Lifepo4 Battery shorted

[gerrydesign]

just shorted his Lipo battery 24V , accidentally connected + and - . Is it ruined for life?

Thanks in advance.

 

[Farfle]

For how long? If it no longer outputs voltage, you probably cooked the cell tabs off of one cell, they seem to be the failure point in a short-circuit scenario. If its still outputting voltage, its probably ok, run it thru a couple balance cycles and check it for dead cells. Past that, I would use it in a non-critical application, and keep an eye on it if possible.

 

[liveforphysics]

Farfels advise is perfect.

 

[Metallover]

I've shorted a few 6s Turnigy packs and they are doing fine now. One blew a tab and I resoldered and was good. They perform a little less than the others; say .04V out of balance vs .02V out of balance, but overall they aren't too bad.

Be careful tho, listen to the above

 

[gerrydesign]

Thanks for the response.

It was split second thing. Something popped from inside the pack. It's at 26.5V now and it was 27.1 before it shorted.

I just opened it and thought I can find a loose tab. Everything seems to be intack but I didn't attempt to remove the BMS because it looks it's way over my head.

Any advice will be appreciated, Thanks!

 

[gerrydesign]

I made an attempt to find anything burnt or any clues for a tab that might have popped disconnected but I chickened out on exploring further. The BMS is hot glued on a fiber glass and it looks PITA to dismantle. Perhaps I should just sent it somewhere to get it repaired. Anybody here point me to where I can sent it for repair?

Pics below

 

[Spacey]

I shorted 66v 17.8ah 25C Lipo pack yesterday by connecting it to itself

Was in a real hurry and was not thinking straight, won't do that again, very black had and blew one of the main connectors out and vapourosed it lol.

Hand not hurt and batteries seem fine, hoping your pack is ok. I will be soldering up a fool proof wiring harness tomorrow.

 

[gerrydesign]

So I tested the battery and here's some picture of the meter reading. Anybody can help explain what's happening and any recommendation to make it work. I was thinking of removing the Battery BMS totally on one that got shorted, will that work? Thanks in advance.

Meter reading directly from battery

Meter reading with Lyen Controller connected to positive and negative

Meter reading with Lyen Controller connected to positive and negative AND the GROUND/IGNITION

 

[hillzofvalp]

...

 

[gerrydesign]

The thing is when I check just the battery connected, it shows 53.8V (2 24 volt battery in a series, almost newly charged). When I connect it to my controller, the voltage just goes down, see pics and comments. It that the battery BMS causing voltage to go down when connected to the Controller?

TIA

 

[neptronix]

try skipping the BMS and connecting straight to battery.

PS: you don't have a lipo battery.. that's probably what got some people confused. This looks like lifepo4 to me.

 

[gerrydesign]

Thanks for correcting my noob title, I updated it. I will trying to further mangle the pack and bypass BMS. I guess when I charge it, I need to connect it the BMS again.

 

[gerrydesign]

I did some more poking around and found a way to bypass BMS. I soldered a 10 ga. wire on the tab of a Neg that goes to the BMS. Tested it with the controller and the motor, and it work.

Now my questions is can I bypass BMC to charge my battery?

Again, Thanks in advance.

 

[999zip999]

You can but not advised. You will lose the hvc and the balancing of the pack when charging. when discharging you lose lvc. That being said Yes you can charge and discharge the battery without a bms. But you must be the bms. Don't let the cells go above 3.8v if lifepo4 and go below 3.0v any cell. Good luck.

 

[gerrydesign]

I contacted the person I bought the lipho4 from. Still waiting for response. Im wondering if anyone here knows how to fix it for a fee?

 

[Pure]

If you can solder, it's a pretty straight forward fix. Contact the vendor and buy a new BMS. They (usually) are not expensive. Cheap Chinese BMS's are not worth the time it takes to fix them. Unless you are bored and have a very good idea of what you are doing.

 

[gerrydesign]

Thanks for the advice. Im actually learning more and the old posts here when doing a search are starting to make sense to me. Can you point me to site to order bms.

 

[gerrydesign]

If you can solder, it's a pretty straight forward fix. Contact the vendor and buy a new BMS. They (usually) are not expensive. Cheap Chinese BMS's are not worth the time it takes to fix them. Unless you are bored and have a very good idea of what you are doing.

