Well who would have guessed that 'less' can be more
Performed a load check on the system and found that all power was being supplied by the alternator and almost no current from the batteries.
No wonder the old Honda couldn't keep up on the slopes.
I have removed the alternator (temporarily) and fitted a car battery which i will give a good run tomorrow to see how it goes.
If the battery is strong enough to drive up the slope i might install a remotely operated relay to turn off the alternator circuit before i hit the slopes head on. That way there won't be any load from the alternator on the engine(apart from the free wheeling of course).
Once i have reached the top of the hill i can re-energize the alternator and then keep going.