Jump starting a CC electric cart

DVR

Ok, So my friend-girl has a later model club car precident.
Somehow the pack discharged below the nominal voltage to kick in the charger (which I do not know the threshold). I tested the pack today and it is well below 48v. I believe it was 35v.
I also have a 48v CC precident. All the chargers work on my cart which has a healthy battery pack.
When I had an ezgo I could bring them up in pairs with a 12v charger. I need to trick the charger so it will charge her battery pack.
Can I use jumper cables from my first + terminal to her first + doing the same with the final battery - terminals? Then plug charger in to her cart? I want the charger to see enough voltage to kick in at which point I would disconnect the jumper cables.
I realize her pack my be damaged. However, the batteries are pretty new, look great, cables are good... I would like to charge this pack at time or two and see if it will come back at all.

Lastly, if anyone can tell me another method or trick to fool the charger to cycle I would greatly appreciate it.
Thanks in advance.

Worst case I'll load it up and take it to tahoedog but I'd like to at least see what I can get the pack to do.

BGW

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Sergio

Don't jump to another cart as the current could be very large if the package voltage is that low.

Use a 12v charger set to 2 amps and charge each 8v battery individually.

The two important things to remember:

Always make the charger AC connection the last one.
Always disconnect the charger AC first.

The reason for that is if the batteries are really discharged, there will be a lot of explosive gasses around the battery posts during rapid charge, so You want to minimize the possibility of a spark.

So the procedure is (Multi-Meter set to 20v DC):

1) Clip the alligator clips to each battery post along side with your meter probes, it does not matter which probe you connect first.
2) Connect the charger AC plug in.
3) Whatch the meter and Disconnect the AC plug once the voltage gets above 10v.
4) Disconnect the alligator clips from each battery post.
5) Repeat steps 1 -4 for each battery.

DVR

Thanks for the reply. I'll try bringing them up with a 12v charger monitoring the battery voltage as it charges. If I can get the charger to kick in, I think I'll be in good shape.
If anyone has any other suggestions please let me know. Particularly anything that would allow me to get the CC charger to kick in on a depleted pack. I have an extra charger so don't be afraid of suggestions that require permanent modification.
Thanks for reading

Volt_Ampere

You don't have to charge each battery very long to get it up high enough for the charger to kick in. Often 10 minutes per battery is all you need. Make sure that the batteries have water up to the top of the plates.

DVR

Thanks for the additional info. So, it's a six pack job. No problem.
Thank you for the suggestion. I have already confirmed the batteries are full above the plates. I will top them off once I get them charged to avoid overfilling.

kendeiss

I did this once and it worked!!

joesam

Then you got away with something...to me - its a sure recipe for "accidental welding" to the battery posts with the jumper cables.

DVR

Thanks for the input!
I understand the difference in raising the voltage present vs moving amperage to the other pack. Seems like it would be no different from connecting jumper cables to a car but not trying to engage the starter. Little amps would transfer. I would guess this has been done in the golf course world where the employee has no regard for the equipment?
I was going to use a 16ga wire and fuse between the cable clamp and post.


However, I don't want to hurt either cart or me. If I can charge and monitor with a 12v charger safely- I'll give it a shot.

Muddog

Pay attention to Sergio's instructions and you'll be good.
Remember: Last and First rule with AC plug in.

Sergio

I think folks under estimate the amount of energy stored in these golf cart batteries, specially a 48v pack.

If the other pack is really discharged, a 16ga wire without a fuse would catch fire and if fused it would immediately blow the fuse.

Your good pack is able to deliver 500amps of current and only drop a few volts.

Your discharged pack is able to absorb all of that current instantaneously.

Like joesam said, a good set of jumper cables could get welded to the battery post.

Your 12v charger set to 2 amps will not be able to maintain 12v when placed on a 8v battery.

You will probably end up with about 8-10 amps of current depending on the charger and the voltage will drop near the discharged battery voltage and ramp up from there.