I led some slightly astray. Went out to charge things up (today is the club weekly training day), and decided to top off my starter and pump batteries.

For the Dynatron starter - I'm using a 5S LiFe 4500 maH. (had said it was a 6S) It has only been used for the trainer this season, running a .40 engine. Engine was new, so there was a lot of starting and adjusting. But it always started right away, so no prolonged cranking on it, either. Plane has 22 actual flights. Let's be conservative, and assume 30 starts. Probably many more, has I helped others start their engines, too.
MaH consumed = 254. So I could get at least 500 starts before I have to recharge (!)

Fuel pump (Sullivan 6v) uses a 700mAh 2S LiFe. 1.5 gallons of fuel used. mah consumed = 263. So about 4 gal of fuel before I have to recharge.

Of course, mileage may vary a lot. But in any event, one doesn't need big batteries for these things!