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Battery and charging

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Marko69

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Hi all my boat has been in the water now for a few weeks and I'm having a bit of trouble starting the engine !
I have a 85 HP v4 Johnson J85TlCSA the problem I am having is this .. I have a 71amp maintance free battery ! but this isn't turning the starter very fast but it does start after a few goes . I am going to change the battery and install two through a change over switch when I'm running the volt gauge shows 16 volts what charging system has my engine as I read somewhere "maitainance free battery's damage the rectifier" how and why I don't know
Any help getting me going would be great thanks
 
The starter is very easy to take apart for inspection.-----That is what you should do.------Do not know how , then today is a good day to learn.---Could be as simple as needing a new set of brushes after all these years.
 
Hi do you think that could be why it's slow to turn ? I will ring around and see if anyone has a set ! It seems knowone in the US will post to the UK bit of an arse really
 
Just take the starter apart first and inpect it.---ask questions if you are confused.----Local starter / alternator / generator shop will likely have brushes in stock.
 
Hi the battery I have has a CcA of 670 thought that would be plenty maybe I will test it before I remove the starter and have two battery's and a changeover switch
 
The proper way to go about that is first have the battery load tested. Then once you know you have a good battery do some voltage drop tests on the cables and connections. Those starters are pretty reliable, but like anything else, don't last forever. There might not be anything wrong with it. Or at the other extreme, it might have shattered field magnets. You have to inspect it before buying parts.
 
Hi do you mean the stator , that's working and charging the battery going to check all the wireing may have something loose as my earlier post I said the battery cables were warm to touch ,could be the solenoid ???
 
get rid of the maintenance free battery...you have a rectifier only charging system on that engine...you need an old style battery that you have to check the fluid level and add water..sooner or later you will loose a rectifier with maintenance free battery...

if you have one warm spot in a battery cable the that spot has resistance and should be fixed...if the whole cable is warm then you are turning the key to start and turning the motor for too long a time..a motor has to turn 300 rpm or better to start and if it does that and everything else id in good shape it should start start quickly..
 
do the starter thing as racer suggested...when you put the new battery in clean up all the connectors etc..if the battery comes with wing nuts throw them away and use regular nuts...after you do these things if you still have the turning slow problem please get back to us...
 
Hi all woo hoo ,duff battery was the problem so happy I didn't have to go and take anything apart . next job is to sort out the tilt and trim pressure release screw which is weeping fluid out ,that will have to wait until the boats out of the water which is going to be a while as I'm now going to enjoy what I've built !!!! thank you to everyone who chipped in with advice .......mark
 
Hi all regarding batteries ,what does an conventional battery have that a "maitainance free" battery doesn't, why would I need an old style battery ????? can anyone give a reason
 
Marko69 said:
Hi all regarding batteries ,what does an conventional battery have that a "maitainance free" battery doesn't, why would I need an old style battery ????? can anyone give a reason
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Removable filler caps.

With an unregulated charging system, you have mentioned 16volts, the battery will lose water from the electrolyte and periodically need topping up again. You cannot do this if there are no filler caps!

I am surprised that your charging system is unregulated though. I thought power tilt and trim models had a 10 amp stator coil, rectifier and regulator. You might like to check that out. If there is a regulator and you get much over 14volts the regulator is not working!

With a correctly functioning regulator you should be OK with a maintenance free battery although some people will say that there's no such thing as a maintenance free battery. Only low maintenance ones!
 
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hi all is OK now the warm cables were a result of cranking to long (in my earlier post) I had a duff cell in my battery resulting in the starter turning slow ,as for my battery choice I do have a regulator and a rectifier
 
you should get in the 14.8 range with a regulator..no higher than that...a rectifier only system will normally run higher than that but you start to get into trouble at or above 16 volts...

the simplest way to explain the difference in a maintenance free battery and the old style is this...if voltage gets too high on the old style there is an internal discharge in the battery...on the sealed or gelled ones there is none of that going on and they will take whatever voltage is fed to them...there is no damage to the battery but it will damage the rectifier in a rectifier only system...he first external indication of a failure id the tach going crazy sometimes...then one day the tach don't work and you look at the voltmeter and you have only battery output..
 
Hi all been out on my boat, just goes to show how my last battery was I connected a new one up showed it the ignition key and the engine fired up so good thing here the starter spinng like it should .Also I've spoken to a marine engineer and he can see no reason not to use the battery I have ,,which is good ,....
 
Marko69 said:
Hi all been out on my boat, just goes to show how my last battery was I connected a new one up showed it the ignition key and the engine fired up so good thing here the starter spinng like it should .Also I've spoken to a marine engineer and he can see no reason not to use the battery I have ,,which is good ,....
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If you are using a maintenance free battery then you need to look at your voltage regulator.

16 volts is not right, nor good for an MF battery. It will result in excessive loss of water from the electrolyte which you will no the able to replace.
 
the rectifier fails with the mf battery on a rectifier only system..i have yet to see a damaged battery...we probably get close to 20 of these problems on here every year plus personal experience..in 2006 we had a thread that went in depth on the problem..its prob in the archives..
 
papyson said:
the rectifier fails with the mf battery on a rectifier only system..i have yet to see a damaged battery...we probably get close to 20 of these problems on here every year plus personal experience..in 2006 we had a thread that went in depth on the problem..its prob in the archives..
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I'd be interested to know why maintenance free batteries cause rectifier failure.

AGM batteries will accept a very much higher charge current than FLA batteries . Perhaps it's AGM batteries that cause the problem, rather than ordinary MF batteries, although the current will be limited to the maximum output of the stator coil and one would assume that the rectifiers would be able to handle that. Perhaps not continuously, but then they'd not be fit for charging a large deeply discharged battery of any type!
 
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