Battery Question???

[bigjc]

Does anyone know what voltage I should get when testing a fully charged 12v battey?
What is the proper liquid to using when fillng traditional trolling batteries?

[Slipkey]

You'll probably get between 10-12 when the alternator or chargers aren't running and will see it jump to 13-14 when the big motor is charging it.  If you go lower than 10, you likely have a failed cell or a low water situation.  Use distilled water only in traditional batteries.  I'm not saying I haven't had to use purified water (even bottled once) in a pinch, but any water with minerals in it is not good for the plates.

[bigjc]

thanks again

[Slipkey]

No problem!  Glad to help on both counts. 

[Manxfishing]

A fully charged batt should read 12.6

http://en.wikipedia.org/wiki/Automotive_battery

[Cy]

A fully charged batt should read 12.6

http://en.wikipedia.org/wiki/Automotive_battery

Yes.  Each cell us 2.1 volts, so 12.6v is fully charged battery.  Anything over that is considered surface charge, it has to do with air bubbles trapped on the plates creating extra voltage but that surface charge is drained off very quickly during use and you should see 12.6v.  The best way to test a battery is to fully charge it and then have it load tested.  This can be done a automotive stores, shops, etc.  The other option, if you can access the cells is to use a Hydrometer.  This will give you the specific gravity of each cell and help you find a week battery or bad cell.

[Lightningboy]

Well, you guys are all over it!  I agree, 12.6 fully charged, 13-14 running. 

Distilled water is cheap by the gallon at the grocery stores.  I buy a gallon & keep it in the garage.

Now my special trick; while you're in the grocery store, get a cheap turkey baster.  Great tool for filling the cells.

Also, I put a couple of paper towels over the cap when I pry it off to fill.  That way there's no suction spill on the top of the battery.

I don't know how many t-shirts I put little holes in until I did that.   

[Waterfoul]

12.6 volts on a newer, fully charged, good battery.  Less than that shows the battery is "wearing" out and will need to be replaced in the near future.

[bigjc]

thank you all for the help.  I think that I have come to the conclusion that my trolling batteries are ok for another season, my crankin bat. could really stand to be replaced and I definitely need a new on-board charger!