Page 2 of 2 FirstFirst 12
Results 11 to 20 of 20

Thread: Can lithium deep cycle batteries be used with powerchairs?

  1. #11
    Senior Member grommet's Avatar
    Join Date
    Aug 2008
    Location
    California
    Posts
    2,661
    Quote Originally Posted by wes4dbt View Post
    They are already using lithium batteries in wheelchairs. I have a Smart Chair (a portable electric chair) and the battery life is awesome, also I've seen some lightweight scooters with lithium batteries and Smart Drive does too. I've not heard of any battery fire/explosions. As far as ballast, you can always add that. It's time for the makers of full size power chairs to embrace the lithium ion technology. In the space where two Group 24 batteries go you could have lithium batteries that last 3 or 4 times at long. Well that's my rant and I'm sticking to it.
    I have a SmartDrive too. The lithium battery lasts a long time, never a problem. I haven't heard of a Smart Chair. We could add ballast, I thought of that, but I would rather have high capacity and light weight. Current powerchairs are designed for that ballast. I have been wondering about us getting lithium batteries especially since the electric cars began using them.

  2. #12
    Smartchair is another thing altogether: https://kdsmartchair.com/
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  3. #13
    You have to use a Li-Ion charger or the battery will become an incendiary device.

    The Li-Ion charger listens on the 3rd terminal for events such as any cell reaching its temperature or Voltage limit and then stops charging. If it keeps on charging you will have great balls of fire.

    The 3rd terminal will also model charging and gives the proportion of charge read out. If the Li-Ion is charged to less than 100% it will last longer.

    Large and heavy lead-based batteries are a daft idea for power chairs and Li-Ion technology is not exactly new.

  4. #14
    Quote Originally Posted by zagam View Post
    You have to use a Li-Ion charger or the battery will become an incendiary device.

    The Li-Ion charger listens on the 3rd terminal for events such as any cell reaching its temperature or Voltage limit and then stops charging. If it keeps on charging you will have great balls of fire.

    The 3rd terminal will also model charging and gives the proportion of charge read out. If the Li-Ion is charged to less than 100% it will last longer.

    Large and heavy lead-based batteries are a daft idea for power chairs and Li-Ion technology is not exactly new.
    You always have to use the correct charger. What third terminal are you talking about? Do you mean the hobby Lipo packs that do not have battery management systems, (bms)? Or are you talking about the wire coming off the bms to the battery cell and calling that the third wire? I have several lithium's that use two wire chargers and should have a bms, but I am suspicious of one of them.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  5. #15

    Great balls of fire

    Quote Originally Posted by nonoise View Post
    You always have to use the correct charger. What third terminal are you talking about? Do you mean the hobby Lipo packs that do not have battery management systems, (bms)? Or are you talking about the wire coming off the bms to the battery cell and calling that the third wire? I have several lithium's that use two wire chargers and should have a bms, but I am suspicious of one of them.
    There are two main terminals +Ve and -Ve that handle power. Then there is a sense terminal that talks to a microcontroller that senses Voltage and temperature of each cell and models charging. This is defined by battery manufacturer and it up to the charger to read it and obey. If for any reason the charger fails to respond the battery will fail catastrophically.

    It is possible to have just 2 terminals and then the battery must have a switch built in to disconnect itself from the charger. A boost circuit driving a power MOSFET could be used. The substrate diode allows you drain the battery, but forward biased MOSFET can then control charging. However, if a fault occurs the MOSFET will most likely fail short circuit and will no longer be able to provide protection. A suitable fast semiconductor protection fuse to protect the MOSFET will also be required.

    Some chargers sense the battery Voltage rather than the Voltage across each cell, but if they guess the wrong number of cells or one cell overcharges then you will have a catastrophic failure.

    As software becomes more bloated and less efficient Li-Ion will no longer be able to run laptops. For this application Hydrogen fuel cells are being developed. Now, these will store lots of Hydrogen in an alloy and burn really well.

    Where I work we have scary batteries on our Storage Area Network gear. Racks cubed off with millboard and fire suppression systems.

    https://en.wikipedia.org/wiki/Wirth's_law
    https://en.wikipedia.org/wiki/1-Wire
    https://en.wikipedia.org/wiki/Sense_(electronics)

  6. #16
    Good info zagam, I'll ask a battery question on a new thread as soon as I can determine what the question is.
    Last edited by nonoise; 03-30-2017 at 03:14 AM.
    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

  7. #17
    My Boma 7 off road wheelchair is converted to LiFeP04 batteries, they don't have the same fire risk as other lithium batteries, are lighter, handle heavy current load better and give greater range. Built from individual cells with monitoring for charging so that you don't overcharge. Charger was expensive but can fully recharge from flat in 3 hours. No BMS after reading wheelchairdriver.com. I've just had conversion done so haven't fully tested them but everything works well and engineer who did it said they would be much better than LA. He was from a UK charity that help the disabled so unbiased.

    Not cheap to do initially as good chargers are expensive.

