Date: Sat, 5 Sep 2009 10:17:05 -0400
Reply-To: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Dennis Haynes <d23haynes57@HOTMAIL.COM>
Subject: Re: Run time to charge Aux battery
In-Reply-To: <976337.19408.qm@web44712.mail.sp1.yahoo.com>
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This is a difficult question to answer as there are many variables.
Deep cycle batteries will never fully charge on a fixed voltage system.
The size of the alternator does not affect charging time assuming it can
keep up with the load.
True battery charging system control current and proper battery charging is
done in stages.(Bulk, Absorption, finish).
On a fixed voltage system, as the battery state of charge increases the
current return will drop.
Battery charging is not a linear (amp/hour not= amp/hour out).
Assuming sufficient alternator output and adequate charge wire size the
GC-2s will probably take ~40 A/H during bulk charge. This will mean 3-4
hours to bring the battery to ~70%. Remember that all other electrical
consumers will take away from the 100 amp capacity so night driving, AC,
radiator fan etc may cause the voltage to drop further extending required
charge time.
I hope this somewhat answers your question. Battery charging can become
quite complicated.
Dennis
-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Malcolm Stebbins
Sent: Saturday, September 05, 2009 5:04 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Run time to charge Aux battery
I know very little about electricity! I checked the archives and I found
this article, but it did not exactly answer my question:
http://gerry.vanagon.com/files/motorhome/Motorhome-Alternator-Charging-Syste
ms.txt
I have 2, 6 volt deep cycle batteries hooked up and I have about 200-ish
amps (I think) in the aux batteries. This is used to run my Waeco fridge,
which takes about 7 amps when it runs, but only runs about every 10 minutes
for 2 minutes-ish.
Usually I only park for a day or 2 max, so all is OK with the aux battery,
but this last trip I stayed parked for 4 or 5 days in a row, and the
fridge's 'low battery' light came on.
My question is: APPROXIMATELY what is the charge rate IN AMPS for a nice
good working system. I say good system as I have a new Zetec engine with a
100+ amp alternator and the wires are all new and the batteries are
relatively new.
I use a SUREPOWER 1315 isolator for the 2 battery sets.
When the battery got low, I took to idling the van for about 15 minutes in
the morning, and again 15 minutes in the evening, to help the battery a bit
and this seemed to help. Is this folly?
Thanks Malcolm