6000 Series Cameras and Lens Controller S:
First the back story on the older batteries then the solutions: The original 6000 series NiCd battery packs caused lots of rumbles, and they have even been called the Achilles heel of the platform, but the issue was mostly about learning to use them correctly. NiCd batteries loose performance and capacity if they are not fully discharged and then fully recharged since they have a memory - meaning they discharge down to where they stopped the last few times and only charge up to where the charging was stopped the last few times. If you didn't let them fully discharge down before charging or pulled them from the charger before they reached capacity, you'd end decreasing the batteries capacity for the long run. Every time a photographer unwittingly tried to top up a charge, or pulled the batteries from the charger early in a rush to shoot a job, the batteries capacity was affected. Furthermore, the original chargers also did not have a way to discharge the batteries fully. That said, what are the solutions? New batteries are available for order with NiMh cells that do not have a memory. Secondly, the latest Type C chargers have a discharge button that should be used to maintain the older NiCd batteries capacity. Successive fully discharge / recharge cycles has been known to bring some of the older batteries back to life. Some after market universal battery chargers such as the Maha-C777+ have special reconditioning profiles that can help bring older batteries back to life. Buying new batteries or refitting old packs with new cells is probably the best way to go, but many people, including myself, have re-celled their batteries themselves with packs found on Ebay, or had battery shops rebuild them. There is are several posts on the photo.net Rollei section about rebuilding the batteries and Graham Mitchell put up a page on his website about it which you can see here: http://graham-mitchell.com/blog/rollei-6000-battery-upgrade/Several people have had good luck with Batteries Plus on the rebuilds. DHW can rebuild your batteries too, but the cost of shipping back and forth makes this less economically viable unless you have lots of them.
Lastly many people have asked about whether the new NiMH cells work with the older chargers. DHW recommends customers use the C type charger which was the latest one (older models are labeled N and G), but customers are reporting that the older ones are working too.