Alternate solar panel layout on a project box?

I’ve a RAK node on a mountain here in Scotland with a 400mA 5v 2W panel. Facing South with no obstruction its holding its own. I’ve another in a less fortunate position that doesn’t. I received a Soshine 6W panel but before I faff about with brackets and such forth I came across a box on another mountain (no idea what it was…repeater/weather?) that had solar panels on three sides! I could probably make up a test rig but would this work if all connected in parallel? Or would the weakest one pull down the others (much like house solar without optimisers)?

In my opinion, it’s better to put them in serie and use an mppt dc converter. If you have an mppt for each pannel then it’s probably the better way to produce maximum power.
By using them in parrallel, if there is no electronic component like at least a diode, you will lose power because some pannels will act as resistor.

serial would not work for 3 different orientations. not at all. less energy than 1 module alone

i am not sure, but i would expect it to give the desired results.

if you put 3 modules in 3 different orientations
, and connect those in parrallel, you should get more mAh over the day, than with only one module.
maybe you will not get the theroretically maximum mAh, because she “shadowed” modules will pull down the full sun module a bit, but overall you will have a better result in powering the device.

this is only valid for very small, low voltage, low power modules , like used for Rak and other meshtastic devices ! you cannot do that with higher power modules, like 20+V an100+Watt there you will have a risk of damaging the modules- fires …
if you want to build also the small devices safe, you can put in small fuses on each module, aorund the double of mAmperage of the module…

so put a 500 or 700mA fuse on each 400mA Module, that way the possible back-current cannot exceed dangerous limits…

@kilroy I think you didn’t read my comment or don’t understand it… I said, in my opinion, the better option is in series if you use an MPPT for each panel. Using mppt for each panel in parrallel will lose a bit more power than in series as you will increase current in your cables and theses cables are going to produce more heat.
Also, I doubt in your electricity knowledge as you confuse energy and current…

thank you for the hint,
i corrected mAh to mA for the fuse specifications :slight_smile:

While searching on ali, I found this reference ‘CN3791’ that appears to be a very cheap mppt solution.
After I found this IC, I found 2 userful videos talking about the subject and comparing multiple solutions: #154 & #155 by Andreas Spiess. I recommend to watch it.
It confirms that CN3791 seems to be a good choice.