Are my Lithiums failing?

[svcharisma]

Hi. I had a question about my LiFePO4s. I have 2x300ah 12v LiFePO4s from TimeUSB in parallel. 2x550w 48v panels. 150/60 Victron MPPT. All 12v system. Solar is pulling in an average of 4kwh per day.

So, the batteries are only about 3 months old. But I've noticed there is a pretty good drop in voltage once the panels stop producing power. I know there is usually a small drop but from the time the panels stop producing power to 3 hours later, voltage goes from 14.17v to 13.27v, and it sits at 13.27v for the rest of the night. I have a shunt on the neg terminal of the battery which all power flows out of and its averaging about 2.5amps. Everything is off at night except for an inverter to charge my phone.

I don't know much about batteries overall but is this normal for LiFePO4s?

 

[sunshine_eggo]

Normal. LFP is like lead acid in that it is typically charged to a higher voltage. Once the charge is removed, even with no loads, the voltage will drop.

LFP has near constant voltage discharge until Low SoC is reached.

Please include your MPPT config screen with the expert switch turned on.

If you have a smartshunt, please include the settings as well.

Inverters consume power simply by being on. It sounds like yours is using about 30W. You may want to consider a 12V to 5V USB converter for phone charging if you need no other AC power at night.

 

[svcharisma]

Normal. LFP is like lead acid in that it is typically charged to a higher voltage. Once the charge is removed, even with no loads, the voltage will drop.

LFP has near constant voltage discharge until Low SoC is reached.

Please include your MPPT config screen with the expert switch turned on.

If you have a smartshunt, please include the settings as well.

Inverters consume power simply by being on. It sounds like yours is using about 30W. You may want to consider a 12V to 5V USB converter for phone charging if you need no other AC power at night.

Thank you for advice on the usb charger. I'll have to order a couple. I just have a cheap shunt right now but have a SmartShunt coming in the next few days.

 

[sunshine_eggo]

Reduce absorption duration to 1 hour.

Note that if you don't have a separate temperature sensor, the low temp charging protection will disable charging all day if below 5°C at power on, AND it will NOT engage protection if it drops below freezing after restart.

It uses its internal sensor to take a snapshot at power-on. It then behaves that way for the entire day. Once in operation, the heat it generates influences the temperature reading.

A Smart Battery Sense or the temp sensor option for the smart shunt give it an accurate reading, and it will react in real time.

 

[svcharisma]

Reduce absorption duration to 1 hour.

Note that if you don't have a separate temperature sensor, the low temp charging protection will disable charging all day if below 5°C at power on, AND it will NOT engage protection if it drops below freezing after restart.

It uses its internal sensor to take a snapshot at power-on. It then behaves that way for the entire day. Once in operation, the heat it generates influences the temperature reading.

A Smart Battery Sense or the temp sensor option for the smart shunt give it an accurate reading, and it will react in real time.

I'll definitely keep that in mind and was planning on using the temp sensor from the Smart Shunt. Also, do all of these settings look good to you? Should I change anything else?

 

[sunshine_eggo]

Yes. I commented on the only setting of concern.

 

[svcharisma]

Yes. I commented on the only setting of concern.

Awesome! Thank you very much! I have a lot to learn with all the technicalities of batteries and such.