[RE-wrenches] Off-Grid Sizing Case

[Darryl Thayer]

The system is way short on PV, and I would think that it is already a Gen with PV support.  I agree with everybody more PV is the way to go but the batteries must be cooked by now with this many Deep cycles.  BTW C/10 is not important, in fact I feel better if I charge slower.  I know fast charging is a good way to kill batteries.  Operating cost needs a high efficiency engine.  So until you can get the PV up to become the dominant source, a gen is probibly in order.  I tend to use smaller generators than most people, and the fuel efficency of a Honda inverter gen is hard to beat.

--- On Thu, 12/3/09, Windsun at wind-sun.com <windsun at wind-sun.com> wrote:

> From: Windsun at wind-sun.com <windsun at wind-sun.com>
> Subject: Re: [RE-wrenches] Off-Grid Sizing Case
> To: "RE-wrenches" <re-wrenches at lists.re-wrenches.org>
> Date: Thursday, December 3, 2009, 12:18 PM
> 
> Off-Grid Sizing Case
>  
>  
> 
> 
>  
> The rate of charging is not the
> real problem in most 
> undersized systems, it is the fact that the batteries
> seldom, if ever, get fully 
> charged. Given the ratio of PV vs battery capacity, I would
> suspect that their 
> batteries have been chronically undercharged for ages. We
> usually recommend 
> around 1 watt of pv per AH for a 12 volt system, 2
> watts for 24 volt 
> etc.
>  
> A generator is not usually the
> answer, because it may 
> have to run for hours to get that final 5-15% of charge
> into the batteries. 
> Generators are good for equalizing, not so much for general
> 
> charging.
>  
> ..................................................................................................
> Northern 
> Arizona Wind & Sun - Electricity From The Sun Since
> 1979
> Solar Discussion 
> Forum: http://www.wind-sun.com/ForumVB/
> ..................................................................................................
> 
>   ----- Original Message
> ----- 
>   From: 
>   Mark 
>   Frye 
>   To: 'RE-wrenches'
> 
>   Sent: Thursday,
> December 03, 2009 10:56 
>   AM
>   Subject: Re:
> [RE-wrenches] Off-Grid 
>   Sizing Case
>   
> 
>   So being able to achieve C10
> charging from the PV is not so 
>   important?
>   
> Mark
> Frye 
> Berkeley Solar
> Electric 
>   Systems 
> 303 Redbud 
>   Way 
> Nevada 
>   City,  CA 95959 
> (530) 401-8024 
> www.berkeleysolar.com  
>    
> 
>   
>   
>   From: re-wrenches-bounces at lists.re-wrenches.org
> 
>   [mailto:re-wrenches-bounces at lists.re-wrenches.org] On
> Behalf Of Windsun at wind-sun.com
> Sent: 
>   Thursday, December 03, 2009 9:51 AM
> To: 
>   RE-wrenches
> Subject: Re: [RE-wrenches] Off-Grid Sizing 
>   Case
> 
> 
>   
>   I would go with #1.
> The solar is obviously 
>   undersized for the battery bank he has. Another panel +
> MPPT should give him 
>   about 25-40% more, depending on temps etc.
>    
>  
> ..................................................................................................
> Northern 
>   Arizona Wind & Sun - Electricity From The Sun Since
> 1979
> Solar 
>   Discussion Forum: http://www.wind-sun.com/ForumVB/
> ..................................................................................................
>   
>   
> 
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