Date: Thu, 22 Feb 2007 06:21:58 EST
Reply-To: RAlanen@AOL.COM
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Frank Condelli <RAlanen@AOL.COM>
Subject: Re: was fav 12 V acc, now 2nd battery relay system
Content-Type: text/plain; charset="US-ASCII"
In a message dated 21/02/2007 11:56:49 A.M. Eastern Standard Time,
LISTSERV@GERRY.VANAGON.COM writes:
Hi Frank, I'm not seeing any normal conditions where my relay system is
at a disadvantage when compared to the 1315. My starter battery is
always connected to the charging source, just like in a system using the
1315. My aux batter is connected to the starter battery/charging source
under only two conditions:
1. The alternator is putting out enough voltage to extinguish the dash
ALT lamp. What's that -- 13 volts or more? Bridging the aux battery to
the starter battery under these conditions is appropriate unless the aux
battery has suffered a major failure, in which case all bets are off
with my system.
2. I have operated a switch to manually bridge the aux battery to the
starter battery/charging source by applying voltage from the aux battery
to the relay coil. This would be done in the case where the starter
battery is low and I need to steal some power from the aux battery to
pump up the starter battery. There also should be no problem unless the
starter battery has suffered a major failure.
I did use the phrase "normal conditions" in my opening paragraph, and I
noted above two unusual conditions which involve the near or total
meltdown of one or both batteries. In the situation where the aux
battery was hosed, the 1315 would allow a fellow to keep driving because
it would refuse to connect the bad battery, whereas my system has no
such safeguard. If the starter battery is low, both systems allow a
fellow to bridge the aux to it for starting, but if the starter battery
was massively failed neither system would help.
The 1315 does not require metering: it appears to be smart enough to not
connect ugly-dead batteries to the system. So that's an advantage -- but
to me, not much of one because I like meters -- even with a 1315 I'd
monitor battery voltage.
So, unless I'm missing something, the 1315 only provides two advantages
over the relay system: no-brainer operation (always useful when you have
a squirrel's brain) and it refuses to connect a hosed aux battery. Those
two may be advantages enough for some folk to recommend the 1315 to
them, but to say that "relay systems work but not well," is a bit much.
Mike, this is all well and good and correct, however your missing one
important point. Using a relay system has both batteries connected together as
soon as the engine starts and the alternator red light goes out we all agree on
that ? OK, so if that is true and the aux battery is dead and your staring
battery is full what happens ? Well, what happens is the main battery will
try to dump it's charge into the aux battery until they both become equal. The
rate at which this happens depends on the size of the wire used to connect
the two batteries and the speed at which the alternator can keep up replacing
the missing voltage in the batteries. So, this is not a problem if you don't
mind changing two batteries more often than usual as ordinary car batteries
do not like to be discharged and charged constantly. That was the reasoning
behind using a deep cycle battery as the aux battery. So then we're back
where this thread all started. The only deep cycle battery that sort of fits
under the seat is the OPTIMA Yellow Top which we see by recent experience is a
piss poor battery ! So.......some of us have gone back to using a regular
car battery with a good warranty as the aux battery. Those of us who have
done this most likely already have the 1315 as it is required to charge the
OPTIMA correctly in a two dissimilar battery situation. It also make more sense
to charge the batteries independently and this is what the 1315 does best.
Cheers,
Frank Condelli
Almonte, Ontario, Canada
'87 Westy, '90 Carat, '87 Wolfsburg (Forsale) & Lionel Trains (_Collection
for sale_ (http://members.aol.com/Fkc43/trainsal.htm) )
Vanagon/Vanagon Westfalia Service in the Ottawa Valley
_Frank Condelli & Associates_ (http://members.aol.com/Fkc43/busindex.html)
_Vanagon Stainless Steel Exhaust Systems_
(http://members.aol.com/Fkc43/stebro.htm)
_BusFusion_ (http://members.aol.com/BusFusion/bfhome.htm) a VW Camper
camping event, Almonte, ON, June 07 ~ 10, 2007
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