Horrible burning smell Dolphin pack charging

Stu Summer

100 W
Joined
Apr 27, 2016
Messages
147
Location
Hillsdale, NY
So my son's bbshd bike has a little wreck. The display harness pulled loose. Plug it back in, tiniest of surges in the motor then nothing, no display, 52V Dolphin battery dead. Take it home, try my 52V Dolphin battery from my bike. Tiniest of surges in the motor but again nothing displayed and won't turn on. And now BOTH batteries won't take a charge and won't turn on (nothing at the output ports according to multimeter.) I tried "Jump Starting" both batteries by charging through the output ports. Still nothing. A: What went wrong? B: Did I blow both BMS's and what on the BBSHD system would do that?
 
since there was a little accident check the wiring with a meter and look for a dead short somewhere,
 
I have three Dolphin 52v packs. The two I bought from Luna do not have fuses or fuse sockets under the fuse flap. There is nothing there. Both BMS's have been fried by shorts. The Dolphin I bought from BafangUSA does have a fuse. It survived the same short with only a burned fuse, now replaced and back in operation.

Anyone else out there have a Dolphin? Does it have a fuse and where did you buy it? Anyone else have this problem with a Luna Dolphin pack.

Thanks!
 
That is the next project. As I have two bikes, I needed to deal with the batteries first.
 
I'm trying to problem shoot a dead BBSHD which killed two Dolphin packs, probably a short. But before I get to the BBSHD, I have plugged my Luna 58V charger straight into the xt90 that leads to the stock controller. At the output xt90 the multimeter shows the charger putting out 58.8v. But 2 inches from the plug toward the motor, when I poke the probes through the insulation, the multimeter shows 18v. A 10 inches further up the wires there is ~17v~. Why is this? Why the voltage drop-off so soon after the plug?
Thanks!
 
That's a lot of voltage drop over a short distance, which generally would be a high current and noticeable heat wherever the short is, and along teh path from the source to the short.

The short itself would be the cause of the voltage drop, in such a case.

When you measure with a multimeter on ohms across the power input to the controller (with NO battery connected!), what does it read?
 
There has to be a break in the wire someplace to get that kind of drop. Could be right at the connector.
 
I'm trying to trouble shoot a BBSHD which has blown two bms's and some fuses. When I connect a dolphin 52V pack to the leads to the bbshd and turn it on, the leads literally jump or jerk, and it blows the fuse (though invisibly.) A new fuse reactivates the pack. But when I do a continuity test on the leads, they test fine. why would the leads jump and why would they test fine?

Thanks!

Stu Summer
 
Total guess, but blown controller comes to mind. Could be short in the throttle or pas though.
 
Yeah when my controller blew it created a nearly dead short between the power leads. Blew one of the pins off my battery connector.
 
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?
 
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.
 
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.
 
I was just charging with my Luna advanced charger my 52V Luna Dolphin pack after a 7 mile ride. Everything seemed normal until my son passed by and said, "Dad I think your ebike is burning." No flames but a horrible smell and the battery no longer works. I left the battery outside for now. Any ideas?
 
Stu Summer
are you serious they would sell dolphin packs with NO fuses?
under fuse cover there is fuse, no fuse holder you say?
Cannot believe that
 
Are you sure the smell was from the battery and not the charger?

About the only thing you can do is try to open the case and look for where it burned. That will give you a clue about whether it is repairable or not.
 
You have a serious short somewhere causing a lot of problems you need to start at the accident site find what wires are touching. You're going to make more trouble for yourself until you find out about the possible short first.
 
Thank you all for your replies. When I need to charge my second battery, I will see if the smell is from the charger, I don't think so. Also, Somehow two separate posts, my old one about my son's bike and my new one about the horrible smell got combined. Different bike with a working bbshd.

And yes, my two luna dolphin packs DO NOT have fuse holders under the fuse flap but my BAFANGUSA one does (even though I can't recommend the BAFANGUSA battery. It has had mysterious inconsistencies.

Thanks for your help, I will keep you posted.
 
I have the 48V11.6Ah BMS Battery Bottle-09 Panasonic Battery Pack without Controller (NCR18650PF cells), and yes, it has a 30A fuse beneath the rubber fuse cover.

Quite frankly, I'm surprised anyone would skimp on what is a $0.10 modification which can easily prevent so much grief :shock:
 
More likely the burning smell came from the BMS. It may be possible to replace it. If any of the cell groups were drained by the failure, they should be brought back up to normal voltage with a very low current to avoid cell damage.
 
molybedumium
it is surprising to what extent would China manufacturer go to save less than a dollar on a product like battery for CHiNA market.
that is China market.
But if that battery is sold in USA by supplier like LUNA that's completely different story and almost criminal that they sell unfused battery to end user.
 
I've seen lots of packs with no fuses. The BMS is intended to protect against a short circuit on the load and this feature generally works.

Of course we all know that a BMS can fail too. Ideally, the fuse should be located mid pack to help protect against shorts between parts of the pack. Even then, unless each cell is fused, there are ways a pack could short that would bypass the fuse location.

I know Luna has gotten away from the chinese manufactured packs for exactly reasons like this. Their current production packs use wire bonding on each cell (like a Tesla) that is supposed to act like a fuse.
 
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