I had a dead battery and needed a jump in my 54 3100. A guy getting gas next to me offered his jump starter. Before he pulled it out he told me not to laugh. It was one of the NOCO. It was only 8.6 inches long and 5 inches wide. He said he has jumped CAT 9's with it. It about spun that 235 out of the engine bay. I was so impressed I bought one. I have used it several times and it put the old style ones to shame. NOCO GB40 Genius Boost Plus 1,000A Jump Starter. Expensive but worth it. About $100 at Walmart. Lithium jump starter rated at 1,000 Amps (7,000 Joules) for up to 20 jump starts on a single charge. Ultra-safe and mistake-proof design with spark-proof technology and reverse polarity protection, which allow it to safely connect to any battery. I don't know if that applies to 6 volt or not. With it being a lithium battery it holds a charge for a very long time. I had it in my AD for probably 6 months. I thought I better take it in and get it charged back up. I plugged it in and it was almost full charge still. It also has a usb port to use as a charger for your phone or tablet. You can charge it with a usb cable. There are different brands out there of similar design. I know they carry a different brand at Home Depot and Lowes but I did research and there are tons of great reviews for NOCO and I am sold on it. I have gone through several of the old style ones and they always seemed to be dead when I needed them.
If you have a battery that is so dead it does not want to even jump start with cables you can start it with this thing. If it doesn't have enough juice to start it will actually start charging the battery. A neighbor had a car that hadn't been started in months. Completely dead. First attempt it would not jump. I let it sit there a few minutes and tried again. Fired right up. He wanted to know all about it and said he was getting one.
NOCO said no to 6 volt and they have nothing for it. I was very surprised
