M116A3 Build

[featherliteCT1]

I found a deal on Facebook Marketplace I couldn’t pass up!

So ..... how much did you pay for both panels?

[lfhoward]

I found a deal on Facebook Marketplace I couldn’t pass up!

So ..... how much did you pay for both panels?

$150. It came with a bunch of cabling and the parallel adapters I need, as well as a 30 amp Renogy PWM charge controller. I don’t need the charge controller so that is up for grabs if anyone wants it.

[featherliteCT1]

Good deal!

I have several new Renogy panels, substantially the same as the ones you just bought.

After I bought the Renogy panels, I bought some additional new Rich Solar panels, with specs identical to the Renogy panels.

The Rich Solar panels consistently produce 17% less current under identical conditions, whether the conditions are morning, noon, evening, overcast, full sun, and cold and hot weather. I performed multiple bench tests as well as in service tests. Same poor results.

Heretofor, I thought panels were fairly generic. In my experience, not so.

[foxontherun]

Thanks for the link to the battery stud connectors. Great find on the solar panels!

Harry

[lfhoward]

Good deal!

I have several new Renogy panels, substantially the same as the ones you just bought.

After I bought the Renogy panels, I bought some additional new Rich Solar panels, with specs identical to the Renogy panels.

The Rich Solar panels consistently produce 17% less current under identical conditions, whether the conditions are morning, noon, evening, overcast, full sun, and cold and hot weather. I performed multiple bench tests as well as in service tests. Same poor results.

Heretofor, I thought panels were fairly generic. In my experience, not so.

Wow, thanks for the insight on Rich Solar panel quality. I have had good luck with my Renogy Eclipse suitcase panels so I took a gamble that their other panels would be good too. I am glad to hear it was a good bet!

For the roof I am still looking for a deal on Renogy’s newer 100 watt panels, the ones with Vmp of 20.4 volts and Imp of 4.91 amps. Those would play nice with the 200 watt Hightec Solar panel on the roof.



Two new Renogy panels in parallel:
Vmp = 20.4 volts
Imp = 9.82 amps

Put in series with the Hightec Solar panel:
Vmp = 42.8 volts (added together)
Imp = 9.3 amps (lowest common denominator)
42.8 x 9.3 = 418 watts

I would also need to find another Victron 100/30 charge controller to handle that. But I will keep my eye on Craigslist and FB Marketplace and see what pops up.

[lfhoward]

Found a Victron Smart 100/30 charge controller for sale on FB Marketplace for basically 50% of what it would be new… scooped that up!

[featherliteCT1]

Found a Victron Smart 100/30 charge controller for sale on FB Marketplace for basically 50% of what it would be new… scooped that up!

Good for you!

You are braver than me. Every time I have bought a used electronic device, the device failed to work properly.

[lfhoward]

Found a Victron Smart 100/30 charge controller for sale on FB Marketplace for basically 50% of what it would be new… scooped that up!

Good for you!

You are braver than me. Every time I have bought a used electronic device, the device failed to work properly.

Thanks! This one was brand new, still in the box and wrapped in plastic. I connected it to power last night and was able to connect to it via Bluetooth and update the firmware and set the parameters. I may have gotten lucky, but it seems good!

[featherliteCT1]

Given the packaging you described, sounds like everything should work just fine.

[bdosborn]

Found a Victron Smart 100/30 charge controller for sale on FB Marketplace for basically 50% of what it would be new… scooped that up!

Party at your house, you can buy the beer with the money you've saved on these purchases!

Bruce

[lfhoward]

Party at your house, you can buy the beer with the money you've saved on these purchases!

Bruce

[lfhoward]

I finished the solar suitcase project this morning. The build process for that is documented here:

https://www.tnttt.com/viewtopic.php?f=30&t=76176

A few pics of the new 24 volt solar panel array deployed:

[lfhoward]

More 100 watt Renogy panels arrived! Open box pair from Amazon for an insane price ($130).


