Re: Battery amps
Simply speaking, total power elecrically is amperage times voltage. However since all newer starting batteries are 12 volts, the amp rating alone tells you approximate power the battery can deliver.
Again, simply: With batteries, the amp rating they claim is not the delivered amps at cranking, it is the total power the battery can hold as amp-hours. (A 40 amp battery supposedly can deliver 1 amp for 40 hours or 40 amps for one hour. ---but not really. Other factors influence power delivery.) NOW: with small plates (small battery) the area of the plates is not great enough to deliver the momentary AMPERAGE necessary to crank the engine. The small area of the plates just won't sustain a high discharge rate. So even though there is enough power in the battery, it is not available in the form the starter needs. By high discharge rate, your 45 starter motor is probably drawing somewhere around 80 amps at cranking.
Auto batteries have (here in the US) two ratings: One for the cranking capacity and another for the reserve capacity. I don't know how the 120 amp battery is rated.
I thought that you were saying that the 40 amp battery was turning the engine over but only once or twice, then dying. But upon reading your last reply, I see you are saying that the 40 amp battery will not crank over the engine sufficiently.
SO; The 120 amp battery may be enough for starting the engine, but then again, it may not be.
Given that most Seloc users are a bit confused by that manual, it has a rather poor reputation on this forum. SO: I would see if I could find another reference manual and see what that one claims you need for a starting battery. I personally have never used a battery as small as 120 amp rating so I can not in good conscience tell you it will absolutely work. Even on my 20 horsepower engine with a small starter, I use a car sized battery.
If you can't find better information, Google The Chrysler Crew and ask on that question forum. If anyone will know for sure, it will be Franz.
