Date: Sat, 3 Aug 2013 13:10:34 -0500
Reply-To: Tom Hargrave <thargrav@HIWAAY.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Tom Hargrave <thargrav@HIWAAY.NET>
Subject: Re: Battery Charger Sizing (Amperage) Woe and Warning (?)
In-Reply-To: <201308031700.r73H0Co91148@sbw.org>
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In my experience sulfated plates are caused by discharging a battery too far
& the longer the battery remains discharged the more sulfated the plates
will become. Technically, a lead acid battery is discharged when the voltage
drops below 11.9 volts, so you guys who are draining your batteries down
lower than 11.9 volts are damaging your house batteries & shortening their
service life. Sometimes you can reverse sulfated plates by pulse charging &
some better battery chargers have a pulse charge or "condition" mode. The
longer your battery stays discharged the less you are likely to reverse the
damage.
A smart charger like the one for sale on Amazon is the best charger to use
even though it will cost a little more than a simple charger. A smart
charger starts with a heavy charge, then it steps down to a lower charge
rate as the battery charges. At the end it should go into float mode. The
old style bulk battery chargers will also charge your battery but because
they aren't "smart" they don't step the charge rate down and will generate a
lot of heat & can boil water out of your battery cells.
Thanks, Tom Hargrave
www.kegkits.com
www.stir-plate.com
www.towercooler.com
www.grow-sun.com
www.raspberryproject.com
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@GERRY.VANAGON.COM] On Behalf Of
Steve Williams
Sent: Saturday, August 3, 2013 12:00 PM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: Battery Charger Sizing (Amperage) Woe and Warning (?)
Karl wrote:
>I'd recommend a 20-30A Iota charger.
Fair enough. This 30-amp model is not quite twice as expensive as my 8-amp
ProSport:
http://www.amazon.com/exec/obidos/ASIN/B0074JVMUC/sbw/
I consider that a reasonable price for an important component of my camper's
systems.
>A 7- or 8-amp charger will never bring a battery that's been drained
>significantly back up at a proper rate. This can lead to sulfation on
>the plates, shortening the lifespan and/or storage capacity.
I looked on the Interstate web site and others for guidance on the proper
current for bulk mode charging of a deep-cycle battery. I haven't found
anything clear and convincing.
I trust Karl's experience and knowledge. I just wish I could find some
confirmation from a few more sources.
My 8-amp ProSport charger does get my battery up to the proper voltage
during the charge cycle, but the question is whether 8 amps is enough to get
the voltage up that high quickly enough to keep the battery optimally
healthy, especially when it's deeply discharged.
I've only charged the battery from down around 10.5 volts a couple of times,
and I didn't watch closely to see how long it took. I'm tempted to
instrument the camper and record some data!
Anyway, I'd welcome some references to battery charging advice you consider
authoritative.