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!