Car battery charging with desktop power supply

[dav]

Get some cheap 55 W car bulbs (headlamps).

That's exactly what I did 

Cycling the battery with a gentile discharge and recharge a couple of times can help recover tired batteries and you'll get a feel for when it's charged from the charge current falling off.(CV)
Good luck as you don't get them all back. 

I cycled 2 times.
Now the battery retains the charge and works fine