Jeff McDonald – Wheelchair Battery Solar Charger – EE

For individuals that require the use of an electric wheelchair, their freedom of mobility is limited by the life of the batteries that power them.  One possible way to extend the range of these wheelchairs would be to add a solar charge system.  I’m not sure if the efficiency of relatively small solar cells could keep the wheelchair charged and running in the sun indefinitely, but it could certainly add to the total time the wheelchair could operate before needing to be recharged, especially if it were non-operational for periods of time (say sitting in a park). 

I’ve seen some ideas for these types of wheelchairs but not much commercial production of either wheelchairs sold with the solar charger installed or a kit to add the capability. 

It would also be interesting to see how feasible it would be to add the ability of the solar panels to track with the sun for maximum output of the solar cells. 

Another interesting thing I found, was that most of the smaller scale solar panels were 12V and almost all electric wheelchairs operate on a 24V system.  Some panels were 24V but the prices were considerably higher.  If a 12V panel were to be used an inverter would need to be added as well. 

01
January 29th, 2013 2:50 pm

There has been some work for solar cells to track the sun. It has even been worked into new-media art: trees and plants that move to where the sun is.

In terms of solar cells assisting the length of time a battery lasts, I’m concerned that the current you will get out of a reasonably sized/weight solar cell will not make a serious impact on the battery. You might look at what is available for cars as a model. There are some trickle chargers out there, for example: http://www.harborfreight.com/15-watt-solar-battery-charger-68692.html

From here you can look up how much a wheelchair motor draws and see if there is some possibility. I’m a bit sceptical but would love to be proven wrong.

02
Hector P.
February 3rd, 2013 6:12 pm

another interesting thing to consider is how much does the solar panels will cost,how fragile are they ,and how much space will they occupy on the wheel chair?

03
nickgarcia
February 4th, 2013 11:05 am

I wonder if you would be able to use regenerative braking like they do in the electric cars to capture and reuse energy lost in braking and supply it back to the battery along with solar cells.

04
codyhastings
February 4th, 2013 6:02 pm

Through a quick google search, I came across a similar idea at this website: http://www.ecomelectronics.com/prodinfo.phtml?id=3274441&ref=froogle but I’m sure that you could create something to improve upon this by creating a permanent fixture to the chair for continuous charging.

05
codyhastings
February 4th, 2013 6:20 pm

After a quick google search, I found a similar product at http://www.ecomelectronics.com/prodinfo.phtml?id=3268113&ref=froogle However, this does not appear to be something that is made to be a permanent fixture on the chair, so perhaps by making the charger to be fixed on the chair for continuous use you could improve upon the current products on the market.

06
williamdrescher
February 4th, 2013 6:47 pm

I think you would have trouble getting much power from a wheelchair sized solar panel. If you’ve seen the solar challenge racers, they have much more surface area, but still spend time parked to charge their batteries.

07
kishor
February 4th, 2013 11:07 pm

i also agree with Hector P. thought. How much space will solar panel occupy in wheel chair.

08
alibouhouch
February 5th, 2013 12:16 am

self test battery to check for the charge left. This concept is very conman . you can find a chart for this ratio or plot one
http://onsolar.co.uk/blog/47/keeping-a-healthy-12v-battery-pack/

also you can study the distance traveled on full charge and 1/2 charge and so on. not sure if the relation between charge and distance is linear but it shouldn’t be hard to figure it out. in all cases this idea is very good

09
imranmalik
February 5th, 2013 10:34 pm

sound very interesting to me

10
gregcarpenter
February 15th, 2013 12:58 pm

A user will normally use 20 to 45 AH from a 24V battery.
Alot

11
September 28th, 2013 9:13 pm

I am a wheelchair user and somewhat concerned about a power outage which would totally incapacitate me. While having an onboard charger would be nice, I wondered how I might just charge my batteries enough to move around my house and yard using solar energy which would then move my wheelchair. Sure, having a chair that would take me miles would be great, but the minimum a power chair user needs is the capacity to move a few feet or yards to get food, a bathroom break, and so forth. Survival.

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