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stealth solar install on van

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madlabs:
For me, ground clearance and FWD is more important than comfort. :-) So no semi trailers for me.

As to fridges, my plan is to gut a small dorm fridge and make a combination ice box/fridge. Lots of insulation, good drainage, access from the top.

Jonathan

dnix71:
Short report. The max wattage I have seen is about 20, but that was from parking it in the sun and with the engine off, starting the inverter and a/c. Otherwise it was about 16 watts. I'm seeing over 100 watt hours a week, but I don't know how well the power meter actually correctly reads the pwm output of the controller. My dash voltage controller samples every few seconds and misses some events. Sometimes it sees the voltage drop when cranking, but it the engine starts fast enough it misses it.

Last week the van battery died. I thought it was a bad diode on the alternator as the battery was going dead overnight. Turns out the solar panel was preventing the battery from dying during the day. The strain of running the a/c from the inverter may have hastened the battery's death. Maybe not, it's been a brutally hot summer here, heat kills batteries.

Good news is that the battery was only 22 months old and a premium battery from a major chain. They tested it thoroughly and then replaced it free.

With the new battery and a dash plugin volt meter it's much easier to not stall the inverter sitting in traffic. No I can see when the alternator stops charging completely and rev up the engine a bit to bring it back.

Before the battery replacement I was seeing system voltages above 15 with the engine off. Now it's rarely above 13. The van sits in the shade of a tree at work until about 3pm. If it's sunny late in the afternoon then the voltage creeps up to maybe 13.5.  Engine running the system voltage is 14.5 when cold and drops to about 14.2 after a few minutes even with the a/c running.

Ungrounded Lightning Rod:

--- Quote from: madlabs on July 18, 2015, 06:51:52 PM ---Have you seen how much power they put out, flat like that? I'm going to be building an expedition van soon so I'm curious.

JOnathan

--- End quote ---

That will vary depending on your latitude and the season.  With solar panels the open circuit voltage is dependent on temperature, the max current is dependent on illumination (of the least-illuminated cells in the string), and the power is a function of those, the load, and the metalization and wiring resistance.

You can compute an approximation easily enough, given your latitude and the panel's nameplate ratings.  The cosine function is your friend.

MattM:
The vibration during driving may have weakened some solder tabs?

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