 bazza wrote:OK ... now for the revelation as to why the battery went flat !!! My previous motors had alternators, therefore assumed all larger HP motors would. Not so it would seem a many, my current 90hp Merc included have a far less efficient system ... forgotten what it is called. If you are 100% sure your motor has an alternator then read no further as you are not affected. What is the main difference between the two systems ? Alternator :- starts charging the moment the motor is running & provides a healthy amount of charge power. Other system :- is far less efficient with not only a relatively low output but motor has to reach 2500 rpm before it even starts to do so. I have always started the motor & left it idling whilst using the anchor winch in the false belief battery power being used would be balanced by the charge being used ... but not so it would seem, also same applies to hydraulic tilt. OK on this trip as well as a couple previous we have been trying to come to grips with the newly installed GPS/Chartplotter/Sonar, therefore mostly puddling along, also leaving it on when anchored. As a result but unknown to us, the battery was probably in a very healthy condition when we launched on Thursday, nevertheless performed all the required functions at that stage. From there on we were moving much slower than normal & shifted position a short distance about 4 or 5 times using the anchor winch each time. So basically using the winch, key start, bilge pump, sonar, hydraulic tilt, vhf etc. was draining current with little or any input until it reached a point where there was insufficient power to start the motor. In retrospect, altho I was peed off at the sequence of events at the time have come to realise it was maybe rather fortuitous inasmuch as am about to do a couple of long trips oblivious to the fact that both the wagon & boat batteries were likely to cause significant problems if either or both would not start ... whereas ... I now have a new battery for the wagon, a new one for the boat plus a fully charged jump start for either & a fully charged spare battery, so peace of mind has been restored. Have also purchased a hand held VHF as a backup & will probably install a voltmeter so as can keep an eye on the state of the batteries. Plus I now know what to do to avoid excess battery drain, so am even more knowledgeable than I was when starting this thread !! I think it was Rex ( AKA Letsgetem ) that mentioned battery power can be viewed on the sonar/plotter/gps unit .... is this so? Best of all, called into Simon Lucas yesterday & an obliging salesperson managed to subdue the female gps scourge who was constantly nagging me to take every off ramp, perform U turns or anywhere contrary to my intended destination. The salesman said she was trying to get me to go to New Plymouth where no doubt she had some sort of tryst planned however my mother warned me about women like that! |
| cirrus wrote: Is the battery charging system on a 4 stroke any more efficient than a 2 stroke |
| cirrus wrote: Is the battery charging system on a 4 stroke any more efficient than a 2 stroke |
| Steps wrote: What is your engine Bazza? |
MacSkipper wrote:
|
| Steps wrote: Done a bit of digging 90 hp 2012 mercury charging system.. covers many yrs around then... have alternator.. as thought would.. NOT early 1900s magneto or mid 1900s generator.. Therefore it should be charging to some degree at idle and near full charging just off idle.. If not maybe a stator issue, but since charging at higher rpms then would suspect the solid state rectifiers, as suspected previously... most proberly a rectifier diode failing or failed.. SOMETIMES these faults will also show as a tach reading wrong or not working.. The most common reason why these units fail is because the battery has been disconnected, switched off, loose or bad terminal connections. If failing then need to replace before completely doesnt so. They are not cheap The factory service and or repair manual has detailed method to check out puts / connections and resistances between Bottom line thu, I believe the comment that doesnt charge at idle or just off idle is a load of rubbish IF that was the case there would also be huge up cry from merc owners who trawl lakes etc going back to at least the early 90s...and in that time cant believe merc would not have changed how the alternator fields got their field voltage from. |
bazza wrote:
Yep ... a Merc 90 hp ... 2012 or thereabouts. I can relate to how the battery felt as I am ( in the words of the ancient Romans ) stuftus completus after doing the Tongariro crossing yesterday. My biggest concern was the likelihood of extreme heat so made sure was carrying sunblock, hat & 3 ltrs of water, but apart from 1/3 of the water, none were needed as was near blizzard conditions all of the 20 kms .... will add a pic later, when I recover. Was so exhausted this morning that when hooking into a decent fish in the Whakapapa I felt in danger of it dragging me down the river, so was quite relieved when it broke the leader. Looking back down the valley had just come from at this point was thinking that very soon will be able to exclaim in true Hillary fashion "I knocked the barstard off!" but that ambition was to be gradually eroded with the reality was less than a 1/4 of the way to the highest point before the descent began. Could only make out the crater lakes if there was a momentary respite from the icy cold storm driven rain. |
Fish galore! Coming off the back of Easter Weekend and with some very nice weather... Read More >
Excellent snapper action There is some excellent autumn snapper fishing straight out and up the... Read More >
Whangarei Harbour fishing well Like the weather, the fishing has been patchy throughout Bream Bay... Read More >
Party time! Inshore fishing and offshore fishing are on now. It’s that perfect time of... Read More >
Major Bites
Minor Bites
Major Bites
Minor Bites
Forum Topics
New Posts
Search
FAQ
Register
Login
Topic Options
Post Options
Likes(0)
