Thread: Battery charger question

I've got a 2 amp trickle charger that I use on my trolling motor battery. Last winter it accidentally got submerged in water. I took it apart, dried the circuit board out and put it back together. The lights come on, but I'm not sure whether or not it's charging. Is there any way to use a digital volt/ohm meter to check it out?

You can measure the battery voltage with the charger off, then look for a small voltage rise when you plug the charger in.

I'd advise against the use of a trickle charger on any battery. They have no sensing circuit to detect battery condition, so they will continue to charge the battery and can eventually destroy it if left on long enough. 2A is such a small charge rate, that your battery loses a portion of its capacity in the time between use and reaching full charge.

A 10A charger with a float mode is a far better choice.

CatFan,
What do you mean by "Float Mode"?
1perchjerker

Originally Posted by 1perchjerker

CatFan,
What do you mean by "Float Mode"?
1perchjerker

Float mode means the charger maintains a current of 1A or less into the battery. This is at level where very little or no boiling or gassing occurs. It's designed to maintain charge, not actually to add charge.

It's the mode that onboard chargers are in when they are showing green lights. As a battery ages, it may never reach a state of charge where it draws less than an amp, so you get no green light.

Catfan (or anyone else),

My situation is that I have access to an electric outlet, but my boat stays unattended over the week. Would this charger overcharge the battery?
Amazon.com: Battery Tender 022-0150-DL-WH Waterproof 800 12V Battery Charger: Automotive

Thanks for all the help!

Originally Posted by MaggiesMaster

Catfan (or anyone else),

My situation is that I have access to an electric outlet, but my boat stays unattended over the week. Would this charger overcharge the battery?
Amazon.com: Battery Tender 022-0150-DL-WH Waterproof 800 12V Battery Charger: Automotive

Thanks for all the help!

That charger is an 800mA output. It would be good to maintain an already charged battery, but would be very, very slow to charge a battery. It may not be able to charge the battery at all as the battery gets older.

If a 10 amp charger has float mode, could you leave it hooked up for as long as a week without it overcharging the battery?

I bought a 2-4- 6 amp charger at wally world for about $30. It is called automatic and will drop from 6 to 4 to 2 and then into maintain mode by itself. Haven't cooked a battery since I bought it. It isn't waterproof, so if I use it outside I put a 5 gal bucket over it with something to shim one side of it off the deck for air circulation. Most all on board chargers I looked at recently had a maintain mode, but even a one bank was twice what I paid for mine. My .02.

Up untill this year, I have been using one of the digital chargers like what you buy at walmart or kmart.It has the 2 8 12 amp settings and I had used the 2 amp setting everytime with absolutely no problems.Actually I think my batteries are as in good a condition as anybody I know of.Takes about a day to get a full charge on 2 amps.Will also make the point it was NOT a trickle charger though.Have just this year purchased a 3 bank charger from bps, and no more 3 trips to the boat all week to rotate the charger.Its a 5 5 5 and seems to be doing fine.Will charger heavily used batteries back to full in 3 or 4 hours and automatically goes into maintain mode.

Originally Posted by MaggiesMaster

If a 10 amp charger has float mode, could you leave it hooked up for as long as a week without it overcharging the battery?

Yes. Float chargers can be left on all the time if you want. If the batteries aren't sealed, it's a good idea to check the water in the batteries once a month until you get an idea how often they need to be checked.