Battery Draw Bogus Math? Peukert UPDATE 2
Update- 11 Oct 20, Update 2- 12 Oct 20 Thinking one 100AH battery that can be drawn down to very low SOC gives you nearly the same "usable AH" as two regular AGM or Wet batts, as seen advertized, ...
Forum Discussion
Using the numbers from your spec chart
Peukert increase effect is a only a few percent going from from 5 amps load to 1 or 2 amps
Big decrease effect going up to heavier loads
Double the batteries and double the load
Is exactly the same as single battery and 5 amp load,
Even a single battery with a 10 amp load
Is almost 1/2 time for the same SOC, not a big change in computed ampHrs or time
I know you thought that if you double the battery bank from 100ah to 200ah, with same load, it would give 3x use time to the same SOC,
Not so.. it is going to be only 2x or slightly over, when using small loads
Now if your load was 40 amps, twice the batteries would make a more significant difference, as 40 amps continuous is a big strain for one battery,
Which Is why i have 400 ampHrs of Deka AGM,
I can have fans powered by the inverter all night, and still have 70% battery capacity and heat up a cup of coffee in the morning
Peukert increase effect is a only a few percent going from from 5 amps load to 1 or 2 amps
Big decrease effect going up to heavier loads
Double the batteries and double the load
Is exactly the same as single battery and 5 amp load,
Even a single battery with a 10 amp load
Is almost 1/2 time for the same SOC, not a big change in computed ampHrs or time
I know you thought that if you double the battery bank from 100ah to 200ah, with same load, it would give 3x use time to the same SOC,
Not so.. it is going to be only 2x or slightly over, when using small loads
Now if your load was 40 amps, twice the batteries would make a more significant difference, as 40 amps continuous is a big strain for one battery,
Which Is why i have 400 ampHrs of Deka AGM,
I can have fans powered by the inverter all night, and still have 70% battery capacity and heat up a cup of coffee in the morning
