My project KA has been sat for awhile and the battery wasn't starting the Ka anymore. So I bought a noco genius 7200 charger which is suitable for start stop batteries and charged the battery back to 100%. It's holding charge and starting fine however I get a warning when the Ka would normally start stop showing the start stop A sign and off. Didn't quite catch it in this picture.

I've taken it for a 40 min drive today and still showing the warning. Has the charging ruined the battery?

stop start on ka is not the best, fiat systems. how did you charge battery, still connected to vehicle or battery leads off?

Hi Ian. I took the battery totally out.

The engine briefly jumped over norm on the first 10 minute run. I think maybe this was why it didn't start/stop. I've completely replaced the radiator and re-filled. It could be that there was some air in the radiator. I took the cap off when I got back and topped the water up slightly. On the second trip the heat never got above norm but I think this may still be the issue.

What's the best way to bleed the KA radiator? Start it with the filler cap off?

as you charged battery off vehicle the stop start has lost its monitoring status, cant remember how to reset monitoring on ka, differnt to rest of fords. its something like disconnect monitoring cable, run engine on idle for 10 mins, engine off, reconnect monitoring cable, leave for 4 hrs or overnight preferably.

as for bleeding, nothing special im guessing. not refiled coolant on ka

I tried disconnecting the sensor from the battery but the car won't start. Is there another procedure it might be for the KA?

I think a flattened battery probably killed the battery lol. That looks like a fairly new ka for just a project car?

Just to follow up on this, did try disconnecting the sensor, running the car, reconnecting and coming back the next day. Still the same issue. I've been assured by Ford that this is pretty standard and you'll needs a weeks worth of motoring for the smart charge system to re-calibrate and begin working again.

If the start/stop (ACS) doesn't see a steady minimum voltage (enough to guarantee restarting every time) it won't operate.

I'd say duff battery or that it still hasn't reached a stable output yet after refitting.

Get the battery checked, but only by someone who has stop start enhanced flooded baťtery tester, not an ordinary tester as that wont show correct state of charge.