Originally Posted by jyasaki
Need to be able to crank the motor, which is why it's huge.
Trust the manufacturer; they've been there before.
Yes of course but a FAR smaller battery will crank the motor. Its not a big motor, 90hp, 3 cyclinder, 1.3 litres. Much smaller batteries turn bigger car engines. As I said, I will get the battery he recommends because this guy really knows his stuff and is extremely helpful but I'm just curious as to why and wondered if anyone else has had any experience of running smaller batteries.
I read somewhere that the compressor for the fuel injection requires a bigger battery but shouldn't the engine's alternator supply all the current required when the motor is running? If it didn't, the battery would just drain away as you used it.
Ian M, its been a while, how are you? Yes I think you're right there which is even more puzzling to me because the Ah are a measure of supplying a certain current over a long period (i.e. to power electronics and lights etc. in a boat/motorhome when at rest) which doesn't really apply to an engine battery as the alternator should be able to do this while its running. For the record, I have minimal electronics on my boat, some gauges a fish finder and a bilge pump.