amp hours

[globalworrying]

could somebody please clarify the difference in a twelve volt system
eight six volt L16's 370 ah at 20 hours    or
six two volt  at 1000 ah 20 hours
thank you for any comments.
rick

[globalworrying]

looking at an online calculator the 2 volt group is 1100 ah and
the eight 6 volts is 1480ah.
correct?

[DamonHD]

The available energy to do actual useful work is volts times amp-hours.

So "eight six volt L16's 370 ah" would be 4 sets of 12V 370ah, so 4 x 12 x 370 = 17760Wh or ~18kWh.

And "six two volt  at 1000 ah" would be 1 set of 12V 1000ah, so 12000Wh or 12kWh.

(Someone else check my arithmetic, I'm tired and old!)

The first lot has about 50% extra oomph.

Rgds

Damon

[globalworrying]

thank you

[kitestrings]

The math looks right to me.  I'll just add a couple of thoughts if they're not apparent.  When Damon says "sets", really what we are talking about are series strings.  If you put two batteries - of the same age, voltage and type - in series the voltage doubles, but you have the same number of AH as the nominal rating of each.  If you put them in parallel, the voltage stays the same but you get 2x the AH rating of the individual batteries.

There are some maintenance factors when you get too many parallel strings.  If the application is such that you need more power, increasing the voltage of your bank is probably a better choice in the long run.

Also, while the kWh units are correct, in reality you only want to be discharging the batteries to about 50% (or less) of their capacity, so the usable storage is about half that stated.

best, ~ks

[DamonHD]

Hey, good catch about the 50% DoD: sorry I missed that.  It is very important.

Rgds

Damon