Portable / Solar power for plane camping

Digitalpilotnm

Hi,

I am going to attend OSH this year its been 20 years since I've been there :(

Flying an Aztec with a couple of students, plan to camp in the N/S 40

Was thinking that a portable power back that uses solar would be good to keep devices charged, etc

What is the groups wisdom / thoughts / recommended product(s), etc ?? Would also apply for when I go back country and camp with one of the planes.

Thank you

jacobsja

This comes down to a requirements question, so will leave the sizing aspect out. There are also far too many options for actual solutions ranging from DIY to commercial, so will leave these out of the thoughts as well. No matter what the solution, just make sure there is a feature which will prevent shorting of the battery leads when the system is not in use.

For energy storage, my go-to is LIFePo4 as it is the least likely chemistry to go thermal runaway. BMS is a must for any solution though.

If this project is just for charging mobile devices, might consider seeking out a used power pack that has a lead acid battery (the kind that somebody might use to jump start their car) and swapping the lead acid battery for a LIFePo4 of the same size. I have actually gone this route and it is working rather well. If charging the power pack from something other than solar with a charge controller, make sure to get a charger which is able to use a profile for lithium batteries.

At the risk of insulting, reminder that the solar panel's charge capacity rating dependent on optimal position and 100% sunlight. So, downward adjust the expected numbers accordingly. Related, might also need a charge controller.

When doing the math of sizing for the battery capacity and solar array's wattage, reminder that the system will have some losses in it (ie: converting from 12v to other voltages, or converting from DC to AC), so factor these numbers into the requirements.

Another path, or possibly a parallel path, is getting a few small power banks which are specifically for mobile devices. Here is an example:

https://www.amazon.com/Solar-Power-Charger-Flashlight-Splashproof/dp/B07FDXDB3W/

There are two common downsides to the power bank path. Storage battery is something other than LIFePo4 (read: higher risk of thermal runaway) and the solar array (commonly) only charges the storage battery to 50% SoC. The only way to get the storage battery to full SoC is via an external USB charger (which kind-of defeats the utility).

There are also backpacks with flexible solar panels built into the unit which are specifically designed to charge portable devices. Here is an example:

https://www.amazon.com/ECEEN-Backpack-Charger-Tablets-Speakers/dp/B06WVGP8ZX/

I have zero experience with these items even though it looks like a useful idea.

Jack Fleetwood

I use the Jackery Portable Power Station 300 and 100 Watt Solar Panels. The solar panel charges the Power Station and you can also plug a few things directly into panel.

Also, the restrooms in the N/S 40 have plugs all around them and there are charging stations that are free as well. I've found the best way to do this is to buy a small power bank (like this one) that will charge your phone several times, and just recharge the power bank when needed.

N56404

I used a Solix 1000W generator and a fold out 100 wt solar panel. I depleted the generator the first day after using it to cook and was never able to recover power beyond about 50%. The sun did not shine enough and I was not at camp to constantly position the panels at the sun. Depending on usage, I might recommend a 300W panel.

griff390

https://piperowner.org/talk/discussion/comment/1448267#Comment_1448267

N56404;

As you've found out, lot of the pre-made systems are not balanced, but instead are tightly optimized only to work under perfect conditions. The real world is never perfect.

From an engineering standpoint, the rule of thumb for solar systems is double the panel wattage and double the capacity over your expected (or calculated) usage.

Doubling the charging wattage and doubling the watt-hour battery capacity also means your batteries don't work as hard, and will last much longer. Deep discharges kill batteries quickly. [edit] the downside when flying is doubling the capacity also doubles the weight.

For maximum lithium-ion battery life, don't charge above 80-85% and don't discharge below 35-40%. You will find variances in the numbers, but these are safe values.