Solar panel setup questions.

[freebeard]

You're adding solar on a tight budget and you don't know what you'll be powering with it? Isn't that kinda putting the cart before the horse? I would wait on the controller and battery until you decide what you're going to be powering.

Or, alternatively, not spending a lot on what is essentially learning experience?

[M_a_t_t]

I wasn't planning on buying the controller until I bought a battery, probably at the same time.

I was thinking about this and I realized that unless I added unnecessary height to the roof of the van I wouldn't be able to fit the battery(ies) inside the cap. My roof rack is only 2.25" tall, the solar panels are 1.38" not much room underneath, they would be angled but that only gives a max height of like 5" max. That might be enough for a custom pack of 18650 cells, but definitely not a lead acid or a volt battery (which was a little costly anyway).

I read an article that said that some of the 18650 cells have balancing built in, I think I'll look into that and see where it goes.

For the cap I would guess ~55-60 sq. ft of the poly metal, or wood, would be enough with a decent amount left. the inside of the van is about 50 sq. ft. add like 10 sqft. for the sides. There is a sign store in town, I've never been there but I'll have to check it out one day.

[freebeard]

That's what I was getting at earlier. I think you're on the right track.

If you fit the panels between and below the roof rack rails that would be a good fit. The hole is 68x44"? Two pieces 2x4ft and two 6'x.5ft should suffice. If my math is correct, that's about 22sq ft.

I was promoting a box above the windshield (an LED light bar might fit better with your rectangular headlights) as a location for the controller and batteries, that could be taller and narrower than the rack.

I have no investment in the outcome. Any chance there is a penetration in the roof already?

[M_a_t_t]

When you asked about the sq. ft. needed I thought you meant for a whole cap.

The only penetrations (I assume you mean holes?) are the roof rack holes (maybe a hollow bolt for wires if thats what you looking for) and the third brake light. I don't want to drill any holes in the roof either.

I ordered 8 18650 Lithium Cells to play around with, I'm going to use them to make a battery pack I can use in my R/C car (redcat tornado for those who R/C)

I think I understand what you mean about the box. I drew what I was thinking, thats what you meant right? I did some math and things, It should fit pretty easily. I don't quite understand the point of the LED bar though, is it just for load so the batteries don't just sit?

If all goes well with the cells I ordered, then I'll probably go for a 48v 30A battery (12s,~15p Thats 180 cells!). I am wanting to be able to remove the stock battery, I think I'll try it with both see how the solar holds charge and maybe after awhile hook it up instead of my stock battery. The only thing I'm worried about is the CCA, I know that lithium is better than SLA but is 30Ahr enough to start? Does anyone know?

If I get time I'll go looking around local recyclers for laptop batteries. I watched video series attached and I think I'll start with the old laptop lead.

And thats the biggest resolution I could get to upload.

One thing at a time tho

DIY "733" lithium ion cells How to build a 48V ebike battery

[freebeard]

The light bar was for load, and an excuse to do it, and ...why not? That's three reasons.

I forgot about the 3rd brake light. Eight 18650 cells is only about 24" isn't it? Those could easily get lost on the top, but with 180 cells you'd want them lower down. It's a long way from the 3rd brake light to the battery. Your battery pack could go anywhere in between.

I was picturing the LED bar being no higher than the roof rack. If you only radius the sides and rear you might get down to 8-10sq ft. Strips of aluminum roof flashing would be adequate if they were rolled.

[M_a_t_t]

Solar panels showed up a few days ago, haven't put them on the roof for a test fit yet.

Looked around and found these, 3.2v 20Ah lithium, 4 for $112 plus 12 shipping. I'm not sure if I want to do 20Ah or 40Ah, but I think I would try 20 then maybe upgrade to the 40.

[botsapper]

https://www.youtube.com/watch?v=G01A51L-5Vc

https://www.amazon.com/Adjustable-So.../dp/B00SBCKLYO

[freebeard]

Their testing was A-B, not A-B-A. Wing nuts? Crawling around on the roof? Why no benefit until the last panel was moved?

The interesting test would be tilt-up reflective panels.The benefit would be somewhat less than 100% due to spillage, refraction and etc. but it would be adding instead of reclaiming solar incidence.

[oil pan 4]

Problem is there are no 24 or 48 volt lithium ion charge controllers that I know of.
Everything is "12volt" based.

[freebeard]

Try ...cat=22. Things are sorted by price. It looks like the least expensive choice is $295:

EVTV Motor Verks Store: GENUSUN WATERPROOF 105-350W 56.8V LITHIUM BATTERY SOLAR CHARGE CONTROLLER, Solar, Boat and Golf, GVBoost