Re: Leaving 7355 on battery (was Leaving fridge running when stored)

On Tue, 18 Apr 2006 14:14:22 GMT, "B F Lake" <nomail@xxxxxxxxxx> wrote:


"Lon VanOstran" <RVnFT@xxxxxxxxxxxxx> wrote in message
news:4ajvnpFtisqkU1@xxxxxxxxxxxxxxxxx
B F Lake wrote:

We have a 7355. It is ok, and it is safe to leave the RV on shore power
all
the time and it will not overcharge the batteries. It drops its
charging
voltage to a maintenance level for exactly that reason. However, it is
not
much of a battery charger. It seems to have been built to go with a
simple

According to this page, it's only 2 stage charging. IMHO, it's not a
good idea to leave it on all the time.

http://rvpowerpartsplus.com/oscommerce/product_info.php/cPath/24_61/products_id/71

The actual pamphlet that comes with the 7300 series says its charging rate
starts at a "nominal 14 volts" with whatever " amps are available" which is
actually 13.7ish volts (at mystery amps) but it "tapers off to a few hundred
milliamps when the battery(s) are at full charge" It explains that after
the normal charge, the converter drops to 13.5 volts which is "designed to
minimize overcharging the RV battery(s) during extended periods of operation
on 120 vac shore power"

"This method of over charge control works well on good batteries that are
properly maintained...." It says when on shore power to check the battery
water level at least once a week in hot weather. It says if not connected
then re-connect at least once a month for 8 hours to re-charge the battery.
(warns about sulfation) ---note the 8 hours is to re-charge for a degree of
self-discharge and not how long it would take to re-charge from useage down
to 50% (days!)

So my interpretation of this Delphic instruction is that it is ok to leave
it on all the time, but the charger is not a 3 stage "smart " type. It is
slow to re-charge due to the voltage being 13.7ish instead of 14.5ish, and
the charging amperage is a complete mystery, but I suspect to be low
compared with the bulk stage of a smart charger.

In real life, with a pair of golf cart batteries, I have found it works ok
to leave the 7355 plugged in all the time, but it will take days to
re-charge them if we have been dry camping, so I use my smart charger which
only takes a few hours, and then I just leave them on the 7355.

I think this procedure works as well as if I had a 9160 with Charge Wizard
except I have to do a little more work, but I am not Neon John, so I am sure
there is more to learn about all this. It seems being an RVer is worse
than being a U-boat captain in that you are always obsessed about the state
of your batteries <G>

Regards,
Barry

Hi Barry,
Your's works differently then mine did. My 7345 I had with our travel
trailer put out over 14 volts when the battery needed charging and then
dropped down to 13.5 or so. It would then take hours to get the final
10 percent or so of charge in. But even when it did it stayed at 13.5
volts and keep charging. Eventually the batteries would overcharge.
It's a two stage system, that doesn't drop the float charge low enough.
If it did the batteries would never finish charging. :) I never saw the
thing put out it's full amperage rating while charging either, though I
only monitored it once in awhile.

I had to keep setting the float voltage on my solar panel controller
lower because even at 13.4 volts it would cause the batteries to slowly
bubble. Took me one summer to figure out what was going on there and why
I started having to add water to my batteries. I had to turn it down
to 13.2 volts and it seems to work fine now.

Ha, the comparison with a submarine commander is pretty close! I've
spent a lot of time and money with new controller/monitors, solar
panels, inverters etc. just to have lights and be able to watch TV and
use the microwave :)

Take care and Happy Campin...
--
RichA
"We Get Too Soon Olde and Too Late Smart"
.

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