  8. #18
    Senior Member
    Join Date
    Mar 2012
    Location
    Hampstead NC
    Posts
    1,078
    There are multiple battery technologies (chemistries) that use Lithium in their name. Most are dangerous under any conditions (ie: hoverboards) for our Powered wheelchairs LiFePO4 will not explode or burn, they are bullet proof. However, LiFePO4 batteries are not plug and go. As Rusty said on the web site WheelChairDriver.com there are people who have been using a LiFePO4 system for a very long time relatively speaking. Several contributors in the USA as well. These batteries used as these people have proven will have as many as +2000---80% cycles. Far more than Lead/Acid Batteries, however, they are again NOT plug and play. They require some specialized charging and those bricks batteries are NOT applicable for our use long term. Your Batt condition system lights that indicate state of charge will not work because the norm of 24VDC-- LiFePO4 battery will always read full it will carry 25.6 volts until you destroy them by over discharging them however, here again you will get more Amp hours use 2x-2.5x from LiFePO4 as well.. They basically do not drop in voltage but use the amperage stored. If you are interested in all types of lithium batteries or even for better knowledge of any kind of battery even Lead/Acid refer to http://Battery University,com There is nothing anyone cannot learn to use or be required to do that will prevent you from using this technology. All "you" have to do is get it in your head what has to be done, and do it.

  9. #19
    Quote Originally Posted by grommet View Post
    After doing some reading I see the suggestion that using lithium batteries with powerchairs - a straight swap or add-on, would most likely cause problems with the chair's electronics. Anyone have ideas about using or adding lithium batteries for our chairs?

    Shorai LFX36A3-BS12 ( http://shoraipower.com/lfx36a3-bs12-p126 ) 36 amp hour batteries.
    Would you be changing them just to change them or changing them because you are running out of charge miles now...

    With the right MK batteries 24s working right one should be getting 17 plus miles ...

    That for most can be a lot of running time...

    Plus it would void your warrenty if one put it on a newer chair.

    Dont get me wrong espresso and Burgeman are getting 30 plus miles. Espresso can roll from Manhattan to New Jersey and back and still have a lot of charge.

    I think the start up as in the $1200 to $1500 cost but pays for itself in a few years if your someone buying your own batteries because your looking at 10 years plus life time.

    The lithium batteries they are using at WCD don't burn and have more of a risk on the lead batteries being used now.

  10. #20
    Quote Originally Posted by Bob Sullivan View Post
    There are multiple battery technologies (chemistries) that use Lithium in their name. Most are dangerous under any conditions (ie: hoverboards) for our Powered wheelchairs LiFePO4 will not explode or burn, they are bullet proof. However, LiFePO4 batteries are not plug and go. As Rusty said on the web site WheelChairDriver.com there are people who have been using a LiFePO4 system for a very long time relatively speaking. Several contributors in the USA as well. These batteries used as these people have proven will have as many as +2000---80% cycles. Far more than Lead/Acid Batteries, however, they are again NOT plug and play. They require some specialized charging and those bricks batteries are NOT applicable for our use long term. Your Batt condition system lights that indicate state of charge will not work because the norm of 24VDC-- LiFePO4 battery will always read full it will carry 25.6 volts until you destroy them by over discharging them however, here again you will get more Amp hours use 2x-2.5x from LiFePO4 as well.. They basically do not drop in voltage but use the amperage stored. If you are interested in all types of lithium batteries or even for better knowledge of any kind of battery even Lead/Acid refer to http://Battery University,com There is nothing anyone cannot learn to use or be required to do that will prevent you from using this technology. All "you" have to do is get it in your head what has to be done, and do it.
    My Dynamic Controls DX system was altered with a new min voltage, I've had a power meter fitted which shows volts, amps and watt hours and never run them down below 1400 out of a theoretical 1560 wH. Charging is more complex, leads connected and disconnected in order, individual cell monitoring essential. We did a lot of reading up prior to purchase and went for a good charger (same as BM) and no BMS as per the suggestions on WCD. My support workers are still getting used to it and need the instructions each charge but will eventually get there. I'd never have managed the conversion myself even if I had hand/arm movement, I needed a good engineer which luckily I found and the wheelchair maker arranged for me to get the DX interface to alter controller. Dynamic Controls have been helpful as well giving us the unlock code for the hidden software that emulates the hand held programmer. Definitely not a conversion to undertake unless you are confident and competent electrically and can access the interfaces you might need.

Similar Threads

  1. Replies: 17
    Last Post: 07-14-2012, 07:41 PM
  2. Replies: 14
    Last Post: 05-26-2011, 04:59 PM
  3. Replies: 0
    Last Post: 08-07-2010, 09:46 PM
  4. Question about lithium ion batteries
    By orangejello in forum Computers
    Replies: 4
    Last Post: 04-16-2009, 10:41 PM
  5. E Motion Wheels- YNot Lithium ion batteries?
    By NoDecafPlz in forum Equipment
    Replies: 7
    Last Post: 06-06-2007, 07:31 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •