First of all you only need two things. Knowledge (on this page)
and a Digital Volt Meter.
These are available if you don't have one in many places
All it needs to do is read VOLTS accurately.
The batteries in your wheelchair are 12v Lead Acid Deep Cycle
batteries. In about 99 percent of all current powerchairs. They are generally
wired in pairs, and connected in series.
The chart below will apply to ONE battery only! You will need to
double those voltage figures if you measure both batteries together Obviously.
Now how do you measure these voltages? And When? Well to
begin with you will need to switch OFF your Powerchair and wait at least 4 hours
to get a true reading.
Overnight is better still. You cannot get very accurate reading
just after charging or using your Powerchair. The voltage has to "settle" or
"stabilise" so you just have to wait! Although after say 30 minutes or so
after you arrive home you will often get a reasonable idea. With this in
mind, how do you do a quick and dirty "read"?
Take a look at your powerchairs charge socket. In most modern
powerchairs it generally has three holes for the "pins" in your chargers plug.
Two of these connect directly to the wheelchairs batteries. The
third you can ignore. It is used in programming, and inhibiting your
chairs movement while charging.
The two we want are generally the bottom two. If you carefully
stick the Volt meter probes into these two holes then it will read the true
It will be about 24v to 27v. If you have it connected backwards it
will read minus this amount! If you connect to the wrong pin it will read
nothing, or a strange figure, but wont hurt anything.