Dave,
Thanks for the correction on the voltage drop, I KNEW there was a reason(other than
being an old-timer) that I preferred a good ol' relay! <<grin>>

I can flip the key switch on the vehicle to the ACC position and chargethat battery
from the UniVolt, so that's another reason to use it.

Fooling around with the alternator regulator isn't something that Icare to get into,
either.

On the subject of batteries: I've done a lot of study and have a bitof experience with
them also, both in forklifts and in my own setup. If you've lookedat my web pages at
http://www.toltbbs.com/~jims/computer,you'll see that I use pairs of trolling batteries
on my UPSs. Although only 2 are shown, I have 3 of 'em rigged up inthis manner.

This may or may not apply to AGM or gel-cell batteries, but I can relatemy experience
with wet lead-acid jobs:

Undercharging will kill those things in a short time. My UniVolt floatsthe battery at
about 14 volts, and I'm not sure that's high enough to equalize thecell charges. The
UPSs float them at about 13.5 volts, and that's DEFINITELY not enough.Once a month or
so, I load-test all of the batteries, recording the readings on a clipboard.Then, I
connect my homebrew battery charger and set the current to 5 amps andcharge 'em for 5
or 6 hours at that rate. (the charger has a Variac feeding the primaryof the
transformer and a simple bridge rectifier in the output, plus a timeron the primary) If
I don't do this equalizing charge as described, the batteries slowlydeteriorate and
will be unrecoverable by the time they're a year old; they'll go severalyears if
treated well.

You also don't want to over-discharge batteries that you want to last(with the
exception of Ni-Cads, of course). Running them down to 20% of capacityor further will
drastically shorten the life of them.

I'm strongly considering rewiring my A/S control panel, as the ammetershows only
discharge, and the voltmeter measures voltage at the panel, not thebattery. It wouldn't
be too bad a job to rewire things, especially if I can find an ammeterwith a seperate
shunt. I'm also considering running heavier wire from the battery tothe control panel,
as it appears to be only #10 and there's significant voltage drop.Like Tom, I like to
see what's going on. :-)

<<Jim>>

David Newell wrote:

> Jim, I love it.. a silicone diode has .5 volt drop across it. theyuse to recommend
> that you step up the atlernator to make up for the 1/2 volt drop.Then they out the
> regularors on the inside of the alternators and unless you were Mandrakethe
> magician you were stuck with whatever the damn alternator put out.The relay dosn't
> have a voltage drop accros it unless it is defective. The trick isto control when
> it goes on and off. Jim's Acc control is a good choice as the relayis moot until
> the ACC line is energized which makes it possible to borrow energyfrom the trailer
> battery if you need help starting the tow vehicle. incidently anywire bigger that #
> 8 becomes a serious problem as far as phisicaly fitting things together.I do
> trolling motors and bought a $275 tool just to crimp #8 and # 6 electrical
> connectors. It is not as complicated as it sounds and the addageI've always had is
> the simpler the better. Works for trout too.
> Dave/ from Pepperell
>

--

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<<jdunmyer@toltbbs.com>>
<<lower SE Michigan, USA>>
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