Battery SOC minimum %

Enzo Matrix said:
Any facts to back this up?

You are saying a battery that depletes to 0% vs one that depletes to 80% will last just as long and it will make fokkal difference.

Sure buddy
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People who try and keep their lipo,life batteries full to increase their life do far more damage than they think they do.
If you want to decrease degradation keep them between 30 and 80% for the majority of the time.
 
B-1 said:
People who try and keep their lipo,life batteries full to increase their life do far more damage than they think they do.
If you want to decrease degradation keep them between 30 and 80% for the majority of the time.
Click to expand...
Its very high and very low voltage that causes it. It is 100% charged between 55.2V - 58.4V. As you can see there is no reason to go higher than 55.2V. On the low side, the spec sheet says not to go below 2V per cell (32V), which is also impossible with inverter cut-off, so 2.5V (40V) is conservative cutoff.
 
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B-1 said:
People who try and keep their lipo,life batteries full to increase their life do far more damage than they think they do.
If you want to decrease degradation keep them between 30 and 80% for the majority of the time.
Click to expand...
If you want it to last 80 years yes.
 
B-1 said:
People who try and keep their lipo,life batteries full to increase their life do far more damage than they think they do.
If you want to decrease degradation keep them between 30 and 80% for the majority of the time.
Click to expand...
This is more for NMC chem than LFP by the way. LFP needs cell balancing at the top of the voltage curve (once a week, I would just do it daily), just dont need crazy high voltages to get 99% SOC.
 
wingnut771 said:
Its very high and very low voltage that causes it. It is 100% charged between 55-2V - 58.4V. As you can see there is no reason to go higher than 55.2V. On the low side, the spec sheet says not to go below 2V per cell (32V), which is also impossible with inverter cut-off, so 2.5V (40V) is conservative cutoff.
Click to expand...
You want to avoid high C rates in the lower part of the lower knee.

In the upper knee you want to avoid both high C rates and high cell tempretures (or both at the same time).

And then calender aging, which cannot be mitigated.

I agree, just use 100% of capacity and set up the system to limit the C rates in the knees and in high temperatures.

I charge to 55.2v in summer and have set up the BMS to read this as the 100% SOC trigger. Lower end cut off voltage is 47v. BMS reports zero SOC at 49.5V.

So technically is discharge to negative a few % SOC.
 
Koosvanwyk said:
You want to avoid high C rates in the lower part of the lower knee.

In the upper knee you want to avoid both high C rates and high cell tempretures (or both at the same time).

And then calender aging, which cannot be mitigated.

I agree, just use 100% of capacity and set up the system to limit the C rates in the knees and in high temperatures.

I charge to 55.2v in summer and have set up the BMS to read this as the 100% SOC trigger. Lower end cut off voltage is 47v. BMS reports zero SOC at 49.5V.

So technically is discharge to negative a few % SOC.
Click to expand...
The lab tests are done at CC 0.5C or 1C between 2.5V and 3.65V at 25c though.
 
wingnut771 said:
This is more for NMC chem than LFP by the way. LFP needs cell balancing at the top of the voltage curve (once a week, I would just do it daily), just dont need crazy high voltages to get 99% SOC.
Click to expand...
It’s for Lithium Ion battery family. NMC and LiPO fall in that.
 
Koosvanwyk said:
You want to avoid high C rates in the lower part of the lower knee.

In the upper knee you want to avoid both high C rates and high cell tempretures (or both at the same time).

And then calender aging, which cannot be mitigated.

I agree, just use 100% of capacity and set up the system to limit the C rates in the knees and in high temperatures.

I charge to 55.2v in summer and have set up the BMS to read this as the 100% SOC trigger. Lower end cut off voltage is 47v. BMS reports zero SOC at 49.5V.

So technically is discharge to negative a few % SOC.
Click to expand...
Yeah there is a guy I was watching the other day with 15 year old Lipo batteries.

But he had a shed full of destroyed Lipos because of over charging and discharging and he mentioned something like what you are saying also if I’m not mistaken.
 
denmendez65 said:
Yeah there is a guy I was watching the other day with 15 year old Lipo batteries.

But he had a shed full of destroyed Lipos because of over charging and discharging and he mentioned something like what you are saying also if I’m not mistaken.
Click to expand...
Lipo, not LFP.
 
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