Calculation of temperature compensation

[frankz66]

Hi everyone, I wanted to know if the temperature compensation calculation for the batteries is correct:

My battery manufacturer provides me with a compensation figure at 20 degrees of 0.018 (total for six cells at 12 volts), so 0.003 per cell.

So to charge with epever my batteries at a maximum boost voltage of 14.55 in the parameter of the epever related to compensation ( I wanted to insert -2 then 0.002 mV ) I performed the following formula :

Boost : 14.57 volts so 0.002 * 6 cells = 0.012 mV * degrees that go above 20 ( in my case maximum degrees 28 ) 0.012 * 8 = 0.096 mV . Having acquired this value, I calculated that if the batteries reach 28 degrees, I subtract the boost value that is 14.57 - 0.096 mV = 14.474 Vols at 28 degrees maximum.

So I ask if the formula is correct or is my calculation wrong?

 

[12VoltInstalls]

So I ask if the formula is correct or is my calculation wrong?

I live in Vermont. Super cold sometimes.
I don’t think I ever adjusted anything for temp comp, and my battery bank was outside. It got down to -38*F once and was fine.
Doesn’t Epever have a default in there?

I don’t think lead acid batteries really care.

The only thing that ever harmed mine (before I went LiFePo) to my notice was when they never got even close to fully charged for like five weeks when I had covid and that killed like 50% of my capacity.

 

[frankz66]

I live in Vermont. Super cold sometimes.
I don’t think I ever adjusted anything for temp comp, and my battery bank was outside. It got down to -38*F once and was fine.
Doesn’t Epever have a default in there?

I don’t think lead acid batteries really care.

The only thing that ever harmed mine (before I went LiFePo) to my notice was when they never got even close to fully charged for like five weeks when I had covid and that killed like 50% of my capacity.

Ok thanks for answering, but I wanted to know if the formula was correct.

However, I have the opposite problem to yours ..... even 45 C in summer ...

 

[Hedges]

It got down to -38*F once and was fine.

I don’t think lead acid batteries really care.

Lead acid cares about voltage vs. temperature, needs higher voltage to fully charge in cold, lower to not overcharge in hot. Some SCC have temperature sensor and can be programmed with V/degree (required parameter varies, should be given in battery manual.)

Cold can freeze lead-acid batteries, especially at low SoC. Apparently AGM has higher acid concentration, tolerates colder temperature for a given SoC.

Lithium, all I've seen (beside degradation hot) is reduced max charge current as it approaches freezing. But I haven't seen anything about SCC or inverter/chargers adjusting for that. Likely EV do.

 

[frankz66]

Lead acid cares about voltage vs. temperature, needs higher voltage to fully charge in cold, lower to not overcharge in hot. Some SCC have temperature sensor and can be programmed with V/degree (required parameter varies, should be given in battery manual.)

Cold can freeze lead-acid batteries, especially at low SoC. Apparently AGM has higher acid concentration, tolerates colder temperature for a given SoC.

Lithium, all I've seen (beside degradation hot) is reduced max charge current as it approaches freezing. But I haven't seen anything about SCC or inverter/chargers adjusting for that. Likely EV do.

Thank you for your opinion .

 

[12VoltInstalls]

Lead acid cares about voltage vs. temperature, needs higher voltage to fully charge in cold, lower to not overcharge in hot

Yes, I was being a bit sarcastically practical, but perhaps myopic. The higher temp aspect isn’t really an issue in my locale, and 13.8 charging is usually innocuous