[RE-wrenches] Solar Boost Controller in Senegal

[Larry Crutcher, Starlight Solar]

Hi Walt,

You are right! Gel batteries will give many more cycles than AGM's.  
And they cost more so you you are not getting an equivalent value by  
them suppling AGM's.

A very big downside to Gel is if you accidently over-voltage the  
battery, you can permanently ruin it. I have seen many battery banks  
damaged from accidental high voltage charging. For that reason, I  
mostly sell AGM (in my market). They also charge slower because of the  
reduced charge voltage required. Also they are not quite as efficient  
as AGM so it takes more power/time to fully recharge.

On the plus side, an AGM battery can be equalized if needed but never  
a Gel battery. Hope this helps.

Kindest Regards,

Larry Crutcher
Starlight Solar
(928) 941-1660
Renewable Energy Products, Service and Installation

Mailing Address (NO SHIPPING):
11881 S Fortuna Rd.
#210
Yuma, AZ 85367

Shipping and retail store (NO MAIL):
2998 Shari Ave
Yuma, AZ 85365



On Jun 30, 2009, at 2:43 PM, Walt Ratterman wrote:

> Hello,
>
> Why do you say that AGM batteries are a better choice?
>
> I have been reading about the differences, and all I see (comparing  
> DEKA Gel versus DEKA AGM is that the cycle life of the AGM (at 50%  
> DOD) is 500 cycles versus 1000 cycles for the Gel.
>
> The AGM seems to have better resistance to freezing, but of course  
> that is not a concern here.
>
> What are the benefits of AGM that I am missing here?  (This could be  
> important, because I was going to jump all over the fabricator for  
> shipping AGM when the literature quotes GEL, and I was thinking GEL  
> would have been a better choice.  Maybe they were trying to right  
> think, but I would need to be educated more here…
>
> Thanks!!
>
> Walt
>
> From: Wind-sun.com [mailto:windsun at wind-sun.com]
> Sent: Tuesday, June 30, 2009 7:30 AM
> To: wratterman at sunenergypower.com; RE-wrenches
> Subject: Re: [RE-wrenches] Solar Boost Controller in Senegal
>
> The AGM batteries are probably a better choice than gelled, but the  
> fact that some are down to 5 volts is the real problem.
>
> A typical AGM will lose around 1-2% charge per month at 25 degrees  
> C. If they are at 5 volts, that indicates that they either sat  
> around for over a year unused and uncharged, and possibly in a very  
> high temperature environment. The 2nd possibility is that there is  
> some kind of constant load on them, even when the units are not  
> turned on - which would be poor design.
>
> The Midnite controller is not available yet, so your only real  
> choices with the panels you have are the Outback FM60 or the Xantrex  
> XW-SCC - both of them are in the $600 range.
>
> ..................................................................................................
> Northern Arizona Wind & Sun - Electricity From The Sun Since 1979
> Solar Discussion Forum: http://www.wind-sun.com/ForumVB/
> ..................................................................................................
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