Hi everyone. I have had exactly the same problem with my bl1830 battery. I spot welded in (don't solder Li ion cells as it's much too risky) a new Sony Li ion 18650V cell as one had vented. All other cells tested fine. Battery was recognised by charger and charged OK. I used it and then tried to charge it and charger didn't accept it. I then charged it via my regulated power supply by bypassing the bms to 18.8 volts. I then put it back on to Makita charger and it was fine. I have purchased a new bms from China which doesn't have a suicide chip on it. The new bms boards you see on eBay don't have a individual cell balancing feature. They seem to work OK by giving protection to the whole pack. Testing these batteries reveals that they self balance reasonably without too much deviation. Seems that using these retrofit bms chips and replacing duff cells is the way to go to get more life from the battery. I'm lucky as I get a free source of high quality Li ion cells from faulty e bike batteries. Just be extra careful with Li ion and read up on safety precautions before tinkering!
