What Voltage should be for EG4 all-weather battery when 100% charge?

[JoeX]

I spent some time to get my system running, see my other post: https://diysolarforum.com/threads/e...rge-and-solar-only-charge-the-battery.109398/



Now, the system is running normal.

Battery’s both BMS and firmware are up to date.

It seems my both battery stop charge at 99% and the voltage are around 53.54V and 53.55V. See picture in next post.

I believe I did not see it every reach 100% after the firmware updated.


I did set "Use SOC%", and the "stop AC charge SOC% =100%".

Battery communication protocol was set to:” CAN, P07-LUX”.



I was told before the 53.x V might not be the real 100% charge due to the firmware not up to date.

But now, my firmware is up to date, the Voltage seems does not change to much, plus it does not reach to 100%.



Is anything wrong of my setting?

 

[JoeX]

This is the main Battery.




This is the second battery:

 

[Zapper77]

I spent some time to get my system running, see my other post: https://diysolarforum.com/threads/e...rge-and-solar-only-charge-the-battery.109398/



Now, the system is running normal.

Battery’s both BMS and firmware are up to date.

It seems my both battery stop charge at 99% and the voltage are around 53.54V and 53.55V. See picture in next post.

I believe I did not see it every reach 100% after the firmware updated.


I did set "Use SOC%", and the "stop AC charge SOC% =100%".

Battery communication protocol was set to:” CAN, P07-LUX”.



I was told before the 53.x V might not be the real 100% charge due to the firmware not up to date.

But now, my firmware is up to date, the Voltage seems does not change to much, plus it does not reach to 100%.



Is anything wrong of my setting?

Which inverter?

 

[JoeX]

Which inverter?

EG4-18kpv

 

[fnnwizard]

I spent some time to get my system running, see my other post: https://diysolarforum.com/threads/e...rge-and-solar-only-charge-the-battery.109398/



Now, the system is running normal.

Battery’s both BMS and firmware are up to date.

It seems my both battery stop charge at 99% and the voltage are around 53.54V and 53.55V. See picture in next post.

I believe I did not see it every reach 100% after the firmware updated.


I did set "Use SOC%", and the "stop AC charge SOC% =100%".

Battery communication protocol was set to:” CAN, P07-LUX”.



I was told before the 53.x V might not be the real 100% charge due to the firmware not up to date.

But now, my firmware is up to date, the Voltage seems does not change to much, plus it does not reach to 100%.



Is anything wrong of my setting?

The correct answer is that the min V cell needs to be > 3.45V at current taper of ~4A charge current to truely have pack be @ 100%. That would be 55.2V IF your cells are perfectly balanced ( they're not).. so it's likely to be closer to 57V if reasonably balance.. tbd.

And worst, >58V if typicallly out of balanced EG4 wall mounts.

In SOC mode, the current tapers way too fast for any reasonable bulk/absorb phase so they suggest going way too high in V to be able to keep cells in reasonable balance.

Anyway, go to history data and post what the min and max cell V's are at this ficticious 100% soc level. Sounds like a cell or more is below 3.45 to get the 53.xx V.

Staying in coms mode (close loop), switch to V base and charge to a level when a single cell hits 3.55V and see what pack level is and rest of cells' V are.

Report back so we have data to go by.

 

[Zapper77]

EG4-18kpv

Did you change the max system voltage?

 

[JoeX]

Did you change the max system voltage?

Not really.
What's Max voltage should I change? And where should I change it?

 

[Zapper77]

57 max system voltage and 101% for SOC

 

[JoeX]

57 max system voltage and 101% for SOC

I remember, when I set up this system at the first time, I did see the invertor's default setting is 105% SOC. I didn't understand at that time and set back to 100% SOC.
Now I understand that why the default is 105% SOC.............

 

[JoeX]

The correct answer is that the min V cell needs to be > 3.45V at current taper of ~4A charge current to truely have pack be @ 100%. That would be 55.2V IF your cells are perfectly balanced ( they're not).. so it's likely to be closer to 57V if reasonably balance.. tbd.

And worst, >58V if typicallly out of balanced EG4 wall mounts.

In SOC mode, the current tapers way too fast for any reasonable bulk/absorb phase so they suggest going way too high in V to be able to keep cells in reasonable balance.

Anyway, go to history data and post what the min and max cell V's are at this ficticious 100% soc level. Sounds like a cell or more is below 3.45 to get the 53.xx V.

Staying in coms mode (close loop), switch to V base and charge to a level when a single cell hits 3.55V and see what pack level is and rest of cells' V are.

Report back so we have data to go by.

I set the Max V to 57V max system voltage and 101% for SOC as per @Zapper77 suggested.
And I get the first 100% charge, last for around 2 hours.
See battery date below.
The 100% charge voltage is around 55.6V Max. After it reach to 100%, it start to drop to 55.1V by some reason. The current at that time is around 1A to keep the battery V.

The Max Cell Voltage is 3.618V and at the same time, the Min Cell Voltage is 3.42V.

Dose everything looks normal?

 

[fnnwizard]

I set the Max V to 57V max system voltage and 101% for SOC as per @Zapper77 suggested.
And I get the first 100% charge, last for around 2 hours.
See battery date below.
The 100% charge voltage is around 55.6V Max. After it reach to 100%, it start to drop to 55.1V by some reason. The current at that time is around 1A to keep the battery V.

The Max Cell Voltage is 3.618V and at the same time, the Min Cell Voltage is 3.42V.

Dose everything looks normal?

Not normal.
But can't tell if it is purely from cell imbalance or an actual bad cell. Need to dig deeper = individual cell V from the BMS display with steady loads/charge currents.
At >55V you have cell(s) going too high to be in safe low current balance modes.

