The PowerTech Sigma Power center has helped to make life a little easier for me.
I’m in a wheelchair and recently had to start using a ventilator to assist my breathing. The “laptop” ventilator was small and light enough that it could be carried on the back of my chair—no ugly modifications were necessary to mount it. However, some modifications would be necessary to hold the clunky external rechargeable battery for the ventilator. The Powertech center proved to solve this problem—it’s so small that it fits in the side pouch of the vent’s backpack-like carrying case on my chair.
The PowerTech center transfers power from my wheelchair battery to my portable ventilator—without interfering in the way my chair operates. The wheelchair battery must be charged every night. Surprisingly, it gets me more power than the typical 9-hour external battery! Once, I was out somewhere 10 hours straight without any significant drain in power—the wheelchair power gauge indicted only 1/5 had been drained.
The best part is the fact that when I’m not moving—just watching TV or on the computer—the ventilator itself can be plugged into an electrical outlet. That way the chair battery power is saved.
The wheelchair battery needs to be replaced yearly (depending on battery size) ensuring that there won’t be any lack of power. The PTC never needs to be replaced!
We want to thank the wonderful people at Richardson Products who brought us the Powertech Sigma. Becky is free now to work and play as hard and as long as she wants during the day without worry about her vent needing batteries. Prior to using the converter, we used 3 batteries a day and had to make sure we always had extra with us and had to make sure we were close to our extra battery or carry it around. We had to recharge three batteries every night (the insurance doesn’t reimburse for the charges either). It seemed that the battery was always running out at the most inopportune moments, often interfering with a family outing. But all of that has changed now. With the PowerTech Sigma, we go all day with no worries about batteries, no worries about getting too far away from our spare battery. We’re enjoying the freedom. The pictures you see show our busy little girl as we played at home, went to school, went in the van to a doctor’s appointment, and came home to enjoy the outdoor fun with friends. At the end of our busy day, Becky’s joystick still showed the charge almost complete. We lost only 1 or 2 bars on the wheelchair after a whole day ( which typically starts at 7 am and concludes at 9pm) of busy activity and continuous ventilator use. Since we don’t need the vent tray now for the battery, we are planning on eliminating the ventilator tray on Becky’s new wheelchair. We absolutely love the Sigma! Thank you again!
RPI Tutorial: Installing a Battery Quick Disconnect Kit
Wheelchair Manufacturers have made it quite easy to access once hard to get wheelchair batteries. New designs allow most wheelchairs
to physically separate the battery box from the chair itself. It is our hope that you own a chair similar to the one below. If you have an older style wheelchair it might prove quite difficult to gain access to the battery compartment on your wheelchair. You might have to work at it a bit harder to complete this modification but it will be a valuable asset when the steps are completed.
Before you begin, we have found it helpful to assemble all the equipment you will need in advance. Also, make sure you have a large area to work in. Keep the area clean & safe. Never make modifications to a users wheelchair with the user still in the chair. These simple steps will help you safely make this modification to your wheelchair.
Potential Equipment List:
All Wheelchairs are different, so this list of equipment might be different from your equipment list.
Digital or Analog Voltmeter
Flat Blade Screw Driver
Monkey Wrench (size to fit battery terminal post) (BE VERY CAREFUL NOT TO ACCIDENTALLY SHORT THE BATTERY WHILE USING THIS TOOL!)
Cordless Electric Drill
Assortment of Drill Bits (To make holes in the battery box if required)
Step 1: Determine what voltage is required for your application.
The PowerTech Sigma requires 24Volts DC to operate properly. Always take proper precautions and observe all safety regulations when working with any type of battery. The Sigma will use both wheelchair batteries simultaneously for input voltage requirements. The batteries are already wired in series on your wheelchair. Your task with this first step is to find the ground and the positive terminal that yields the required 24 volts. You must make sure you select the proper terminals (The “proper” terminal combination are the terminals that yield 24 volts with the right polarity!)
Step 2: Primary Goal is to gain access to your wheelchairs battery box, observe polarity, and install the battery quick disconnect kit.
Most modern wheelchairs physically separate to allow people to easily access the batteries. We hope you find this to be true for your particular situation. Read the operating manual that was given to you when you purchased your wheelchair. Your primary goal is to gain access to your wheelchairs battery box. All wheelchairs are different. The one shown here had two clips that had to be squeezed together in order for the locking levers to release. This chair comes apart in less than 5 seconds. Access is very easy….Again we hope that you can access your wheelchairs battery box this easily. If you are having trouble…take your time. Look and study the chair…if you can place a call to your wheelchair manufacturer to ask them how to gain access to your chair specifically that would be great. Remember, gathering information about your wheelchair can really make this a very simple task. The following pictures have been provided to help show the process.
Determine the proper Battery posts that yield the 24Volts you are looking for. Every Chair is different! So take the probes of your volt meter and begin probing. I usually take the negative probe of the meter and place it on the negative terminal of one of the batteries. Next, take the positive probe and touch it to the other batteries positive terminal…if you see approximately 24 volts on the voltmeter, you have guessed correctly…if you do not see a voltage…you have your probes on the common wire or series jumper wire. Move the probes to the opposite terminals….place the negative probe on the negative post of the other battery…and the positive probe on the positive terminal of the other battery…you should see 24 volts. (This is the hardest part…the rest of the steps are just mechanical in nature.)
Simply attach the battery kit to the proper terminals. If your battery has wing nuts like the one shown in this picture…Unscrew the wing nut, and put the Positive Ring of the Battery Quick Disconnect Kit around the post. Replace and tighten the wing nut. Remember to double check for proper POLARITY! Make sure you have tightened the wing nut to ensure a good electrical connection.
The same thing again only with the Negative battery Post. Unscrew the wing nut, and put the Negative Ring of the Battery Quick Disconnect Kit around the post. Replace and tighten the wing nut. Remember to double check for proper POLARITY! Make sure you have tightened the wing nut to ensure a good electrical connection.
Neatness Counts! Re-Apply Any Battery Insulators that may have been moved during this process. This particular battery box has a wire channel, so the plug can come right out the side of the battery box. Because every wheelchair is different, you may have to use a cordless drill to drill a hole in order to get physical access to the plug. If you do need to drill holes. TAKE THE BATTERIES OUT OF THE BATTERY BOX!
DO NOT RISK DRILLING INTO A BATTERY! BE SAFE!
Ensure you have the proper voltage at the plug end. Your voltmeter will read somewhere around 24volts. Don’t be alarmed if the voltages are higher or sometimes lower than expected…they should be somewhere close to 24volts. Make sure you double check the voltage and polarity before you replace the battery box cover.
Replace your battery box cover and put the wheelchair back together. Feel free to use wire ties or other wire harness equipment to ensure a neat job. Setup is now complete. You should now have a terminal that you can access your chairs battery voltage. This terminal can be used with many of our products. It is an industry standard connector…it can also be used to connect other types of assistive technology to your chair. After you have verified the voltage and also verified for proper polarity, simply plug your accessory equipment into this plug. If you have any questions at all please contact us. We hope this information was helpful.