This may be slight overkill (they claim it's good for 100W) but it's
inexpensive:

www.oatleyelectronics.com/kits/k168.html

Alternatively, you could put together something quite simple using
an MC34063A (try Google) - easy to use, readily available.

Bill

"Rightrik" wrote in message

snip
not ott expensive kit or ready-to-go-module to obtain this 24-26 v dc
voltage from 12 (13,8) dc volt input.