cranking battery versus marine battery

[Kuncicky]

This is kind of a continuation of my previous thread regarding parallel batteries. But it is different enough so that I thought I should make a new thread of it.


I have always assumed that a deep cycle marine battery would serve just fine as a cranking battery. But from reading stuff on the internet (yeah, yeah, I know -- but sometimes there is a jewel in all that nonsense) I get the impression that maybe a cranking battery should not be a deep cycle marine battery. Something to do with the instant power needed for cranking, the thickness of the plates, etc., and other things near and dear to the hearts and minds of engineers. Of which I am not one.



So does this mean that a good automobile starting battery (with plenty of amp-hours, of course) would be preferable for the starter bank???


Bill

 

[DavidM]

An automobile starting battery would work fine as a marine engine starting battery. Roughly speaking:

G24 or G27 up to 3 liters
G31 up to 6 liters.
Two G31s in parallel up to 11 liters.

David

 

[O C Diver]

Yes, I use automotive style AGM batteries for my engine, generator, and bow thruster. My preferred ones are the red topped Optima batteries.

Ted

 

[Bacchus]

You need to be careful about batty type when deciding deep cycle vs start.
If FLA there is a big difference between true deep cycle and start. Golf Cart battys a great choice for deep cycle thicker plates and more room (acid) below plates so any sediment collecting at bottom doesn't short plates. Higher instantaneous Amps with more thinner plates but not as durable. Most Marine/ RV dual purpose are a compromise but not optimized for either.

https://marinehowto.com/what-is-a-deep-cycle-battery/

When you consider AGM most will do both very well and little. / no difference in plate designs between GC and say a GP31. According to East Penn and Trojan they perform equally well in either application. You will find most AGMs spec both AHs and CCA/MCA... not so with FLA.

 

[Iggy]

In my last boat, I used five Odyssey G31 batteries. I had them for 9 years and sold the boat with them. They were used for both starting and the house with no problems.

They were pricy, but you get what you pay for. Others, had warranty that were not as good. Which says something!

 

[Kuncicky]

OK, given all the wisdom freely handed down to me so far, I went down to Walmart this morning and bought a G27 battery. They are not cheap!



The problem with an automotive battery, though, is that they do not have the bolt sticking up alongside the post, such as marine batteries have. So also had to buy a couple of battery terminal clamps with bolts.



So now we shall see how this does.


Bill

 

[mike66]

What engine are you starting?

 

[Comodave]

OK, given all the wisdom freely handed down to me so far, I went down to Walmart this morning and bought a G27 battery. They are not cheap!



The problem with an automotive battery, though, is that they do not have the bolt sticking up alongside the post, such as marine batteries have. So also had to buy a couple of battery terminal clamps with bolts.



So now we shall see how this does.


Bill

I used these terminals to convert from a post to a ring connector. Got them on Amazon.

Crimp Supply Corrosion Resistant Military Style Battery Terminal Top Post Kit (+ and -) With Covers