what size and type of batteries ?

[pdt]

what type and size batteries are you all running on engines in the 40hp to 90hp category ?

do you mainly have just enough power to crank it over and use ultra lightweight agm style ?
or do you use conventional car battery's with a bit more amp/h rating.

i know that the agm type batts can be a lot lighter for a given amount of voltage and amps etc, but is the cost of such batteries realy worth it.

Plus ive read on a electrical site that says most outboards need to use lead acid rather than sealed maintainace free batteries or you
could destroy the electronics !!!!!!!!!!!

any thoughts on this subject ?

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[Fastjeff57]

I've used a standard, lawn mower size battery for years.

This spring, thanks to ethanol gas leaving crude in a carb, my Merc triple died out in the middle of Beltzville Lake--and it was damn cold! I crank started that sucker at least THIRTY times on that little battery before I was able to limp back to shore. Does that answer your question? Also, I use the same battery to start my Merc 850.

Jeff

[pdt]

cdi electronics installation sheet tell me.

DO NOT USE A MAINTAINENCE FREE, AGM OR DRY CELL BATTERY WITH THIS TYPE REGULATOR/RECTIFIER AS
THIS WILL VOID THE WARRANTY !!!

maybe omc do some weird stuff with their electrics, as ive read this in a few places now.

[omcstratos]

500cca Interstate battery

[pdt]

is the Interstate battery a lead acid battery that can be topped up if need be ?

if so its probably the same type that i am looking to buy right now.
i have found a Banner P7209 that's 72amp/h and 660 CCA battery, Brand new for just about half the normal price, it is slightly on the
heavy side at around 37 pounds total weight. But i think ill have plenty of power for starting plus any other stuff.

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[Fastjeff57]

Good idea, in boating, to only use a battery that you can check and fill the liquid levels.

Jeff

[pdt]

must admit I do like to be able to check battery for fluid level, its something I done as a kid with my dad every couple of days on his trucks and cars.
back then battery's were real bad for losing fluid compared to todays .
it was back when you could have a new cell dropped in very easy, the battery's with the lead on the top that looked like little dog bones ha ha .
so now its just instinctive to keep an eye on the battery.

don't know the situation in the states, but battery over here have not realy gone up too much in price over the last 10 years,
equivalent of $100 dollars us money gets a good heavy duty car battery of around 70 amp hour capacity.
the new one im hoping to get is supposed to be non spillable upto 45 degree angle, so should be fine . need to get new battery box as well ha ha

.

[Fastjeff57]

Something to keep in mind is that most, older OBs have a very basic charging system that lacks a voltage regulator. (My automotive buddy was stunned to hear about that.) That they don't just boil the battery dry all the time is a bit of a miracle! So, having the ability to check fluid levels and refill the battery is a good idea.

Jeff

[pdt]

wow no regulator

how old are these engines ?

I wonder how they don't bugger up the cells of the battery, the regulator going bad is what kills most battery's ha ha

.

[Fastjeff57]

Typically, OBs of the '8s and older vintage had an alternator, a rectifier that changed AC to Dc, and... Nothing else! Amazing, they work fairly well.

Jeff

[pdt]

well I got the banner 72amp/h battery with 660 cold cranking amps.
this should do the job pretty easy.
the engine starts quick anyway, but it was the power trim that was killing the old one a lot.
I will remember to switch this one off completely in future and not let it drain till completely dead.
I am not sure what amps my engine kicks out when its running, but I think about 8 amps !!!!!!!!!!

[Ron Hill]

In the college Solar Boat class there few rules, which I like. Here are two rules:

100 pounds of batteries (total weight) and 36 volts maximum.

Does cranking power have anything to do with endurance? As part of the race is a 2 hour endurace race.

[pdt]

well its a weird one to answer as
cold cranking power does have something to do with endurance if the motor takes large amounts of current like a starter motor etc.
if its small like a led light then no I suppose its upto the amount of amp/h the battery has.

try putting a battery with 60 amp/h 200cca on a truck that normaly had a 100 amp/h 1100 cca battery and see how long it takes to go completely flat and burn out.

But the battery used to start up fighter planes is very small and kicks out huge amounts of cca, but is crap at keeping a headlight bulb going for long ???????

so I think the battery is something that needs looking into a lot more, (and I don't mean make it a see through case )
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