18650 battery protection pcbs.

Discussion in 'The Projects Forum' started by Dodgydave, Apr 2, 2016.

  1. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    Right i have this problem, i have a protection pcb module for 18650 lithium ion batteries, connected them in series as per diagram and i get 11.8V across the B+/B- terminals ok, i get nothing at all on the P+/ P- terminals, so if i measure between the B- and P- they are commoned, ..

    I am right in assuming that the P+/- terminals are for supplying the charge voltage to the pcb, or is this where i connect the load,

    Even if i connect a 12 to 15v supply to the P+/- terminals to charge them, and measure the current i get 25 microamps??

    Has anybody used these pcbs before, and how to use them to charge the battery and use it to power a load?

    DSC_0016.JPG DSC_0019.JPG DSC_0018.JPG
    DSC_0017.JPG
     
    Last edited: Apr 4, 2016
  2. Marcus2012

    Member

    Feb 22, 2015
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    Hey Dave

    I had one of these with some 3.7Li-Ion cells phone batteries I got once. It was a three cell configuration like yours but the P connections were for load and Charger. Similar to this one on ebay, it doesn't seem ideal but I think it is just over discharge protection. Probably a silly question but what are the cell charges at the moment?
    connectiondiagramfor4packs.jpg
     
  3. Dr.killjoy

    Well-Known Member

    Apr 28, 2013
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    Do you have any link or more information about the pcb ??
     
  4. Marcus2012

    Member

    Feb 22, 2015
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    Thinking about it don't 18650s have built in protection? This happened with my phone cells which also had built-in protection and their circuits would supersede the main controller if I tried to draw more than 1C. I would find two of the cells had tripped and I had 3.7V total across all three cells, it was strange.
     
  5. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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  6. Marcus2012

    Member

    Feb 22, 2015
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    Yeah there does seem to be a lack of detailed description there. I always find it a bit odd when listings disappear after one sale as well. This happened to me with a fan controller that was faulty. I bought one and the listing suspiciously when down a few days later and I was none the wiser until it arrived. I can't find any others that match yours either, I can find a similar one but it seems to miss that big power resistor you have on you load outputs. :(
     
  7. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    I have ordered another different type to see if its the pcb problem, i have 11.7v across the batteries, yet Nowt at the outputs,

    strange how it doesn't work.
     
  8. Marcus2012

    Member

    Feb 22, 2015
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    Yeah it is a bit odd. They probably did something wrong with the PCB maybe like put that current sense resistor in parallel with the output instead of series lol.
     
  9. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    Fixed the problem, it was the battery holders wiring, replaced them with thicker wires and lift off!!,
    ....:rolleyes:
     
    Last edited: Apr 4, 2016
  10. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    To HP1279....and.... AnasMalas....

    battery

    Batteries where from ebay China, yeh i know Chinese shit,,, but they've been charged up for an hour on my atx at 12.8v, start current was 267mA, then dropped off to 17mA after an hour or so,,,and now are running my radio, at 148mA discharge current, keeping an eye on the voltage and current drain...:D clock ticking time will tell.....
     
    Last edited: Apr 4, 2016
  11. AnasMalas

    Member

    Nov 27, 2015
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    If they achieve even half of that capacity oh boy i will buy the entire factory! sell them at 200$ a pop and solve the entire energy dilemma! GENIUS
     
    Dodgydave likes this.
  12. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    Its been on for three hours now and its 11.72V,, still working....... :cool:
     
  13. AnasMalas

    Member

    Nov 27, 2015
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    i would like a small photo... time-laps is better....
     
  14. AnasMalas

    Member

    Nov 27, 2015
    66
    10
    Still discharging? I need to apply for the bank loan now!
     
  15. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    Batteries down to 7.5v, one of the cells is faulty binned it,they lasted 23hrs at 245ma, thats 5600maH approx, so much for 9900ma Chinese shit....
     
    Last edited: Apr 5, 2016
  16. AnasMalas

    Member

    Nov 27, 2015
    66
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    That is still double the normal capacity, all jokes aside that is very very impressive for that size... i really cant believe there is no error...
     
  17. Dodgydave

    Thread Starter Distinguished Member

    Jun 22, 2012
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    Anasmalas,,,

    New batteries fitted, replaced the battery pcb and is now charging and discharging normally, must have been a bad pcb, radio now working on batteries, monitoring current and voltage will note length of time it takes to shut down as of 10am gmt.
     
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