charging question

[caloundra]

i have a 40hp yammie 4 stroke that is pull start
my question is i am looking at upgrading the electrics and was thinking if it is worth it(or can it be done) fitting an alternator (or the boat equivelent can't remember the name of it) to charge the battery?
is it expensive to set up?
knowing my luck the day the motor breaks down is the same day i forgot to charge the battery and can't use the radio to call for help :-[

thanks
Daniel

[dfox]

Normally costs about $150 for a charge pack fitted to a 25hp.

[caloundra]

could be worth the investment [smiley=thumbsup.gif]
thanks foxy

Daniel

[baldyhead]

There is already a charging coil under the flywheel. A simple 12v bridge rectifier from dick smiths ( converts the 12 - 16v from ac to dc current) and a length of 6mm or so cable and you are able to then charge your battery for under $20.
Go to your local outboard mechanic and ask him what 2 wires to hook the rectifier up to. I have hooked mine up by putting the rectifier into the lead and fitting a M&F spade connector then plugging them into the 2 pin fitting on the front of the motor. This way when I'm not using the battery the lead is not required.
I have an NP12-7 gel battery and when charging it I usually only hook the lead up for the trip out (high revs = full charge output) and sometimes on the way back as I dont want to over charge it. The sounder and gps dont draw much and at home I have a regulated gel cell charger.
Hope this helps
cheers baldy

[Aaron_Fogarty]

If your motors still under warrenty dont muck around with after market products. If you frazzel something the dealer wont want to know about it...If its out of warrenty go hard!
Regards Aaron

[Brewer]

Hey Baldy,

Now 15 months later im curious how the gel cell held up to the unregulated voltage output?

I have been reading up on the subject & from what i can gather AGM, SLA, GELL etc type batteries need to vent if they cop voltage much over 14V.

Cheers.

[Mantaray]

Hey Baldy,

Now 15 months later im curious how the gel cell held up to the unregulated voltage output?

I have been reading up on the subject & from what i can gather AGM, SLA, GELL etc type batteries need to vent if they cop voltage much over 14V.

Cheers.

that's for sure, at the battery shop the other day they had on display one of those 7ah gell type batteries after somebody had charged it with a conventional charger. had to ask the guy what the soldified lump was on the counter, that used to be a gel battery after being abused. well you would never have picked it as a battery! not in the condition it was anyway

[Brewer]

Well ive wired up a rectifier & as expected i get DC voltage out if it ranging from 8-18 volts.

Im thinking a SLA charger such as would work to regulate the voltage & maintain a charge when the outboard is putting out over 12V #http://www.master-instruments.com.au/browse/Model/MW301CR.html

What do you guys reckon?

[finga64]

You would have to be carefull of the input voltage. Easier to bung a regulator in with the rectifier and no more problems

[Brewer]

Any suggestions for a cheap regulator?

I figured an old reg off a car i have lying around would work but have been told by an auto elec it wont work.

[finga64]

yep, he's right.
what sort of regulator did you put on??
what is the full load current of the other charger you were thinking of putting on??

[eggbeater]

G'day Daniel.I got a 40 Yamaha 2 stroke with a charger/rectifier fitted.

You are welcome to check my connections/wiring out if it is of any help to you.

I am at Golden Beach,close to you. Give me a PM if interested

[Brewer]

We havent fitted a regulator as yet, just a rectifier.

Actually now i reckon I will ditch the idea of charging off the outboard & just charge the battery with a 240v charger before/after trips.

[finga64]

sorry I should have said rectifier #:-[

[Brewer]

Ahh, the rectifier is a dick smith unit rated to 50A.

If i can find a regulator that will maintain a constant voltage between 12-14.5v I will go ahead & set it up. Surely theres something cheap that will do the job.

Do any bikes run a 12v system?? Bikes run the same stator/magneto setup dont they?

[A_DIFF_PERSPECTIVE]

## all I will add to this conversation is that in many small boats, (pull start outboards) that run a sounder, and maybe a light or 3 and at times even a radio, should be careful as to how much charge their batteries recieve from the rectifier or 240 V land based chargers. Pull start outboards don't require battery power to start them, and sounders, navigation lights, bilge pumps etc usually always run whilst the motor is running, meaning that the current that is produced from the outboard's rectifier is actually creating the power that these electronic units are using. Much travelled distances, and motor running time inevitably 'over charges' your battery and 'cooks' the living hell out of it! Not enough power draw is being exerted from your electrical units to warrant any extra and continual charge from your rectifier. The end result in time is a damaged and destroyed battery which is useless to you in times of need etc. Possibly try to leave a small light on whilst at home, or run bilge pumps whilst you clean your boat out to help the situation slightly. I'm also aware, (90%) sure that if you disconnect the wires from your rectifier to stop it charging yor battery, it can damage the rectifier etc as charge is being created but it has no where to go.
Just a few points for consideration.
Speaking from experience,,,,,,,,,,5 batteries later over a few years!!!
240 V shore based chargers are not required if running a rectifier.
Maybe a shore based charge system may be a better option in small boats with little battery usage.
Johnny M,
the 'king of battery cooking'