esk8.news esk8 calc donate now

Solar experiments - How a single solar panel powers all my boards

Welcome to the solar thread. This is how I made a cheap solar setup that makes more power than my boards need. And shows how a single panel can make way more power than you thought.

  1. You need a panel, this is a cheap 100w renogy panel off amazon for around $99. Based off more research I would no longer recommend this panel as the Richsolar 100 Watt Polycrystalline (also on amazon for $79) Produces more power for your money. Check out this guy for panel testing and more info on what makes a good panel.


    You can also see here it’s angled. After a week of experimenting I found this general angle and moving the panel once a day gives the most power with the least work. In the morning it should be toward the rising sun, at around 1-2pm switch it around to face the midday and setting sun. Since we only have 100w to work with, we need to keep it working at peak output as much as possible. If you are not home around 1-2pm, face the panel with a lower tilt angle south-southeast. That should grab the most sun with 0 movements. Perhaps even put it on your roof?

    It’s held up by a PVC pole, but for the first few weeks was held up by a camera tripod. Anything that angles it works.

  2. Inside the garage/workshop.


    Top right is the first thing to talk about. A super cheap charge controller. Literally $15. The two red wires are input from the panel, the black output to the batteries. I was low on properly color coded wire. Next is the batteries, I found them cheap on craigslist, $200 for both with about 20 cycles. New is $415 for both. They are hooked up in parallel (12v) right now, but if I got another panel I would change to a 24v system. (will explain that in a min) Since this is 200ah of storage, this actually takes 2-3 days of sun to charge if I drain them down low.

This is another “solar charge controller”. I have the battery bank hooked up to the panel input and whatever board, bike, or onewheel I need to charge hooked up to the “battery” output side. It’s just an adjustable boost converter with presets saved for 10,12,and 15s batteries. By using a DC-DC stepup converter we generate less heat (and less energy loss) than running the inverter plugged into your standard 110v charger. Now input voltage has an effect on output amps. So at 12v in 42v out I can only output 1.8a. If the system was set up in a 24v configuration, I could charge my boards much quicker. (but my lipo charger and inverter are 12v only, so… :man_shrugging:)

On the left is a fancy touch screen lipo battery charger. It can do basically anything I need when it comes to batteries that have dropped a P group. Or more often checking capacity through cycle programs. To the right of that is a normal 12v inverter. I run fans, lights, anything that I can’t power off the dc-dc converter.

Recently we’ve had a lot of extra sun, so I’ve been using the inverter a bit more to run things inside my house.

  1. Can you do with less? Yes. Now I ride during the day and charge at night. If you ride at night, then the panel can be hooked up directly to your board using the dc-dc boost converter. You don’t need the 12v batteries or the charge controller.


This setup charged my XR in about 3-4 hours, and kept going a bit past sunset. It’s honestly surprising how little light a panel needs to make power.

Wanna go camping? No problem, took one of the 12v batteries and had power for all of thunder in the mountains.

  1. Cost roundup and links. This is intended to be a cheap sub hobby. Don’t even think you could make a junker board for this much. These links are non-affiliate.

So for about $200 you can smugly ride around on the power of the sun. And keep riding when the power goes out. Neat.

43 Likes

Nice little write up. Some day I’ll do something like this!

2 Likes

I’m about to move house, this will be one of my first projects. Nice!

6 Likes

Truly great write up man. Much appreciated!

3 Likes

Great stuff!

That green MPPT you have makes for a great charge-n-ride pack. Just substitute a battery for the solar input. It does only step up though, as you found.


(Hastily thrown together before Colorado)

3 Likes

Well done, thank you

That’s what I originally bought it for. 40mi range onewheel. Yep.

1 Like

Very nice! My home runs on 6 300watt panels and 4 278ah agm batteries run in series for a 48v battery. It was a fun experience installing everything and then seeing how much power i was generating

3 Likes

Don’t use starter lead acid batteries for a longer period of time btw, they’re designed for high burst discharge and continous discharge only while charging (high surface area on anode and cathode, they actually look a bit like sponges when they are clean).

