36V Connection - Old ParCar

[bwthor]

I recently picked up an old 36V 1980ish ParCar, and I wanted to hook up some lights and a battery meter. I picked up a 36V to 12V converter, and figured it would be pretty straight forward to find a place to connect, but I'm a bit stumped...

Anywhere I measure, I'm only seeing 18V. Batteries are two sets of three with the wires running back to the solenoids. Attached is the wiring diagram.

ParCar_Wiring.jpg

The thing that really confuses me is that measuring the voltage at the charge plug, I only get 18V. As soon as I start charging, I get around 40V.

What component on this cart is taking the two sets of batteries and putting them in series to get 36V, and where could I possibly tap in to hook up my 36v-12v converter?

Thanks!

[Tech Support]

All 6 batteries should be connected in series by the short cables, with the two long cables that exit the pack being at 36v. can you upload a photo of the battery wiring as it is now?

[bwthor]

Batteries are wired identically to the wiring diagram I posted in the original post. I would have thought that they would have been in a series as well, but watching the volt meter during charging, then in the unplugged state, then as the kart goes through the 1st, 2nd and 3rd speed, it appears that it is using the two 18v sides in parallel, then switches them to series on the 3rd speed.

This is only my second post, so I can't post links yet, but I'd bet if you paste the following in your browser you could see the video...

photos.app.goo.gl/w9FdIgzFPv8bNu3u2

[CartPros]

Where is your volt meter hooked up? Could you attach a visual picture of your batteries? Is the cart running?

The reason you are getting 40 Volts when you hook up the charger is because that is the voltage you pushing to the batteries. Once you disconnect the charger, it is no longer charging the batteries.

[bwthor]

Originally Posted by CartPros

Where is your volt meter hooked up? Could you attach a visual picture of your batteries? Is the cart running?

The reason you are getting 40 Volts when you hook up the charger is because that is the voltage you pushing to the batteries. Once you disconnect the charger, it is no longer charging the batteries.

Volt meter was connected to the charger plug in my video.

I colorized the wiring diagram a bit to help understand it some. My batteries and wiring are connected identically to this image, so looking at this image is better than a photo.

The cart is a three speed, and I'm guessing it goes like this...
1st speed - Two 18V banks are run in parallel with the power going through the big resistor on solenoid C
2nd speed - Two 18V banks in parallel with full 18V power going to the motor
3rd speed - Two 18V banks are run in series, supplying 36V to the motor.

Wiring.jpg