Saturday, 21 June 2014

Makita 18v LXT Battery - Repair

So as I mentioned in my previous post I have purchased a replacement control board from Ebay for my Makita 18v Li-Ion LXT batteries.  This weekend I finally had enough time to have go at fitting it and whilst it is not just a plug in affair I would say anyone with a multi meter and a half decent soldering iron should be able to do this.

I was lucky and had a battery that had ok cells but a faulty control board so I decided to try repairing this one first. The control board came with ok instructions on how to fit but they don't explain everything, this may be because it can be used with all of the models of 18v LXT battery Makita have made.  Providing you have a bit of common sense you should be ok.

So apart from the soldering you might expect you also have to cut away a lot plastic and that's assuming you are lucky like me and don't need to replace any cells.  If you do spot welding to the cells is the best way to go, as if you solder you risk overheating.

As I had previously got the battery pack out of the case the first thing to do was remove the existing pcb and cut away the plastic pcb support etc as per the instruction.  I opted to cut the nickel contacts instead of desoldering. Fitting the pcb and soldering the wires to the contacts was simple although I had to break out my larger soldering iron.  By far the hardest part was getting the covers back on this took a little fettling of the plastic to get it to fit.

Next came the moment of truth, I put the battery on a charger and it charged ok.  I then discharged the battery using my circular saw and once again recharged the battery and that also worked ok.  Needless to say I will need to let it go through a few more cycles before I am confident enough to call it a success but all in all things are looking good!



12 comments:

  1. What did you search for on Ebay? who was the seller?

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    1. Hi Peter, The seller was wyliek0 but he does not have any listed at the moment. I did a quick search and found this in the US http://www.ebay.co.uk/itm/like/221539762612?limghlpsr=true&hlpv=2&ops=true&viphx=1&hlpht=true&lpid=108&device=c&adtype=pla&crdt=0&ff3=1&ff11=ICEP3.0.0-L&ff12=67&ff13=80&ff14=108&ff19=0

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  2. Does the baterry work as it should or not?
    BR,Boris

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    Replies
    1. Yes it works just fine. No issues with charging or in uses.

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  3. I have ordered 1 piece from china. I will replace it and then we will see.
    Thank's for your information.

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    1. Providing your cells are ok, you should not have any problems. If you get stuck please feel free to follow up with any questions.

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  4. I have changed the damaged cells, resoldered them, changed the chip, but i get the blinking red light on the charger, as if the baterry is to hot to charge.
    Any suggestions?

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    Replies
    1. Ok lets start with the simple stuff first. I assume the charger works ok with other batteries? Have you tried the battery in a different charger. Have you checked the temp sensor?

      Did you order just one board or do you have others or a replacement temp sensor?

      Cheers,
      Stuart

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  5. Charger works ok with 6 other-new batteries.
    Tried in 3 other chargers - all the same thing.
    Didn't check the sensor, but looks ok. Do you have the readings in OHM at 21*C?
    Ordered one piece, don't have the replacement sensor.
    I have 21 batteries, some new type, some old type. New type has 7 attachments to the cells.

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    1. At 20C (the temp in my temp workshop). The temp sensor on the old boards reads about 9.6k, on the ones on the replacement boards its 26.3k. This is with the components in place.

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  6. I'm having the same problem as above: I replaced the board, as the cells were good, and the red light blinks and the fan turns on as if it's overheated, and it doesn't charge. I even tried swapping out the heat sensors from the old board to the new one and it did the exact same thing. Do you know how I can fix this and complete this repair?

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    Replies
    1. Hi Steve, sorry I didn't spot your post. I have had this issue before, one thing I have discovered is that they have not used the same sensor for all batteries. So make sure you have swapped for the same model. It would be worth testing the sensor separate to the battery. Let me know if I can be of further help.

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