I fried my battery... don't do that.

[Pwd]

So I decided to take the rear cover off of my GM battery to tighten up the charging port since it was rattling around a bit. I stood the battery on edge and removed the nut from the back and then the nut slid down the wire and contacted a part on the circuit board and sparks flew

Clearly this was my own fault but I feel bad now since these things are not cheap... (over $500 CAD after shipping) and part of buying my GM kit was to save money. Just a reminder to people to be careful.
I will post some photos eventually.

So not the most uplifting post from my end but now I have to decide what to do next. I'm assuming its not worth the repair since who know how many parts got fried besides the ones visible (one of the mosfet looking things is half melted).

I have cut my e-bike season short (probably about a month of decent weather left here) and now I have to pay for gas.

My plans assuming the battery is not worth repairing:

WINTER/SPRING:
strip down my bike and turn it pack into a normal bike
clean up all the wires etc.. and hub motors (is there any risk in cracking these things open so I don't destroy anything else?)
sell bike for like $30-50

buy a better bike like a Giant or a Kona up to $650
get a new battery
slap the Pies back on and hopefully have a trouble-free year with this new setup


Strange thing is I hooked a multimeter up to this battery after the incident and it read full voltage but the bike wont turn on. Would the cells still be useful to someone? If I decide to get rid of this damaged battery, I'd like to try and at least get a a bit of money for it since I'm sure the cells are still ok.

[MonkeyMagic]

Strange thing is I hooked a multimeter up to this battery after the incident and it read full voltage but the bike wont turn on.

Hey mate

Sorry to hear about what happened... Not a good moment.

I would try and remove your BMS, I've done that with a pack I'm currently using and it is charging okay.

Just unplug the balance connector and desolder the big tabs, or if you want to leave it in there, just solder your discharge black wire to the Battery - tab which will bypass the BMS

Hopefully you can still get some use out of it

Here are some pics if that helps Good luck man!

[Leslie]

Ive been using a 15 amp hour pack with no BMS for 6 mths now.

I have a ping charger and adjusted it to do 3.52v per lifepo4 cell, 56.32 for 16 cells.

With the occasional 2 montly balance with a single resistor around 6 ohm to take the higher cells down, I can make no complaints.

The pack seems to balance very well, perfectly and goes out just a little after 60 days or so of constant use.  Even after 2 months the pack charges up enough and the high cells never overcharge @ 56.3v

I make sure I do not over discharge the pack, and a simple relay or fet shut off set at 47v could be an easy DIY job. I have used a 40 amp solid state relay and a tiny npn transitor as a sensor before as a basic LVC but removed it to put a harder edge upon the acceleration.

I could well get another BMS but I didnt like the logistics of where to place it with adequate cooling.  I use a 40 amp controller limted to 25, 30 amps peak.

Getting a 60A SSR should make for a better LVC as I am noticing some voltage slump across the 40A SSR,

[Pwd]

Thanks guys,

I will disconnect the BMS and see how it goes. In the meantime here are some pics of the damage.




The washer slid down the yellow wire and then sparks flew... You can see that it seemed to damage the 101 resistors and it has melted that last of the four square chips (mosfet?).

[GM Canada]

Hi pwd,

I am looking at this damage and am thinking maybe just a new BMS would resolve this battery issue. I am thinking that your cells are most likely still ok. But I am basing this on nothing but a hunch. What battery is this? If its lithium 48v12 or 36v16 maybe we can arrange a replacement bms to try. If its lifePO4 I have nothing to help you with at this time.

Gary

[Pwd]

Hi Gary, this is the 48v12aH pack. That would be great if I could get this working again! Thanks,

 - Paul

[GM Canada]

Hi Gary, this is the 48v12aH pack. That would be great if I could get this working again! Thanks,

 - Paul

Please send an email to garysalo@goldenmotor.ca. We can take it from there.

Gary

[Kirk]

Looks like you fried a few of the HVC shunts. Check the internal resistance of the cells and replace the BMS if they look good and you should be all right.

Good luck

[Pwd]

Just finished replacing the BMS and everything seems to be back to normal now  .

Battery is on the charger and I can't wait to get back on the bike before winter arrives!

[MonkeyMagic]

Just finished replacing the BMS and everything seems to be back to normal now  .

Battery is on the charger and I can't wait to get back on the bike before winter arrives!

Awesome !!!!

You would be wrapped @!!

Good outcome

[GM Canada]

Glad to hear things worked out for you

Gary

[GM Canada]

Strange thing is I hooked a multimeter up to this battery after the incident and it read full voltage but the bike wont turn on.

Hey mate

Sorry to hear about what happened... Not a good moment.

I would try and remove your BMS, I've done that with a pack I'm currently using and it is charging okay.

Just unplug the balance connector and desolder the big tabs, or if you want to leave it in there, just solder your discharge black wire to the Battery - tab which will bypass the BMS

Hopefully you can still get some use out of it

Here are some pics if that helps Good luck man!

So using this theory I should be able to clip the yellow and two blacks on this lifePO4 pack. Then unplud the bms and remove it. Then attach the yellow to the two blacks and the bypass is done. Correct?

Gary

[Cornelius]

Correct.

Do keep in mind that LiFePo4 are more robust when it comes to cell differences than the LiMnPO used in GM's (older?) packs, and therefore are usually ok without a bms, as long as the controller have LVD, and you doesn't overcharge.
I wouldn't run GM's LiMnPO packs without bms, without checking the cell balance often...

[e-lmer]

I wonder if this could be used on the balance connector
to check 6 cells at a time.
http://www.astroflight.com/index.php?main_page=product_info&products_id=21
You could just move it down the line...

[Leslie]

I think you could prolly use 3 of them in series E-Lmer.  As it allows from 1 to six cells on a 16 cel pack the last two isnt required..

I noticed when building voltage multipiers for charging 60v+ from large 15v transformers that none of the series parts required to be above 20v.  Only the output  parts required this voltage.

Nothing over 18v except the at outputs..  So my guess you could use those BMS's in series..

I was charging a 48v SLA pack with a V multipler that reached over 74v.  Nothing charged the SLA's like the curves I was getting with this homebuilt device..  So much current on the initial charge and the amps curved right down as it charged up.

Great to hear of your repairs.

My LIFEPO pack is still running perfectly with no BMS.

Nice to learn about the old LiMnPO batteries don't keep a balance so good without BMS,

Whats more awesome is GM has moved to the lifepo4 which from reading is a better chemistry.  The Cells look nice.