These will mount on the trailer roof to either side of the roof fan. I will delete the extra tall fan housing so it won’t be casting shadows. The only disadvantage there will be not being able to have the fan lid open in the rain.


The voltage and amperage of these panels makes them a good fit for the existing Hightec Solar 200 watt panel on the rear of the trailer.




The plan right now is to parallel the two 100 watt panels to make a 12 volt 200 watt panel, equivalent to the Hightec. Then I could put those in series, couldn’t I? I have heard of arranging panels in series-parallel, but this would be parallel-series. I could go all 3 in parallel but the combined amperage would be a little high for the 12 AWG solar cables that I built into the trailer’s roof. Back in the day I had a 140 watt panel on the roof and that was it! I never dreamed of having this much solar. I found a Victron 100/30 charge controller that I’ll use, so that will not be a limiting factor either way.

Once I get the 75/15 charge controllers swapped out for 100/30’s and replace the 10 AWG wiring that connects them to the battery with thicker gauge (6 AWG?), the trailer will have 410 watts on the roof and 400 watts of portable ground arrays. Adding the 90 amp hour battery I built recently to the 156 amp hour battery that’s in the trailer now will total about 246 amp hours (about 3250 watt hours) of storage.

What will we do with all that power, you ask?
Not worry about running out of power no matter how many cloudy days in a row is the main thing.
Be able to use my CPAP for days at a time.
Be able to run computers for my wife’s business and my job as a professor.
Charge phones, gps units, run lights, etc.
I could even run the baseboard heater while the sun shines, with up to 810 watts (60 amps) of solar coming in.

[featherliteCT1]

Another good score!

I think parallel-series array vs. series-parallel array would yield equivalent results: provided that there is no shading. If there is shading, shaded parallel panels would perform better than shaded series panels. In a mobile environment, I suspect that you would never know the difference.

However, when parked for the winter, you might possibly know where the higher risk of shading would occur.

I presume you are talking about an even number of panels in each array. Correct?

If you have more than two panels paralleled in an array (e.g., 3 or more panels), you would need to fuse all the panels in that array. If so, the fuses would need to be positioned immediately before the junction point.

[lfhoward]

Hi featherlite!

I really doubt I will go for the 3 panels in parallel option. I don’t have the wiring for it, and the panels need fuses if the total array amps is above 15. It would be closer to 20 amps in that triple parallel scenario. With a parallel-series arrangement it would be 9.3 amps and no fuses needed.

Roof: parallel-series
Parallel two 100 watt Renogy panels, then connect in series to the 210 watt Hightec panel. Even with inefficiencies of combining different panels, it should give us a 24 volt array with max of about 400 watts.

Aux: series-parallel
Series two 100 watt Renogy Eclipse solar suitcases
Series two 100 watt Renogy panels (the new DIY solar suitcase)
Parallel these two, for a 24 volt, 400 watt system

Each (roof & aux) would have its own Victron 100/30 charge controller and work independently of the other. That size controller has a max wattage of 440 but can be overpaneled by 30%, so should work great. The input from each array would not exceed 100 volts or 30 amps (it would be 9.3 amps for the roof and 11.4 for the aux ground array, not anywhere close to 30 even when freezing cold).

I am not sure about how much shading would impact the combined solar generation of each of these arrays. For the roof, I would probably want to keep everything in full sun if possible, and prioritize the 210 watt panel. If one of the 100 watt panels got shaded, it would be in parallel with the other and not kill total power generation. But if the big one got shaded, since it is in series with the others, it would probably curtail generation by a lot more. On the aux array, as long as one pair of panels is in full sun, generation should be pretty good. I sort of suspect the suitcase panels might be internally wired to deal with shade a little better than the rigid panels, but I will have to run them side by side to test that.

I am excited to get all this wired up. However it may have to wait until the summer when I am not teaching. There is a lot of wiring organization to change around the second battery and larger charge controllers before all these panels will be able to run simultaneously. In the short run I have some repairs to do on my Jeep that need to take precedence when I have some free time. But eventually I will get there!