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<font size=3>Peter:<br><br>
I have built several of these portable display units. Allow me to
free associate some issues:<br><br>
1. Who will deploy unit? Our trailer has been damaged more than
once due to improper hitching, towing, backing, and mis-handling.
If you are at every event, then no problem, but it ties up your
weekends. If others will tow trailer, write up SOPs and get a
signature assuming liability.<br><br>
2. Will the unit be able to solar charge while parked? We have
developed a method of folding panels for travel and storage where most of
the panels are exposed to sunlight and can keep the unit charged.
It was parked in a spot for a while with limited sun exposure in the
winter and this caused problems with self discharge, but we remedied that
by revising SOPs.<br><br>
3. How do you handle loads in excess of capacity? This applies to
loads exceeding the inverter capacity and those exceeding storage
capacity.<br><br>
The last time our unit went out (to the Wiener Dog Races) it was parked
by the promoters in the shade. It was supposed to power a PA only
but the hot dog vendor plugged in and depleted the batteries by
11:00AM. The unit was scheduled to power a fundraiser that night,
but I was unable to retrieve the unit due to it being surrounded by
booths until late that afternoon. This lead to frantic grid
charging to get batteries recharged in time for the evening
gig.<br><br>
Other times, we have powered lights for a street concert. During
the summer, twilight comes later and we have adequate battery
capacity. During winter months, twilight is earlier and there is
not enough battery capacity. The loads are somewhat greater than 20
amps. We have access to one 20 Amp circuit, but when applied to the
Outback inverter, the inverter transferred loads and we tripped the 20
amp breaker which is behind a locked door. I wish we had used a
Xantrex inverter with true generator support so the inverter could assist
and defray battery loss without applying the entire load to the input
circuit. We eventually installed a 24 volt battery charger that can
charge batteries from a current limited AC Source and increase battery
life with a given load.<br><br>
4. Stability when parked: We have had a trailer blow over with
panels tilted up. We still need some type of outriggers.<br><br>
5. Stability when towing: You need side to side balance and a 60/40
front to back weight distribution. We numbered all components of
any appreciable mass and then wrote a simple spreadsheet to calculate
moment (mass times distance from axle, plus in front, minus in
back). We moved batteries around until left to right moment
difference was near zero and front to back moment was near a 60/40 ratio
with the hitch positive. I have a friend that supports weight and
balance software for the maritime industry and he ratified this
process.<br><br>
Good luck,<br><br>
William Miller<br><br>
At 08:49 AM 1/19/2009, you wrote:<br>
<blockquote type=cite class=cite cite>We are designing a "Mobile
Solar Power Center" to power Eco-Events and the<br>
like in Southern California. We will have 1,600 Wp of solar panels, 6 kWh
of<br>
24 V AGM battery backup and a 1kW / 120 VAC inverter. I am designing
the<br>
system from scratch, and I wondered if anyone else out there has
put<br>
together a similar system and was inclined to share notes. When I'm
finished<br>
I'd be glad to do the same.<br><br>
One stumbling block I have right now, is to find a DC rated 70A
in-line<br>
fuse, to put between the battery bank and the input to the inverter. 70A
may<br>
seem an odd value, but it is the best choice for the surge rating of
the<br>
inverter I'll be using (Xantrex Prosine 1000). Does anyone have a source
for<br>
DC-rated in-line fuses? <br><br>
Thanks in advance, -Peter<br><br>
Peter T. Parrish, President<br>
California Solar Engineering, Inc.<br>
820 Cynthia Ave., Los Angeles, CA 90065<br>
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885<br>
CA Lic. 854779, NABCEP Cert. 031806-26<br>
peter.parrish@calsolareng.com <br><br>
<br>
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