LiFePower4 Battery State of Health degradation...

[JLBinTN]

lost another 0.1 % less then 3 weeks between drop

View attachment 131001

I lost another 0.1% since starting this thread! (4 cycles)

 

[sunshine_eggo]

2nd reference

 

[shopman]

lost another 0.1 % less then 3 weeks between drop

View attachment 131001

When did you purchase the affected battery? I'm wondering if there may have been a bad lot and it's just starting to show.

 

[brucenolan]

When did you purchase the affected battery? I'm wondering if there may have been a bad lot and it's just starting to show.

That is a great question, I have purchased 14 of the Lifepower batteries. installed at 3 different locations. I will have to research that aspect to see what went where. I will follow up with that next time I visit the remote locations, 6 batteries are located at my house others are at two locations 4 and 4

bruce

 

[JLBinTN]

Down another 0.1% to 99.5% SOH! This trend is beginning to disturb me. The battery is being used within the specifications provided by Signature Solar. To the best of my knowledge, the battery temp has never dropped below 40 degrees, so charging below 32 degrees can't be a contributor to the issue. It has been discharged to 0% a couple of times and charged to 100% a couple of times due to Growatt software glitches, but as stated earlier, has almost always been operated between a 20% and 91% state-of-charge level. Battery was purchased 3/1/2022, so it has been in use for less than 11 months. I guess I better get that warranty information registered.

 

[Jack Rabbit Off Grid]

I have 6 Lifepower4 packs that are just over a year old now. After reading this I checked mine.

Battery 1 is closest to the inverter. I never flipped the negative buss bar. all 6 of my batteries show 100% SOH. If all 6 batteries don’t see an absorption cycle for a few weeks batteries 1 and 3 will lag behind On the SOC meters by one green dot.

Cycles
1.91
2.84
3.84
4.86
5.83
6.78

 

[sunshine_eggo]

Down another 0.1% to 99.5% SOH! This trend is beginning to disturb me. The battery is being used within the specifications provided by Signature Solar. To the best of my knowledge, the battery temp has never dropped below 40 degrees, so charging below 32 degrees can't be a contributor to the issue. It has been discharged to 0% a couple of times and charged to 100% a couple of times due to Growatt software glitches, but as stated earlier, has almost always been operated between a 20% and 91% state-of-charge level. Battery was purchased 3/1/2022, so it has been in use for less than 11 months. I guess I better get that warranty information registered.

Again, that number likely has no meaningful predictive value and is more likely a result of cell imbalance due to your habitual failure to regularly push all batteries to 100% SoC on a regular basis.

And:

2nd reference

 

[timselectric]

I can't believe that this is still going.

 

[JLBinTN]

Again, that number likely has no meaningful predictive value and is more likely a result of cell imbalance due to your habitual failure to regularly push all batteries to 100% SoC on a regular basis.

And:

As you may have surmised, I'm not particularly interested in your "likely" analysis. SOH is calculated in a specific way using a specific algorithm. If you have specific knowledge, please share. If not, then have a good day.

 

[timselectric]

Truthfully these BMS's can barely guess their SOC.
Guessing their SOH is just a gimmick feature.

 

[DougfromdaUP]

Truthfully these BMS's can barely guess their SOC.
Guessing their SOH is just a gimmick feature.

And when they do guess their SOC they get it wrong.

 

[Jack Rabbit Off Grid]

And when they do guess their SOC they get it wrong.

My 6 batteries guessed correct SOC today for the fist time in about 3 months. First day the Panels have seen a full day sun.

 

[Alkaline]

This is how SOH is calculated I think:

1) You set a WH or AH at the factory based on different states of charges
2) The BMS than compares what it was at time when it was new to what it is now
3) If it detects a difference then it deducts from the SOH
4) So in lamans terms, if you got 100AH new, but now you are only getting 95 AH then your SOH would be 95%

 

[sunshine_eggo]

As you may have surmised, I'm not particularly interested in your "likely" analysis. SOH is calculated in a specific way using a specific algorithm. If you have specific knowledge, please share. If not, then have a good day.

That has been well documented to be influenced HEAVILY by cell imbalance.

 

[Sparky7]

After roughly 350 charge-discharge cycles, my 5.12kw 48V LifePower4 battery's State of Health (SOH) dipped 0.3% to 99.7%. The Growatt SPF3000 All-in-one is set to cycle the battery between a 20% and 91% state of charge, but there have been one or two glitches where these parameters were exceeded. All that said, I'm wondering if a 0.3% decline in SOH over 350 cycles is reasonable, and what a chart of SOH vs Charge Cycles will look like over the estimated life of the battery (7000 cycles per the literature). Thoughts?

I just recently came across this chart. It may be helpful.

 

[JLBinTN]

I just recently came across this chart. It may be helpful.

Thanks. Do you know if this chart is for LiFePO4 batteries specifically?

 

[Johno1066]

Brucenolan, excuse my ignorance but how do you get that tabulated information on each battery giving you the SOH and cycle information.
I have 6 EG4 lifepower4 batteries and would have to isolate each to use the software to check each one on its own, I think.

 

[brucenolan]

Brucenolan, excuse my ignorance but how do you get that tabulated information on each battery giving you the SOH and cycle information.
I have 6 EG4 lifepower4 batteries and would have to isolate each to use the software to check each one on its own, I think.

Hi John, each battery has a unique address set via dip switch and are then daisy chain together with short cat5 cables. laptop running BMS test software is connected and reads all battery data, up to 16 batteries

 

[JLBinTN]

I have 6 Lifepower4 packs that are just over a year old now. After reading this I checked mine.

Battery 1 is closest to the inverter. I never flipped the negative buss bar. all 6 of my batteries show 100% SOH. If all 6 batteries don’t see an absorption cycle for a few weeks batteries 1 and 3 will lag behind On the SOC meters by one green dot.

Cycles
1.91
2.84
3.84
4.86
5.83
6.78

It is curious to me that each battery seems to cycle somewhat independently of the other five even though they're all connected in parallel.

 

[Jack Rabbit Off Grid]

Brucenolan, excuse my ignorance but how do you get that tabulated information on each battery giving you the SOH and cycle information.
I have 6 EG4 lifepower4 batteries and would have to isolate each to use the software to check each one on its own, I think.

I do not have the short cat5 cables connected. I just move the adapter going from my laptop from battery to battery and the screen on the laptop refresh’s each time with the new information.