Mecer LiFePO4 12.8V 200Ah Lithium Battery SOL-B-L-M200 DOA

garybenade

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I received 2 of these units on Friday direct from Mecer, they state that they are still good for 1500 cycles.

I installed 2 in series for my 24V RCT trolley inverter and all seemed well until the first time the inverter kicked in and the house tripped and the inverter died

I inspected the batteries and found on with 0V

I have spare BMS's so I assumed worst case I would need to replace that, there is no way to open these batteries so I had to cut it open

The BMS supports WIFI but I could not connect to it or even detect it

I measured 0 volts across the battery terminals, so I removed it to inspect and found 4 dead and swollen cells

One of them was swollen on top, this one also has a clear sticker while the others have a blue ring (see photos, I don't know what these are but I assume they indicate cell failure?)

Are cells in this bloated condition safe?

And if so are they capable of another 1500 cycles?
 

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Why did you open them and not send them back?
I have no problem fixing things if I can and I was 99.9% sure it was just the BMS - I was not expecting to find what I did.
I only opened the one, they are both going back and I'm staying a mile away from this second life lithium scam from now on
 
I would check the voltage per cell

And then place it on charge and measure again

I would bet the bms is faulty and some cells exceed the recommended max voltage or bms is fine and some are extremely low SOC
And thus once you charge it, it will stop accepting a charge very quickly as the full ones get the bms to stop charge in cell over voltage protect and thus the moment shedding hits the flat ones trigger a low voltage protect again

If they don't take it back (cause opened.) You can either use a buck converter set to 3.65v and charge individual cells full one by one or baby sit the cell with a charger and switch off charger as soon as it hits 3.65v
(When my buck converter broke i used 5v tablet charger and just don't leave it unattended things happen fast when it riches full

Have seen a youtube clip of someone that made mistake while balancing cells to build a battery , the cells bloated , and yet he could get close to capacity when he tested capacity

Is it safe to use i don't know
As far as i have it the cells does deform a bit if not compressed
 
You can either use a buck converter set to 3.65v and charge individual cells full one by one or baby sit the cell with a charger and switch off charger as soon as it hits 3.65v
I tried what you suggested and charged each cell with 1.5A and 3.75V for 45 mins and the BMS came back to life. My inverter is charging the 2 batteries in series with no problems although it hovered on 83% and took a day to settle down and hit 100% - I guess that was the BMS regulating things while the cells balanced and charged up.

They did 2 hours of load shedding today with 50% load on the 2000W inverter without a problem, stayed on 100% the whole time. They were fully charged again in an hour and a half.

The bloating still bothers me but I'll keep an eye on it

Thanks for the advice
 
I tried what you suggested and charged each cell with 1.5A and 3.75V for 45 mins and the BMS came back to life. My inverter is charging the 2 batteries in series with no problems although it hovered on 83% and took a day to settle down and hit 100% - I guess that was the BMS regulating things while the cells balanced and charged up.

They did 2 hours of load shedding today with 50% load on the 2000W inverter without a problem, stayed on 100% the whole time. They were fully charged again in an hour and a half.

The bloating still bothers me but I'll keep an eye on it

Thanks for the advice
Now you still have to parallel them and fully charge with 12V charger to top balance them. Or get a balancer.
 
I received 2 of these units on Friday direct from Mecer, they state that they are still good for 1500 cycles.

I installed 2 in series for my 24V RCT trolley inverter and all seemed well until the first time the inverter kicked in and the house tripped and the inverter died

I inspected the batteries and found on with 0V

I have spare BMS's so I assumed worst case I would need to replace that, there is no way to open these batteries so I had to cut it open

The BMS supports WIFI but I could not connect to it or even detect it

I measured 0 volts across the battery terminals, so I removed it to inspect and found 4 dead and swollen cells

One of them was swollen on top, this one also has a clear sticker while the others have a blue ring (see photos, I don't know what these are but I assume they indicate cell failure?)

Are cells in this bloated condition safe?

And if so are they capable of another 1500 cycles?
My director also got 4 of these. They have been in for RMAtwice and just broke again earlier this week. He requested a return and credit.
 
I tried what you suggested and charged each cell with 1.5A and 3.75V for 45 mins and the BMS came back to life. My inverter is charging the 2 batteries in series with no problems although it hovered on 83% and took a day to settle down and hit 100% - I guess that was the BMS regulating things while the cells balanced and charged up.

They did 2 hours of load shedding today with 50% load on the 2000W inverter without a problem, stayed on 100% the whole time. They were fully charged again in an hour and a half.

The bloating still bothers me but I'll keep an eye on it

Thanks for the advice
Now you can either do what wingnut said

Or change the buck to full voltage for the batteries ie 14.6v

And then once inverter tops out its charge cycle

check if there is a voltage difference and connect the buck to the low voltage one and top it up until it matches the high voltage one, ie mcgyver balance in place

Edit : note you have to check as the inverter hits full just before it switches to float

The 2 batteries will come to a resting voltage much closer together under float that looks balanced
 
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