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EG4 battery SOC question

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shaggy745

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Nov 5, 2022
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Hello,

I'm running and eg4 6500ex and 2 Lifepower4 batteries. Last night I shifted my house back to grid power before going to sleep,.leaving the batteries at 20% and the inverter on standby mode. The pv array was left connected. My thought was that when the sun came up thos morning, the pv input would wake up the inverter and it would begin charging the batteries.

You can see in the attached SO SOC graph that the battery held at 20 % through the night. Just before 8 it dropped, then back up to 20 briefly, then bottomed out.

I guess I have three questions. 1) did the batteries bottom out because the pv input early in the morning wasn't sufficient to cover the overhead on the inverter? 2) why did the inverter not shut down when the batteries reached 5% as programmed? 3) have I damaged my batteries by running them to zero? ?

Thanks.
 

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Last edited:
Also should mention that the inverter was throwing up fault 71 when I got up...
 
Anyone have guidance on this, and on if there is any concern I should have around having damaged my batteries? Thanks.
 
Just a shot in the dark since you haven't had any other replies, I have no experience with your hardware.
But I would suspect that your inverters turned back on when they first saw current from the panels, but the charge current wasn't enough to support the inverter loads so it pulled from the batteries.

If you recharged the batteries after the were below the cut off voltage, you should be fine. You don't want to leave them for days at 0 but a few hours isn't going to hurt as long as the BMS LBCO kicked in.

You can't always trust the inverter's voltage readings, it's thrown off by the heat of the inverter. A separate shunt and meter will let you track the voltage levels without interference from the inverter. On my magnums I use a separate shunt and it's readings are always closer to actual pack values than the inverter readings.

Even then I use a 10 minute delay on LBCO because in the bottom 25% of the pack range, the voltage will fluctuate due to load, and it can look "empty" when it's just low and the load is high. (Think running the microwave for 10 minutes when the pack is at 20%) I don't want to just cut off the first time the voltage looks low, I want it to be low for at least 10 sustained minutes before it cranks the generator, sheds a load, turns off, etc.

Maybe that helps OR contains enough bad info for someone to jump in an post. ;)
 
I have 3x of the same batteries, with a 4th pack of signature solar 24v packs w/ Killer BMS(same ones in the eg4 lifepower 48v). Now the 18 month old built pack is 100%SOH no swelling, no goofiness, the eg4 units are all 11 months old are all in the 90% SOH range 92.3 to 94.8, all 3 will charge to 100 ah, and show a 100+%, have had them also show the exact same voltage per cell and sth SOC be off by 20%( 1 @98% soc, 1 @95% soc, and the last one at 78% soc. Had to drain them all down below 20%, and charge ti get them with in 5% soc with cell showing same volts.I just have come to realize, that you do indeed get what you pay for, spend a little more or and go with a good company with better products.
 
Shiv3 said:
I have 3x of the same batteries, with a 4th pack of signature solar 24v packs w/ Killer BMS(same ones in the eg4 lifepower 48v). Now the 18 month old built pack is 100%SOH no swelling, no goofiness, the eg4 units are all 11 months old are all in the 90% SOH range 92.3 to 94.8, all 3 will charge to 100 ah, and show a 100+%, have had them also show the exact same voltage per cell and sth SOC be off by 20%( 1 @98% soc, 1 @95% soc, and the last one at 78% soc. Had to drain them all down below 20%, and charge ti get them with in 5% soc with cell showing same volts.I just have come to realize, that you do indeed get what you pay for, spend a little more or and go with a good company with better products.
Click to expand...
SOH% lowers on any battery for any chemistry as the cells are cycled and they begin to degrade. Just so you know it's not accurate to base voltage on SOC% with lifepo4, so saying they are at the same voltage and expecting the same SOC% can be misrepresented unless the batteries are nearly fully charged or fully dead. Then at the fully charged State the passive balancing circuit will bleed voltage into the precharge resistor to balance the cells. State of charge is based on coloumb counting which is tracking amperage while charging/discharging. Batteries in parallel have a tendency to not have equalized loads between them that can lead to a SOC% imbalance that you have experienced.
I have 310 cycles on one of my 51.2V lifepower4 batteries and have never had any issues and it still has 97% SOH. So to say these aren't from a "good company" and to refer to them as a lesser quality battery is an opinion based on your lack of experience because I've built A LOT of server racks with EG4 batteries and maintained them overtime and have had very minimal issues because I did my research. Not to mention I have opened many server racks batteries from multiple companies and EG4 batteries build quality is higher quality compared to others I have seen. Now I understand this is not everybody's experience here but to jump to the conclusion that these are not good products because your not understanding your battery bank correctly is a bad assumption.
 
LithiumCowboy said:
SOH% lowers on any battery for any chemistry as the cells are cycled and they begin to degrade. Just so you know it's not accurate to base voltage on SOC% with lifepo4, so saying they are at the same voltage and expecting the same SOC% can be misrepresented unless the batteries are nearly fully charged or fully dead. Then at the fully charged State the passive balancing circuit will bleed voltage into the precharge resistor to balance the cells. State of charge is based on coloumb counting which is tracking amperage while charging/discharging. Batteries in parallel have a tendency to not have equalized loads between them that can lead to a SOC% imbalance that you have experienced.
I have 310 cycles on one of my 51.2V lifepower4 batteries and have never had any issues and it still has 97% SOH. So to say these aren't from a "good company" and to refer to them as a lesser quality battery is an opinion based on your lack of experience because I've built A LOT of server racks with EG4 batteries and maintained them overtime and have had very minimal issues because I did my research. Not to mention I have opened many server racks batteries from multiple companies and EG4 batteries build quality is higher quality compared to others I have seen. Now I understand this is not everybody's experience here but to jump to the conclusion that these are not good products because your not understanding your battery bank correctly is a bad assumption.
Click to expand...
Thank you for the input, I was basing my experience on 3x eg4 vs 2 trophy and 2x jackiper and 1 killer solar with eg4 cells, I was not trying to rag on the build quality so much as what I perceive as bad/low quality BMS in the base battery. My trophy and jackiper both have 2x the cycles that my eg4s have, and my killer solar bms on the eg4packs has 3x the cycles. So????
 
Shiv3 said:
Thank you for the input, I was basing my experience on 3x eg4 vs 2 trophy and 2x jackiper and 1 killer solar with eg4 cells, I was not trying to rag on the build quality so much as what I perceive as bad/low quality BMS in the base battery. My trophy and jackiper both have 2x the cycles that my eg4s have, and my killer solar bms on the eg4packs has 3x the cycles. So???
Click to expand...
The Lifepower4 BMS is made by Pace which is the same BMS company that is in Jakiper and SOK server racks, all these bms pcb's are just custom made for each company. It's a smaller world then you think.

Did not mean to come off so blunt but I just try to get straight to the point to help out everybody on this forum regarding batteries since I've had a great opportunity to work with a private company installing and testing out multiple lifepo4 batteries from different manufactures.
 
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