Recommended watt hour capacity for Arri 16SB battery pack?

[David Chapman]

I have a recently acquired Arri 16SB that I am tinkering with that has a battery belt that although it charges to green and is in excellent condition obviously has very little capacity left. Seeing as how I am also into electric vehicles and pretty familiar with battery pack construction I am thinking of rebuilding the belt with new technology cells and converting to 12v at the same time. Googling on this subject and watching a couple YouTube videos where guys are running a couple of R/C car battery packs makes me wonder if this re-powered belt would not just be huge overkill - capacity wise? IE: realistically how much battery capacity do I really need for even the most extreme usage? BTW I already know about converting the magazine to 12v (no problem) and havn't decided whether to try using the Arri variable speed motor I already have (until it gives me trouble) or to by one of the newer Tobin 24v VS motors. I already have a 115v motor for indoor use. Any comments, thoughts or input from some "power users" would be greatly appreciated.

[David Chapman]

Correction to my earlier post: when I said Tobin 24v motor I meant 12v. I cross confused the model # and the voltage, LOL. Probably should have used "AHr capacity" too but used to working with much bigger battery packs.

[Dom Jaeger]

According to an Arri manual, the original 8V battery options were 4Ah, which would run an Arriflex St for aprox 1200 ft, and 8Ah, which would run for aprox 2000ft.

 

The current draw of the variable speed motor was rated at 3.6A, though the Tobin motor draws less I believe. The start-up current can spike to 6A, so if you put in a battery fuse, make it something like 10A.