[Elecraft] charger recommmendation for k2 internal battery

[Gary Lee]

Have a k2 with kbt2 installed.  Have a rs 3.5 amp power supply, but only 
puts out 13.6v according to my rs volt meter.

Would like something to fully charge my battery, and according to list 
wisdom, I need around 14.2v out of the supply.

Any recommendations for a charger?

Point of background, preferrably something I don't need to adjust.  Am 
totally blind, and hate to have to rely on the volt meter all the time.

Wouldn't have to run the whole k2, just keep it charged.

Thanks for any help.