cheap portables experiment


A few years ago I picked up a couple Grape Solar 100w panels like this at Home Depot for $73 each. They worked fine. I tired of carrying them around, setting up and taking down so I donated them to a worthy recipient.

Two factors are nudging me back to carrying portables

  1. summers appear to be getting hotter, which makes me more eager to park in shade in the afternoons
  2. my boondocking circuit is smaller, limiting options a bit

afternoon shade

The trick here is to camp on the eastern edge of a treeline with the panels facing WSW. The panels mounted on the van collect sun in the morning before it gets too hot. After the sun passes solar noon the treeline shades the van (and mounted panels) but the portables are on long extensions angled toward the sun.


I’ve also used them in winter, propped up against the van to harvest more of that low-angle winter sun. Not as important now that I’ve been wintering in ELP.

finding some portables

I did look for ~200w of used panel for local pickup around SFE but found nothing. Panels are too large to go to amazon pickup locations, so I checked Home Depot. I have a 10% vet discount there that basically offsets sales tax.

I originally put 2x Renogy 100w like this into the cart, $168 out the door.

oddball cheap panels

Then I saw some oddball panels like this for $110 out the door. The construction and specs are weird. I wouldn’t consider them at all if they didn’t have MC4 connections, which sometimes happens with weird/cheap panels.

Normally 100w panels are 36 cells at 0.5v for ~18vmp. That puts Imp around 5.5A. These must be 24 cells, since they appear to be 12.0Vmp (15Voc) and 8.33Imp. This would be A Problem for most people who buy this kit.

The included single-stage PWM is often mocked but they can be useful in the hands of someone who understands their limitations. I’ve used them for projects and giveaways before.

the weird specs are not a problem for my use case

… since I will be running them in series into an MPPT controller. 24Vmp is just fine….

The MPPT that’s been in place is 10A EpEver 1210. It’s both the backend for a DIY converter and handles portables. It’ll max around 140w and run at 133w in Float. I have a spare 50A EpEver 5415AN I could drop in, but then the panels would be the bottleneck. Might see 170w in that case. I’ll wait to see if the 10A will be sufficient; it was before.


When I get them I’ll test them with the cords running through the window. If they meet needs I’ll install the SAE solar port I bought previously. If that doesn’t work I’ll try this Anderson port.

If they turn out to be useless I’ll return them at HD and put the Reno panels back in the cart.