New battery charge question

Okay, I've just purchased a new battery. It's a trojan dual purpose deep cycle 12v battery for my trolling motor. I've also purchased a Die Hard fully automatic die battery charger / engine starter.

Innitially, when I hooked up the battery, I was on 2a for a longer charge. After reading further in the manual (yes, I should have done this first, I know) I realized I should have been on the 10a charger, so I switched it without unplugging. There was a click when I switched.

Anyway, I'm wondering if my charger is fried. When I turn it off and back on again it resets from nearly 100% charged down to 75% charged. Should I return the charger or is something wrong with the battery possibly? Did I possibly damage the charger by switching from 2a to 10a while it was charging?

Any advice will be appreciated!

Re: New battery charge question

Should not have damaged the charger and it would not have done anything to the battery. If the battery is labeled dual purpose, RV/Marine, or something similar, take it back and get a Deep Cycle. Dual purpose are just that, they serve as starting and RV/Marine duty but do neither as well as a regular deep cycle when it comes to trolling motors.

Re: New battery charge question

Thanks for the reply!

I did look around nearby shops for a plain deep cycle marine battery... but all of them were too large for my small boat. I did a voltage test this morning after the 7 hours of charging yesterday and it tested at 12.7 volts (full). So I wasn't worried.

What I'm worried about now is... is my charger going to overcharge my battery?

After about 110 minutes of trolling today it was at 12.34 volts (70% ish?). I put it on the charger... and the charger shows it at 20%. It is now 4 hours later and it's showing 75% charged... should I let the charger go to full? (which looks to be another 6-7 hours at 10 amps the rate the charger is going) or will that overcharge the battery? This charger has a green light that should go off when the battery is done charging... and done looks to be twice where the 100% mark is on the ammeter.

Should I just let it run till I get a green light and see how it goes... or quit after 7 hours and check the voltage after letting it rest 12 hours just to be safe?

Re: New battery charge question

10 A is a heck of a lot of current. I always charge my batteries, which are deep cycle, dual purpose on 2 A. I also let it charge for 6-8 hrs each battery. These chargers have a lot of safety circuitry. You can imagine using one for starting cars, boats, etc. I doubt that there is any damage to it. Also using a voltmeter does not put the battery under any load, which is the proper way to check a battery. There are testers that will do that.

Re: New battery charge question

Okay, I'll let it charge till the charger says it's ready. It's set on 10A automatic... and yeah that is a lot of amperage, which is why it makes me nervous. Maybe the "automatic" part of my charger means it has a variable amp rate.

Here is a link to the charger if it helps any.

http://www.kmart.com/shc/s/p_10151_...mv=cf&vName=Tools+&+Outdoors&cName=Automotive


So, just to clarify, your advice would be to let it sit till the charger says it's ready even if it takes 10-12 hours? As a side note, I bought the battery 2 days ago so can still return it.

Re: New battery charge question

Use the 10 amp setting. 2 amp is for very small batteries like used in a lawn mower or motorcycle.

Re: New battery charge question

bhile said:

Use the 10 amp setting. 2 amp is for very small batteries like used in a lawn mower or motorcycle.

Click to expand...

It's on 10amp.

My problem now is just that I think my charger is not telling me when my battery is full charge. I let it go 7 hours today when the battery was about at 70% full charge... and it still doesn't indicate the battery is full... and it's on 10 amp.

So I pulled it off and tested it and got a voltage reading of 13.40 (without running the battery, so it could just be cooling down) it's at 13.00 now after 2 hours.... not sure if that's still too high or not. Going to retest in the morning and see how it is.

Frustraitng that I've just bought a battery charger that doesn't seem to give good readings.... I've replaced it too, same results from both chargers. (diehard 2/10/50 amp automatic charger/starter).