Luna Wolf BMS Issue

Bonwit

1 µW
Joined
Apr 5, 2019
Messages
3
Hi,
I have a Luna Cycles Wolf Pack 52v battery which is giving me problems. Range has significant reduced, and the pack shuts down when showing an under-load voltage of around 48v. When I check the static voltage, it reads 52v. Fully charged, I'm at 58.6. Luna think the BMS is bad, and wants to sell me a new pack, but I'm not ready to shell out another $600 right now. I know this is a potted battery, but has anyone been inside one of these? Is it likely I'd be able to remove and replace the BMS w/o doing major surgery, and risking a short? Any other thoughts as to what might be going on with this pack.

Thanks!!
 
Bonwit said:
Luna think the BMS is bad, and wants to sell me a new pack, but I'm not ready to shell out another $600 right now.

Really? Their solution to a pack being faulty is to state the probable cause and then charge you full price for a replacement???

Taking it apart, it depends on the exact potting material, but generally said, everything is possible if you have the patience.
 
This is why I would never pay money for a potted battery pack.
 
Bonwit said:
Range has significant reduced, and the pack shuts down when showing an under-load voltage of around 48v. When I check the static voltage, it reads 52v. Fully charged, I'm at 58.6. Luna think the BMS is bad, and wants to sell me a new pack...

Sounds like bad cells. Your voltage could be sagging more instantaneously than the readout is showing, and tripping the BMS. Either way, seems like a lot of work to fix, so replacement may be the answer in the end anyway.
 
Way back in the 1980's, when pay per view programing was broadcast by "ON TV" I knew a guy who worked as an electrical engineer for a defense contractor. Being the curious he wanted to crack the coding system that kept anybody from just putting up an antenna and watching the paid programing. So, he got one of the On TV boxes and his Dremel tool and like a surgeon he slowly took off paper thin layers of the potting epoxy until the electronics that housed the encoding chip were reveled. Then, he then kept going grinding the upper layers of the encoding chip until he got it down to the actual metal network of circuitry in the chip. Once the part he wanted to jumper was reveled, he was able to jumper the chip and get free paid TV. It took him many nights of meticulous work, but he did it.

The moral of the story is this: Do you really want to take the time to go through a lot of work to grind out the epoxy, like a surgeon, paper thin layer by layer, to expose the parts that you need to repair, while running the risk of cutting into something that will ruin your battery? And, maybe cause a fire? It can be done, but I think it is more cost effective to get another battery even if it is not a Luna battery.

:D :bolt:
 
" any other thoughts ? " -- yes , BMS has not had enough time in charging mode to balance the cells to equal voltages . Common when a charger turns the green light on at 58.6 total pack voltage. More time charging is required to balance all the cells . Try setting the Luna charger to 100% at 3 Amps. Charge in a safe place in case of fire , for at least 24 hrs. More of these balance charges may be required until you get your full range back. After that, balance charge when you see range decreasing.
 
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