The meaningless tests ignore
the following: Hills,
some turning left and right, and a few street ramps and road
cambers and a normal weight human and expect about half of that quoted range. And remember as
your batteries age capacity reduces slowly after about the first two weeks until it starts
to bother you after a good few months. For the first two weeks capacity will increase by around
6 to 10
percent as the battery gets "run in" or its plates "formed".
And even that figure will vary enormously. And
remember that an average discharge level of 50 percent is preferred if you want
your batteries to last more than a year and you begin to see the problem. Their
"test" presumes a 100 percent discharge. As it
is WITHOUT adding any off road use I run out of range and kill a set of batteries
every 10 to 12 months.
The best way to evaluate and make a "guestimated"
real range figure on a
powerchair is to look at the following:
a) its top speed.
Speed means taller gearing which murders batteries! With 70Ah group 24
"big" full sized batteries and a normal human being, 6mph is a sensible maximum.
4 mph if you are fat takeaway eating slob like me, 8 mph is ok if you are built like a
13 year old ballerina. Sorry to be blunt. But this is the REALITY if you
expect all or most of a days use.
b) user weight.
A skinny young girl will go twice as far on a charge as an average guy. A fat
person will go HALF as far. Its all about power to weight. Double the weight?
You need double the batteries. Or a chair with half the speed.
c) battery size.
In Ah (Amp Hours) A 100Ah (Amp Hour) battery has twice the energy of a 50 Ah
battery. (But not all of it is always usable) And a double capacity battery is double the
weight too - see user weight! In real terms you want the BIGGEST Ah battery you
d) usage. All
day? Hills? Many miles? Sat at home? Thick carpets/grass? Of road? Ramps, or
flat shopping centres? HUGE differences in the amount of power used up
here. Travelling fast on the flat uses about 1/4 of the power that turning on a
carpet, or climbing a small hill does.
So the ultimate bad case?
Fat guy with attitude that goes miles everyday and goes
off road or on grass walking the dog, uphill, and to the pub/club at night (me!) with
small 50Ah batteries in an 8mph powerchair.50Ah batteries under these conditions
will get about 3 or 4 hours heavy
use at very best.
So the ultimate good case
scenario? Batteries like huge 100Ah, slow 4mph
wheelchair, skinny 7 stone ballerina, lives in a flat smooth area, doesn't have a dog, doesn't
go far, stays in at night, no off-road, sits at home most of the time. Her
powerchair will go all day long (or two) without problems and batteries will
last 3 or more years easily if she charges them every other night.
Even tyre pressures
type) effect range.
Correct Powerchair Tire (Tyre)
What this all amounts to is that
you need to understand Powerchair dynamics and batteries gearing (speed) and assess what you
need based on usage/environment and user weight.
Don't expect the "pros" to do it
for you, because mostly they are
VERY clueless about these things. And salesmen the same. Plus they just want to sell you something
to make a dollar.
And absolutely ignore the
wheelchair services in the UK since I have yet to speak to anyone there in 12
years with any remote clue about Powerchairs whatsoever! Same with all the OT's I ever
If you REALLY want all day
range, and some speed as well as a few takeaway's then learn to
fast charge your powerchair
during the day to top up! It helps your batteries live longer too.
MORE BATTERY INFORMATION
Batteries for Both Vans & Power Wheelchairs
Inverters & Chargers
Which batteries to buy
fast charge your powerchair
Very flexible charger!
Lithium Ion Batteries for
Powerchairs and Scooters
Powerchair Battery State of Charge
Power Add On for manual wheelchairs
After reading this page you probably already know these are a bad idea!
Detailed PowerChair Only Menu