Date:         Thu, 13 Dec 2001 13:58:18 -0500
Reply-To:     Julian Burden <julian.burden@SYMPATICO.CA>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Julian Burden <julian.burden@SYMPATICO.CA>
Subject:      Fw:      Re: Battery Isolators vs. Relays
Content-Type: text/plain; charset="iso-8859-1"

<SNIP>
> I didn't know anything about the
> amperage limiting capabilities of the relay.  That certainly would make a
> difference.  I'm still not clear on one thing though.  You mention that
> "VW/Westfalia used it themselves for 20 years on those campers that were
> equipped with two batteries" and "As for the advantage of using the Hella
> kit versus modifying your fridge relay to do the job, I can't comment on
the
> latter as I have never done it".
<SNIP>

There are instructions on how to do this on Vanagon.com - I tried it, but
added a 30A fuse (the relay is rated to 30A) because I didn't like the idea
of the starter battery dumping charge to the second battery. As I suspected,
the fuse blew as soon as the engine was started after the first night's
camping. I would not recommend this method - but as Ron says, others are
using the modification and seem happy.

<SNIP>
> I'm not sure here if you're suggesting
> that the fridge relay setup is somehow different from some other VW
> dual-battery setups or something else?  You seem to be stating that the
> factory system is the same as your Hella kit but that maybe the fridge kit
> is different or would have to be modified.
<SNIP>

Ron previously emailed me that the existing fridge relay is a similar but
different relay to the Hella he sells, and the current limiting factor of
the cabling is not gained through the fridge relay modification.

<SNIP>
> You've convinced me that the
> relay is the way to go but I don't know if I've got that particular relay
> system already in place.  Does my "fridge" relay also limit the aux
battery
> charging amps to 15 or do I need to buy your kit and replace my relay?
<SNIP>

No, there is little or no current limiting with the fridge relay - my
experience is that more than 30A goes through the fridge relay ('cause the
fuse blew).

As to being convinced, I am too. I like the 15A limitation in one way (not
dumping from the starter battery), but not in terms of keeping the second
battery charged. I run a notebook computer off an inverter and I'd like the
second battery to be charged faster than 15A. I'm exploring other options,
but will probably end up with the relay.

Another factor to be considered is the type of battery to be used as the
second battery. I replaced the main battery soon after I purchased my
Westie. The old one went under the driver's seat. Regular lead acid
batteries are not ideal, but I understand it is hard to get a decent deep
cycle battery that fits in the space under the drivers seat. Additionally,
deep cycle batteries should be fully discharged before being charged. In my
mind the ideal setup would be a pair of deep cycle batteries with a smart
controller - $$$$!!!! I think I'll stick with the battery I've got for now.