"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.

There's a reason, other than marketing, why batteries are labeled
'starting' or 'deep cycle' or 'dual purpose'.
I believe the main difference is the thickness of the plates. Starter
batts, are built for short duration, high loads. DC are for less
load over a longer time period. DP are a compromise between the two.

All true.

Doug
s/v CAllista


--
Scott Vernon
Plowville Pa _/)__/)_/)_


"Roger Long" wrote in message
...
Is there any reason to consider using dual purpose or a one starting,
one deep cycle set up with a 20 hp Yanmar diesel? I would think the
starting loads on the small engine are low enough that two deep cycle
batteries would do fine.

--

Roger Long

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.


Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


--
Scott Vernon
Plowville Pa _/)__/)_/)_

Scott Vernon wrote:
"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...

Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.



Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


Actually, I think the bigger issue is the non-starter loads. If the
boat has a fridge or other high house loads, you want to add house bank
capacity, which then makes it hard to do the "swap 1 & 2" trick. Once
you have dedicated banks it pays to use a proper starting battery.

OTOH, my previous boat had a finicky Westerbeke, which has a pre-heater,
and it never had a problem starting off a Surrette deep cycle.

I also live in the MD area (actually I live in MD proper) , and
"sometimes" isn't really a factor, and "cranking more than usual"
isn't either as long as it isn't the norm. I can start my engine at
freezing temps with maybe 5 revs rather than the normal 2. If your
engine requires alot of revs to start then a dedicated starting
battery is probably a good idea. But even so, 80A isn't a heavy load
for a decent deep cycle battery. I draw 50A to run the refrigeration
and 100A to run the microwave.

Doug
s/v Callista

"Scott Vernon" wrote in message
...

"Doug Dotson" dougdotson@NOSPAMcablespeedNOSPAMcom wrote in message
...

"Scott Vernon" wrote in message
...
Yes, a deep cycle will start your Yanmar, but you are reducing the
life of the battery by doing so.

Not by enough that you would even notice it. A recreational boat
starts so seldom and a load of 80A isn't enough to do any harm.


Right, I agree. But, being in the MD area, I've got to consider
sometimes starting in cold weather and cranking more than usual.


--
Scott Vernon
Plowville Pa _/)__/)_/)_