Batteries Yanmar 3YM30

Darith

Hello,

Thanks in advance. I have to replace the batteries in my westerly which uses a yanamr 3ym30. The batteries there are a yuasa swl 2500 anda bosch 610047. The bosch is a truck battery while I am unsure if the yuasa is a leisure or motor battery? I thought my yacht had at least one deep cycle leisure battery and a starter battery; now I am not so sure?

Mick Tator

You should have one of each, house battery and cranking battery, switched separatel. They are designed/built differently to perform specific jobs. (Just don’t turn the switch when the engine is running!)

The house battery is designed to provide a steady amount of current over an extended period of time and to be recharged many times. Discharging it past 50 percent will shorten its life, so keep it topped up. Be conservative, buy one for double your expected amp-hour needs. (Add up the draw from all equipment/lights.)

Cranking batteries are designed to give a heavy ‘burst’ of current for a brief period to get your engine started. These batteries are a poor choice for deep-cycle / house applications.

Yuasa used to manufacture Halfords’ own brand batteries, I don’t know if they still do. I bought one of each from them a few years ago, no complaints. It’s worth shopping around, big price differences.