Lithium Conversion 48 volt system

[Volt_Ampere]

Originally Posted by WalterM6

Not saying this will solve your problem but you might want to consider wiring your modules like the person in this post did.

http://www.buggiesgonewild.com/lithi...onversion.html

That is the way mine is wired and I have been running it for four years that way with no current limit via the BMS. My controller current limit is set pretty high - I think 400 amps. It's a 500 amp rated Altrax controller. Golf carts draw lots of current during acceleration but not for long so my batteries do not get hot. I have a temperature probe mounted to my motor to monitor motor temp.

[gman@engineer.com]

I think the Zeva BMS with Monitor, and Hall Effect coil (not shunt) is about ~$300.00 + disassembling the batteries and rewiring, while another battery is $700.00. Another battery pack would buy me more amp hours, I am not sure I understand the comment concerning the techdirect design of passing current through the BMS. Also 3 batteries in parallel, I am not sure if that should be a concern.

[gman@engineer.com]

If you have 3 48 volt battery packs in parallel, should I have 3 independent BMS, one for each.

[Volt_Ampere]

Originally Posted by gman@engineer.com

If you have 3 48 volt battery packs in parallel, should I have 3 independent BMS, one for each.

Depends on how you wire it. I have Leaf modules in parallel but each cell is in parallel with another so I only need a 14S BMS to handle a 14 module 120AH pack.

[WalterM6]

I'm thinking that you might have problems with your car instead of your batteries. 200 Amps should be enough to take you up any hill. The problem comes in when you stop on a hill and try to restart. 200A just won't get you going. Tell us about your Citicar Golf Cart. What year is it, does it have a modern electronic controller on it or resistor coils, does it roll easily when pushed?

[gman@engineer.com]

I attached a couple of pictures. The golf cart moves easily. The batteries switch off by themselves. This happens when under stress, such as climbing a hill with people on board. I did hook up a power meter with a shunt that I watch amps as I drive around. I can reset the batteries quickly and go on my way.

[gman@engineer.com]

The citicar was purchased 5 years ago. This is the first replacement of the batteries. They had run dry, my first attempt was to add acid to the batteries and recharge, that did not work. Removal of the batteries took a little time. There may be enough room for a third battery in the rear. These are G2 Leaf. Techdirect seemed to believe the addition of a battery would solve the problem, so I suspect this is not the first time this issue has occurred.

[gman@engineer.com]

There are a couple of videos I wish I had seen before the purchase. This guy I really like, take apart the black box I bought. https://www.youtube.com/watch?v=rbkE4jxk3u8
I don't see any reviews on the techdirect site and this system is heavily marketed to the golf cart industry. I posted a review but it has not shown up.

[WalterM6]

Is the item I circled in blue your contactor/solenoid for your cart? If it is it's too small for an electric cart.

[gman@engineer.com]

Not sure. Here are pic