I just direct shorted my brand new 135amp LiFePO4 battery - is it toast?

[iClick]

This is a case of being a noob and not paying proper attention to what I was doing

I'm gathering equipment to build a all in one solar generator (battery, inverter, DC to DC and AC charger) I just received the last component which was a DC-DC charger with inbuilt MPPT solar.

Before the sun sets, I wanted to test the efficiency of the MPPT and began wiring in the DC to DC charger. I added a cable with a 60 amp ANL fuse to the positive terminal and just as I was positioning the fuse, the tail accidentally touched the negative post of the battery for a split second. There was a spark in now the battery looks like it is toast..

This is my first lithium battery and I'll be extremely annoyed if I've fried it. The case is sealed so checking inside for damage won't be easy. It's been 30 minutes since the spark and it hasn't come back to life. I was hoping the BMS had possibly shutdown temporarily but that appears optimistic.

What is frustrating is that the 60 amp ANL fuse did not do it's job. The battery has a 200A max pulse discharge current and 100A sustained.

I'm not sure if this would be covered under warranty so would it be likely that I'm up for a new BMS or could I have also fried the cells?

 

[hankcurt]

Hi iClick. It might be helpful to post which battery brand and model you have. From your description I am thinking its one of the 12 volt lithium batteries in a plastic case with dimensions similar to a lead acid car battery.

A brief short like that would not have damaged the cells. It may have damaged the BMS inside the battery case. With the battery information, someone may be able to give advice on ways to try to wake it back up if it just went into a protective mode.

 

[Norwasian]

From one noob to another (the blind leading the blind), I would suggest that it might be possible for the batteries to have sufficiently discharged that the BMS has taken them offline. If that is the case, you might need to charge them manually until they are above the low-voltage threshhold. But I have yet to build one of these setups--I've just been studying the process for a couple months, trying to learn as much as I can.

THIS THREAD suggests that one type of fuse would not have protected the batteries in the event of a short.

THIS ONE leaves off before the conclusion is reached as to why the cells appear not to show full voltage.

And THIS ONE gives some practical advice for what to do (or not to do) next time. Hah!

 

[Crowz]

Most of the batteries claim they have protection against that happening so if has that in the manual or on the battery you might be able to get it warrantied.

Attempting to charge it might reset it too if its not fried internally.

 

[iClick]

From one noob to another (the blind leading the blind), I would suggest that it might be possible for the batteries to have sufficiently discharged that the BMS has taken them offline. If that is the case, you might need to charge them manually until they are above the low-voltage threshhold. But I have yet to build one of these setups--I've just been studying the process for a couple months, trying to learn as much as I can.

LOL, yes, I've been doing lots of research into various components and trying to educate myself along the way yet the lesson learnt today will stick around for a very long time. Unfortunately it may have been an expensive lesson!

The battery was at full capacity as it has been charging via a solar panel while I waited for my DC charger to arrive. I also purchased a capacity tester which I had planned to run tonight given the battery was at full SOC

THIS THREAD suggests that one type of fuse would not have protected the batteries in the event of a short.

THIS ONE leaves off before the conclusion is reached as to why the cells appear not to show full voltage.

And THIS ONE gives some practical advice for what to do (or not to do) next time. Hah!

Thanks for those links, interesting about the fuses. I hat a MRBF terminal fuse arrived in the post today and it is classed as a type T fuse so perhaps regrettably I had not installed that before my misadventure.

 

[iClick]

Most of the batteries claim they have protection against that happening so if has that in the manual or on the battery you might be able to get it warrantied.

As it is a brand-new battery I had the warranty card on hand and unfortunately it claims that in the case of a short circuit of the battery terminals it won't be covered.

Attempting to charge it might reset it too if its not fried internally.

This might be my next step to take however not having any experience with lithium batteries I will look carefully into that. I did read somewhere that a lower amperage charger of approximately one amp could be utilised safely.

 

[iClick]

Hi iClick. It might be helpful to post which battery brand and model you have. From your description I am thinking its one of the 12 volt lithium batteries in a plastic case with dimensions similar to a lead acid car battery.

A brief short like that would not have damaged the cells. It may have damaged the BMS inside the battery case. With the battery information, someone may be able to give advice on ways to try to wake it back up if it just went into a protective mode.

Thanks, you are correct in your assumption.. there seems to be little information about this particular battery online. I suspect it will be just a rebadged version that is mass produced in China. This is the specs

 

[iClick]

Can I ask the brains trust here, if I’m denied a warranty claim, how do I determine if it’s the BMS or batteries that are fried?

 

[upnorthandpersonal]

From the manual:

Over-current /short circuit protection: Disconnect your battery, if it recovers abnormally, please use LiFePO4 battery charger to activate it.

Try it.

 

[mikefitz]

There was a spark in now the battery looks like it is toast..

