Re: Battery Questions

On Sat, 17 Mar 2007 13:27:23 GMT, "BF Lake" <nomail@xxxxxxxxxx> wrote:


"rvfulltime" <rvfulltime@xxxxxxxxxxxxxxxxx> wrote

. When we arrived
at our the dry camp location the voltmeter read 12.6 volts, which
according to my chart was fully charged.

I think there should have been a higher voltage on arrival from the surface
charge from the 7-pin connection while travelling. However the batteries
would still have been up from the 3 days prior. Is your truck a Chev
without the fuse in Stud 1?


No. Truck is a Ford. The initial voltage reading was taken a couple hours
after arriving. The only draws were the little phantom ones, like frig, thermostat,
LP detector.

During the evening
we ran the vent fan (with 4amp fuse) for about 4 hours plus 1
flurescent light about 3 hours. In addition there were other
various draws; water pump, thermostat, etc. We didn't waste
much electricity. In the morning the voltage was 12.2v which
accoring to my chart is 40% of full charge.

That 12.2 was with some things on, so the real reading would have been
higher with everything off and after allowing the batteries to rest for a
day. Not a conclusive indicator of something wrong just from that one
time. The main thing is it was all working next day. Would be a better
test if the furnace were on too.

All voltage checks were done with lights out and fan off.


So later in the day I fired up the generater and the charger
and recharged the batteries for 2 hours starting at the maximum
charge rate of 40 amp. I didn't allow the
charging process to finish as it was getting late. I checked
voltage immediately after and it was 13.0.

How far down was the count-down when you quit? The Vector has different
voltages at different stages but at this point (if counting down) it would
have been 14 something and left that as a surface charge. Of course things
were still running so the reading would be lower. If the charger was still
at 40amps after 2hrs and the voltage was still rising to 14 something and
only up to 13 by then, then the batteries would have been down quite a bit
at the start. Need more info on that.


The digital display started at 32 and dropped continously to between 14.5 and
15.0 when I turned off the charger. The user manual doesn't appear to
document what the digital display means during charging, but I suspect it's
really the voltage.

30 minutes later
it was 12.6. After running the vent fan and a light for a couple
of hours, the voltage was down to 12.2 again.

Not the way it is supposed to be that's for sure. Was the trailer plugged in
to the gen also? It is possible that the Vector could be confused by the
voltage from the trailer's charger and not go through its stages properly.
The trailer's charger might not have gotten much done in two hours if it was
the dominant charger. Not enough info.


The trailer was not plugged into the generator. The trailer was dead with
respect to any electricity.

We have a 7355 converter, and when using the gen and the Vector when dry
camping I either leave the shore power unplugged from the gen or else use
the 7355 plugged in to supply DC and AC, and take off the wires from the
neg battery terminal and charge with the Vector so it does not see 7355
voltage. Same if at home and I use the Vector while trailer is plugged in.


1. Has anyone done the desulfation or equalization processes and
do the help extend the life?
I just tried it on our battery bank and it seems to have perked them up a
bit. Hard to tell.

Are my batteries too far gone for
these procedures to help?

You can take the batteries to a shop for a load test where they measure the
"reserve capacity" against their rating. Then you know where you are at.
It is difficult to run tests at home for before and after state of charge
due to the requirement to have the batteries at rest (at least a day) before
taking a voltage. Takes days to get the info and it is inexact. You don't
know if you started from the same state of charge each time so your
comparison test is suspect.

2. If I do either of these should I remove the batteries from
the trailer first?

The Vector does "recondition" at normal voltage so it does not damage
trailer electronics. AFAIK it does not have a desulfation feature using
high voltage --if it did you would disconnect batteries first.

3. When recharging batteries should I disconnect them from
the trailer? (There is large switch that does this.)

On our trailer, the battery disconnect switch does not cut off
everything--the radio and LP gas detector stay connected for instance. I
undo the neg terminal wires on the battery bank to ensure they are
disconnected from everything.

On our trailer, disconnect means disconnect. In the off position, even the
LP dectector gets no current. It, the LP dectector, makes a short beep
as the current disappears.


4. Is it ok to recharge 2 batteries connected in parallel or
should the be recharged separately?

We have 2 6v and a 12 v charger so there is no choice. When dry camping
with 2 12s you could run the trailer on one battery and charge the other
while it is disconnected. Then there would be no trailer draw on the
battery being charged subtracting from what the charger is putting in. I
don't think you would lose anything in gen running time as your amphr
replacement would be the same total.

I think it is better to do them together so they are for sure at the same
voltage for paralleling though.

If on shore power at home and using the trailer's charger you can do both
together no problem.

5. Are there any other tips you can give me?

You can use a hydrometer instead of or to confirm your voltage readings, but
I have not had any luck with using one. I think it gives wonky readings due
to surface charge too, plus you need to use a temperature chart. Taking the
batteries out of the compartment so you can deploy the hydrometer is also a
major PITA.

Regards,
Barry


The reason I'm asking now is that in a couple of days, we'll be in Tucson for
a week or more, then we head to the empty quarter for a couple of months.
Places like NE Arizona, SE Utah, and then SW Colorado. Places too small
for even Wal-Mart to have a store. And if I have to buy new batteries I'd rather
do so in a big city rather than in Bluff, Utah in April.

--
Posted via a free Usenet account from http://www.teranews.com

.

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