startup voltage drop

[swazz]

I realize it depends on the battery used, but for the most part what have people been seeing for battery voltage during cranking? Curious as to what kind of drop to expect for a motorcycle battery as we've been using a massive car battery while testing our f4i. Thanks.

[swazz]

I realize it depends on the battery used, but for the most part what have people been seeing for battery voltage during cranking? Curious as to what kind of drop to expect for a motorcycle battery as we've been using a massive car battery while testing our f4i. Thanks.

[Erich Ohlde]

10.5-11.5 volts with a 12Amphr Yuasa on our F4i

[Nick McNaughton]

Beware of the difference in cranking voltage between a cold start and an "everything stinkin' hot" start. Also beware of the difference between an "everything going to plan" start, and a "cranked for a minute after forgetting to turn the ECU on" start.

Figure out what minimum voltage the car needs in worst case conditions, which may be governed by ECU, fuel pump, injectors, ignition circuit or cranking speed... and make sure you're a volt or more clear of that.