When they get charged and discharged slowly for longer periods of time sulfate builds up on the surface till it’s clogged, the performance is reduced over time till it’s fully covered after that it won’t charge/discharge anymore.

Partial sulfated lead can be recovered by strong pulse charges and even full sulfated batteries can be fixedby electrolysis but doing that by yourself isn’t advisable for most people (hydrogen build up, hot or even boiling sulfuric acid -sitting in a cheap plastic container- in your basement can fuck you up pretty hard)

Use power delivery lead acids instead, like boat batteries (which are usually enclosed gel, so no leaking hydrogen/sulfuric acid) or camper power delivery batteries for example.

5 Likes

I almost asked this question! Thank you for the in depth and educated reply.

Awesome post!

About battery selection: I would like to add that you can sometimes get “deep cycle” (this is what you want, not “starting” batteries, as mentioned above) at walmart or wherever. They are significantly more expensive and heavier (thicker lead plates). If it says something like “deep cycle/starting” and it’s cheap, it is not a true deep cycle battery. I tried a cheaper battery on a similar solar array and it didn’t last more than a year. I’ve heard guys getting 10+ years out of a true deep cycle cell, like the Trojan 105 (which are of legendary quality but expensive)

These are actually solar batteries designed for this type of work. It’s this one specifically.

That being said, lifepo4 is much more suited for this type of environment and if used batteries of that type been available in my area for this price, I would have gone with them. I expect these to last 5-6 years. Lifepo4 would be 10+ years and still have 80% capacity.

Being a crazy environmentalist I spent years studying sustainable architecture in my spare time (before I found electric skateboards) and I love this project. Here’s a tip.

For a fixed solar cell you need to place it facing south tilted to the same degree as your latitude. Cheers!

Great write up. I’m glad to see topics like this arise because it’s a great subject. I’ll be starting my own solar project soon but on a slightly larger scale. I live on a sailboat so I already have everything except solar panels and a charge controller. My goal is to completely supplement my energy needs with solar. So far based on the maths and available surface area, it’s a total possibility, and I’ll only need about 6 panels.

2 Likes

I just wanted to make sure you are aware that the common starter batteries with X years left in them are not suited for such applications, iamasalon made a similar comment that a little note one cost roundup would be ideal for a hint that starter battieries won’t work for a long time.

I actually like lead acids for stationary DIY stuff, I think they make much sense on the small scale we use them.BTW Some non gel batteries can be opened up to refill distilled water or acid when needed and as I said pulsing clears the leadsulfate on the lead plates which extends the life time of the battery imensly.

Lead Acid has it’s pros and cons

con:

  • weight and volume per watthour isn’t great
  • poor performance on low temperatures
  • need ventilation when stored (at least non gel lead acids)
  • the gases they produce are highly corrosive
  • pretty nasty when they get physically damaged

pros:

  • probably the best recyclable battery tech out there, the only thing that really non reversible degrades is the plastic housing. The lead, electrolyte can both easily seperated and reused for a new battery
  • cheap
  • easy to charge/discharge
  • very tolerant if misused
  • easily available and less affected from future fluctuations in price compared to other battery tech
1 Like

Re: pros/cons
I don’t think lead batteries can burn, but they absolutely can explode if the hydrogen gas is allowed to accumilate and there is a spark.

Regarding “starter” batteries, I am under the impression that if you don’t drain the battery below ie, deep cycle, the starting battery can have a long life. Typically, this means sizing the battery bank up a notch or setting a voltage cutoff higher to ensure you don’t go into “deep cycle” territory.

If you have the money upfront. Don’t bother with lead acid or it’s variants.
Especially for solar applications where the batteries are used inside a garage where it won’t get that cold.

Love it! Thanks for sharing! I have been looking for exactly such a DC-DC converter.
Have you encountered any better/upgrade alternatives?

Could you put some straps on it and ride with it on your back?

image