You don't have to do anything. You can use alkaline,NiCad, or NiMH battery cells without any ill-effects.

For the 45CT series, NiCad or NiMH may batteries may result in the strobe is a bit weaker (someone tested it to be about 1 stop).

But for the 45CL series, there is no difference in the strength of the strobe.

Metz just over-engineers.

I currently have CT-1 (2 copies), CT-4, CL-1, CL-4, and Hasselblad ProFlash 4504 (CL-4 clone, I think). I've been using nothing but Sanyo Eneloops and Quantum Turbo.

I did open up 2 copies of the CT-1 and did the modification of moving the ground connection, but then I found out that it made little difference, if any.