Mike:

I had similar problems with another similar charger. Here is what I found.

1. The charger timed out, it took too long to finish.
2. Not enough voltage was input into the charger. I could not do it from a 12 volt car battery, I had to buy a powersupply that put out 13.5 volts.
3. I think your charger is a UK item, you might contact them.

I probably didn't help, but, what the heck, I tried.

Al