This is a 2 part post and will likely be long winded:
Looking for insights on how, if even necessary, to correctly bypass the factory installed Delta Quiq charger. I own a golf cart repair business and a customer purchased a 2019 GEM e6 with bad batteries and an ECO 51v 160AH lifepo4 battery/charger bundle. I installed everything including the new charger in the rear battery compartment. I left the OEM Delta charger in place and did not make any changes to any of its DC connections. I cut and spliced the wires coming from the back of the OEM charge port and ran AC power to the ECO charger.
This was about 6 weeks ago. The cart runs great as far as I know (I haven’t heard any complaints). I’m inexperienced with GEM vehicles and it never occurred to me that there might be other components impacted by not utilizing the DeltaQ charger.
Then last week another GEM I replaced batteries in 8 months ago started having problems. I replaced the LEOCH 6v gel batteries with Trojan T105AES AGM units and did not make any changes otherwise, including the algorithm in the factory charger. That cart has been running fine for 8 months and 1200 miles (both of these carts live at homes that are vacation rentals and the carts are driven a TON). I was called out for a complaint that this one wouldn’t turn on. Found the 12v battery in the dash was dead. Replaced it and everything worked fine. I did not think to check that voltage increased on the 12v battery when the key was on. The very next day the cart was inoperable again. I returned and the 12v battery was down to 8v already so I knew it was not charging like it should. Because of the urgency of having it fixed for guest use and my lack of advanced knowledge with GEMs, I referred my customer to the local GEM dealer. They found the DC converter faulty and replaced it for a whopping $1200. They then told my customer he needs all new batteries because the ones installed were incorrect for a GEM and had not been charged properly. Since I’m responsible for the batteries I advised my customer to request the dealer change the algorithm to the profile for the batteries in it and have it returned to his property so I could verify any issues with the batteries.
When I arrived the cart was connected to the charger had 51.8V but the DeltaQ had a fault (mistakenly didn’t observe the number of flashes yet) and the SOC reads 0 charge. Everything else works in the cluster and the cart was driven for 7 miles with a DVM connected both to the total pack and then each battery individually for multiple full throttle jaunts up to 25mph. After 7 miles, total voltage never dips below upper 45v range and none of the batteries individually drop below 5.7 at peak acceleration. Once cruising at 25mph pack voltage is upper 49v. Parked the cart after 7 miles and left it for an hour and ran another call. When I returned, resting pack voltage was still 51v. Those voltages seem to be normal in my experience, albeit I primarily deal in the more standard golf carts/LSVs.
The SOC was working fine for 8 months before it went to the dealer for the DC converter. I’m offering to remove the batteries I installed and refund my customer and let the dealer handle it, but they’re quoting him $5400 for batteries and he is (rightfully so) apprehensive. He and I both feel something fishy is going on since everything was fine for so long. He is willing to give me the opportunity to fix it or swap in the ECO lithium bundle at a discount. Is there something simple that might be causing the SOC not to register? The vehicle runs fine otherwise.
Thanks in advance for any help. I tried searching for both of these issues but didn’t really see any exact replicas of my issues and the closest ones I found did not really have clear resolution. I have acquired the SpeedBX for this customer and will be going out to install in a few days, so it would be a good time to do any bypasses that may be necessary.