Lithium Ion Battery Parameters

It is not possible to fill in the second table without contacting the manufacturer(s) of the batteries directly. It might take several calls and do let the forum know the outcome, for it might prove useful to others.

Battery charger....

Just make it bigger, add cooling...

That is a nice charger.. i like the independent info for each cell.

do you have any experience with this model?

tia

No I have a different one, older more expensive, but similar...

Your numbers appear a little confused.

8 cells in parallel at 3.3Ah each equates to a total available Ah rating of 26.4Ah.

If you then apply a maximum DOD of 80% you have a tad over 21Ah available for use, not the 33.67Ah that you suggest.

I'm confused by the correlation between your discharge current and expected run times namely 1.32 amps (a really small RV) and 2.5 hrs. 21Ah capacity at 1.32 amp draw should provide around 16 hours runtime.

Another anomaly is that charge current of 1.32 amps. Based on your figures of 33.67 Ah capacity, your C rate of 0.4 suggests a charge current of around 13.2 amps, perhaps your have misplaced the decimal point, in which case your runtime would be closer to 1.6hrs to 80% DOD, not the 2.5hrs claimed. I would see the charge current at 0.4C to be closer to 10.5 amps. I would point out that most Li chemistries can accommodate charge rates of up to and sometimes beyond 0.8C with no ill effects

You also fail to mention whether the ambient temperature is in °C or °F which will significantly affect performance particularly when charging.

You also need to consider the actual chemistry of the cells as different charge parameters exist for various types, as do the relative energy densities, charge times, run times etc. For example typical charge parameters for LCO and LMO would be 4.2V 0.7 - 0.9C, for LFP would be 3.65V up to 1C, Getting these wrong can be quite expensive.

"If you then apply a maximum DOD of 80% you have a tad over 21Ah available for use, not the 33.67Ah that you suggest"

Okay - Formula Updated

"I'm confused by the correlation between your discharge current and expected run times namely 1.32 amps (a really small RV) and 2.5 hrs. 21Ah capacity at 1.32 amp draw should provide around 16 hours runtime."

21AH Capacity is of the whole Pack with 8 Series Pack cells in Parallel. SO the Run time is correct i feel

"Another anomaly is that charge current of 1.32 amps. Based on your figures of 33.67 Ah capacity, your C rate of 0.4 suggests a charge current of around 13.2 amps, perhaps your have misplaced the decimal point, in which case your runtime would be closer to 1.6hrs to 80% DOD, not the 2.5hrs claimed. I would see the charge current at 0.4C to be closer to 10.5 amps. I would point out that most Li chemistries can accommodate charge rates of up to and sometimes beyond 0.8C with no ill effects"

1.32A is the single cell current and not of the Pack

Also do we have any temperature Factor to be added when calculating. I couldn't get much info and hence with whatever info i got, i have added a factor. please let me know some of the parameters that still needs to be considered here

Please see a updated table below

Updated Table