Date:         Thu, 11 Nov 2010 11:53:49 -0500
Reply-To:     David Beierl <dbeierl@ATTGLOBAL.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         David Beierl <dbeierl@ATTGLOBAL.NET>
Subject:      Re: Group 41 Battery at Wal-Mart
Comments: To: "Mark L. Hineline" <hineline@OCOTILLOFIELD.NET>
In-Reply-To:  <736421D2-E08C-46CA-BE2E-6C9D3425EA17@ocotillofield.net>
Content-Type: text/plain; charset="us-ascii"; format=flowed

At 08:10 PM 11/10/2010  -0800, Mark L. Hineline wrote:
>Is the shorter-but-still-measurable-in-years story right?

It all depends on how deeply you discharge it.  True deep-cycle
batteries are good for about a thousand cycles if you only discharge
to 50%; maybe 200 if you discharge to 80%.  Starting batteries aren't
*meant* to be deeply discharged ever.  They're optimized for
delivering huge current for brief intervals, but mostly operating in
what's called float service -- no significant drains, charging
voltage 13.9 or so.  If starting takes 200 amps for five seconds,
that's about one-third of an amp-hour.

Optima makes a fancy one that they rate for fifty deep discharges to
80% (i.e. 20% charge remaining) -- normal starting batteries wouldn't
survive that.

Yours,
David