New Starter Battery

[nigellongland]

In a dedicated only/starting battery for a John Deere 80hp deisal- can I use 6V batteries or do I need the large D cell batteries-I have a seperate house battery system? My D cell finally died after many good years. thanks nigel longland

[btrayfors]

Nigel,

If you've been starting your 80hp John Deere diesel with a D battery (1.5V flashlight battery), congratulations to you :-)

I assume the diesel has a 12V starter. If so, you'd be best off with a battery designed for starting, i.e., a 12V starter battery. While two 6V deep cycle golf-cart batteries in series would work, they're really not designed for starting.

Bill

[DeepFrz]

You can use 6v or 12v as long as they have the MCA or CCA required by the engine manufacturer. Make sure they are starting batteries, not deep cycle.

[foggysail]

Originally Posted by DeepFrz

Make sure they are starting batteries, not deep cycle.

Do you really believe that makes a difference?

[belizesailor]

Nigel, your terminology is a bit confusing, "D cells" go in flashlights. I assume you mean you mean a Group 8D battery? If so, note that the group classification of a battery only refers to it's physical size, not its capacity or voltage.

Aboard boats, an 8D battery would typically be a high AH capacity, deep cycle battery used in a house bank. This is way overkill for a start battery. You don't need high AH capacity or deep cycle performance for a start battery. Most start batteries are Group 27 (or thereabout) in size and not deep cycle.

Also, most starters run off of 12V. Is your starter 12 volt?

[belizesailor]

Originally Posted by foggysail

Do you really believe that makes a difference?

Makes a big difference in price. Why pay for deep cycle when it is not necessary?

[barnakiel]

Deep cycles are fine too as long as the condition on sufficient cca / mca is met. But since they deliver fewer CCA per volume one would end up with a bigger bank. Hence dedicated start batteries work out best - small pack and plenty of CCA.

b.

[foggysail]

Originally Posted by belizesailor

Makes a big difference in price. Why pay for deep cycle when it is not necessary?

I took Deepfrz's comment to pertain to performance, not price.

[DeepFrz]

You can take in any way you like. I don't see any sense in installing deep cycle batteries as engine start batteries, either price wise or performance wise or weight wise or...

[btrayfors]

foggy,

Yes, I do believe that it makes a difference.

Starting batteries have thin plates and are designed to deliver a lot of amperage for starting over a short period of time. Starter motors like this!

Deep cycle batteries, in addition to being more expensive, have thicker plates and are designed for relatively smaller amperage loads at a slower rate.

Believe what you want, but I believe in using the right tool for the job. Start batteries are for starting engines. Deep cycle batteries are for handling a variety of loads over a much longer period of time.

Start batteries live out their lives at a very high state of charge, with the typical engine start requiring less than 1AH of energy.

Deep cycle batteries live out their lives being cycled, often down to 50% or less. Start batteries don't like this...and it's an easy way to kill them prematurely.

Bottom line: Yes, indeed, there's a difference between start batteries and deep-cycle batteries.

Bill

[foggysail]

Originally Posted by btrayfors

foggy,

Yes, I do believe that it makes a difference.

Starting batteries have thin plates and are designed to deliver a lot of amperage for starting over a short period of time. Starter motors like this!

Deep cycle batteries, in addition to being more expensive, have thicker plates and are designed for relatively smaller amperage loads at a slower rate.

Believe what you want, but I believe in using the right tool for the job. Start batteries are for starting engines. Deep cycle batteries are for handling a variety of loads over a much longer period of time.

Start batteries live out their lives at a very high state of charge, with the typical engine start requiring less than 1AH of energy.

Deep cycle batteries live out their lives being cycled, often down to 50% or less. Start batteries don't like this...and it's an easy way to kill them prematurely.

Bottom line: Yes, indeed, there's a difference between start batteries and deep-cycle batteries.

Bill

I have many years in boating, first in a sailboat before moving to power. I have never had a performance problem using a deep discharge battery for engine starting. As to starting batteries, I purchased my FIRST last year for starting purposes only because it was far less expensive choice.

Anybody who believes that a deep discharge battery with an equal ampere hour rating that satisfies the engine's factory recommend battery size, cannot crank that engine does not know what he is talking about. Further he should not be advising others to not use them for starting purposes.

Foggy

[foggysail]

Originally Posted by DeepFrz

You can take in any way you like. I don't see any sense in installing deep cycle batteries as engine start batteries, either price wise or performance wise or weight wise or...

I was wrong in thinking you knew better!

[Nemo55]

I think you will find that once you have combined your two six volts you will end up with a lot more cranking amps than if you had one 12 volt battery.
Plus,,a boat engine is not a car engine and is not subjected to the constant drain charge cycling that auto batteries are subject to.

[bobconnie]

Well foggysail any old battery will start a Crusader engine LOL but for the diesel engine in any boat I have owned or now own will have a lead acid Starting Battery ! and thats from 50+ yrs of boating starting in Comm. Fishing vessels !! even the companys that make deep cycle batts. do not recomend them for starting use !! Just my 2 cents

[foggysail]

Originally Posted by Nemo55

I think you will find that once you have combined your two six volts you will end up with a lot more cranking amps than if you had one 12 volt battery.
Plus,,a boat engine is not a car engine and is not subjected to the constant drain charge cycling that auto batteries are subject to.

Yes Nemo and further, the CCA test temperature is 0 degrees F. Not many I know of who need to start their engines at that temperature. Another thing to consider is the cranking amperes at say 60 degrees vs 0 degrees. For example, a 350 CCA will increase to 546 cranking amperes at 60 degrees for a 56% increase.

Consider all this plus modern engines require far less cranking amperes then engines of yesteryear. It is foolish to believe that a deep cycle battery is incapable to provide reliable engine starting when sized to equivalent AH of a starting battery. If I remember correctly the difference in CCA between a deep vs starting battery is about 20% where the starting battery wins out. This is insignificant in the whole of things.

Foggy