If you want to try and fix this, and be able to use the pack daily, stay in closed loop, but run under V.

Set System to 55V for now, bulk charge to 54.8 and float at 54.6. You won't get 100% capacity of course, which you are not getting that now.
But these settings will allow a much less stressfull balancing activity. Only as the cells become balanced, I would increase bulk and float by something like .2V at a time up until all cells are close to 3.55V.

I'd go even further by lowering balancing thresholds to start at 3.40V/cell and 15mV. At default, the window is smaller for baancing totake place = it'll take 3-4 times longer to balance... and, the best you will get to is to within 40mV so something like max - min of 3.570V - 3.530V

The standard replies from eg4 on setting any V >57V and even trying to drive a cell > 3.7 is a complete misunderstanding of how these (typical bms and lfp) operate without knowing individual cell's V status.

 

[JoeX]

Not normal.
But can't tell if it is purely from cell imbalance or an actual bad cell. Need to dig deeper = individual cell V from the BMS display with steady loads/charge currents.
At >55V you have cell(s) going too high to be in safe low current balance modes.

If you want to try and fix this, and be able to use the pack daily, stay in closed loop, but run under V.

Set System to 55V for now, bulk charge to 54.8 and float at 54.6. You won't get 100% capacity of course, which you are not getting that now.
But these settings will allow a much less stressfull balancing activity. Only as the cells become balanced, I would increase bulk and float by something like .2V at a time up until all cells are close to 3.55V.

I'd go even further by lowering balancing thresholds to start at 3.40V/cell and 15mV. At default, the window is smaller for baancing totake place = it'll take 3-4 times longer to balance... and, the best you will get to is to within 40mV so something like max - min of 3.570V - 3.530V

The standard replies from eg4 on setting any V >57V and even trying to drive a cell > 3.7 is a complete misunderstanding of how these (typical bms and lfp) operate without knowing individual cell's V status.

From my understanding, the system is closed loop.
Do you mean I should set the system as 55V max system voltage and 101% for SOC? right? (or 100% SOC?)

 

[fnnwizard]

From my understanding, the system is closed loop.
Do you mean I should set the system as 55V max system voltage and 101% for SOC? right? (or 100% SOC?)

Closed loop, coms, lithium mode... all the same.

Under this config you can run in either soc or Voltage based. Keep the SOC at 101%, enable Voltage mode ( SOC is then greyed out).

I stopped running in closed loop a few months ago so going off memory.
If you can post your settings page i can better assist.

 

[JoeX]

Not normal.
But can't tell if it is purely from cell imbalance or an actual bad cell. Need to dig deeper = individual cell V from the BMS display with steady loads/charge currents.
At >55V you have cell(s) going too high to be in safe low current balance modes.

If you want to try and fix this, and be able to use the pack daily, stay in closed loop, but run under V.

Set System to 55V for now, bulk charge to 54.8 and float at 54.6. You won't get 100% capacity of course, which you are not getting that now.
But these settings will allow a much less stressfull balancing activity. Only as the cells become balanced, I would increase bulk and float by something like .2V at a time up until all cells are close to 3.55V.

I'd go even further by lowering balancing thresholds to start at 3.40V/cell and 15mV. At default, the window is smaller for baancing totake place = it'll take 3-4 times longer to balance... and, the best you will get to is to within 40mV so something like max - min of 3.570V - 3.530V

The standard replies from eg4 on setting any V >57V and even trying to drive a cell > 3.7 is a complete misunderstanding of how these (typical bms and lfp) operate without knowing individual cell's V status.

This is today's voltage, for each cell's voltage from the battery screen. Setting is still the Max V to 57V max system voltage and 101% for SOC.
Battery voltage are 55.41v and 55.55v for each battery.

Battery Cell voltage Max is 3.54, Min. is 3.44

Battery Cell voltage Max is 3.55, Min. is 3.42
Is that balance enough?

What do you think?

 

[fnnwizard]

This is today's voltage, for each cell's voltage from the battery screen. Setting is still the Max V to 57V max system voltage and 101% for SOC.
Battery voltage are 55.41v and 55.55v for each battery.

Battery Cell voltage Max is 3.54, Min. is 3.44

Battery Cell voltage Max is 3.55, Min. is 3.42
Is that balance enough?

What do you think?

You scrolled through all 16 cells and these are the min and max out of all 16?

If so, pack 2 is not too bad. Pack 1 could use a few hours of balancing. But it's less than 3% imbalanced.

What you also want to do is check all 16 cell V per pack when you have a steady charge current through them ( the higher the current the better) for at least 5 minutes , and then again when you have a steady load current ( again higher = better for 5 minutes) through them.

This procedure will help identify suspect connections and cell quality.

 

[kampto]

My single Wallmount with 6000XP in SOC mode to 100% gets to 54V in bulk then slowly drops to 53.3v to float rest of day. I've run it in lead acid mode for a week at 57.4v bulk and 54.6v float. When I go back to SOC mode nothing changes, still 54v and 53.3v. Is SOC broken? Max/Min cells from monitor site are only .003v apart. Off grid.

 

[fnnwizard]

Here's a typical solar charging profile for when we have plenty of sun while on a mini trip.

Charge V set to 56.4V at inverter resulting in 56.32V at Batt terminals. Cells diff <20mV.

See how long it takes for the pack V to settle just above 54V =3.750V/cell. thats the full charged open circuit V. Also see how long it can just sit there with just bms idle current. It takes a load to drive the V lower.

This can be used for a good reference.
Data taken directly off BMS @ 2-3 second intervals.