Need To Replace Starting Batteries On Lagoon 420

[trosenthal20]

Looking to replace my two starting batteries which have recently failed. Tested both with my volt meter and voltage drops dramatically when engine start button is pushed and engines won't start. I have two 75hp Yanmar 4jh4-te engines. Looking at 12 volt group 24 maintenance free batteries online and see quite a price range and difference in CCA and reserve minutes. The Yanmar manual doesn't reference these ratings but it does only require 1.4 kw to start. I've looked at West Marine, NAPA, Sears. The lowest CCA would seem sufficient and most cost effective, but wondering what others would recommend.

Happy 4th by the way!

[colemj]

For start batteries, we just use common automotive 12V's. Get them at Sam's or wherever cheaper. Our starting batts last longer than our house batts.

Mark

[trosenthal20]

Thanks Mark for the quick reply. Yes was definitely looking at auto batteries as suggested by you and others. Interesting the old batteries were rated 1125 CCA, which seems way more than necessary. Very heavy too, guessing 45 lbs. A bear to remove and no handles in cramped small space under the berths. But I got it done.

Looking at batteries rated 460 cca. Only 35 lbs and with handle. Assume that will still get the job done? Any suggestions on that front are most welcome.

[smac999]

if you have boxes in place easier to just replace with same size.


getting the smallest starting battery isn't the best idea. sure it'll work when it's new and full. but when it's not...

[Bill Seal]

Quick and dirty way to (maybe) get some of the sulfation off the plates, take the battery out of the boat -safety first- charge it up, crowbar it with a heavy duty jumper cable until it's flat , re-charge it. Sometimes it works, sometimes it doesn't. Might get you going until you can get a new battery.

[lonesoldier0408]

As to, same size due to battery box size, shim as necessary, when necessary, where necessary.
A heavy drain on the batteries, when attempting to start would lead one to examine the starter circuit for a short.
However, a lot have suffered from water intrusion into the engine cylinders, via exhaust elbow deterioration.
Although, not perfect, one can draw additional power from the house bank, to jump start the motor.
Then one must affect repairs, as is necessary, provided you haven't sent a rod tearing through your engine block due to the aforementioned water intrusion.
Then again, there are the sails to consider.

[trosenthal20]

Thanks all for your very helpful input. I did end up getting new starter batteries and have installed them. Happy to report engines started up right away so all good. Ended up with West Marine Starter Batteries made by East Penn rated 800 cca and 1000 mca. Price was competitive. Free replacement if they fail within 12 months.

We were a few miles offshore under sail several days ago. When we decided to return under power to our marina the engines would not start. Sailed close to the inlet prepared to get a tow but were talked through a way to jump start the engines which got us home safe and sound. One of the previous owners had upgraded the engines in 2010, so assume the batteries were installed the same time. Some have told me that's about the life expectancy.