Battery logic
Comes a time in every battery’s life to be replaced. The challenge is determining when. In this case, after the cruising season concluded I was beginning to question the lifespan of the main engine start batteries.
The starter on this Gardner 6LW is a 24V beast. I’ve been told that not all 6LW engines used an electric starter; some used a compressed air arrangement. Throughout our time with Sandavore we’ve not had a start problem, except for the rare instance when the solenoid engaged but the starter didn’t budge. I’d just cycle the switch to off, then re-engage the starter and she would fire up. What got me thinking about replacing the batteries was the fact that there was no installation date on the cases. So even if the batteries had been replaced just before we bought Sandavore it was coming up on 6 years. And that’s about lifespan of a starter battery.
As you can see, the batteries are Group 24 12V; this required them to be wired in series, i.e., negative to positive. Testing start batteries with a tester is helpful, especially with a testing unit that can place a load on the battery. But it’s not the only measure of battery health. When I enlisted the help of Markus of Mark’s Marine Repair, he came out to take a look.
Both batteries were discovered to be bulging. Markus says this is a common sign with start batteries that are aging, used infrequently, but are often fully charged. When a battery case swells, the lead plates inside are starting to oxidize and gas begins to build up, pressing on the valves (this is in the case of sealed lead acid, or SLA batteries). Left alone a battery like this is at risk of explosion. Definitely time to have them replaced!
So I went with Lifeline Group 24s, which Markus expertly installed. We were both concerned about bare terminals, so I installed silicone terminal covers all around. The next day I went to start the main engine and WOW, a huge difference. Much faster flywheel engagement and starter RPM, which really helps a non-glowplug engine fire up! Notice that I’m not going to forget when I replaced THESE batteries….
