I would assume the FFH's ICE still has all those same (or largely similar) sensors and electronic modules that require power from the 12 V battery before it can be started. Granted, the ICE may not start until you have driven a half mile down the road but it still requires 12V power even with the absence of a 12 V starter motor cranking the ICE.
Sure it does. But that happens later. By the time the ICE tries to start, the HVB has already been connected and can charge the 12-volt battery. In a normal car, once the engine has started, all devices are fed 12V by the alternator no matter how weak the battery is. The same happens here - once the HVB has been connected, the charging system provides 12 volts regardless of how weak the battery is. Or at least that's how I imagine it. I could be wrong.
The only critical action is connecting the HVB. If that succeeds, then all is well.
I don't think the 12 V battery issue is limited to just hybrid cars. Today's non-hybrid cars also place larger demands on the 12 V battery then cars of the past. I think you can find this same issue being discusses on forums for conventional cars.
There may be non-hybrid cars around there suffering from the same weakness, but the Ecoboost and diesel variants of the latest Mondeo don't seem to be among them, at least as far as I can tell from two other Ford forums I happen to frequent. Neither was the previous generation Mondeo in all its petrol and diesel incarnations, despite its being as stuffed with electric and electronic devices as its younger brother is today.
The hybrid Mondeo is still too new in Europe to draw meaningful conclusions about it, but I think it's essentially the same as the Fusion. Which makes me wonder why the hybrid Fusion is so sensitive to weak batteries, when its non-hybrid siblings aren't.
Going by my reasoning above, a hybrid wouldn't need as big and powerful a battery as a non-hybrid. Could it be that Ford thought of that and decided to install smaller, weaker batteries in the hybrid? And maybe they went just a bit too far? Maybe they made them just a bit too small?
Edited by Vlad Soare, 16 June 2017 - 03:30 AM.