Starter Battery

[JamesC28]

We are on our original batteries on our 2013 C28 so it's time to change them out. Has anyone used different batteries for their starter and or thruster vs. the house batteries? I'm thinking of group 31 AGM, but a starting battery for the starter and thruster and deep cycle for the house. Thoughts/suggestions?

Thanks,
James

 

[S. Todd]

Our 2015 R25SC came from the factory with a starter battery for the engine and deep cycle for the others ( I think the thruster battery was a deep cycle). As long as they are the same type, regular wet cell or AGM, I don't think there is any reason why they can not be different.

 

[j&lgray]

About batteries, check the owner's manual for the recommended Cold Cranking Amps (CCA) first.

For example, our Ranger 27 is powered by a Yanmar 180 HP engine. Yanmar recommends a battery with 800 CCA. Starter batteries are designed to do just that. Sidepower makes the thrusters and recommend a deep cycle battery with 380 CCA. Two different applications, two different batteries. What must be same is the type of battery, flooded (also called wet) or AGM (Absorbed Glass Mat) because the battery charger can be set for one type but not both. Thruster batteries and house batteries can be same and there is a school of thought to combine these into one battery bank.

 

[Hamster]

What must be same is the type of battery, flooded (also called wet) or AGM (Absorbed Glass Mat) because the battery charger can be set for one type but not both. Thruster batteries and house batteries can be same and there is a school of thought to combine these into one battery bank.

Check your battery charger to see if that is true. It isn't with my Abso Charger. My charger doesn't have different settings for flooded and AGM. I just put two flooded batteries for my house because I could get 115 ah for each battery in a Group 27, which increases my capacity by 25 ah for each battery over stock. My starter and thruster are AGM. I looked at my charger manual and it treats the AGM and flooded the same. The only different profile would be for Lithium.

My local battery expert confirmed this set up would work as well. Your charger may be different, but some experts would say that the profiles are not that different and you can still proceed to have different types. Ask around if there is a valid reason to consider mixing battery types like I ended up doing.

 

[CaspersCruiser]

>>.....Check your battery charger to see if that is true....<<

I have the same vintage boat as John Gray. My charger is a ProMariner ProNautic 12-20P and it has charge profiles for these battery types: Flooded, Sealed, AGM, GEL, LiFePO4-Lithium, Calcium/Custom

 

[GaylesFaerie]

I think if you change your battery chemistry from FLA to AGM you are going to need to change more than just the settings on your Battery Charger. You should probably look into the alternator charge settings (if it has them) as well. If you have Solar and an MMPT controller, I think it will automatically sense the AGM but I'm not 100% sure. Not sure about any Genset (still learning). GF

 

[Scuba Too]

I just changed out my batteries. I stayed with the same battery for house and thruster but changed out the engine battery per a suggestion from the factory on this forum. They suggested Optima Yellow but I went with Optima Blue - same battery just different posts. The Yellow has the regular stud connectors while the blue has that as well as marine connectors. The Blue was a little more expensive but saved me the trouble of adapting the cabling.

 

[GaylesFaerie]

Here is an interesting video (short and to the point) on AGM charge profiles and an alternator. The point to pay attention to is the charge voltage output by the alternator which in general is NOT configured to what an AGM battery would prefer. In the video Jeff recommends using an External Regulator to appropriately match (change) the alternator output (which is generally manufactured for a FLA battery profile) to the charge profile spec'd for an AGM. You can charge AGM using a FLA charge profile but I think it will either decrease the battery life (expensive) or expected performance (a key benefit of AGM) of your batteries. HTH, GF

https://www.youtube.com/watch?v=d_JPSz7qsJk

 

[kjoverbeck]

I just replaced my batteries with Duracell AGM deep cycle Group 31 batteries. They are rated at 800CCA so meet Volvo starting requirements.

 

[j&amp;lgray]

I, too, am about to replace Trilogy's batteries. A couple of BTW tidbits:

- Duracell, NAPA, and host of other batteries are all made by the same company, East Penn Co. What is different? The price. How can you tell? Google the brand name and ask for the manufacturing company.

- Some batteries are rated using Marine Cranking Amps. How can you compare Cold Cranking Amps to Marine Cranking Amps? Marine Cranking Amps are 25% more than CCA.

- The marine electrical expert that I listen to, recommends replacing all the batteries in a bank at the same time with the same make, model, and date of manufacture batteries. A bank is only as healthy as the weakest battery in the bank and you want the same charging and discharging characteristics in the whole bank.