Trailer - Disable PIP for long term storage

prepared1

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Jan 17, 2021
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OGITC: if you switch the system off during a time when the PV panels are still getting input, will that damage the panels? It is a concern with typical hot water solar panels, so people put in some sort of dump load or a cover. Just curious. I have considered doing something similar to your project, would like to know.

Thanks for the interesting posts...
 

OffGridInTheCity

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Dec 15, 2018
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OGITC: if you switch the system off during a time when the PV panels are still getting input, will that damage the panels? It is a concern with typical hot water solar panels, so people put in some sort of dump load or a cover. Just curious. I have considered doing something similar to your project, would like to know.

Thanks for the interesting posts...
Thank you for the thought. The 2s2p panels go to thru standard circuit breakers, are combined, and then on to the MPP. The disconnect procedure not only re-routes the AC around the PIP but also includes turning off the battery bank and disconnecting the PV input.
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OffGridInTheCity

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Dec 15, 2018
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Lately the sun is high enough to reach the 4 x 300w panels on the roof of the trailer. Mid day - there is band of shadow from the roof of the house, killing optimal performance but beginning and ending 1/3 of the day they are in full sun ....
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and producing pretty good power. Here's the kwh vs hours of the day from the PIP logs for yesterday. The dip in the middle is the shadow from the roof in the pic above. They're wired 2s2p length-of-trailer-wise - so 1 string is full sun and the other has shadow on both panels.
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With the dip I'm getting 2kwh/day (June 2) and would expect to get 3kwh/day in full sun. I've been running the 9000 BTU heat pump maintaining 75F/24C 24hrs/day on a 48v@260ah 18650 battery bank and its keeping up.

The temp spiked this week to a few days of 100F/39C but will be back down to 80-90F/29C'ish soon. The system looses some ground at 100F but gains just a bit of ground at 85F. The trailer is 14x7 with 1" insulation + radiant tape *everywhwere* (ceiling, wall, floor, in the tail-gate, and all the nooks-crannies.

I'm really pleased at how well heat-pump / 1200 watts of panels / PIP / 14kwh battery is performing. With modest power management and good sun - this thing can actually run on Solar.

The DIY 18650 14s88p battery made of RING cells is performing very well. Sat for the last 4 months and just turned it on... and balance is holding at 20mv max difference same as 4 months ago.
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**Lessons learned.
1) FLAT mounted panels means the rain/water pools on them due to the frame lip all around them and when the water evaporates the dust/dirt is caked on and is not washed off the way tilted panels are. Hadn't considered that... and would warn others to allow for some tilt for better self-cleaning.

2) The Honda EU3000is generator was converted to support Propane and it turns out you can still use Gasoline. The Gasoline mode will produce 2,200watts of continuous charging. The Propane mode will only produce 1,800watts... the motor isn't quit as powerful under load. and that's 20% less charging power.
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