Went all in on a Lithium Iron Phosphate Battery, but my inverter went nuts

[UNL1988]

I have a 400w solar panel array that was feeding two lead acid, 12 V 100 amp hour batteries in parallel through this charger controller:

EPEVER MPPT Charge Controller 40A 12V/24V Upgrade Tracer4210AN + Remote Meter MT50 Monitor + RTS for Solar Panel Charge Controller Regulator with LCD

The system is used to run some small appliances on the farm, primarily a 100w water cooler and some battery/phone chargers.
I decided to upgrade the battery to a larger capacity, lithium Iron Phosphate, 200 Amp Hour, Expert Power battery:

ExpertPower 12V 200Ah Lithium LiFePO4 Deep Cycle Rechargeable Battery | 2500-7000 Life Cycles & 10-Year Lifetime | Built-in BMS

so that I could run some larger loads overnight.

I hooked the new battery up to the system on Saturday morning, and left it charging Saturday and Sunday. Panels were pushing 14-20 volts, depending on the clouds, etc. The inverter was turned off, so there was no load on the battery.

I came back Monday morning the battery was charged to 14.1 V according to the multimeter and display panels.

When I turned on the inverter with no load, all of the display panels showed the battery totally drained, the alarms all went off, and all of the farm animals ran away.

No blown fuses, the panels are pushing 20V, great sun this morning.

Inverter:

Novopal 2000W Power Inverter Modified Sine Wave DC 12v to AC 110v with Big LCD Display (Peak 4000W)

Do I need to charge the battery longer at home using an AC charger, then hook it up to the system?

I am not sure about it because the battery shows 14 V when there is no load.

I took the big battery off the system and put the two SLA batteries back on and everything is running just fine.

Any suggestions from the internet?

 

[Zil]

Is your BMS open. blown. disconnected.? LiFePo should not be charged with the same settings as LA. I don't know how to reset your BMS, but that could be the problem if charged to over-voltage.

 

[JoeHam]

This should help you with the MPPT settings:

Then double check ALL your wiring connections and report back.

 

[UNL1988]

Is your BMS open. blown. disconnected.? LiFePo should not be charged with the same settings as LA. I don't know how to reset your BMS, but that could be the problem if charged to over-voltage.

I do not have a BMS, is that a requirement for LiFePo? The battery as listed on Amazon has an internal one.

 

[UNL1988]

This should help you with the MPPT settings:

Then double check ALL your wiring connections and report back.

thanks, I was able to change the temperature compensation coefficient, but could not change anything after that. I was holding down on OK and the cursor would not highlight. It is not a battle born battery, but an expert power.

 

[JoeHam]

thanks, I was able to change the temperature compensation coefficient, but could not change anything after that. I was holding down on OK and the cursor would not highlight. It is not a battle born battery, but an expert power.

The battery manufacturer is not important. These settings will work with all LiFePO4 batteries.

Follow the video again and if it doesn’t work I would suspect a problem with your MT50/Epever combo.

 

[UNL1988]

tried it a few times, no joy. Is there a way to reset the MT50 and charger controller?

 

[svetz]

What's the voltage on the battery after turning the inverter on?

...No blown fuses...

I'd double check the fuses... possibly the in rush current from "turning the inverter on" blew the fuse?

If the battery voltage is zero, possibly a fuse/wire inside the battery?

 

[UNL1988]

The fuses are all good.

When I took the battery off the system and checked it again, it was at 4.1V? which was a surprise.

It may have been a battery voltage problem all along. I did not check it before I put it on the system.

I put the two SLA batteries back on and everything is working just fine.

I am going to take the battery back home and put it on a regular AC charger and see if it goes back up.

 

[snoobler]

When you connected the battery to the inverter, if you didn't pre-charge the capacitors with a resistor, you could have popped the BMS due to the inrush current, but I would expect to see 0 volts.

 

[UNL1988]

The capacitors in the battery? I have never done that before. The inverter was one that was recently connected and turned off, so would the capacitors in the inverter already be charged?

 

[snoobler]

Capacitors in the inverter. If empty, they get charged when you connect the battery even when off. This surge of current may pop the built-in battery BMS. Given your description, I wouldn't expect that to be an issue.

 

[GXMnow]

Did it ever make a spark while connecting the inverter? If it did, it may have damaged the BMS, but if you never even noticed a spark, I doubt it would have popped anything. The ad for the battery even lists short circuit protection, so even a capacitor charge spike should not have done permanent damage. once the load is disconnected, it should turn back on.

If you are very lucky... The lead acid settings in the solar charge controller may have just brought the battery voltage up to the point where the internal BMS has shut off to protect the batteries from overcharge. I would try leaving a small 12 volt light bulb connected for a while and see if it come on after the cell voltages can come down a bit. If it is in a protect mode with no load on the cells, it could take quite a while to bleed off enough charge to turn back on. It may take days.

 

[Zil]

Well then. i guess you do have a BMS if Amazon says you do.