Battery Charging Issue
Printed From: The Fishing Website
Category: General Forums
Forum Name: The Boat Shed
Forum Description: Discuss all things boating.
URL: https://www.fishing.net.nz/forum/forum_posts.asp?TID=136721
Printed Date: 09 Jun 2026 at 5:14pm
Topic: Battery Charging Issue
Posted By: kitno
Subject: Battery Charging Issue
Date Posted: 09 May 2022 at 9:35am
I have this battery in a Mac 360 to power the sounder and nothing else. Battery and charger came with the boat (CTEK). Recently left it on (unaware) and ran it flat. Now showing 4.6 volts with no load. Can't seem to add any charge to it. While on charge the multi metre reads 0.23 volts. Only one green light in the bottom left of the charger comes on. I have charged it before with this charger and it worked fine. Basically, do I have a battery issue or a charger issue? Can I use a car battery charger instead?   |
Replies:
Posted By: Titahi
Date Posted: 09 May 2022 at 12:38pm
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From my past experience I suspect its a battery issue.
You should be using a lithium specific charger for a Lithium ion battery. The ctek's require some counter voltage to start providing current ------------- "I love standing by the ocean and just knowing what its for" |
Posted By: MB
Date Posted: 09 May 2022 at 12:50pm
| Agree with above, do not charge a lithium battery with a non-lithium charger. Ideally, you could borrow someone's lithium charger or give them your battery to charge so that you can workout where the problems lies. |
Posted By: smudge
Date Posted: 09 May 2022 at 1:31pm
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I just did a quick google as I've not had much experience with Lithium Ion batteries but I think the advice above is good. I doubt a quick charge on a conventional charger say 5 or 10 mins to counter the effect Titahi says would cause any issues and then put it on the proper charger. As long as the battery doesn't heat up that is. From my own understanding of those types of battery I definitely wouldn't charge it for much longer on a conventional charger though unless I had some advice otherwise. Lithium batteries are touchy things and could very well start a fire if left unattended if not on the correct charger ------------- Best gurnard fisherman in my street |
Posted By: SaltyC
Date Posted: 09 May 2022 at 2:33pm
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These "drop in" litium batteries have an built in battery management system (BMS) that is there to stop the worst from happening (fire!). It protects the battery from both overcharge and also will disconnect it when the it is discharged to 20% or less. It is called "load dumping" and is a bit of a draw back as it can cause problems for alternators that suddenly have nothing to charge and turns off all connected loads, and thus all your electronics, when it drops below the 20%. |
Posted By: SaltyC
Date Posted: 09 May 2022 at 2:35pm
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Link: |
Posted By: kitno
Date Posted: 09 May 2022 at 4:27pm
| Thanks for the replies, had a look into the CS one charger. No much change out of $500. |
Posted By: kitno
Date Posted: 09 May 2022 at 4:36pm
| Bay Batteries have offered to try it on their lithium charger tomorrow, hopefully that gets a result. |
Posted By: SaltyC
Date Posted: 09 May 2022 at 4:42pm
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you may be able to bypass the problem by connecting a 12 volt source to the battery before connecting the charger, another 12 volt battery , positive to positive, and negative to negative, then connect your charger and when thecharger says it is charging disconnect the other battery. Only with a lithium charger though (I see your ctek is a lithium one, but just in case someone else reads this!) |
Posted By: kitno
Date Posted: 09 May 2022 at 7:13pm
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You're a clever bastard SaltyC. Connected to the car battery, left it for a minute and checked incase it was heating up. Connected charger, charging lights came on and boom (not literally) she's charging.   |
Posted By: smudge
Date Posted: 10 May 2022 at 4:36am
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Good work Salty
------------- Best gurnard fisherman in my street |
Posted By: Steps
Date Posted: 10 May 2022 at 8:12am
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The issue of low charge battery and charger not charging has come up several times in posts over the yrs. Most chargers that har bit more on the 'expensive ' side have a sensor that will not allow to charge if under something like 8v or 9 v (from memory) Reason is its assumes the battery is due , end of life, or has a dud cell, or incorrect internal resistance. Pretty much basic Sparky stuff. Simply putting another charged battery in parrell as connect the charger .. the charger sensors the higher voltage, and the initial connecting plus charger working is enough to hold that voltage up. If disconnect the good battery to quick the voltage can drop and no charge. Most chargers mention this voltage thing in the instruction manuals. They do not mention the connect in parallel bit.
