Mike-
"Mr_D" is right on the money, as usual. The Fit's battery is pretty small. On the other hand, I think the AFO doesn't draw from the toad battery at the same rate as the Stay-in-Play Duo, which is what we have on our Fit Sport. Call the folks at SMI and ask them. Or, you could install the charge line and be done with it. If you do, make sure there's 12V at the charge line pin on the hitch when the coach ignition is on.
Three other points:
1) The brake lights on the Fit will come on when the AFO depresses the pedal. The result is that during a braking turn the Fit will have its brake lights on, instead of the turn signal. The way to fix this is with a brake light relay; link to on such product is
here. Some light kits do not require a brake light relay.
2) Follow the instructions for preparing your Fit for towing to the letter. You will find the instructions in your Fit's owner's manual. I copied the instructions from our manual onto a piece of paper and had it laminated. We refer to it every time we set up to tow.
3) Replacement Fit Sport fog lamp assemblies run upward of $150. It's easy to crack them, as they are low to the ground. If we're towing for just a short ways I'll leave things be; if we're towing for multiple days in a row, I'll pull the fog lamp fuse and tape some sheet foam over the lamp lenses.
Enjoy the Fit Sport- we do. It makes a great tow car, and is fun to drive when set free.