There’s something perverse about running out of mobile battery whilst sitting in a wheelchair with huge batteries. Various commercial products bridge that gap; the best of which is Cripple Concepts’ charger. These plug into the charging port on an electric wheelchair and provide a turbo USB charging socket.
These products suffer from some limitations however. Many of them (notably NOT Cripple Concepts’) give out too little power to charge a modern mobile phone. Many of them are expensive (CC’s $40 isn’t bad.)
It’s comparitively easy to create your own charger that is more powerful and versatile, and cheaper. You don’t need to know any electronics to do it either – if you can solder a wire onto a pin you can make this.
wheelchairdriver.com shows how to create such a USB adapter. I found his instructions invaluable (and wouldn’t have been able to make mine without them), but I have concerns about his creation. The first is heat dissipation: if doing similar with a high power charger, sufficient heat may be generated within the USB adapter to cause it to fail. I also think the connection to the adapter may not be robust enough to survive use and abuse. I would prefer a more powerful rapid charger. Also I would prefer a more “universal” product with e.g. 2+ USB sockets (and that also applies to the Cripple Concepts’ one.)
There’s an alternative, clunkier solution:
It’s clunky but cheap, powerful and useful.
1) Neutrik microphone plug.
Any will do. They are about £3 on eBay.
2) Cigarette lighter inline socket.
The cheapest way to get one of these is to buy a cigarette lighter extension and cut off / discard the plug end. However, I have discovered that those sockets aren’t very robust so break quickly. I advise against getting this very common socket:
Try to get one of these less common but more robust sockets:
They are about £4-5 if you shop around.
3) A cigarette lighter USB adapter of your choice. But NB: the adapter must work with 24 volts, not just 12 volts.
I use one that has two Qualcomm Quick Charge 3 USB sockets. This is about £2 delivered on eBay.
Solder the wires from the cigarette lighter socket to pins 1 and 2 of the Neutrik plug, as described on wheelchairdriver.com.
Strengthen the wire if you want, using heat shrink, hot glue or whatever. I also cable tie it to the wheelchair cable that runs to the control / joystick module, for extra strength and convenience. That way it’s always at hand.
Put the USB adapter in the cigarette lighter socket. That’s it, really, all done.
The only thing I also did however, is to find a way to cable tie the USB adapter into the socket. Reason being that otherwise it tends to work loose over time, which is frustrating – I’d discover my phone hadn’t been charging when I thought it was. Pushing the charger back into the socket does the trick until next time it works loose, however in my case I drilled a hole through the cigarette lighter socket and the USB adapter (carefully, to avoid damaging its internal circuit board) and put a cable tie through. Otherwise you could glue the adapter into the socket etc.
To use it: plug the Neutrik plug into the charging socket on the wheelchair. The USB sockets are now live and can be used for anything USB. In my case this is charging my phone, my Go Pro camera and/or my battery banks, and running a USB fan (I recommend the “Key Nice” fan below from Amazon) and/or Christmas fairy lights.
The charger doesn’t stop the wheelchair being driven, like plugging the wheelchair in does. It has a negligible effect on the wheelchair batteries. My wheelchair has 72 amp hour batteries and my mobile battery is 3.3 amp hours. So it can be used pretty much as much as you like without concern.
To charge the chair, simply unplug the USB charger and plug in the wheelchair charger.