BafangUSA 52V Dolphin pack problems

Batteries, Chargers, and Battery Management Systems.
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Stu Summer
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BafangUSA 52V Dolphin pack problems

Post by Stu Summer » Apr 15, 2018 5:48 pm

I bought a Bafang USA 52V 11.6ah Dolphin pack. The voltage starts fading after 2 miles of riding at 20mph even when it was new 3 months ago. Also, sometimes the charger reads 58.8v when the pack is fully charges and sometimes it reads 54.1v. BafangUSA advertises these as Panasonic batteries NCR18650PF, but I doubt it. I haven't opened the pack. Anyone else have this experience?
2013 DB Haanjo Commuter with BBSHD and Zzipper fairing
Marin Rift Zone FS with BBSHD
Kysmo "lab" bike with 350w hub motor

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fechter
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Re: BafangUSA 52V Dolphin pack problems

Post by fechter » Apr 15, 2018 9:49 pm

No experience with that specific brand, but batteries can fail to meet specification for several reasons. Most commonly one cell group gets out of balance and triggers early shutdown. This could be from a defective cell or from a defective BMS.

The only way to test is to open the pack to where you can measure the individual cell group voltages.

About the only other thing that might help is to try a balancing charge. If one cell is just low, but not defective, you can sometimes just charge long enough to get it balanced. Some chargers cut off too early to make this easy, some chargers you could just leave on charge for a few days and do it. The balancing process is very slow at best. With chargers that cut off early, the approach is to charge until cutoff, then discharge just enough to get it to charge again, then repeat the cycle many times.

If the pack failed from the start, you can claim it was defective and ask for a replacement.
"One test is worth a thousand opinions"

999zip999
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Re: BafangUSA 52V Dolphin pack problems

Post by 999zip999 » Apr 16, 2018 2:25 pm

When it charges to just 54v what is the charger putting out ? The voltage will go down as soon as you hit the throttle. How much depends on quality of cells and ampage demand.

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