Hi!
I think must of us who has been into this hobby 10-40 years use some kind of motor cykle battery in our field box to power both our electric starter , fuel pump and glow driver.
When I started 34 years ago I used a 12v , 7A lead battery but this is rather too small and now I prefer a slightly larger one on 10-12A.

For pylon racing I have converted to using a 14,8V, 2200mAh Lipo battery and it puts out much more power compared to the lead acid battery I used before (12V, 10A). It's also much lighter and smaller in size. Small automatic glow driver fits on top. (old racing box to the right)