I'm starting to understand why 6 volt can be such a head banger. I got a brand new battery a big 6 volt lead acid from Lincon. Intial charge was fine , got Katy back no problems. Then somewhere along the line it looks like I knocked the light switch to blackout. Anyway total flat battery. So I brought the battery home and stuck it a Ring 6/12 volt chrger, the one I'd used for intial charging. Battery wouldn't come above 5.4 volts and took .75 amp. Hygometer check showed flat. I contacted Lincon after the battery had been on charge for about 2 days with no change. They were very helpful and we discussed a plan. I left the battery on charge for nother 3 to 4 days, still nothing, no voltage not taking the charge.
I fitted the battery to Katy yesterday, flat as a pancake. Some verbal enginnering later, I tow started Katy and left her running. The dynamo put out 7.5 volts and the amps nearly melted my test leads reading about 49 amps! The battery charged up! I left the battery on the vehicle overnight to check if there was an earth leack. She started sraight off this morning! the plan now is to leave the battery on the vehicle for a few days (Some of us have to keep the wheels of commerce turning) and see what happens.