[RE-wrenches] offgrid system question

[R. Walters]

We had this same issue with a single string of Rolls Series 5000s at  
48 volt. A 3 Hp well pump would pull the voltage below 44 vdc and  
shut off the inverters anytime the system was less than fully charged.
We see this in Electric vehicles as well. No matter the battery, AH,  
state of charge, age, etc., if you pull enough amps out of it, its  
voltage will be pulled temporarily below operating voltage.
On the Rolls system, we added another battery in series for a 54 volt  
nominal  system. The Outbacks have enough range to accommodate this,  
although equalization was a bit low (64 v). It definitely stayed  
above 44 v after that, though.

Ray Walters


On Aug 19, 2008, at 7:29 PM, Darryl Thayer wrote:

> Hi all
> Don,t miss Phil's point, The batteries can be good, but be of low  
> surge capacity.....

> Darryl
>
>
> -