[RE-wrenches] How many Ahs?

[Mark Frye]

> Suppose I have a battery bank made up of 4 - 12V Enersys HUP flooded lead
> acid batteries. The batteries are wired in series for a nominal 48VDC
> system.
> 
> The side of the battery, which is actually a forklift battery, is marked
> as 1320 Ah @ C/6. The vendor also rates the battery as 1690 Ah @ C/20.
> 
> So, for the purpose of evaluating the battery back relative to the
> charging system settings, what size is the battery bank?
> 
> It is interesting to think that at a normal discharge rate of C/20 I can
> get 128% more energy out of the bank (1690 Ah) than I can put back in at a
> C/6 charging rate (1320 Ah)?
> 
> Is it fair to say the following: For rapid bulk charging to bring the
> voltage up from some discharged voltage of say 48VDC to a bulk charged
> voltage of say 60VDC, I want a charger that can provided a constant
> current of C/10 or 1320/10 = 132 A across that voltage range. And at the
> time that I complete this bulk charge, the battery bank will be restored
> to 1320/1690 = 78% of its starting capacity. 
>  
> Mark Frye
> Berkeley Solar Electric Systems
> 303 Redbud Way
> Nevada City,  CA 95959
> (530) 401-8024
> www.berkeleysolar.com 
> 
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