Re: [pvusers] battery size and charge

[cor_van_de_water@dolfijn.nl (Cor van de Water)]

Bill,

Each string will need the charge of one battery as the current
does not change, just the voltage of the series connection.
So, you have three strings of 220 Ah at a total of 660 Ah.

I guess you have 75Watt panels that can be connected to a
12V charge controller directly (via circuit breaker)
with 5 panels parallel you get 22A at full sun and your
estimate of 3 full sunhours per day may be correct, depending
on your location and the time of year - make sure that the 
worst case still delivers you enough current!
If you do not know the amount of sunhours you get, then
look it up at (for example) NREL.

22A x 3 hours are 66 Ah or 10% of your battery during a day.
Adding 10 more panels in parallel gives you 66A in full sun
and 198 Ah per day or 30% of battery so it may take 2 or 3 days
to fully recharge a battery when you still use a little energy
yourself (remember - a battery should not be discharged further
than approx 40% charge left).

If your charge controller can handle 66+ Amps (in case the full
sun appears from behind a cloud and you have full sun +
reflection from the cloud, the output can be approx 120% so
when a peak of 80 A can be handled, then you are fine.

Hope this helps,
Cor van de Water
the Netherlands
http://www.cvandewater.com

> I have a battery pack made of three strings (1, 2, 3) of two (A,B) 6
> Volt TROJAN T105 220 Ahr, cost $60 each battery.
>  
> LOOKS SOMETHING LIKE THIS:
>  
> B-1A     B-2A     B-3A
> B-1B     B-2B     B-3B
>  
> What is the total Ahr of this pack?
>  
> What should be the typical charge current for a total charge in one
> bell curve (sun day)? I estimate it at 20 Amps x 3 = 60 Amps.
>  
> If your answers are as I expect, then since the 5 pvs are at 22 Amps in
> the single charge panel I now use, how do I add 5 or 10 more pvs so as
> to get to the 60 Amps in one sun day?
>  
> Must I split the pack?
>  
> Bill Neill.
>  
> __________________________________________________
> Do you Yahoo!?
> Yahoo! Mail Plus – Powerful. Affordable. Sign up now.
> http://mailplus.yahoo.com
>  
> --*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*
>   List sponsored by CREST/REPP
>  http://solstice.crest.org/   http://www.repp.org/
>  
> 


 ______________________________________________________________
 Gratis e-mail en meer: http://www.dolfijn.nl/

--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*--*
  List sponsored by CREST/REPP  
	http://solstice.crest.org/   http://www.repp.org/