18 Beginner Facts about DIY Solar Power

Even with some good books for beginners, understanding the basics seems to take a bit too much digging. Here’s what I’ve got so far.

And by the way, I’ve watched about 30 Youtube videos, spent $600 on a simple test system to learn how to power some of my backyard lights and stuff, and am reading one beginner’s book: Off Grid Solar Power Simplified (on Amazon).

1. There are two types of technology for the panels: monocrystalline (more expensive and efficient and lasts longer) and polycrystalline.
2. There are several types of batteries, but lithium-iron-phosphate (LiFePO4) seems to be the preference for solar lately.
3. LiFePO4 won’t explode or catch on fire unless you throw it in a fire.
4. Batteries are sold as DIY cells or ready-to-use batteries.
5. Ready-to-use batteries generally include a battery management system (BMS) which is electronics to prevent over- and under charging… which in turn reduces risks of damage to the battery.
6. Solar panels only produce direct current (DC).
7. Solar panels produce extremely erratic electricity.
8. For use in travel/vehicles, the DC can be used for some things that you purchase specifically because they run on DC… but it’s rarely as simple as connecting something to the panels. Hooking up 12-volt lights might be the simple exception.
9. DC devices with motors are not simple to power with panels because they cannot use erratic power and they need higher power when they start up.
10. For typical household devices, the DC has to be converted to alternating current (AC).
11. The device that converts the DC to AC is called an inverter. This is because it inverts the charge for half of the time, resulting in the alternation of charge.
12. Hooking an inverter to solar panels can create AC, but it would still be extremely erratic, following the sunlight presence. So batteries are almost always a necessity.
13. But what if you were satisfied running a device only when it were sunny, such as an air conditioner or fan? Newer technologies are answering this need. I learned of at least two companies that sell all-in-one air conditioners that run when it’s sunny… https://signaturesolar.com/ and https://www.airspool.com/
14. For a good-size mini-split unit, it looks like those companies can provide one for just under $3000 with solar panels, but not installed. You could do it yourself with good mechanic’s skill but no expert skill or tools… and no “charging” of AC fluid; it’s pre-charged.
15. Inverters are expensive, several hundred dollars for one that’s able to run any significant appliances. A 1000-watt converter is cheaper but only runs lights or impractical combinations of items.
16. Charging of batteries is tricky. As near as I can tell one can’t directly measure the amount a battery has left in it. Instead one only measures its voltage, and then looks up that voltage on a chart for the particular battery… and sees what “% full” that corresponds to.
17. Perhaps some of the devices I see on the web do that conversion for you— it would seem simple — but it’s unclear from their Youtube content.
18. Battery charging has this subtlety that took me a while to understand. I have a 12-volt battery, but it’s only 50% charged when it reads “12 volts”! It is rated to be charged with a 14.6 volt charging current… and most of its power is stored when it is over 13 volts. Picture stretching a stiff spring. The further you pull, the more strength it takes; that’s where it higher energy is stored. It’s no coincidence that the high-voltage lines on tall towers are often called “high tension” lines.

TO BE CONTINUED