Yanmar 2GM20 CCA requirement?

Ephesian

Member
Joined
31 Jan 2011
Messages
27
Visit site
My existing engine/battery arrangement is: two 110AH "leisure" batteries, connected via a traditional 1, 2, 1+2 switch. Engine is raw water cooled Yanmar 2GM20.

This system is OK, and I tend to keep battery 1 for engine start, and 2 for domestic. But battery 2 tends to get low after one or two nights at sea, esp with Anchor light on. Also I often forget to turn the switch to "2" or "both" when the engine is running, so battery 2 doesn't get fully charged.

I'm looking to add a dedicated engine start battery and then connect my current twin 110AH batteries in parallel to make a 220AH domestic bank. Then add a Voltage Sensitive Relay and do away with the 1,2 switch and just have one switch with an emergency switch to link the domestic bank to the engine.

Anyway .. first question .. anyone know the Cold Cranking Amps requirement for a 2GM20? I can't find it in the manual anywhere. Second .. does my proposed arrangement sound sensible?
 
The arrangement sounds sensible to me.

I don't think there is a published CCA figure for the GM series. They do publish a capacity requirement in amp-hours, which is a bit odd because that has little bearing on starting, but there you go.

It's not a very big engine (600cc or thereabouts?) and any normal "car" battery ought to be fine.

Pete
 
Your engine is only 600cc so a small diesel car battery is more than adequate. No need for a leisure battery. I would fit a VSR if you are changing your set up, this will ensure that the starting battery is always re-charged imediately before putting any charge into the 'house' battery without any manual switchover. They are relatively cheap approx £50. A battery would be about £60.
 
Last edited:
I've actually measured it and it was about 225A peak. Remember that cranking amps will change with temperature. Suggest double that for the battery
 
I wanted to fit the smallest starter battery I could get away with, consistent with the published CCA for the 1, 2 and 3-cylinder Yanmars, 200 A. The Red Flash 900 CCA is listed as 450A by many retailers, including Tayna, Totalbatteries and others. I bought one and it performs reasonably well, but then I discovered that DMS, who make it, list it as only 156 A http://www.dmstech.co.uk/pdfs/battery_redflash_hr_01.pdf

Although it will start my 3GM30 quite well it will only do so when fully charged and I suspect that in the event of a reluctance for the engine to start it would not cope. If buying again I would go to a bigger one, maybe the 1000. Otherwise the battery has performed well, surviving a winter when its charge fell considerably due to a charging fault.
 
Top