Typically, most other NiMh bots deep discharge during running, delta-peak charge their batteries upon return to the dock, then let them fry indefinitely on trickle charge whilst constantly draining to keep the scheduling/IR functions going - they're never "off", just on standby, with permanent draining. As such, the batteries are already in a less than perfectly peaked state before even commencing a run.
Conversely, Karcher delta-peaks its' NiMh packs immediately
before running, uses only that surplus energy during running, and
never depleting below full rated value (it's a 12-volt pack, and is never depleted below 12 volts). It
doesn't permanently trickle charge on dock either - it doesn't need to as it has no schedule function - and
physically switches off completely after running, not causing a permanent drain on the pack(s).
I did quite a bit of testing to discover this here:
http://www.robotreviews.com/chat/viewto ... =4&t=15929. It's a totally different approach to how other bots insist on using/destroying their NiMh packs, and an approach that seems to work well.