Re: [A/S] Power converter question

[Jim Dunmyer <jdunmyer@xxxxxxxxxxx>]

Dan,
 Although I bought my Inteli-Power converter and Charge Wizard from
Camping World, someone posted a URL a while back from a dealer who has
better prices than C.W. Sorry that I can't remember who it was. <<sigh>>

In any event, it's under $250.00 for both, even from C.W. They carry 2
different models, mine is the smaller, with a 40 amp rating. [going to
the catalog] It's the Model 9100 "switcher/converter". President's Club
price is $231.29 for both in the Master 2001 catalog. It's about half
the size of the old UniVolt and weighs under 5#.

The I-P works like this: When you first plug the trailer in after a
boondocking stay, it sets itself to 14.4 volts. This will charge the
battery at a fairly high rate, as much as the converter rating if the
battery is low. (IE: 40 amps) The charge will begin tapering as the
battery voltage rises until it hits that 14.4 volts. At that time, the
I-P adjusts itself to 13.6 volts. The charge rate will be quite low,
usually under an amp, especially after a few hours. It'll hold there as
long as you're using the trailer. When you go 24 hours w/o using any
lights, etc., the Charge Wizard will reset the output voltage to 13.2,
low enough to not boil off any water. Once every 23 hours, the C.W. will
kick the voltage up to 14.4 for 15 minutes to keep the cells equalized
and the electrolyte stirred up, then returns to 13.2.

Standard converters like the UniVolt have a number of drawbacks: They
usually have their output voltage set to 13.8 or thereabouts. This is
too low for fast charging of a 'low' battery, yet is too high for
continuous floating. Because of the low voltage, the cells will never
get equalized, and because of the high voltage, the battery will tend to
use water. They also have little to no filtering, so the output is
"dirty"; this is worse when your battery is old and nearly worn out.
Some converters have a seperate battery charging circuit and put out AC
on the main leads. This will ruin your new stereo radio if you happen to
connect it to that. They incorporate a relay to connect the AC output to
the battery when the input power is removed, that puts battery voltage
on the main low voltage buss in the trailer. Another problem with
standard converters shows up if you try to charge your battery using a
genset for power: they don't work well at all. The have a low charge
rate to begin with (see above), and it's even worse when powered from a
genset, as the peak voltage is lower than "factory" power. Because of
their technology, that lower peak voltage means a much lower charge
rate; this is NOT the case with the InteliPower.

The output from the Inteli-Power is very "clean", so you'll get no hum
from your stereo. It has a cooling fan that comes on only when some of
the components warm up a bit; ours cycles on every so often for a minute
or so when we're using "some" lights. If the load is very light, the fan
doesn't come on at all, and it's pretty quiet in any event. The
converter is under the front couch in our Avion, and the fan doesn't
bother me when I'm sitting right next to it. OTOH: I couldn't stand it
if one of those old UniVolts was under my seat!

If you have the UniVolt with the branch circuit fuses in it, you need to
make other provisions. One fella removed the panel from the old UniVolt
and installed it in a box of some sort. Folks like West Marine sell fuse
panels, and I'd bet that NAPA has something suitable.

Anyone who's not familiar with RV wiring should have both Livingston's
"RV Maintenance & Repair" and Barre's "Managing 12 Volts". They'll get
you off on the right foot. One thing that you should always incorporate
is an OhMyGawd! fuse. It should be 50-100 amps in size and should be
wired into the main battery lead, physically very near the battery(s).
These are usually installed in the NEGATIVE lead (it seems backwards, I
know, but that's how the experts recommend doing it). The purpose of
this fuse is to prevent a catastrophe in case of a direct short
someplace.

                                   <<Jim>>