On Mar 12, 9:42 pm, Wayne.B wrote:
On 12 Mar 2007 10:30:21 -0700, "jim.isbell"
wrote:

Now, what if the one on the engine fails? Well, I have four more on
the house bank and any one of those can replace the engine battery
with a flip of a switch.

You can't start a big diesel on a small 12 volt Walmart battery, not
for very long anyway.

Period.

If you're boat has 8Ds on it, they are there for a reason.

Garden variety 12 volt batteries are lousy performers in deep cycle
marine service as well.

Well, I am running a Perkins 4-108 so I don't think that could be
called a "big diesel"

I agree that for a 12 cyl Detroit you will need special batteries of a
type that Wall Mart does not sell.

As to deep cycle, I don't deep cycle the engine battery as the engine
starts on the first turn and I have enough house batteries that they
don't deep cycle either. If your engine doest start on the first turn
then you have some engine maintenance to do and its going to be a lot
more expensive than batteries.

But how long they last is not the point as long as they last a couple
of years. They are GUARANTEED so its only labor to replace them and
at 40 pounds apiece its a piece of cake. They weight about what a 5
gallon can of diesel weighs and I take on two 5 gallon cans of diesel
at every stop but don't complain about the fuel consumption or having
to lug it down the dock on a cart. I think I can handle a battery
every 6 months or so....if its free.