Brand New Battery suddenly drops power (Luna Shark, BBS02)

J

jpwalton

1 mW
Joined
Jan 3, 2017
Messages
13
Location
San Francisco, USA
Hello,

I just received my 52v Shark Pack, charged it to 100% per all instructions. Today, on maiden ride, the power suddenly cuts.

- Riding along, everything fine.
- Apply throttle or increase PAS level.
- Power drops, screen goes black.
- The on-battery power meter displays red (empty) when pressed.
- Remove battery, wait 1-2 min, re-attach.
- The on-battery power meter displays greens (full) when pressed.
- Everything works until the next cut out (1-2 min).
- Repeat.

Specs:
Luna BBS02
52v Shark Pack (Panasonic GA)
750c Full Color Display

I solder-spliced the motor wires to the battery cradle wires directly. I give myself a B- on the soldering job; could be better, but I don't see any obvious issues.

Anyone have any thoughts?
 
can you post a picture of the solder work ? ( not judging, but will judge .. :lol: .. and at least eliminate that possibility )

Sounds like BMS cutout, but will have to go thru all the checks and tests.. let's start with the solder work.

Do you have a DVM ? ( Digital Volt Meter )
 
I heatshrunk it all nice and I'm loathe to undo it (for now).

Let me ask this: if the strands are all twisted together (they are), how could bad soldering affect the scenario here? Let's say I did an absolute shit job on the soldering — what makes that a point of failure? What would go wrong with bad soldering that would make the BMS cut out (assuming that's the culprit).

Yes, I have a DVM
 
if twisted together, then soldered, should be fine. ( without pictures, it's impossible to assume how bad it could have been.. and i've seen some BAD solder jobs !!! ) . it would have to be something like the solder beading completely off the joint and the wires barely touching with only a couple strands making contact.. extreme high resistance situation. ..

Next step is to recharge, probe and note the voltage.... then bolt it on and take a ride (* bring DVM ) when the cutout happens.. probe while the cutout is happening.. then reset and test again.

report back.
 
OK — I am suspicious of my soldering the more I read up. Instead of splicing, I may just connect the motor wires directly to the cradle terminal.

Am I correct in thinking that since the battery is going to "1 LED" and then "resetting" to full, there's a fault (surge/short/bad connection) somewhere that's triggering the BMS? Is that how the BMS works?
 
jpwalton said:
OK — I am suspicious of my soldering the more I read up. Instead of splicing, I may just connect the motor wires directly to the cradle terminal.

Am I correct in thinking that since the battery is going to "1 LED" and then "resetting" to full, there's a fault (surge/short/bad connection) somewhere that's triggering the BMS? Is that how the BMS works?
Click to expand...

This phenomenon is called voltage drop. It stems either from too much internal resistance from poor connections, either from asking too much on the cells (Cells have their own internal resistance).
Also, you BBS02 controller could be set at a too high LVC, but I suspect you first check your soldering job.
 
if the battery pack itself has LED's on it, they will be isolated from your soldering job.. note that those led's are only a voltage reading and not a capacity reading.

if you have a 5 LED thing on the battery pack itself, try holding down the button while pulling power from the motor ( watch the road.... .) or use the brakes to load the motor some in the garage ( if not using ebrakes ) .. voltage under load is not the same as resting voltage.. this can be interpreted in various ways.. but check on it.

Another test, if the display has Levels, set it to a low level, like 1 .. and see if the cutouts keep happening or not.
 
If the indicator on the battery is going to red, then it would seem the problem is in the battery. If it recovers and works properly after being disconnected, it would seem like the over current protection is tripping on the BMS. If it fails immediately again, then I would suspect a low cell or BMS wiring.
 
update: I was suspicious of my soldering so I opened it up and re-soldered. I'm now completely satisfied I did an A+ job this time, totally happy with the connections. Quick throttle test with no load, everything seemed fine

Took it out for a test ride — same behavior:
This time I was in PAS 0, basically coasting down an incline. I went maybe 300 ft, and was about to switch to PAS 1, looked down, and the screen had gone dark. Battery showing 1 voltage LED. Walked it back, and battery has yet to "recover"

No wattage, no power, and voltage drop. I suspect faulty battery/cell/BMS at this point. Should I try to return to Luna?
 
You need to open a trouble ticket with Luna to resolve issue.

They will ask you to do some testing with your volt meter.

Take voltage reading from charge and discharge port and write down voltage.

Charge battery fully

Take voltage reading and write down.

With bike wheel in air run motor unloaded a bit.

Put battery back on charge, check voltage and write down.

Report findings to Luna support

They will instruct you how to proceed next.
 
once you get that sorted your gonna have great fun with that setup, I know I do
 
d8veh said:
Is the battery actually charged up?
Click to expand...

this would be good to know for sure
 
d8veh said:
Is the battery actually charged up?
Click to expand...
Wouldnt be the first time someone soldered up and rode off without charging. Hopefully its simple. Its a painful ordeal!
 
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