Pinout for LiON Rechargeable Battery

Discussion in 'Power Electronics' started by NLightNMe, Jun 23, 2013.

  1. NLightNMe

    Thread Starter New Member

    Apr 20, 2011
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    Hi,

    I have several Milwaukee 'Red Lithium' M18 battery packs that I would like to use in a project. I don't fully understand the pinout, though. Can anyone explain the best way to connect up to these?

    There are 5 pins on the battery. In the attached photo I have labeled them A through E. On both the tool that uses these and the charger, the 'E' connector is longer and makes contact first. I assume that is ground. The photo shows the voltage measured between the other pins and ground.

    The battery is nominally 18 V.

    The tool uses only 4 pins: A, B, D, and E. It does not connect to pin C which has a voltage on it.

    The charger also only uses 4 pins, but it uses pins: B, C, D, and E. It does not use A which I measured as the largest voltage.

    Thank you for any information you have on the pinout of these batteries.
     
  2. wayneh

    Expert

    Sep 9, 2010
    12,154
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    "Managed by Milwaukee's exclusive Digital Power Management (DPM) System, the battery features Overload Protection, a Temperature Management System, Individual Cell Voltage Monitoring, Discharge Protection and a Battery Fuel Gauge. "

    That all sounds great, but it basically means you're screwed. Without taking the pack apart, you may not be able to access the poles of the battery cells directly.
     
  3. bountyhunter

    Well-Known Member

    Sep 7, 2009
    2,498
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    I guarantee you can't get at the battery terminals from the outside. That's the whole point of the protection circuitry so you can't short the battery out and possibly harm yourself.
     
  4. NLightNMe

    Thread Starter New Member

    Apr 20, 2011
    16
    0
    Hi,

    Thanks for the responses so far.

    I may have worded my question poorly. I'm not particularly interested in getting direct access to the battery cells. I would like to use the battery pack as a module and take advantage of the existing charger and and even the built-in protection features.

    I doubt that the drill it is normally connected to has any intelligence in it. Maybe a resistor network to let the battery controller know what current load is expected for that tool?
     
  5. wayneh

    Expert

    Sep 9, 2010
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    I tried to examine the wiring diagram on the tool's diagram, but it's not clear. I only glanced, so it's worth a more thorough look. It MIGHT give you an idea on which conductors are actually used in the tool for normal operation.
     
  6. Dodgydave

    AAC Fanatic!

    Jun 22, 2012
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    745
    I would say the battery is A_E, and the thermistor sensor is A-C, charger is probably C-E,


    if you put a load on the battery on terminals A_E and measure the current/voltage, but it will probably shut down at a safe low voltage to prevent the battery from damage.
     
  7. me217

    New Member

    Apr 23, 2016
    13
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    just wondering how you went. as i am looking at doing the same thing. the batteries in the missus vacuum cleaner have died. and the bit i was worried about was it killing the batteries. the current battery in the vacuum cleaner is a bunch of rechargeable AA's and replacement cells were going to cost more then the vacuum. and i already have a Milwaukee drill.
     
  8. Troyhoo

    New Member

    Jun 28, 2016
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  9. Troyhoo

    New Member

    Jun 28, 2016
    2
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    This is an old thread but I will add that the + and - pins on the ends are directly connected to the cells. The other pins communicate with the m18 tool to shut down the tool when cell voltage in becoming low enough to damage the cells. The advantage is there is no semiconductor between the load and the battery to reduce performance , that is found in lithium batteries that fit older design tools that previously used nicd batteries, to prevent over discharge of the lithium cells. And other pins comunicate with the charger to prevent overcharging. What input would be needed on the pin to enable tool and charger operation is what I was hoping to find. To power another project with the batteries, just connect the + and - terminals as you normally would. Beware however since your device is not monitoring the pin that disables the m18 tools, the battery will likeky be over discharged, lithium cells are not tolerant of this and will be permanetly damaged if this occurs.
     
  10. Stupidspencer

    New Member

    Nov 18, 2016
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    Old thread, but I must put in my two cents:
    Why don't you take apart the tool? In my experience, if the information you seek is not easily found on the internet, the best way to figure out how something works is to take it apart and see for yourself. Just open it up and see how the tool internally connects to the battery and duplicate that in your device.
    BTW, I ended up on this thread because I was looking for the very same information: the pinout of a M-18 battery. Guess I'm gonna take apart one of my drills. :cool:
     
  11. wayneh

    Expert

    Sep 9, 2010
    12,154
    3,060
    Some folks may benefit from what you find. Take some photos and let us know what you find.
     
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