Perkins M92b 4.4 litre 24v
It's not 440CCA. It's 440amps to bs3911. My guess is I need a pair of 750cca batteries but I am trying to find if there is something a bit more scientific than my guess. A pair 100Ah batteries might be about right. Still a guess.
This gives a list of batteries for various size engines, may be of some help.
Consider a lithium battery. You need a tiny one for starting. For example I have a 50 watt hour capacity battery as factory supply to start an 1100 cc petrol engine motorcycle. It is about a third of the size of what would be needed with lead acid. The battery will last a lot longer, be lighter and should be little different in price given that it needs so little capacity.
I am not messing with lithium for engine starting. We have a bog standard alternator. Two 750cca batteries here are $165 each. A pair of 550cca are $135 each. Can you imagine cost to sort out lithium alternator charging. The last starter batteries were £100 each in Columbia. They lasted four years and had to deal with stupid heat whilst ashore for the summer. Far easier to just bang some standard batteries in. Available anywhere in the world
Charging is dead easy. Nothing to sort out. Most packaged batteries come with BMS built in so a standard alternator’s small over-voltage Is not an issue. Or charge with a battery to battery supply or A/C on a timer. Those are cheap batteries. You have to pay more for lithium in this use, but you get more.
I have a Perkins 4236 (3.8 litre 12V 80HP) which, I think, is very similar to your engine. I use a battery between 850 and 900 CCA with no problem
Lithium is wasted for engine start. The properties of lithium - high charge acceptance, maximum discharge are a mis match for engine start which require shirt periods if discharge, followed by long periods of charge and even longer periods if no activity at all. The high powered AGMs are far more suited, being specifically designed for engine start such as on competition cars and emergency service vehicles.
