>
From: David Johnson <davidj@ELPASOTEL.NET>
To: vanagon@GERRY.VANAGON.COM
Sent: Monday, July 24, 2006 10:10:04 AM
Subject: Trickle Charger (follow up 182 Amps)

Ok, so thanks to all the list for the feedback on the RM 182 amps - sounds
like no matter what, the best I could hope for is a few hours of fridge
time.  Just so far have not gotten my fridge lit on propane yet, so will
probably have to pull it and clean out the combustion chamber and try again.

So, with that out of the question, I am not sure a deep cycle battery is
worth it for the other 12v stuff.  So has anyone used any of the trickle
type chargers to keep a main battery up against a light weight inverter.  I
have seen them in the 2 watt trickle charge range.  That seems awfully light
weight, so has anyone used them to try and keep up a main battery against
moderate use (maybe a fan, a couple hours of laptop draw for a movie, some
lights).

Thanks again,
David.
>
David,
A true trickle charger, like the 2 watt range, is only for keeping the
battery from discharging when it is not being used.  It is not for "filling
it up" after use.  2 watts will basically give you not much more than 100mA
(0.1 amp) of current into the battery, depending upon efficiency of the
charger.  That's great for keeping the battery in shape while your vanagon
sits in your garage for a couple of months, but it's not good for charging.
You want something that puts out amounts in the amp range, not milliamps, to
do that.  Example, you discharge your 40 amp/hour battery to 50% by running
stereo and lights off of it for many hours.  You used 20 amps  A 1 amp
charger will take 20 hours (20 amp-hours) to get it charged back up.  A 2
amp charger will take 10 hours.  This is a pretty simple way to look at it,
but good enough for coarse calculation.  To put things into perspective, a
typical alternator puts out 45 - 85 amps!  Hope this helps some!

Rich