Shorted a cell in multi-cell LifePO4

[Chillboy]

These are sensitive little guys, barely touched it with a sharp knife removing gobs of glue and one discharged the smallest little smoke cloud from near the top.
They are welded so do I have to cut it out? It's already shorted so should I cut the bar (closer to this shot cell). Can I leave it or will heat up a lot and cause more damage?
Best solution I know is to replace that cell, I'm in Canada, Peterborough, ON. Is there anywhere fairly close I could take or ship it for proper repair and balancing?
Battery is a Cammy CC V-Power. Here's some pics. The shorted cell is right at the end of the row in the forth bank.

There was a whole roll of duct tape, 16 glue sticks and some paper holding this together. It is still stripped down.

Thx for input. I'm waiting on 1 more part to get this together and I should have ordered the wider shorter pack, hindsight is 20/20 they say..

 

[steveo]

I could help you repair it..

I'm in woodbridge ontario... I work sometimes in peterborough ... pm me ..

-steveo

 

[Chillboy]

PM sent.

 

[dnmun]

just shorting it out briefly will not kill it. happens all the time. did you just leave the knife shorting it out or did you remove the knife?

did you short the sense wires or the terminals of the cells? does it charge?

 

[Chillboy]

Barely touched it with an exacto trimming down lobs of hot glue and tore the case.
It puffed a small misty white cloud about the size of a golf ball, 3-5 sec after, leading me to believe I've fried it.
I haven't reassembled it let alone try to charge. I was planning to leave the cell in question exposed
and I have a friends heat sensor gun to test it's temp against the other cells but can't find my multi meter anywhere.
And I've been waiting longer for my Turnigy meter to get here than this battery from HK and controller from Kelly.
But luckily steveo works right in my city sometimes, and isn't that far if I have to travel so I think I'll get
some experienced help with this if I can. Has replied will call later, thx man!
It will work much better for me if I can insulate in between and make it double wide and not as tall to get
into my front triangle..is how it started.
I really want to get the weight off the back.

 

[chxs]

Hi ! my actual setup is 140 LifePO4 on my triangle .... i can post somes picture of How-to if ur interessed My friends Doctorbass alert me to not using Doctape directly on it ... so now i post some picture sorry for my english ! i hope this help u

This is a 14S5P pack ... i have both ...


Pack assembly ...


This is the final result ... without shrink ... PCB casing


Now shrinked ... looking good and seeled ( i have to cut and glue the PVC shrink i cant find a tube big fot my pack ! i build one ! )



And be carefull of short ! Powerfull cells !


Tanks
Chris

 

[Doctorbass]

Great Job!

Now let this 5304 to eat some electrons!!!

With that actual 5305 that Maxwell brang to you until he get the 5304 for you, you will be abel to get around 65-70kph with around 140 pounds of torque from a dead start.

Just enough to let you discover the wonderfull world of the electric bike!

Doc

 

[Chillboy]

Nice work in the pics, you are much braver than me

I'm not trying it though, having a hard enough time (when I find the time) to get this thing
actually running. Pretty much fully charged I get 55 volts out of the battery.
I've been plagued with a bad throttle and in trying to fig. it out I've lost interest for a bit.
But I picked one up today at the local ebike store (only one they had).
Hopefully this weekend I'll have it running properly.
Rode my new(er..to me) 24V Daymak scooter to work today and it wasn't too bad. Beautiful day helps but
what a struggle for my 145lbs up hills
Giving one last shot on my own then I'll enlist some help.

Does anyone use a contactor? I just used a blade fuse and put the resistor in the holder for first charge up.
The programming is pretty cool on the Kelly controller, dying to really play with it..

 

[Chillboy]

All cells in this pack are 3.1-3.2 volts but the last row (where the black ground wire is attached) which is showing 0V on all cells in that row. There doesn't appear to be damage to it or the bms (no smells, burned wire...).
I haven't tried to recharge it yet, just short initial top up when I got it.

I've had quite a few little problems, which have taken way longer than they should due to work/kids/sleeping instead reading until 1am ... but I ran it with this battery and I'm not very excited about going back to sla.

