Solar charger?

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Solar charger?

Postby Smark67 » 24 Jul 2022, 18:28

This there such a thing as a solar panel/charger you can plug into your chair to supplement its charge whilst out and about? Thanks in advance…
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Re: Solar charger?

Postby steves1977uk » 24 Jul 2022, 19:06

You'd need quite a few of them! Reallistically it's not feasible due to the very slow charge rate. You'd be better off fitting a LiFePO4 pack.

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Re: Solar charger?

Postby Burgerman » 24 Jul 2022, 21:44

You could fit a couple of 250watt panels. It would in summer, at around 12pm, if they were correctly angled towards the sun, no cloud, give around 350 watts for a short time. More if it was cool and sunny. That would give you enough to keep the battery more or less topped up as long as you stopped now and again to talk, or something. For a few hours a day. In winter not a hope.

Heres a couple of 250 watt panels, I fitted a few. https://www.wheelchairdriver.com/images ... in-996.jpg
http://www.wheelchairdriver.com/images-solar-frame
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Re: Solar charger?

Postby steves1977uk » 25 Jul 2022, 10:21

Yes 250 watts+ panels would work, but how would you carry those around on a chair? :eh: https://duckduckgo.com/?q=250+watt+sola ... &ia=images

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Re: Solar charger?

Postby Smark67 » 25 Jul 2022, 12:01

Okay, thanks, although I did think the forum was for helping people not taking the piss out of them…
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Re: Solar charger?

Postby steves1977uk » 25 Jul 2022, 12:37

Well, it's your choice but if you are looking for more range from your chair then the only sensible solution is a Lithium conversion. Even a 80Ah LiFePO4 add-on pack would work for you. :thumbup:

Lead bricks are just simply not up to the job these days unfortunately.

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Re: Solar charger?

Postby Burgerman » 25 Jul 2022, 12:58

Nobody is taking the piss. Just trying to explain quite how little solar panels give almost all of the time. And so how huge they would need to be. And so not very practical unless you have at least 2 huge 250 watt panels and only then around 5 or 6 hours in summer.

Right now my carefully aimed, south facing 35 degree angles 3kw worth of panels, are making 350 watts. In high summer. At 1PM while sun is high. Because its cloudy. That means that you would *just* have enough power to run your 250 watt powerchair charger. With a little in reserve. But that only charges at 8A and so you would extend range. But still gradually run down the battery as you roll. If you stopped now and again it would probably keep up. If it wasnt cloudy then you would only need 2 big panels.

But unless bright clear sun, that would require all of my 12 of those 250 watt panels aimed south at 30 degrees. In summer! And my panels are typical, and make around 9 times less watts in winter. Meaning that you would need even more of them!

Since theres no way to fit that many huge panels, it cant work. If you fitted just 2 panels as a canopy/roof, around 7 feet x 9 feet (2 panels) above a chair, or on a trailer it would probably keep up mostly in direct sunlight in summer. Angled correctly. But that seldom happens other than a few hours a day in some hotter countries.

So the obvious solution is to fit the panels on your house roof, as I have, and let them charge your lithium battery in the daytime. Or even at night. Then they can really help. How? Because during the day they feed power into your washin machine or computers, or heating water, or running the dryer, and any that you dont need goes into the grid. At night you draw it back.
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Re: Solar charger?

Postby slomobile » 25 Jul 2022, 18:35

8A typical mobility charger * 28.2v = about 225W. And it takes most of the night to charge your chair.
A 50W solar panel is about the right size to barely fit within your chair footprint and provide some shade.
I have a 24" x 26" 50w 19v Grape solar panel for this purpose but haven't figured a good way to mount it yet.
When I added a similar shade to the mower, a backyard tree took it within minutes.
If used to charge the chair batteries, it might add a bit of range. It would probably trigger an over voltage warning every time I go downhill.
My plan is not to charge the chair w/ solar, but rather to run 12v accessories that would reduce range if powered from the chair.
Phone charger, a fan, a small Raspberry Pi computer, a light.
Now that I look at that list, they could all run from 5v so there may be efficiency gains eliminating the 12v-5v conversion, but those panels are harder to find in large sizes. I guess a little solar usb power bank on the lap would be the easiest way. Not much power generation or shade happening that way.
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Re: Solar charger?

Postby slomobile » 25 Jul 2022, 18:52

I think you could probably take a 24v nominal panel of whatever area fits your chair, and wire it directly to an XLR connector and plug in to your chair. No extra charger required. Try it and let us know how it works out.
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Re: Solar charger?

Postby Smark67 » 25 Jul 2022, 21:41

I guess I was just asking, somewhat naïvely it seems, about a device that would fit on the chair to supplement a charge to the XLR input. I'm no good with regards power amps and wattage etc… :-)
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Re: Solar charger?

Postby ex-Gooserider » 26 Jul 2022, 00:07

Solar is not a great solution for all the reasons already mentioned, but if you really do want to try it, you will get the most benefit if you use a DC-DC to convert the panel's DC output directly to charging voltages for the chair. Every change has losses so going from panel DC to AC to Chair charger will waste a lot more of the panel output than going from panel DC to Chair DC... I am not an expert, but I believe that at least some panel charge managers can do this, so no special tech is needed.

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Re: Solar charger?

Postby shirley_hkg » 26 Jul 2022, 00:31


Plug in solar cells to chair ?
Safe and viable ?

I use DC-DC buck boost inverter , with CC / CV adjustable .
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Re: Solar charger?

Postby Burgerman » 26 Jul 2022, 04:28

Unless you like wasting a good bit of the feeble power a small solar panel gives, if the sun happens to appear. Then you should be using at least a simple power point tracking solar battery charger. They are around 10 or 20 dollars.

It tracks the best panel load/voltage and tracks and maintains this, while giving the battery a CC/CV supply at the same time. Without that the solar panel will at best give you a part of what it should. The MPPT part being the important bit. The shirley board above does that too. But looks a lot less user programable and user freindly. They allow YOU to set a charge voltage digitally etc. So I set the one on my van to charge at 13.3V in summer, 13.8V in winter.

Something like this https://www.ebay.co.uk/itm/264991999976
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