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Posted By: SaltyC
Date Posted: 10 May 2022 at 9:20am
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Except in this case Steps we are fooling the BMS inside the battery into allowing the battery to charge not the charger. Oh, and I should add DO NOT DO THIS if you are uncertain as to what has caused the battery to die. In this case Kitno is clear he left it connected and ran it below the low voltage that the BMS would "load dump" at. Current lithium battery technology is inherently dangerous and can burst into uncontrollable fire if it is over voltage, under voltage or just gets too hot, hence the need for either an internal BMS in each battery like this one or an external BMS for larger banks. |
Posted By: Kandrew
Date Posted: 10 May 2022 at 4:24pm
| You well on to it SaltyC not a charger problem, the battery management system within the battery itself. |
Posted By: smudge
Date Posted: 10 May 2022 at 6:03pm
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As a sparky, I clearly missed the basic sparky stuff. As I said I have very little experience with Lithium Ion, I know they are volatile but after reading Salty C's most excellent advice I've done a little digging and while I'd probably do it myself at a pinch, I wouldn't advise anyone else to connect a charger not designed for LI batteries at all. ------------- Best gurnard fisherman in my street |
Posted By: Steps
Date Posted: 11 May 2022 at 9:40am
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BMS can be in a charger , as i suggested above or in a battery.. or both early lithuims didnt have built in BMS. To by pass the BMS for a battery holding a charge below any of the BMS pre sets.. can be fooled by introducing a higher voltage for a very short period... it is potentially dangerous to do so for any more than a few seconds. If it then doesnt start to charge then something else is likely to be an issue as noted above by Salty. Also the correct charger must be matched to the correct battery type to charge.. and correct alternator in vehicles etc. Back in the day of std wet lead acid was never an issue.. then came geled and AGM acid batteries.. these , espec the AGM which we use ad marine batteries should not be charged on a std pb acid charger.... If you have and note a short battery life, that is why. Cd batteries also require a dedicated charger, as do lithuim They all charge at different rates and have different full charge voltages. Now we have introduction of smart chargers that detect type battery, charge rates ans some even have recondition modes. All which pretty knowledge thru hot rodding, car resto guys, marine workshops, sparkies And basic 'technicians' on cctv cameras , security, lighting and similar isolated solar powered systems etc. , and considered pretty basic stuff I repeat if going to 'jump' the voltage to over ride a BMS either in a battery or in a charger or both, only do it for a few seconds.. no more. regardless of lithium or any other type. Once the higher voltage is detected it then supplies its own voltage to maintain the charge sequence All this I have posted before many times over the yrs..maybe decade. |
Posted By: SaltyC
Date Posted: 11 May 2022 at 10:06am
| ya just gotta laugh, don't ya? |
Posted By: Titahi
Date Posted: 11 May 2022 at 10:39am
 ------------- "I love standing by the ocean and just knowing what its for" |
SaltyC wrote:Posted By: Pcj
Date Posted: 11 May 2022 at 11:46am
------------- "Times up" |
Posted By: SaltyC
Date Posted: 11 May 2022 at 12:52pm
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Gel or AGM, yes. Lithium, opinions vary and dangers abound! In my opinion, the issue is why the battery is not working. The BMS can disconnect the battery because it detected over voltage or heat, in either case it wouldn't be wise to apply a shock load to the battery by connecting jumper leads and pushing start. Not only does it not fix the reason the BMS disconnected the battery but it can cause a fire and, in the worst case, an explosion. The other issue is that the load has been disconnected from the charging source by the BMS as well, so when the motor is running again, if it doesn't reconnect successfully then running the charging source with nothing to charge may cause major damage to it! Lithiums are used as start batteries for motorbikes and the general recommendation is not to jump start them from another battery.
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Posted By: Keith C
Date Posted: 11 May 2022 at 2:21pm
It is a real pity that the website has descended to what you refer to SaltyC, and we have to sift to find any posts of value (like yours SaltyC). I could previously learn heaps off fishing.net and this thread has once again provided invaluable learnings around current battery technologies. Thanks SaltyC for taking the effort. Unfortunately there are now a minority like you who contribute positively to this website. It is so frustrating having to troll through the crrap to get to the valuable stuff. |
Posted By: Pcj
Date Posted: 11 May 2022 at 4:02pm
Think I will stick with the flood. ------------- "Times up" |
Posted By: Kevin.S
Date Posted: 11 May 2022 at 4:38pm
Bloody useful info there Salty, I'll definitely remember this for future reference. I had a case just a month ago where I had run a car battery right down and my "smart" chargers would not even look at it -this trick may have fooled them into charging it. In this case it was OK as I got the battery replaced as it was within warranty. Would this work by connecting one of those booster starter batteries across the terminals while you start charging?
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Posted By: kitno
Date Posted: 11 May 2022 at 7:06pm
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I've got to admit, I had oven mitts ready to go and the ranch slider wide open while connecting the batteries lol. |
Posted By: SaltyC
Date Posted: 11 May 2022 at 7:12pm
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Pcj: Gell or AGM - no problem using jumper cables or a jump start pack. I would not recommend disconnecting a battery after starting a motor, it removes the load the alternator or stator/rectifier are trying to charge with usualy dire consequences! Kevin.S: my post is specifically about Kitno's situation with his Lithium battery and fooling the internal BMS. Where a flooded battery can't be charged you will usually have a fairly fatal issue with the battery. Some chargers won't charge below 10 volts or so and may be fooled by connecting a 12 volt source but again I don't recommend it unless you are certain that the battery has simply been run completely flat by a load being left connected. It isn't dangerous to try buit the likelyhood that you can resurrect a battery that probably has a terminal fault and then rely on it as a start battery is quite low.
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