dry camping

[Rob Robinson]

Pete have you ever considered L16s. Randy has four in his rig and swears by
them. He says with a little modification he could put six in the available
space. They sure pack a lot of amps.

On 02/12/2007, Pete Masterson wrote:
>
> The primary drain (through the inverters) is the power to the
> refrigerator. It will limit your ability to operate off the grid with
> an all-electric coach. (My '95 is all electric.) Newer refrigerators
> are perhaps a bit more economical to operate than the 22 cu ft 2-door
> Amana that I have in my coach -- but you're likely to experience the
> similar power drain.
>
> For example, I have 6 model 4D AGM-type house batteries. These have
> about 220 amp hours each. So, 6 x 220 = 1320 amp hours. However,
> that's an overstatement of what's available, as you can't deplete the
> battery more than 50% for standard wet cell or by more than 60% for
> AGM batteries. So that would mean there's between 660 and 792 amp
> hours available from the battery to power all the 120 volt systems
> that are serviced by the inverters. (I have two, 2500 watt
> inverters.) Also, don't forget that the inverters cause a loss (10%
> or more) while changing the 12 vdc to 120 vac. Don't forget that amps
> X volts = watts. So, a 1000 watt refrigerator is about 8.3 amps at
> 120 v per hour. Convert that to 12 vdc, and its about 83 amps. With
> the inverter loss, that's about 95 or 100 amps (per hour while the
> refrigerator is running)... so that suggests about 6 to 8 hours or
> perhaps 10 hours of operation (since it doesn't run 100% of the time)
> just for the refrigerator. Add the microwave (high draw, but short
> period) plus the various lights and the 12 volt stuff... and then you
> can see that the batteries are kind of limiting!
>
> Here's where you have to do some math. First figure out the
> approximate hourly draw in amps of each appliance that runs on 120
> volts. Don't forget that _some_ of the lights run on 120 volts and
> are powered by the inverters. Of course, all 12 volt items and
> appliances also draw from the batteries. So, you also have to figure
> out what 12 volt appliances you have operating. Do not ignore the
> draw from the Microphor toilet compressor nor from the air-system
> auxiliary compressor, if you have one (I don't) along with various
> signal lights, etc. etc. -- well, to be honest, there's a _lot_ of
> load on a 'bird and without a source to recharge, the batteries can
> be drawn down to a dangerous level in just a few days, even when
> everything is "off."
>
> So, back to the refrigerator -- the practical situation is to make
> sure your house batteries are fully charged. If you have an isolation
> switch to "turn off" everything, it would help. Anyway, when you
> think your batteries are fully charged, isolate them (and unplug
> shore power), then check the voltage. (This is the "resting"
> voltage.) For AGM batteries, it should be about 12.9 to 13.0 volts
> (wet cell batteries are different). Then, turn on the isolation
> switch (apply the normal load) -- wait and hour, remove the load, and
> check the voltage. 12.4 volts is 50% depletion and 12.25 volts is 60%
> depletion -- do not let the volts drop below 12.25 volts!!! ---this
> is "resting" voltage measured from the battery terminals.
> Measurements drawn from other locations (e.g. a fuse panel) are
> likely to be much lower due to line losses.)
>
> My experience has been that "boondocking" isn't especially practical.
> I can shut down the generator in the evening, but I usually need to
> restart after about 12 hours or so. So, if I shut down at 8:00 PM,
> I'll usually need to start the generator by about 8:00 AM the next
> morning to avoid causing any damage to my batteries. This has caused
> a fair amount of heart burn when I've stayed in a CA state park that
> had a generator operation ban between 8 PM and 10 AM ... those two
> hours were nail biting time and I had to shut down any/all items that
> made demands on the batteries.
>
> My plan (the next time I boondock) is to pull the breakers on the
> inverters perhaps at 10 PM or so, and see how the batteries are the
> next morning. The refrigerator won't warm up much during the night,
> if it is not opened and if we're in a reasonably cool location.
>
> I've compared notes with another all-electric Blue Bird owner (just
> this past weekend at the Lone Star Birds rally in Kerrville, TX) and
> I'm of the impression that my voltage drain seems to be on the high
> side (so I may need to further explore possible reasons).
>
> The reality is that you can probably turn off the generator in the
> evening then turn it back on in the morning without major problems.
> You can run the generator for 3 hours or so to bring the batteries
> back up to full or near full charge. Then you can shut down the
> generator for a few hours, then run it for 3 or 4 hours until the
> time you wish complete quiet at night (or until any required shut
> down time occurs).
>
> The coach can be off the grid without the generator for periods of
> several hours -- but it will need to have power to recover the
> batteries rather more often and/or for longer periods than coaches
> that have LP gas appliances.
>
> See Poop Sheets by Phred at:
> <http://www.phrannie.org/phredex.html>
> #5 has a thorough discussion of "electrical stuff."
>
> Pete Masterson
> '95 Blue Bird Wanderlodge WBDA 42
> aeonix1@...
> On the road at Lubbock Texas following a great weekend with the Lone
> Star Birds at Kerrville, TX.
>
> On Dec 1, 2007, at 2:08 PM, medpro28 wrote:
>
> > Just purchased a 2005 LXi and need some advice on dry camping. I cook
> > in bbq contests and sometimes no power or 110 only. Dealer says I
> > will
> > have to use the generator all the time. Although the unit is all
> > electric, will not use the stove top or microwave while camping.
> > It is
> > hard to believe I can't dry camp any length of time and then use
> > generator to keep batteries up.
> > Is the dealers advice right or does anyone have thoughts or
> > suggestions?
> >
> > Jerry Smith
> > 2005 450 LXI
>
>
>



--
Rob, Sue & Merlin Robinson
94 WLWB


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