Thread: Ryobi One+ 18v battery

At the time when Ryobi entered its exclusive arrangement with Bunnings, the local Mitre 10 unloaded its stock of Ryobi One+ tools quite cheaply. I bought the impact driver and the two speed hammer drill, each of which has exceeded my expectations. I also bought three batteries (NiCad), and recently one of those has refused to take a charge. When it was inserted into the charger, the green and yellow lights would illuminate, and the manual suggested that this was an indication that the battery was 'dysfunctional'. It tested out at 10.2v, well below its 18v capacity. I tried to charge the battery several times over several days, but with no success. I thought a replacement was on the cards, but an internet search found a process for battery 'rejuvenation'.
The author suggested using two suitably-connected 12v car batteries to provide 24v. A wire from the negative was then held against the labelled negative terminal of the Ryobi battery, and a positive wire was then touched against the Ryobi positive terminal for about one second, giving it a momentary 24v burst. This process was to be repeated three times, and the battery should then be 'rejuvenated'.
Instead of two car batteries, I used a voltage supply. I dialled 24v, then applied the process above.
I then inserted the battery into the Ryobi charger, and lo! the red light came on, indicating that charging was occurring! About 45 minutes later, the green light came on indicating a full charge, and the battery tested at 19.6v.

I am not assuming that this is a permanent fix, but at least the process has extended the use of a battery that I was preparing to discard.