battery charger problem?

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
first this is the charger in question
http://store.schumachermart.com/sc-1200a.html

the story:

i just hooked this charger up to one of my trolling motor deep cycle batteries. i put it on trickle 2A and deep cycle setting. let it sit for a few hours. checked on the battery and it was still registered at 70%. i unhooked it and hooked it back up and it registered 100%. so i moved it over to the second battery and let it go for a while and checked. 100%. hooked back up to the first and now it only registered 40%.

any ideas??

i just used this charger to charge a brand new battery for my lawn tractor and it worked fine. the only difference was that it was set to "regular" battery instead of "deep cycle". still kept it on 2A charge.

also, how should the battery get charged? unhooked from the boat right? so there's no possible load on it.
 

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: battery charger porblem?

Re: battery charger porblem?

It doesn't matter if the battery is in the boat, out of the boat, connected or disconnected when charging. Leave it in the boat and charge it. At a 2A rate it will take a long time to fully charge a deeply discharged battery (deepcycle or other). Put it on a 10A charge rate and get the battery charged as quickly as possible. Use the 2A rate for long term storage.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: battery charger porblem?

Re: battery charger porblem?

Here's what your link says about the 2A setting:
? 2 Amp Slow Charge ? for charging and maintaining small batteries; charges motorcycle, ATV, snowmobile and lawn tractor batteries.

Your trolling battery is about as opposite of a small battery as you'll ever see. You want to get it charged up quickly as possible. Use the highest setting you have that is less than 10% of the RC (reserve capacity), or 25% of the AH (amp hour) capacity.
 

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: battery charger porblem?

Re: battery charger porblem?

That is a very good charger. Set the battery type and set it on the 12 amp setting and forget it. The charger will do the bulk charging in the 12 amp mode and when the charge rate drops below 8 amps it will switch to 8 amps and eventually to the 2 amp setting to finish the charge.

It will likely spend more time in the 2 amps mode than the 12 amp mode. If you left it on the battery a week it would not hurt your battery. You have a great charger so use it. The only time I would start in the 2 amp mode would be if charging a lawn mower or motorcycle.
 

extremez

Petty Officer 3rd Class
Joined
Nov 1, 2007
Messages
83
Re: battery charger porblem?

Re: battery charger porblem?

ok, i'll set it to 12A and let it go.

but another question. it always seems whenever i use a different battery type other than regular the battery % never moves and when i unhook it and reattach it to the same battery it registers at full charge.

ex: it sat at 70% the other day for 3 hours and when reattached it read 100%.

should i ignore that? i'll see how long they last today when i take the boat out.
 

fire831

Petty Officer 1st Class
Joined
Aug 26, 2002
Messages
373
Re: battery charger porblem?

Re: battery charger porblem?

That is the same charger I have and mine does the same thing you stated about having the charger on for a while then turn it off and then hooking it back up and it say's 100%. I was told that even charged for a short time and then restarting the charge it will show that because the voltage is high enough to show it fully charged. Wait a while or turn something on to draw some juice out of the battery and then retry it.
 

jtexas

Fleet Admiral
Joined
Oct 13, 2003
Messages
8,646
Re: battery charger porblem?

Re: battery charger porblem?

When you recharge a battery, it develops what's known as a "surface charge" - a few volts that dissipate over a few hours, or if you put a load on the battery, it'll dissipate in a few minutes. So if you disconnect and immediately reconnect, the battery fools the charger into believing it has a full charge.
 

steelespike

Supreme Mariner
Joined
Apr 26, 2002
Messages
19,069
Re: battery charger porblem?

Re: battery charger porblem?

Allways recharge your batteries as soon *** possible after use.Very bad to sit for extended times discharged.Fully charged should remain at a minimum
of about 12.70 volts.after sitting for a couple of hours.My batteries maintain over 13 volts with a tiny Harbor freight maintainer attached.That extra .30 volts can make a difference as a sole power source.
 
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