can a 36 volt charger be modified easily to 48 volts

[recumbent]

I have a high quality Heinzmann 36 volt charger which has components that are easily accessed. Can we up the voltage to 48 easily?

I took a picture of the inside but have to wait till friend shows me how to transfer it here.

 

[fechter]

It might be possible if it's a switching power supply.
The circuits tend to be pretty complicated and difficult to reverse engineer. If it's based on a standard chip and resembles the circuit in the datasheet, it's much easier.

The usual approach is to buy a separate 12v charger and run it in series with a tap going to the batteries at the 36v spot. 12v chargers are fairly inexpensive and readily available.