Best battery type for Nagra PL-P

Has anyone tried to replace the factory provided eight D-cells with another non-Nagra provided battery. NiCd, NiMH etc. Thanks for sharing your experience.
Used to own a Plp and replaced the stock cadmium battery packs with the radio shack rechargable NMH batteries which were just as good and much less expensive. Also the NMH batteries don't have a "memory" like the cadmium batteries so they don't need to be periodically run down and recharged like the cadmium ones. Always ran the NMH batteries with the charger plugged into ac power with fine results. The people at nagra said that NMH batteries would work just fine, and they did just perfectly for me.
I may have a better solution! First, why do you want to replace the stock batteries? Are they actual D-cells [in series...12v] or is it a battery pack?
Sometime ago I had to replace the batteries of my PLP. I did not want to wait for a Nagra replacement and bought 8 D size NiCd cells that I wraped in two thin cylinders - I did not nottice any difference in performance. I think they are 4Ah batteries.
NiCd batteries have a lower internal resistance than equivalent size NiMH - but it should not be important for this application that does not ask for high peak current.
Anyway, the advice from Nagra should be considered - in doubt ask John Quick at Nagra USA : .
Thanks for feedback. My batteries are two years old. If I listen over a weekend, they discharge over the next day or two. If I want to listen to music say a week later, I need to turn on the charger and charge for 15 minutes before turning the pre-amp unit on. After the batteries have been completely charged up the unit runs less than 2 minutes from battery. My sense is that Nagra is not buying batteries from the best supplier.