Is there anyone (other than steveo, I tried when problem was suspect and he's a busy guy this time of year) who might want to replace this string or reconfig this battery if I ship it to you and pay you for it? Is it worth it? I'm almost ready to get what I can for it and pay way too much retail for a decent battery just to ride this bike. Night and day difference from riding a Luyuan 48V sla scooter, I like to pedal even when I'm already faster.



Thanks for input
Dion

 

[Chillboy]

http://cgi.ebay.com/New-A123-10pc-3-3V-1-1-1ah-LiFePo4-18650-battery-cells-/120578049688?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c13030698

Here are the closest replacement cells I can find to what's in my pack and it's what Cammyc (Vpower at least) seems to be selling for individual cells.
I got my wait 20hrs for reply from Cammy in China but he just asks if I have measured voltage at white bms wires, I measured the cells themselves all at 0V.
It's my understanding that A123 is a registered company name or lithium technology?
A good one that I should have chosen instead of trying to save a few dollars Nice deal with Chrysler btw.

Would you use these cells (with same peak voltage) to replace the unknown Cammy cells?
It's the closest I can find, China incl., but I don't want to wait for the slow plane again

 

[robb]

Have you asked cammy if he would you send you a new string of cells to replace the damaged ones. It is easy to replace a whole string. I had a string of cells short or die somehow. After quite a lot of emails similar to the one you mentioned cammy sent me a new string and a new bms as that was also damaged. I think when emailing Cammy you have to make the email as clear and simple as possible as his english may not be that good.
Good luck
Rob

 

[The Mighty Volt]

http://cgi.ebay.com/New-A123-10pc-3-3V-1-1-1ah-LiFePo4-18650-battery-cells-/120578049688?cmd=ViewItem&pt=LH_DefaultDomain_0&hash=item1c13030698

Here are the closest replacement cells I can find to what's in my pack and it's what Cammyc (Vpower at least) seems to be selling for individual cells.
I got my wait 20hrs for reply from Cammy in China but he just asks if I have measured voltage at white bms wires, I measured the cells themselves all at 0V.
It's my understanding that A123 is a registered company name or lithium technology?
A good one that I should have chosen instead of trying to save a few dollars Nice deal with Chrysler btw.

Would you use these cells (with same peak voltage) to replace the unknown Cammy cells?
It's the closest I can find, China incl., but I don't want to wait for the slow plane again

e

Hi Chilliboy...so those are the cells that Cammy, VPower, Volgood etc are calling A123...when in reality they are just basic LiFePo4 being used in their packs!!

No way your battery packs is genuine A123.

Can you peel the duct-tape off and show me a battery? Does it look like this:

thanks

 

[The Mighty Volt]

Hi ! my actual setup is 140 LifePO4 on my triangle .... i can post somes picture of How-to if ur interessed My friends Doctorbass alert me to not using Doctape directly on it ... so now i post some picture sorry for my english ! i hope this help u

This is a 14S5P pack ... i have both ...
View attachment 5

Pack assembly ...
View attachment 2

This is the final result ... without shrink ... PCB casing
View attachment 4

Now shrinked ... looking good and seeled ( i have to cut and glue the PVC shrink i cant find a tube big fot my pack ! i build one ! )
View attachment 3


And be carefull of short ! Powerfull cells !
View attachment 1

Tanks
Chris

Sorry, but is 140 cells not 14s10p?

 

[Chillboy]

Have you asked cammy if he would you send you a new string of cells to replace the damaged ones. It is easy to replace a whole string. I had a string of cells short or die somehow. After quite a lot of emails similar to the one you mentioned cammy sent me a new string and a new bms as that was also damaged. I think when emailing Cammy you have to make the email as clear and simple as possible as his english may not be that good.
Good luck
Rob

I wouldn't expect him to replace them without charge, since it was my own fault here. Ebay seller above got them from CammyCC VPower
and offered a price of under $60 for 15 and could I have them in days. I never thought for a minute they were A123, that's a US based
company with nice cells I couldn't afford. I would assume it's the new part number for these vpower cells, but could be different?
But yeah I'm not excited about trying to get it back together from individual cells.

 

[Chillboy]

Mighty Volt sure when I pull them out.
I'll take some better close up pics and measure them but that sure looks similar to me.