The good news is that the BMS detected the over current and shutdown the discharge path, protecting you from molten metal and possible smoke and fire. A ' good' BMS will respond faster than a fuse, the fuse is needed if the BMS fails.

The BMS recovery from over current is usually time based, a few seconds. It could be that the battery needs a charge or discharge to assist recovery.
If the BMS and internal connections within the battery are low cost items, there may be an internal failure . Fitting a replacement BMS as a last resort is not too difficult and will cost in the region $ 110 . I very much doubt there is any damage to the cells.

 

[hwy17]

Put an AC charger onto it. Many batteries require that to wake up.

Most batteries don't go into standby mode from short circuit protection, but still everyone needs and AC charger for troubleshooting.

 

[iClick]

This might be my next step to take however not having any experience with lithium batteries I will look carefully into that. I did read somewhere that a lower amperage charger of approximately one amp could be utilised safely.

Agreed, trying to charger is my next step. As I noted above, I read that the charges should be very low amperage to begin with. Is that correct? I assume it doesn’t have to be a specific lithium charger? I have one on order but it hasn’t arrived yet but I do have a standard SLA 12v charger. Using a charger to get the BMS working again sounds like the equivalent of a defibrillator to restart, someone’s heart!

 

[Supervstech]

Agreed, trying to charger is my next step. As I noted above, I read that the charges should be very low amperage to begin with. Is that correct? I assume it doesn’t have to be a specific lithium charger? I have one on order but it hasn’t arrived yet but I do have a standard SLA 12v charger. Using a charger to get the BMS working again sounds like the equivalent of a defibrillator to restart, someone’s heart! View attachment 192665

Hey, i have one of those recovered from a medical building... i dont think i will try it...

 

[wild01]

Agreed, trying to charger is my next step. As I noted above, I read that the charges should be very low amperage to begin with. Is that correct? I assume it doesn’t have to be a specific lithium charger? I have one on order but it hasn’t arrived yet but I do have a standard SLA 12v charger. Using a charger to get the BMS working again sounds like the equivalent of a defibrillator to restart, someone’s heart! View attachment 192665

sla charger should work, but it will need to be a "dumb" charger. smart chargers read the batteries voltage before outputting a charge. since your battery is effectively turned off there will be no voltage out. so if hooking it up to a charger doesn't work check the charger leads voltage with a multi-meter before assuming charging didn't reset the bms.

 

[TomC4306]

Or bench power supply

 

[iClick]

Okay braintrust. I'm at a loss now.

I've tried three different methods to kickstart the battery. No luck with any of them.

1. 12v 1.5A charger from a HDD
2. 12v lithium jump starter pack (according to the flashing LEDs, the house battery was too low voltage )
3. DC-DC charger connected to solar (it has a BMS activation mode see below*)
4. Direct from car battery

Using a multimeter, the battery was reading 4V across the terminals in the beginning. Now it is reading zero volts

When I connected the DC-DC charger the Bluetooth app reported the battery voltage in the beginning at 6.5 V and each time I checked it was slowly getting less.

Renogy DC-DC charger has the activation function of lithium battery. Lithium batteries may enter sleep mode when the in-built protection is triggered. In such case, the battery charger provides a small current to reactivate the sleeping lithium battery. The lithium battery can be charged normally after successful activation.

Unless there's a trick that I've missed, i'll take it back to the distributor and see if I have any joy with a replacement. It would be sad to think that the briefest of short-circuit would kill this battery. I've seen people on YouTube using lithium batteries to deliberately short-circuit as a test with the BMS self resetting each time

 

[Crowz]

Get a volt meter and measure volts at the battery lugs.

If volts are 0 then set the meter to measure resistance. If its showing open aka no resistance then something is wrong internally.

Blown fuse, Melted wire, dead bms etc.

Will require opening the battery up to repair it.

 

[Blakes]

In for tech

 

[iClick]

Get a volt meter and measure volts at the battery lugs.

If volts are 0 then set the meter to measure resistance. If its showing open aka no resistance then something is wrong internally.

It reads 0v at the terminals and it has a circuit. When I plug a 12V 1-5A charger in, it fluctuates between 30-400mV (any reason why the DC charger only puts out such a minimal voltage when connected to the battery?)

The SOC of the battery was 95% at the time of the short. (I was charging it to run a capacity test)

is it safe to leave the 12V 1.5A charger on and trickle charging? To my understanding, if the BMS had tripped for safety, then it should've kicked back in when I applied either the first 12v DC charge, or certainly the DC-DC charger. Leaving the battery connected to the 12V doesn't logically seem it will achieve much if the BMS hasn't already come back to life.

Blown fuse, Melted wire, dead bms etc.

Will require opening the battery up to repair it.

 

[Crowz]

Not all battery chargers will work to bring it back to life. The older "dumb" type chargers are best or a lithium battery charger rated at waking up lithium battery. Several I had seen list it as something they do.