Date: Sun, 29 Jul 2007 15:29:39 -0700
Reply-To: Michael Elliott <camping.elliott@GMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Michael Elliott <camping.elliott@GMAIL.COM>
Subject: Re: Deep Cycle Batteries
In-Reply-To: <BAY125-DAV1069E22EF073A6D5C2D747A0ED0@phx.gbl>
Content-Type: text/plain; charset=windows-1252; format=flowed
Dennis Haynes typed:
> Many of your points are valid. You are working with a 100A/H battery. A
> GC-2 set up will be about 225 A/H. Given the same alternator voltage, the
> GC-2's will be able to absorb more that double the current. The wiring
> should not be designed as the current limiter as this makes for heat. Heat
> is nothing more than wasted energy any way.
You're right: using wire to limit current does heat the wire and one
needs to be certain that the wire has the ampacity rating for the
application. Wasting energy is good thing to avoid, but the amount
wasted in the wire, unless one is working with a very tight energy
battery is a Bad Thing, but driving a Vanagon generates massive waste
heat so to me wiring losses are a small matter in the overall scheme of
things. But everyone's mileage may and usually does vary.
When you start rolling your own energy system you need to design to suit
your needs.
> The main energy efficiency gain of AGM batteries comes from the finish
> part of a charge cycle. Flooded batteries need to be charged to off gas
> the break sulphation and stir the electrolyte. AGM doesn’t have the mixing
> need and in fact this practice becomes harmful for them.
As I understand it, both types are taken up to around 14V and current
tapered off as needed to hold them there. AGMs can't be left there too
long without damage so they want to have the voltage dropped after an
hour or two. Three-stage chargers do this. Flooded batteries are more
tolerant as long as they don't loose too much electrolyte. Flooded
batteries do want the occasional "equalization" process to stir things
up, and that does chew up energy, but it doesn't need to be done all
that often, does it?
>
> The Trojan battery is a "Pasted Plate" design. The plates basically
> consist of an alloy grid. The active material is a paste that pressed and
> baked onto the grid assemblies. This makes for a lot or surface area and
> absorption of the acid to provide the high capacity. Physical abuse and
> running the batteries dry can cause the material to shed and if enough
> falls to the bottom, short out the cells. This is a common cause of
> failure.
>
Thanks for that. I have a hard time finding real hard engineering
information on the various battery manufacturers' websites.
--
Mike "Rocket J Squirrel" Elliott
71 Type 2: the Wonderbus
84 Westfalia: Mellow Yellow ("The Electrical Banana")
74 Utility Trailer. Ladybug Trailer, Inc., San Juan Capistrano
KG6RCR