 

[Chillboy]

Got 2 replies from CammyCC
He confirmed that they are the same cells offered from US seller that they've always used.
He did offer to replace "the bad cell"
Here's what I don't get is he asked if I could charge the battery without the bms?
I didn't think it would be possible to revive a cell with no voltage.
He didn't touch my question of whether or not I can remove that row of cells and what the outcome would be.
It's a parralel group right? So I would loose Ah capacity if removed? Would that mess with the bms, or are it's parameters
low and high voltage cutoff only?

Can I solder onto these cells?
I don't exactly have a welder that could do this but I could tin the bar and battery tops and use some clamps to disapate heat as I go.
The wires will have to be resoldered as they are.

Lotsa questions, I'd rather measure twice on a project like this...

 

[Chillboy]

I went ahead and bought these cells http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=120578648823&ssPageName=STRK:MEWNX:IT
Dude made a special auction just for me :lol: It's all good well it will be when I fig out the best method of getting it back together with limited resources.
I'll post my results when I can.

 

[Chillboy]

Ebay seller was more than resonable and made a special buy it now option with my ebay name right in the title.
They are on route.
I found an online how to on soldering these together. I've also found numerous quotes saying not to solder the ones
without tabs.
I'll have 2 extra to mess up, wish me luck!

 

[Chillboy]

I already thought so but they look like the same cells to me. Looks can be deceiving though
F is the only marking on them.

 

[Chillboy]

New cells arrived yesterday!!

Has anyone used conductive epoxy for a job like this?
I searched and JB weld won't do it but I'm trying to source an epoxy like this today;
http://www.directindustry.com/prod/master-bond/electrically-conductive-epoxy-adhesive-17407-198093.html

Any draw backs. I have a 25W soldering iron ready to go but this seems safer.

I plan to re-wrap the pack with fiber tape then duct tape once it's done.

Any feedback?
I can solder but I don't have a high temp gun. I can borrow one if it's a lot better method.

Cells are 3.2V, my pack is 3.1-3.2 still so I'm lucky there.

 

[julesa]

New cells arrived yesterday!!

Has anyone used conductive epoxy for a job like this?
I searched and JB weld won't do it but I'm trying to source an epoxy like this today;
http://www.directindustry.com/prod/master-bond/electrically-conductive-epoxy-adhesive-17407-198093.html

Any draw backs. I have a 25W soldering iron ready to go but this seems safer.

I plan to re-wrap the pack with fiber tape then duct tape once it's done.

Any feedback?
I can solder but I don't have a high temp gun. I can borrow one if it's a lot better method.

Cells are 3.2V, my pack is 3.1-3.2 still so I'm lucky there.

Don't bother with conductive epoxy, it's not conductive enough. If you want to solder them, yes you're going to need a high temp gun, a 25W iron is not even close to the power you will need. Maybe you can find someone local with a battery spot welder?

 

[webfootguy]

New cells arrived yesterday!!

Has anyone used conductive epoxy for a job like this?
I searched and JB weld won't do it but I'm trying to source an epoxy like this today;
http://www.directindustry.com/prod/master-bond/electrically-conductive-epoxy-adhesive-17407-198093.html

Any draw backs. I have a 25W soldering iron ready to go but this seems safer.

I plan to re-wrap the pack with fiber tape then duct tape once it's done.

Any feedback?
I can solder but I don't have a high temp gun. I can borrow one if it's a lot better method.

Cells are 3.2V, my pack is 3.1-3.2 still so I'm lucky there.

If there is a Batteries Plus store near you, they have a battery tab welder and do a nice job. Mine locally will weld tabs for $1 per tab for small jobs. It is up to the store manager but never hurts to ask. Also, there are lots of custom battery shops around that will do small jobs as well and some folks have their own tab welders who are willing to help.

The problem with soldering directly to the cell is that you have to do it very quickly otherwise you damage the cell. Damage usually shows up as reduced capacity. Whether this is a problem depends on your pack config and BMS.

 

[Chillboy]

Batteries Plus is USA only and I've tried in town and searched Toronto area.
But I found a place called Total Battery in Barrie and I have to go there next week anyways to visit a client.
Thanks for the input!
I did take electrical tape and made it work temp. with black duct tape over all of it and it shoves tight into the carrier bag.