Start Battery

[chaco]

The current House Batteries are (2) 6V 140AH isolated with (3) Battery Switches (1-House / 1-Start / 1-Combiner). The Start Battery is (1) 12V 80AH. Never connect the House and Start Systems other than with an Auto Relay that sends Charger/Alternator to Start Battery first on discharge.
Need to replace the Start Battery. What is the best option.... the Standard Start Battery or the Start/Deep Cycle

Happy Battery Banks

 

[Maine Sail]

Either

Either will work fine. Deep cycle will cost more and generally last longer. Start battery will cost less and generally not last as long.

It does not take much battery capacity to start an engine. I don't even register .01 ah of capacity to start my 44hp engine off my house bank.

That said I never use my start battery because I consider it an emergency battery only. I have started my marine engines on the house bank for years and years. By doing it this way you avoid needlessly switching the battery selector switch and potentially leaving it in the wrong spot, or if you are not wired to prevent frying the diodes, frying the diodes..

 

[Tom Metzger]

...I never use my start battery...

If you never use it what makes you think it will work when you need it?

The reliability comes from testing it. If it worked yesterday it will probably work today.

 

[Maine Sail]

If you never use it what makes you think it will work when you need it?

The reliability comes from testing it. If it worked yesterday it will probably work today.

Sorry I should have clarified. I never use it to start when out cruising but about every other week I use it to vacuum my boat off a 1200W inverter. This gives it some exercise. I also load test my batts every spring. Oh and it is kept up to charge off a solar panel through a charge controller. Every now and then, when doing projects, I will use it to start just for the heck of it but never when out cruising..

I know of far to many boaters who have put themselves in a bad place over the incorrect use of a battery switch. Using one bank for everything simplifies this dramatically. The other mistake I see quite frequently is folks selecting ALL when they have killed one bank already. Selecting ALL with one of the banks dead essentially kills your other bank and can leave you dead in the water..

 

[rwthomas1]

This Interstate battery was recommended to me when I needed a new start battery. http://www.interstatebatteries.com/cs_eStore/Products/RT/PID-31P-LHD(Commercial).aspx?dsNavigation=Nu~Part%20Number,Ns~product%20Type|101|1|,N~21

Commercial grade group 31 truck starting battery. Supposedly has a different chemistry that is more tolerant of over charging and very resistant to vibration. Local price was decent, I bought one and have been happy with it. RT

 

[chaco]

Costco to the Rescue

Went with the Costco/Kirkland Deep Cycle / Start Marine-RV Battery for my Start System. 12V - 110AH - NOT Maintenance Free ! Be sure you Check this feature....even WM sells these Automotive Type Batteries that DO NOT belong on our Boats. Costco was $70....WM was $120 (typical).

 

[Tom Metzger]

Automotive type batteries

Went with the Costco/Kirkland Deep Cycle / Start Marine-RV Battery for my Start System. 12V - 110AH - NOT Maintenance Free ! Be sure you Check this feature....even WM sells these Automotive Type Batteries that DO NOT belong on our Boats. Costco was $70....WM was $120 (typical).

Dan - I'm not sure what you are saying. What automotive type batteries and what objection?

 

[Rhynie]

I have been getting batteries from Academy Sporting Goods and Sam's, both have very good prices and decent selections.
Brian K.

 

[Rocinante33]

The starter battery has different requirements than the house battery. In order to crank an engine, a short burst of high amperage is needed. For the house battery, a long, slow current draw is needed from a battery that has ample capacity so that it won't drop past 50% of full charge (where it could be damaged). So deep cycle batteries are designed as house batteries. An automotive type battery (not a deep cycle) is better as a starting battery because of quick access to high amperage. It is also lighter. We are talking about a battery that only needs to crank a 60 cubic inch engine ( basically from a very small tractor). The smallest car battery (a little one like that in my Honda S2000) should be good as a starter battery as long as it is well made so as to withstand the vibration & the pounding of sailing. How big a battery do you think those little Kubota tractors have?

Keep those big deep cycle batteries for your house bank.

$.02 worth from the peanut gallery

 

[chaco]

Tom.....I am refering to Maintenance Free Batteries. Marine Batteries need to be able to be Maintained by the Operator and not forgotten about like a typical Maintenace Free Automotive Battery that has no removable cell caps.
I even make sure my Auto Battery is NOT Maintenance Free. I am also OLD SCHOOL on Flooded Battery Only thing Like to keep it Simple and Fool Proof