Your right, the more I look at it, it might be a pretty straight forward and I can even use existing connection (provided there are all still in-tack :? ). Perhaps I should work harder to remove that metal plate covering the BMS. Will there be a fuse inside, that I can replace? stay tuned. I have a deadline on the 11th at work so this will have to sit for a while. Good thing the battery was fully charged prior to incident. Thanks again for the advice, and more future advice is great appreciated.

Picture with comment:

 

[goasisenergy]

He is a awesome, honest person.

We are going to ship a free BMS to him


http://www.goasisenergy.com/

 

[999zip999]

Unplug the the balance wires first the plug.All those wires are pos. maybe one neg. ? The big other wires are neg. this makes it harder to short. Solder the wires to the bms broard then solder the broad to the neg. from the batt. I think this is right. If any body has advise please chime in.

 

[joe tomten]

Gerrydesign,

This bms has the typical connections.
zip9 is right. First get that balance connector unplugged, cause that is what livens up the bms with the positive connections to each cell group.

Carefully clear away any of the white cement that they used to stick it together with.

Once the balance connector with the positive leads from each battery group is off then the bms is no longer alive.

I probably wouldn't bother with taking the lid off the bms, as i doubt there are any fuses in there, and it looks like you have a new one on it's way. Very cool..

You can always take it apart later.

There are now 3 (three) negative wires connected to that bms.
the charger neg.
the battery neg.
and the load neg.

Label these if you need to, but it's not hard to see which is which cause they are either connected to one of the 2 cables, or coming from the battery pack for the main negative lead.

You can either clip each of these right at the bms, or try to desolder each one, or a combination. you can always solder on a short extension and put some heat shrink insulation (radio shack has it) over the solder joint.

Now you solder each of these negative leads onto the new bms through the appropriate connection hole. "tinning" the wire first helps a lot.

Once these 3 negative wires are on there then you can attach the balance connector with the 17 leads to the bms (16 positive and one negative). Maybe even take your voltmeter and check the voltage of each cell before you plug the connector in to the bms (or after, doesn't matter but be careful not to short the voltmeter probes together or it will get lively). Start with the black negative wire, and measure up from there to make sure that all these little wires are still connected to their cell group and havn't been mangled in the repair process. If there is an interruption in any one of these lines and you can't measure the voltage of the cell group, then you need to repair that connection in order for the bms to properly do it's deal.

Joe

 

[dnmun]

what was wrong with the BMS? i thought you just shorted the pack, that should not damage the BMS. running and charging the pack without a BMS will damage it.

 

[gerrydesign]

Thanks in advance to John of www.goasisenergy.com for sending a new BMS for this pack that I shorted. I really appreciate all the help. The members in this forum rocks. Thanks for all the helpful tips and will follow the advice from zip and joe once the replacement BMS gets here.

It's clearly the BMS. I tested my motor: when negative is connected thru the original negative wire to the controller, motor NO WORK, when I bypass the BMS, soldered a wire from the negative directly from the welded tab in the battery and connect it to the controller, motor WORKS.

 

[gerrydesign]

New BMS courtesy of goasisenergy.com:

Unplugged connectors, I don't need this since I'm going to use the exsisting ones:

Here's my battery pack with broken BMS (I shorted it), unplugged (removed excess glue and slide it out using screw driver just (to push NOT unscrew) very carefully now to damage plastic connector)

Cut negative wire connection between BMS and charger:

Old BMS on the left and new on the right:

Mount existing fiber glass from old BMS and taped it to the new BMS using electrical tape:

Solder and connect negative wires to the charger and put anderson connector on the other negative wire coming from the BMS:

Connect plastic plug to BMS and connect to charger (now it turned red meaning it's charging, before it just remained green with the busted BMS):

Charger connector from the repaired battery pack (negative is not connected, I didn't mind complaining about that because I can fix it):

Hot of the charger:

Hope this pictures will help newbies like me to fix their battery...

 

[dnmun]

a picture of what shorted to make your BMS not function woulda been more useful. what did you short out? a dead short across the terminals should not have damaged the BMS. that is what it does for a living. so please let us know what shorted if we are to learn something from it.