Permobil SmartDrive MX2 Budget Battery

Max Mobility created a great product. Permobil wants between $1,400 and $1,800 for a battery. I replaced it with a $49 hoverboard battery. This is the same video as "Frankendrive" with the audio levels corrected.

[@mrb2917]

Thanks for this great video. I just bought a used mx2+, now I don't have to worry about if the battery is DOA or not. This looks like a quick easy upgrade, thanks again!

[@timgraves.crittersinmyarea7792]

Awesome. I have the same mx2 from max mobility in 2016 recently the battery finally died, and i didn't want to pay 1500 for a new battery. Permobil said I needed to update my mx2 with mx2+ technology, but I wanted to use my old school Bluetooth wristband. They said it wouldn't work. So I told them I'll just get a new mx2+ and swap the batteries. lol they said the batteries in the mx2+ are not compatible with the old mx2. I didn't believe them but my insurance would pay 100% for a new mx2+. Soon as I got it I opened it up to discover they are the exact same battery. Now my old mx2 is perfect and I have a box of spare parts from the new mx2+. LoL

[@duneroller]

Thanks for verifying the batterie are the same. I found parts diagrams that gave the same part number but your information means the numbers actually mean the same battery! I also have an MX2 and and MX2+ and the batteries had the same number when I took them apart. The MX2+ app on the Iwatch actually has an MX2 mode so it uses the MX2 push sensing rather than the MX2+ double tap to start, single tap set, and double tap stop.

[@vikj1255]

Thanks for that info. very useful. I havent used min MX2 is 2 years and the battery is dead. Wondering if its worth fixing or selling.

[@vikj1255]

Well done sir! Where do you find your parts please?

[@duneroller]

There is a good shot of hoverboard battery pack at 1:03 in the video. Look for 36 volt and 135mmX70mmX60 mm 4.4AH on Amazon or eBay. The wires and connectors are cut from the old Battery (remember to cut one conductor at a time on all batteries to avoid shorting). Both the charge and discharge plug from the MX2 are soldered together with the new batter pack leads to complete the project. I don't post links because they all eventually stop working. I hope this helps. I've been using this setup regularly at work for 8 months with no issues.

[@Warren1814]

Awesome work Jeff!!! I have a question for you.. How did you get your wheelchair brakes to sit so low? i have never seen that before.. i want mine to hang that low too.

[@duneroller]

It's a standard wheel lock position for the Invacare A4 wheelchair. Invacare, Quickie, and TI all have frame mount push to lock that are below the frame. I also have a quickie with scissor locks on the front tubes which are pull to lock and behind the calf when in the chair.

[@Warren1814]

@@duneroller Now that is cool... I am going to get myself a Ki Rogue 2 chair soon i hope.. Dunno if they have that option but i am sure going to look into it.

[@jvv8950]

Thanks

[@mikethe2thman]

how is the run time? and do you think a 40 volt lawn mower battery might work as well maybe faster?

[@duneroller]

The run time is better than stock because the hoverboard battery has a larger capacity. Because I don't have any specifications on the drive board I would stay in the 36-volt range. The additional voltage will not change the speed. That is limited by the software on the board.

[@lanjack3132]

And also I took a screenshot of your battery and if I’m not mistaken if you search Structure: 10S2P battery it’s the correct one right? That way if someone else is looking it might help if I got it right thanks again

[@jeffberry5563]

@@lanjack3132 That's correct 20 cells total in 10p2 configuration. For those who don't mess with this stuff much that's 10 cells in series to get 36 volts in parallel with another 10 to get adequate current. If you played out the batteries like a ladder the sides between each rung would be a battery and the rung would be the parallel wire.

[@alnitty1142]

Hello do you happen to have the link for the hover board battery thanks.

[@brittanygamblin739]

Wondering the same!

[@alnitty1142]

@@brittanygamblin739 in his other video he has the specs of the battery .. you can google it and find it.

[@lanjack3132]

I am really impressed if you where to order connector do you know what connector number they are thanks a lot for the information

[@jeffberry5563]

@@lanjack3132 Which connector? The battery connector depends on which pack you buy. I cut the other connectors from the MX2.

[@jvv8950]

Hi Jeff, my son uses an MX2 for years and depends on it. Recently battery has decreased capacity. I bought a used one on eBay to refurbish as I didn't want to mess up his existing one. I also bought a replacement battery there from Europe for $500. I replaced it and it worked for awhile then stopped working. Wrist band is connected, motor will not kick in when chair is pushed. The unit has an older serial #, so according to permobil r 232 should not be connected but old and replacement batteries have cable for RS 232. Do you think connecting the rs232 could be the problem ? Have you found anyone to replace the cells in the battery?

[@duneroller]

When you say the wrist band is connected I'm assuming when the MX2 and wrist band are powered on the LED on the wrist band blinks blue about 1 time each second. This indicates a solid connection. The RS232 should not have any effect on the function of the MX2 other than you will not get battery error information. If you want to make sure it's not the RS232 just remove the handle (only to make it easier to sit it upside down) then the six screws that hold the bottom on. The RS232 connector can be unplugged with a fingernail. Re-assemble and mount on chair to test. Are you testing the unit mounted on the chair in normal orientation and with a smooth push? The unit needs to be at approximately the operating angle and handle up to function. I've also had issues if I run the wrist band loose because I push and the wrist band detects the wrist band hitting my wrist as a stop tap. I have not found anyone in the US to change cells other than the manufacturer. The US has many attorneys that like to file suit against anyone for any reason. Most people will not work on a medical device due to liability issues. I have built other battery packs successfully but I have not been able to do this one. I purchased quality cells the same capacity as the originals, welded them properly with nickel flat wire, connected the 13 BMS leads by soldering with high temperature (850F) for very short duration. I verified voltages pin to pin on the 13 pin BMS connector and all cells were within .01 volts but it still burned up the BMS as soon as I plugged in the connector. That's when I gave up and put the hoverboard battery inside.

[@jvv8950]

Thanks. According to the Permobil smartdrive battery replacement video, lower serial numbers do not use the battery connection to RS232. I'm not sure what that means.

[@duneroller]

@@jvv8950 Sorry for my slow response. I just read your comment. RS232 is a basic serial communication protocol. It's most often used on computer with a 9 pin VGA port to communicate with peripheral devices. The cable with the small wires running from the battery pack to the board communicates the status of the battery pack to the main board. The earlier drives do not use this communication connection according to Permobil.

[@philliphathaway4399]

Any updates on the battery ?

[@duneroller]

All good so far.

[@philliphathaway4399]

@@duneroller did you have to solder anything on the battery or is that optional? I need to do this also do you have a link to that battery?

[@duneroller]

@@philliphathaway4399 The hoverboard only has a single connection used for charge and discharge (power). You will need to cut the battery wires (remember to cut one at a time). Cut the charge connector and power connector from the old battery and connect the three black wires together and the 3 red wires together. I soldered and put shrink tubing over the joints. The front area of the SmartDrive does not have much room so I don't think there is room for solderless (crimp) connectors.