Can a 24v <span class="highlight">battery</span> charger charge a 12 volt <span class="highlight">battery</span>?

Submitted: Wednesday, Aug 03, 2011 at 15:01

ThreadID: 88255 Views:2318 Replies:3 FollowUps:3

This Thread has been Archived

greg8049

Ok i have a 7amp 24 volt 3 stage battery charger and i want to charge a 105ah gel 12 volt battery.
Is it possable or am i being a scrooge...
It is a one off charge and dont realy want to go and but a 12v charger
cheers Greg

Back Expand Un-Read 0 Moderator Share

Reply By: Member - David Will (VIC) - Wednesday, Aug 03, 2011 at 15:04

Wednesday, Aug 03, 2011 at 15:04

Hi greg8049,

i think if you put another 12 volt batery in line and hook them both up that should be ok, as that will give you 24 volts.

But the experts will be on to this soon to make sure

David

Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat and drink beer all day.

Member
My Profile My Position Send Message

AnswerID: 461708

Follow Up By: disco driver - Wednesday, Aug 03, 2011 at 15:21

Wednesday, Aug 03, 2011 at 15:21

You will have to be careful doing that.
Make sure that you connect the + on one battery to the - of the other and then the charger leads to the other two terminals making sure that you have the positive lead to the + terminal and the negative lead to the - terminal.
The batteries are in series.
Any other connection set-up will damage the batteries and/or the charger.

Disco.

FollowupID: 735410

Follow Up By: Member - David Will (VIC) - Wednesday, Aug 03, 2011 at 15:25

Wednesday, Aug 03, 2011 at 15:25

Hi Disco,

I was thinking after I replied that I should have said how to hook it up, thanks for that.

David

Give a man a fish and he will eat for a day. Teach him how to fish, and he will sit in a boat and drink beer all day.

Member
My Profile My Position Send Message

FollowupID: 735412

Follow Up By: oldtrack123 - Wednesday, Aug 03, 2011 at 19:16

Wednesday, Aug 03, 2011 at 19:16

Hi
hooking them up in series is ok IF BOTH BATTERERIES are discharged to the same level
BUT if one is near fully charged & the other down a fair bit
50% you will end up with the near fully charged well & truly OVERCHARGED
If it is a sealed battery [AGM]it could be stuffed
Definitely NOT a good idea, as any automatic charge control functions of the charger also will not see true state of charge of either battery.
IF YOU MUST do it ,you need to monitor the voltage of each battery to ensure you do not over charge one & that you do charge the other.

Peter

FollowupID: 735443

Reply By: Battery Value Pty Ltd - Wednesday, Aug 03, 2011 at 19:38

Wednesday, Aug 03, 2011 at 19:38

Hi Greg,

...It is a one off charge and dont realy want to go and but a 12v charger
...

So you're only going to do this once?

Ok, here's what to do:

you need a voltmeter (multimeter) and some patience, and the 24V charger needs to be capable of charging a battery which is down to half its rated voltage.
Connect the charger to the battery together with the voltmeter and start observing the voltage.
Depending on how deeply the battery was discharged, the voltage will rise faster or slower.
It could take as little as a few minutes or as long as 12~14 hours to get to 14.15V.

At 14.15V (if it's really a gel, or 14.7V if it's an AGM), turn off the charger.

Be careful not to overshoot these voltage levels.

cheers, Peter

AnswerID: 461742