I have a 2013 Yamaha YDRE electric golf cart with stock controller (Hitachi model#:Jw2-h6510-01). I have converted the cart to Lithium batteries. (Lynx 12v LiFePO4 batteries) The cart runs great on the Lithium batteries and climbs hills VERY well now with the lighter batteries.
However, I have what I call a "cold start" issue where the BMS on the batteries trips only when the cart has been left (not operated) for a while (about an hour or more):
• ONLY happens when the cart is left for more than one hour. (hence my term “cold start). If cart is shut off and then turned back on (within a short duration or right after a ride, for example) this issue will not happen.
• ONLY happens when either (1) the accelerator pedal is pushed on cold start or (2) the ignition key is turned in the cold start condition described above. When either of these is activated there is the “plunck” sound of the solenoid and then one or two of the Lynx batteries BMS trips and the cart goes dead.
• Only way to resolve the BMS tripping issue and start the cart is to disconnect either the positive or negative terminals to the 48v series battery pack. Again, once this is done, the issue will NOT again appear until the cart is left for over an hour.
Based on some research on this forum, I am thinking that the issue is that the stock 2013 YDRE does not come with a pre-charge resistor and the capacitors in the stock controller are causing an instantaneous discharge resulting in tripping the batteries BMS's. Please see link below to a thread with the wiring diagram for the YDRE which shows the stock controller does not have a pre-charge resistor.
https://buggiesgonewild.com/showthread.php?t=155459
I've visually verified that there is no pre-charge resistor on my solenoid (no diode either, FYI).
To try to solve this problem, I have purchased a resistor below:
https://www.petesgolfcarts.com/elect...tor-and-diode/
Questions:
- Do you think I'm on the right track as to the problem?
- If so would there be any risks to the controller or anything else in installing the pre-charge resistor (even though the stock cart did not have one)?
- Anything else I should be aware of?
As I am not very experienced, I appreciate any advice. Thank you!