impacts etc.yet 4x4 vehicles.cars etc travel on roads with pits holes etc equilvent to driving at sea but not so many issues. Is the marine battery a con?? Older car sitting for 2 months battery 3yrs old and started no issues


Posted By: Steps
Date Posted: 25 Nov 2021 at 8:25am
Steps. You may know the answer
 maybe... when I get stuff I read manuals, even get the techicans manuals, find out how what.. its just what I have always done.. always interested me since a young kid.

This is what I understand.. as I had the same basic question in my had as you..

Marine batteries must be strapped down.. putting aside other safety issues for now.
they do not like being dropped , sudden shock.. which sound wrong as you state above.
If not well strapped down.. including inside the battery box the closeness of the plates can cause issue, being too close or even touch in extreme conditions.
When the boat comes down hard, most of the energy of the drop is absorbed (apparently) by the boat. If not strapped down the battery gets left in the air, and when hits the deck, its pretty much the shock of its own weight that causes the problem.


Posted By: Kandrew
Date Posted: 27 Nov 2021 at 8:17pm
The new glass matt batteries are a lot more robust than the older lead acid which haven’t been made for some time. Batteries should always be locked down be it in a car or boat.

The biggest killer of the new glass matt battery is not keeping them charged up, unlike cars, boats sit around and the battery loses charge, amg batteries need a good charger to look after them.

It’s important to have the correct battery for the boat and the electrics on board. Depending on the age of the boat and the type of ignition system some motors require larger batteries so it pays to check the manufacturers recommendation. 2S Hybrid motors like optis and etecs need bigger batteries even for the smaller 90hp motors to keep the battery voltage levels up. If the voltage drops to low the computer will shut down, the motor will sound like it’s winding over ok but it won’t start. Later model 4S use a dynamic voltage ignition system which sense the voltage differently. Too larger battery can be a negative as well. You should always check your battery terminals for tightness and corrosion and I only use Vaseline to coat the battery terminals, spray on oils are conducive and if they are sprayed over the top of the battery can cause the battery to discharge.

Voltmeters are really the only way nowadays to check the change level of the battery, we used to use hydrometers on the old lead acid unsealed batteries which is the best way to check batteries, many times I could pick up a dead cell because the specific gravity would be lower in that cell to the others. Remember digital voltmeters are very sensitive, when you put a sudden load across the battery like lifting the engine or using a capstan, the voltage will drop, normally this doesn’t mean the battery has gone flat it will recover. It’s the continuous loads like fish finders, vhs and stereos that will flatten the battery during the day. This is where keeping an eye on the voltmeter during the day is a good idea, that’s why I like the Ctek comfort light system, easy to keep an eye on and when the yellow light comes on start turning things off. But each to his own.


Posted By: Bounty Hunter
Date Posted: 28 Nov 2021 at 9:21am
Originally posted by Steps Steps wrote:

As stated, Those are not the 'marketing' BS numbers.. they are from the page in the BRP Installation and Repair Manual...for technicians.
Battery spec from the specs pages and the alternator specs from the testing /specs pages

does the product manual declare whether the values are 'hot rated' - if it doesnt stipulate, they probably arent - usually the corrected for load output curves are only available directly from the alternator manufacturers


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Death - Our community's #1 killer


Posted By: Steps
Date Posted: 28 Nov 2021 at 9:47am
Hot rated.. in the actual testing section noting changes as battery charge increases.


Posted By: letsgetem
Date Posted: 29 Nov 2021 at 4:49pm
Ok, Im probably stupid. There Ive confessed.

I thought my boat battery was losing charge between trips with the motor charging.

But - I was reading battery voltage on my sonar screen. I have now taken battery voltage with a multi-meter directly on the battery (terminals). It shows-
Battery voltage, With everything incl sonar off 12.82v
With sonar on 12.61v
With sonar on, voltage into sonar 12.5-12.6v

And, the battery voltage is NOT going down - over 5 days it stayed at 12.82v. This is the voltage after a trip charging the motor.

I dont know why the voltage on the sonar screen varies (when battery voltage is constant), but it doesnt matter.

It was an interesting discussion, and thank you for your input. 

 


Posted By: Kandrew
Date Posted: 29 Nov 2021 at 5:16pm
Originally posted by letsgetem letsgetem wrote:

Ok, Im probably stupid. There Ive confessed.

I thought my boat battery was losing charge between trips with the motor charging.

But - I was reading battery voltage on my sonar screen. I have now taken battery voltage with a multi-meter directly on the battery (terminals). It shows-
Battery voltage, With everything incl sonar off 12.82v
With sonar on 12.61v
With sonar on, voltage into sonar 12.5-12.6v

And, the battery voltage is NOT going down - over 5 days it stayed at 12.82v. This is the voltage after a trip charging the motor.

I dont know why the voltage on the sonar screen varies (when battery voltage is constant), but it doesnt matter.

It was an interesting discussion, and thank you for your input. 

 
Interesting but as you say you could chase around looking for the answer, you might be better installing one of these

https://www.burnsco.co.nz/usb-socket-voltmeter-flush-mount" rel="nofollow - https://www.burnsco.co.nz/usb-socket-voltmeter-flush-mount


Posted By: Big -Dave
Date Posted: 29 Nov 2021 at 6:18pm
I am not surprised by those readings. Wherever you have current flow, connections, switches etc, you will get voltage drop.

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you can't fix an idiot with duct tape, but it does muffle them for a while...


Posted By: Steps
Date Posted: 30 Nov 2021 at 9:26am
I am not surprised by those readings. Wherever you have current flow, connections, switches etc, you will get voltage drop.

Yep , want correct voltages, direct off the battery..The type dash gauge KA mentions are far better than the reading off the gps.. Do not just connect to nearest ground or live wire...ideally run direct to battery, or at least the main buzz bars, clean and check all connections on and between battery ands bars regularly..



Posted By: MATTOO
Date Posted: 30 Nov 2021 at 5:04pm
The reading on your sounder/chart plotter is the current charge being employed via the alternator of the motor of that's the only recharge devise.
It is not a battery measurement while motor is operating.
And it's not the full loading to the battery.

Your battery healt should be in the 13s for a premium load.

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Just cruising in my now sweetas pimped out Southern 755 HT0!



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