I’m only half kidding. I’m a bit of a prepper and I have lots of powerbanks and devices that charge from USB but besides idling my truck I really had no other way to charge any of them in case of a long-term power outage which seemed a bit of an oversight on my part.
Not like this solves the issue. 30 watts (under ideal conditions) isn’t much but it’s a start.


Have you calculated how long it takes/took to pay for itself?
All of the labor has been DIY, and I’ve got about $9,000 invested in the system components.
Back of the napkin math, at current electric rates, puts my ROI at just under 9 years. If electric rates keep going up, it’ll pay back even faster.
Edit: Depending on how you look at it, ROI could be in as few as 1.5 to 2 years. This system is in lieu of a whole house generator that would have cost us about $7,000. Had we gone with that instead, it would never have paid for itself (other than peace of mind) and we would have been perfectly content. So if I’m only considering the price difference between this and the generator, it’d only have to pay back $2,000.
Yeah, buying peace of mind when it comes to self sufficient power generation has no price tag. Decentralization of the grid is a good thing regardless of if you “pay it off” or not.
$10,000? $100,000? 75% of your salary for the rest of your life?
It obviously does have a price tag at some point. If someone wanted true self-sufficiency they’d have to get a full solar setup plus a generator in case the grid went down at a time when solar power wasn’t covering the needs. (That’s likely if, for example, your power is knocked out due to wildfires, and the wildfire smoke is making the solar setup unable to produce power.)
And, you can’t really consider yourself fully self-sufficient when it comes to electrical power unless you have a n+1 setup, so you have a backup generator in case the primary one fails and needs to be repaired.
If you enjoy it, it already has.
I get you but it was worth the money you spent ≠ it earned back the money you spent.
Okay but for real how long
have battery system and solar since jan 2023, still love it
Time, in hours (H), equals average solar kilowatt hours per month (K), multiplied by the price of one kilowatt hour (P), divided by the total cost © of all the purchased components.
H = (K * P) / C
I’m sure if you were patient and dedicated enough, you could approximate each of those numbers using the info OP has already posted and get a general idea (weeks, months, or years).
So you’re dividing the average saving per month by the total cost and expecting to get hours?
If we generously estimate a very high 3000kWh/month generated and high $0.40/kWh price and it cost OP $9000, then you formula is (3000×0.40)/9000 = 0.133 hours.
Breaking even after less than 1 hour?!??! Extraordinary!
It’s pretty easy to cry about bad math, but it’s a lot harder to figure out the right math.
Don’t worry, I’ll try to do it for you again a second time.
Power consumption varies. Use the average monthly power draw from the solar array, let’s assume for demonstration purposes 1,000 kWh/month.
Multiply that by the cost of 1 kWh from the power company, let’s say 20 cents.
In one month, that means you saved $200.
Let’s assume the solar equipment costs $1,000.
The answer is 5 months, or 5,000 kWh.
Sorry, I’ll make sure the free work I do for you is better quality next time.
Bro. Don’t act like this basic arithmetic and unit cancelation is hard. Not my fault you were so confidently incorrect.
Or I could read the comment where he said
Then do that instead of asking random people who aren’t in any position to know.
It was more of a comment on your comment
A hobby pays itself just by enjoying it. I’ve never calculated how long it will take to pay off my gaming rig