The CCA is a battery rating that is unrelated to the contactor ratings. Rotax is giving you the bare minimum rating for a battery that will properly crank the engine.
The master solenoid you mentioned here should work fine as long as it is a continuous operation solenoid. The contactor you select needs to be able to handle the highest possible continuous current your plane could have (100A) and the highest possible inrush current (600A), which occurs the moment you activate the starter.
Phil Nelson
A&P-IA, Maintenance Instructor
KF 5 Outback, Cont. IO-240
Flying since 2016
I stand corrected....the starter should be in series with the contactor solenoid to enable shut off if there is a failure of push button start or the starter contactor. When checking thats the way mine is wired. I reacted too soon to what looked like easy answer.
Jim Corner
KF2 582 1150 hrs
KF5 O-360 1150 hrs
The problem arises when the starter solenoid sticks after the engine has started. With the engine running -- and no indictor light or CAS message -- there's no indication that the starter remained engaged.
Eric Page
Building: Kitfox 5 Safari | Rotax 912iS | Dynon HDX
Member: EAA Lifetime, AOPA, ALPA
ATP: AMEL | Comm: ASEL, Glider | ATCS: CTO
Map of Landings
I installed a wire to sense an active starter in my Kitfox. It's one of the programmable discreet inputs to the Garmin G3X, which means it says "STARTER" on the screen. It's the first thing I check after the engine starts, before checking oil pressure.
This problem is real. I had a stuck start contactor happen once in a C-206. The plane actually had an annunciator panel with an LED light. The problem was the LED was in direct sunlight and was not readable after the start. I didn't see it until I had just lifted off the ground so I came back and landed. The starter was trashed, and had to be changed. Another plane in my company, a Kodiak 100 with a PT6 turboprop, had a stuck starter contactor. After shutting off the engine's fuel, turning off the master switch and disconnecting the external power the engine was still cranking! The crew just let it crank till the battery died. It destroyed the main battery, and we had to send the starter/generator off for overhaul. Fortunately the battery didn't explode during the high discharge.
It is super simple to add in an LED light or wire it into a screen. You just need to add a wire on the output side of the starter contactor. The wire is "hot" or active when the starter is engaged.
Phil Nelson
A&P-IA, Maintenance Instructor
KF 5 Outback, Cont. IO-240
Flying since 2016
Great information Phil, to be honest something I hadn't thought about till reading this thread. An easy solution and I will add the annunciator right next to my engine monitor where my eyes go immediately after engine start anyway. Thanks Bruce N199CL
Just fyi for those using the vpx and g3x, the vpx sends a CAS message when the starter is engaged.
Dustin Dickerson
Building 7ss STI x 2
Oratex
29" shock monster
EP912STI 155hp
Garmin
N33TF......FLYING!
N53TF......FLYING!