CHARGE!
Getting the Most Out of Your Batteries
by Kathy Wechsler
Your battery system is the fuel tank of your power wheelchair. The
fuel it carries is an electrical charge, which needs to be kept full
so it can operate.
Wheelchair and scooter batteries are called deep-cycle batteries,
meaning that they require constant discharging and recharging. (By
contrast, the battery that starts the engine of your car recharges
itself as you drive.)
“A deep-cycle application is like a trolling motor in a fishing
boat, where you run the little motor fishing all day long and then
once you get home you recharge it,” says Craig Starkey, service
manager for Travis Medical Sales in Austin, Texas.
“You deeply discharge the battery before you recharge it. Same
thing with a wheelchair: You use it all day long and then charge it
at night.”
The Facts of Life
Virtually all scooters and wheelchairs use two 12-volt batteries,
which produce 24 volts.
Since the batteries act as your wheelchair or scooter’s fuel
tank, it makes sense that the larger the fuel tank (battery size),
the more fuel (power) it can hold, says Dennis Sharpe of MK Battery,
a leading battery distributor to mobility equipment dealers. (The
company doesn’t sell directly to the public.)
In keeping with this theory, a U1-sized battery system, which is
used in most scooters and inexpensive power chairs that don’t
need to travel long distances, is half the size of a Group 24 system.
If your chair uses a lot of power because you need to have a greater
range, then a Group 24 is for you. The size of the 22NF battery system
is between the U1 and the Group 24.
“A [chair’s] amp-hour rating gives an indication of how
much energy the battery is designed to hold,” says Sharpe, who’s
been with MK Battery for 18 years. “It’s like measuring
how many gallons of gas an automobile fuel tank can hold. It won’t
tell you how many times, cycles, the tank can be refilled so it is
not a measure of longevity.”
The owner’s manual that came with your wheelchair or scooter
will tell you which battery to use. Sometimes the manufacturers will
give you an option, and if that happens, Sharpe advises getting the
bigger battery system for greater longevity and performance because
it can hold more energy.
Who’s in Charge?
Sharpe recommends that you charge your chair according to how often
you use it and the wear and tear you put on it. Never let the batteries
run all the way flat, he says. The deeper the discharge, the harder
it is on the batteries when you go to recharge them.
Let’s say that you only use your power chair occasionally.
Since you’re not putting much running time on the chair, you
can charge every two or three days without running down the batteries.
On the other hand, if you run your chair 12 miles every day, you should
charge it daily.
“Any time there’s doubt about how often you should charge,
it is better to err on the side of daily charging,” Sharpe says.
“No one should ever become stranded because partially charged
batteries did not get them home.”
But the number of hours isn’t the only measure of how hard
your batteries work. That also depends on how you use the chair.
Maybe you use it for eight hours every day, but you always stay indoors.
Your friend only uses his power chair to walk his dog for two hours
a day, but he takes his dog up steep, rocky hills. Even though you
use your chair for more hours, your friend’s going to have to
charge his batteries more often because he works them harder.
“Batteries take some time before they begin to absorb the energy
the charger is trying to provide,“ Sharpe says. “We feel
that a longer charge time allows a better chemical process which benefits
the entire battery.”
Some chairs will tell you when you need to charge the batteries by
the light on the fuel gauge. When the light changes from green to
yellow, it’s usually time to charge.
Some newer power chairs have a multicolor battery display located
on the chair’s controller. The display consists of green, yellow
and red bars.
“To get into a good habit, I tell people to try and drop the
green bars off the graph before they recharge,” Starkey says.
“If that’s every other night or every third night, get
into that routine.”
Time for a Change
How do you know when it’s time to get new batteries?
“Usually they start to fail because of their age, and their
performance starts to drop,” Sharpe says. “I think that
in general, people know when all of a sudden the chair or scooter
is not running quite as strongly at the end of the day or they are
not getting quite as far.”
Starkey says that older batteries usually don’t fail without
giving you some warning signs, such as decreased running distance
between charges. If all of a sudden your new batteries go dead, you
have a defective battery.
“All battery manufacturers warranty against manufacturing defects,”
Sharpe says. “This warranty is given to the dealer, who should
determine if the problem is actually battery-related.”
Before replacing your batteries or letting a technician talk you
into replacing them, consider how they’ve been performing, Starkey
says.
“If you put your chair in the shop for new tires or whatever
and all of a sudden they say you need new batteries, I’d ask,
‘Why do you think I need new batteries?’ They say, ‘They’re
a year and a half old.’ And you say, ‘Well, so what, they’re
working great.’”
Shopping for Batteries
To buy and install replacement batteries, both Starkey and Sharpe
suggest that you visit a DME (durable medical equipment) company with
a service department. These technicians have the proper training and
can find the best batteries for your needs.
It’s never a good idea to buy wheelchair batteries online or
from a battery distributor and install them yourself unless you’re
an expert.
Starkey says to beware of battery distributors that want to install
your batteries, because they don’t specialize in wheelchairs.
“You go to your average battery distributor, and they sell
you batteries all day long, but they don’t know anything about
your wheelchair,” he says. “They may not even know how
to get it apart to put the batteries in, and the last thing you want
is somebody messing up your chair.”
A DME technician may even find that the batteries aren’t the
problem, Sharpe says. He or she will be able to tell you where the
problem comes from or if you have a faulty battery charger.
When you get new batteries, the cost depends on the size of the batteries
and how much work is involved in the installation process.
Installing a U1 system can cost from $150 to $250, depending on how
easy the batteries are to access. Specialty seating such as tilt and
recline systems make the batteries difficult to access.
You can expect to pay up to $500 to buy and install a Group 24 battery,
depending on ease of access.
Medicare, Medicaid and most insurance providers cover a percentage
of the cost. MDA also pays up to $500 per year for wheelchair repairs
and modifications, which include the purchase and installation of
batteries (see “Your MDA Journey”).
Then
and Now |
| It used
to be that you could only buy lead acid batteries. These liquid
electrolyte batteries have to be maintained by monitoring
the water level and refilling with distilled water. A messy
job, especially when an acid spill causes corrosion.
Acid can easily leak from
a crack in the battery case, eating away at your chair’s
electronics and damaging whatever’s around it. This
causes problems for airline travel: Lead acid batteries have
to be removed from your chair and placed in a spill-proof
container before it can be put on the plane.
Thankfully, technology has
improved battery systems.
“We don’t deal
with [lead acid batteries],” says Craig Starkey of Travis
Medical Sales. “All of our wheelchair manufacturers
recommend sealed, maintenance-free batteries in their chairs.”
Sealed batteries were introduced
in the early 1950s and have gradually replaced lead acid batteries.
For starters, they’re spill-proof, easy to maintain
and approved for airline travel. There are two types of sealed
batteries: sealed lead acid (SLA), synonymous with absorbed
glass mat (AGM), and Gel, which is also a sealed lead acid
product.
In SLA batteries, the electrolyte
is liquid, but the batteries are sealed so the acid can’t
spill or leak out. Gel batteries, in which the electrolyte
is a gel, give a longer life expectancy and better performance
than SLA batteries. These are excellent for users who travel
long distances.
“There’s no more
demanding an application for a battery than a power wheelchair,
because we’re looking at 16 hours a day, seven days
a week,” Starkey says. “Only the best of batteries
are going to hold up to active users.”
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