Date: Fri, 20 Jun 2008 12:42:26 -0800
Reply-To: Troy <colorworks@GCI.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Troy <colorworks@GCI.NET>
Subject: Re: Costco Group 47 - cheap aux battery option
Content-type: text/plain; format=flowed; charset=iso-8859-1; reply-type=original
I know all about the theories Al. Yes, an AGM should outlast a flooded
battery, but there's more to it than just that. AGM's require the higher
voltage to charge correctly. Under charging them over the long haul reduces
the effective AH's. I have a $200 AGM that I just replaced with a flooded
battery. Yes, the flooded battery will more than likely die well before an
AGM, so that is why we choose batteries with good warranties. Frank and
Dennis have talked about this quite a bit. I was stubborn, but came to my
senses;) My AGM was purchased from a company 300 miles away, AND they
checked those batteries when you return them. It's very easy for them to
find fault with the user. Overall, for this camper, a flooded battery
represents a much better value and despite similar AH ratings of my AGM and
flooded, the flooded is outperforming the AGM by a very good margin. I
realize that CCA doesn't mean a whole lot for a house battery, but AH does.
Troy
----- Original Message -----
From: "Al Knoll" <anasasi@gmail.com>
To: "Troy" <colorworks@gci.net>
Cc: <vanagon@gerry.vanagon.com>
Sent: Friday, June 20, 2008 12:19 PM
Subject: Re: Costco Group 47 - cheap aux battery option
> The house battery as as been discussed before has different operating
> parameters than the starting battery. CCA is a measure of how much
> current can be delivered for a short period of time (no pun intended).
> A house battery does better if it is designed to deliver smaller
> currents (<30A) over a longer period of time.
>
> The starting battery has porous plates so the maximum electrolyte to
> plate contact is available for high current applications. The plate
> surface per cell dictates how fast the electrochemical reaction can
> proceed. The more contact the faster it goes and the more current
> that can be drawn. However this configuration of plates is not well
> suited to small <30 current draw over longer periods of time. For
> that application a solid plate is best. Batteries that have these
> sorts of plates don't deliver much in the way of CCA but do have a
> larger reserve capacity measured usually in Ampere Hours. They're more
> resilient and longer lasting than a starting battery of the same
> physical size used as a deep discharge current source. More charge
> discharge cycles without damage.
>
>
>
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