I have a little more info on the bigger chargers soon. But I can tell you that non of them even the one I use had a good firmware for charging PB batteries. I have beel helping them fix that and the next firmware (4.8 or 4.9) will address that! Should be ready by last friday for testing but I still dont have it. Soon! And the next charger will be a "double" version of the one I use now. So it can charge two powerchairs from your car. Or one chair and my phone, or my helicopter... Or whatever. It will charge and cell balance and graph, discharge and test any two batteries at once! Up to 900 watts... (from 24v supply) or 500 from 12v.
Expected at the end of the month. And the latest pc software is perfect and has only 2 tiny bugs left that I can see! Of no consequence.
So when I get the next firmware we are all good to go and dispose of all out old powerchair chargers!
For 8 inch rims and 3.50 tyres which are easily available here (I could post) the rims are 2.50 or 2.75 wide. And they are fitted to cheap small gardening trailers etc. Or your powerchairs 2 1/4 inch split rims with a spacer...
They are available as very strong tubeless or cheap and cheerful trailer tyres.
http://www.monkeybike.co.uk/acatalog/Wh ... Tyres.html wheels and tyres. This place is not cheap but probably ship to the US! Ebay much cheaper! But I use 145/70 6 tyres now. Even cheaper complete with wheels!