36 VOLT, 5-25amp Golf Cart Battery Charger

[greenmountainski]

I have a stock in 36 volt ez-go battery chargers that I was considering rigging up to my 2, 36V LiPo4 batteries to. I've got the 36V 20AH Ping Batteries. Will this charger fry them? I have a few of them, (i work on a golf course) and seeing that the chargers Ping gives you with the batteries are cheapy cheap I thought these might work.... Im out of transportation right now because Ping has 2 replacement chargers on the way but that may take a week.

 

[dnmun]

you can use up to 45V on the input to the charging ports on the ping 36V packs. measure the output of your chargers before you do this.

 

[knighty]

carefull.... my 48v forklift charger puts out 72v if it's not connected to anything !

(the size of the forklift battery etc.. pulls the voltage down a lot lower)

your small pack might struggle pulling it down enough !

 

[greenmountainski]

Yeah well you have to figure..

These golf cart chargers are meant to charge 6, 6 volt lead acids.... So Im very scared to think what they'd do to the 36 volt LiPo4. Not really too anxious to try it out until I hear from someone that it works!

Kind regards

Alex

 

[dnmun]

just put a voltmeter on it to determine the voltage. it should be about 42V. that will not completely charge the 36V ping but it will put a lot of charge back if your battery is currently discharged.

 

[greenmountainski]

I got a 48-49V reading on the Volt meter. It's a pretty old school charger.

 

[dogman dan]

The real issue is the amps. I believe pings bms is limited to close to 5 amps. That's what I was told was the max regen mine, 2.5 years old, could tolerate safely.

I'm not sure what the amp rate the bare cells can take is, but once you put two batteries on it at once, you'd be down to 12 amps per pack. That's plausible.

Make a hell of a good quick charger for a big lipo pack, that can do big c rates of charge no problem.

Or, if you have a trailer, that charger and a generator and you got a series hybrid EV.

 

[dnmun]

48V is worth a try, put both batteries together like he said and charge them in parallel. the voltage on the charger should drop to match the batteries and when they get fully charged it will cutoff the charge for HVC so they will be ok then. the 48V is without a load so it will drop down to the battery voltage when you connect it.

i have charged at 7A through the ping signalab BMS without it getting hot.

 

[dogman dan]

I just realized the post says 5-25 amps charger. I was just thinking in terms of 25 amps period. Set it to whatever amps you think your bms tolerates. Bear in mind, you don't have to do all of the charge through a bms, just the last part. With my 48v 5 amp charger, my ping bms charge fet does get pretty warm. But it's the model from almost 3 years ago now, an early V2.

Looking at ping specs, even the 10 ah size can charge at 5 amps. Clearly the cell is not the limiting factor but the bms, or the supplied charger. Since you have 40 ah of cells, I see no reason why charging all 40 ah at once at 20 amps should damage the cells. But do watch the bms fet heat if you run 10 amps through each bms. Solder liquifies, it would be time to stop eh?

On the other hand, if you are home, what's the real problem with slower charging with the 5 amp ping chargers? They go pretty fast at 5 amps. Seems like 36v 40 ah oughta be enough for one day's riding.

 

[greenmountainski]

This is what Ping had to say about it...

Hi Alex,

Every battery pack has charge wires and discharge wires respectively.

Also, if you’re going to connect them in series or in parallel, you have to ways, connect their charge wires or discharge wires.

First of all, they cannot be charged in series by a 72v charger. Or, cells in both packs could be damaged.

If you connect their charge wires in parallel, you can charge them in this way with only one 36v charger. However, the charge current cannot be higher than the maximum of one of them. This is to say, even if you charge them in parallel, the maximum charge current cannot be higher than 10amps. Also, at that time, their discharge wires cannot be connected in parallel.

Best regards,

Ping


NOW, my question is, can I just charge the batteries without going through the bms charger wires, and through the discharge wires, while monitoring the amp meter on the charger while making sure it doesnt draw over 10 amps?

 

[dnmun]

nope.

you would connect the charger output up to the two charging inputs in parallel. of course you should be certain to maintain polarity when you connect the charger to the pack.

disconnect the two packs at the P- B+ connection before you do anything.

 

[wineboyrider]

I have charged my 36v 20ah ping pack with 10.6 amps by bypassing the BMS. I tried it through the bms, but it was making a lot of heat on the mosfets.

 

[dogman dan]

No to through the discharge wires, above 5 amps. At least that is what ping told me about regen.

Bypass the bms, and you could throw a faster charge into both packs at once, 12.5 amps per pack. If it doesn't disbalance you could charge it all the way that way, or you could just give it a partial charge and finsih with the regular chargers to balance.

But like any battery, it will last longer if you charge it slower, and discharge it slower, relative to the max c rates for each.

 

[Tommy L]

I sell these 12s chargers at my website:

www.rawvelocity.com

$79.95 plus S&H

3 stage charger. One nice thing about this charger is that if by chance your pack has dropped
to very low voltage, this charger will sense this and slowing try to bring it alive. It is very smart
for LiFePO4

Tommy L sends... \\m//