Weathershield with supercap

[Kilo95]

Felix, I saw your post on your main page using a 7.5f supercap and solar panel to charge it. do you carry the solar panels in your shop or can you tell me which ones you used? How did you keep it from overcharging or over shooting the 4.25v that it charged up to? Is 4.25v all that the solar panel puts out? If this holds up good in the cold, I'd like to put one outside in an enclosure to keep it from getting wet and try it in the Wisconsin winter

[Felix]

I just had a few of these very small solar cells in my junk box. I think they are 5V cells but there is no spec. They do not seem to charge more than about 4.3v at the very most. But I haven't yet put these out in clear sunlight, just behind that glass block which is not very bright even with a sun blast. So maybe it would go to 5V. This feeds into the supercap + stock Moteino VIN so it really won't matter if its more than 5V. The supercap is 5v, I don't think it will explode if it ever reaches 6V , which i doubt it ever would.

I think these were from ebay or someone gave them to me, can't recall but a simple ebay search can reveal lots of options from china. Most are 5V or 6V for small 1W range cells.

I imagine these would work wonderfully in extreme cold and extreme hot weather.

[Kilo95]

I was thinking it'd be fine if i got a solar panel that was only rated for up to 5v output. I think this will be my next project. Install it in the top of my daughter's playhouse out in the yard where she can't reach it. Do the regular Moteino 915mhz high output boards accept a SMA connector? I was thinking of making a 12 element 915mhz beam antenna for kicks and giggles and connect with a short piece of coax since I'll be 150-200 ft from my Gateway Moteino. It'd need to run at lower power that way

[Felix]

Have at it, but I think even the monopole 0 cost antennas would work at that range.
A 1W-ish 5V panel sounds good with the 7.5F supercap. I haven't gone through a winter (short days with lots of overcast) yet, but i think outside a 1W panel should charge that cap even with not lots/great sunlight - maybe not snow/ice on it - although wouldnt that be kinda like my glass blocks? 
If your charging the supercap enough, full power should be good enough. If the cap can't handle it, add another in parallel.

You can put an SMA (with a little care) on the small regular Moteinos. In R6 I enlarged the ANT pad on both sides and added extra GND pads to help solder an SMA on it. There's even a dedicated u.FL pad on TOP. There's SMA pigtails on ebay, they're SMA case mount on one side, and plain coax on the other, so you can just solder the shielding to GND and feed wire to the ANT port, just trim the coax length to 1/4 wavelength multiples.

[Kilo95]

i'll be buying another moteino for this project, so i can get one of the newer ones. i'll probably try a 1/2 wave or full wave monopole first. i've got a full wave monopole on my gateway moteino now.

[Felix]

Great, post here as you have updates and make progress!

[Kilo95]

Ok. Got it built. Diode in place just like on the lowpowerlab.com home page. It tops out charge at 5.5v per my DVM. Is that going to hurt the Moteino? Also, when it's sitting in the sun, it reads maybe 15-20 deg F hotter. Place it in the shade?

https://imgur.com/gallery/u0WiN

The plastic electrical box has a watertight cover that goes on it

[LukaQ]

I would think that is not exposed to ambient enough. What are your results in box vs. out?

Yes place it in shade, 3-4 ft, 1m, above grass with no metal or concrete or asphalt around it...

[Kilo95]

Not sure without the lid on. I'll put it in the shade. That's probably sufficient.

[Felix]

Ok. Got it built. Diode in place just like on the lowpowerlab.com home page. It tops out charge at 5.5v per my DVM. Is that going to hurt the Moteino?
https://imgur.com/gallery/u0WiN

The LDO on the Moteinos take up to 16v tops so you're safe.

[Kilo95]

Great. Thanks. Eventually I'm going to try to add an anemometer to it. We'll see how it survives the Wisconsin winter with the supercap

UPDATE: i've had my Weathershield +supercap(7.5F)+solar panel out all winter with numerous nights below 0 deg F. I've only had one night where it dropped below 5v. that was down to 4.98v. very pleased

[LukaQ]

So what's your consumption anyway? I don't think you send once per hour, which would make consumption very small + you get through night each day. How much does it drop then? Could you go without any good light for few days?

[Kilo95]

i don't know what the consumption is. it updates every 2 minutes. i haven't tried covering up the solar panel to see how long it lasts. it was serving the purpose i had. My voltage always shows 5.01v. I am using a 5v solar panel with the diode just as Felix did

[LukaQ]

Do you monitor voltage? you should see some drop before sunrise

[Kilo95]

i do. it has only dropped below 5.01v once that i have seen

I suspect my reading on the Gateway is maxed out and I'm i'm sitting a little above 5v all the time. there probably IS a drop but it doesn't drop low enough to go below 5.01v. where could i increase the max that it will show on the Gateway page for the voltage?