07 Precedent 4 12volt system big spark on battery post

[grandpa1]

Hello BGW. I have an issue with a 2007 Precedent cart that has 4 12 volt batteries. Just helped a friend put new Trojan batteries in his cart. Cart was running some what before but kept running dead real quick. 2 batteries had bad cells. Anyways batteries are in and wiring is correct. When you go to hook up the main negative you get a big arc not just a lil arc but a welding type arc. Run/ tow switch is off. What is weird is you can put the meter on the main positive and then touch the main negative cable which is not hooked up and I get 50 volts. I am a lil confused at what is going on. Can I get some help on this please?

[Yamahaman]

Usually a big welding arc like you are discribing is you have a battery cable hooked up backwards or another cable.

[mrgolf]

Can you post a photo? Does the cart have a voltage reducer? Try holding the center contact of a regular light bulb on the battery post then touch the cable to the threads of the bulb. If the light comes on and goes out after a few seconds you should then be able to connect the cable without sparks.

[grandpa1]

I have checked all the cables and everything is in series. Why would I show full voltage without the main negative cable even hooked up? I can put the meter on the main positive and just put the other lead onto the main negative cable which is not hooked up and get full voltage?

[Sergio]

Assuming the entire pack is not connected backwards, I would try the light bulb first.

The light bulb will not light up, if You even see a glow, You have bigger problems.

A voltage converter input capacitors will charge in less than 2 seconds when using a 60w light bulb resistance (240Ω) in series with the last power cable.

If the spark You got is indeed caused by a voltage converter charging, then the capacitors got some charge out of it and You will be able to measure it on the disconnected cables.

The controller will never cause that spark since it already has a pre-charge resistor in series with its input capacitors.

[jakesnake27]

Grandpa, are there any accessories on the cart, such as headlights, golf GPS, fan, 12v plug, etc? Or is it a 'bone stock' cart?

[mardad]

"Weld" arc= direct short.

[grandpa1]

It has a light kit on it. It also was running like the MCOR was acting up.

[jakesnake27]

Originally Posted by grandpa1

It has a light kit on it. It also was running like the MCOR was acting up.

Ok, so it probably has a reducer of some sort on it. When I connect my reducer, it lets off a pretty good spark that would startle you if you weren't expecting it...

[grandpa1]

Well it has 4 12 volt batteries and the lights tie into one battery. I just can't figure out why I read full voltage with the main negative cable not even connected.