[RE-wrenches] Solar Boost Controller in Senegal

[Walt Ratterman]

Hello Larry and others..

 

The slow charge rate for the Gel's you mention confuses me further.  I had
just finished researching this last week when I was in Sierra Leone, where
we were setting up the DEKA 225AH Gel batteries on an Outback system, and
checking the charge rate.

 

I downloaded a charging instruction document from DEKA and was quite
surprised.

 

On the bulk charge rate, Rolls recommended 15% of C6.

HUP recommends a minimum of 10% to a maximum of 20% of C6.

 

But..DEKA recommended, for their GELS, "Maintain <= 30A per 100AH of C20
Rating.  That's twice as fast as the Rolls!!

 

Maybe I am reading this incorrectly.

 

And, in the DEKA's advantages / disadvantages sheet, they list quicker
charging as one of the GEL's advantages.

 

I can forward any of you this DEKA charging sheet if you want, but I don't
think it is OK through the list serve.

 

Thanks,

 

Walt

 

 

From: Larry Crutcher, Starlight Solar [mailto:larry at starlightsolar.com] 
Sent: Tuesday, June 30, 2009 1:37 PM
To: wratterman at sunenergypower.com; RE-wrenches
Subject: Re: [RE-wrenches] Solar Boost Controller in Senegal

 

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/
............................................................................
......................



__________ Information from ESET NOD32 Antivirus, version of virus signature
database 4193 (20090626) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20090630/73013eda/attachment-0003.html>