I have a SHIDO Lithium bluetooth battery which kept flashing up overcharge alarms which is why I looked in the first place. I fitted one of those USB sockets with voltmeter and it became clear what was going on. I also checked it with a good multimeter. Anyway the new regulator is all good and no more overcharge alarms. (The Lithium is not supposed to go over 15V and over charge alarms at 15.5V.Fitted a volt meter? Did early models not come equipped? That’s bogus if so. My 22 has voltmeter built in.
High volts could be issue for sure. You desire a 2 volt increase from resting battery voltage. Most battery’s rest at 12.5 or so 14.5 or so excellent. The caveat being if you have a lithium unit.
Those have a higher resting voltage, thus work better with a little more charge to account for that. Your old regulator might be ideal for a lithium bat ray! Save some serious weight and forget about bat rays for awhile….I’d buy that regulator if you wish to sell it as I will go lithium eventually.