Which Battery to buy?

[brook1724]

2002 21V mercruiser 350 Mag Mpi

-What is the stock battery that was from the factory, how many amps?

We have a perko switch and our second battery is a yellow top optima.

We decided to change out the "house battery"

What size do I need, guys at parts store know nothing

[Moki]

I know I will be shot down by all the gel battery people, but I have Costco Kirkland Marine/RV batteries in mine. 5th year and still going strong.

[urbanstd]

Group 24 Marine starting is what I have.

[laserfish]

WalMart group 29 here. Onboard charger/maintainer keeps them lasting a whole lot longer. Starting battery is 5 years old now. Glad I have a second, that is starting to make me nervous.

[talltigeguy]

It is always not as good of an idea to mix and match battery types. They charge and discharge at very different rates, they have different resting voltages, and I am not sure if any chargers can separate AGM/gel from lead acid batteries as far as charging them. So I always keep all the batteries of the same type.

The Tige system combines them when the motor is running, so it would seem to me that although many have done this, it is another opportunity for premature failure.

The short answer from me would be to get another yellow top. It will crank plenty well to start your engine and run your electronics and charging both together will be fine.

[chpthril]

2002 21V mercruiser 350 Mag Mpi

-What is the stock battery that was from the factory, how many amps?

We have a perko switch and our second battery is a yellow top optima.

We decided to change out the "house battery"

What size do I need, guys at parts store know nothing

So you are replacing the Yellow-Top and looking for a suggestion for a new 2nd battery that will be your "House" battery?

WHat type of battery is you "Starting" battery? i would go with the same type i.e. Gel, AMG, flooded, since you have a manual combiner switch.

Now, im a huge fan of a plain old flooded lead-acid marine deep-cycle. You just cant the Ah to $$$ value. I would say, buy as big as you can fit and budget. Your boat probably came with a group-24. A group-29 would give you roughly 50% more Ah's for only about $30 more, but its a bigger battery, so fitment needs to be taken into consideration.

The other thing that needs to be taken into consideration, is how you plane to use the system. The draw on the system and the number of Ah's will determine how long you can play the system with the engine off. Also, are you wanting to have the "House" as a dedicated stereo battery, or use both as starting/house batteries.

[bigdaddy_houseboater]

I have a single battery system and use a blue top Optima. When I get the big amp for the stereo, I will swap to the yellow top (deep cell)

[Moki]

Chpthril helped me design my system. I have 3 batteries (2 switchable for the engine, 1 dedicated to the stereo), Perko swith, battery isolator, and put on a new high output alternator. Never had a problem with batteries, even on week long trips where it seems the stereo is always going.

[bigdaddy_houseboater]

Moki.. the thread is about "which batteries".... so GIVE brotha.. which batteries are you using?

[lohe]

Two wallyworld group 29 rv/marine battery's here for the house and a interstate group 24 marine starting battery.

[shawn74]

Two wallyworld group 29 rv/marine battery's here for the house and a interstate group 24 marine starting battery.

same here with no problems

[Moki]

BigDaddy,
Ask and ye shall receive...Here is a pic of my Kirkland Batteries and the isolator

Fitment Code:13* Group size:24DC Cranking amps 32 degree: 700 Cranking amps 0 degrees: 550 Reserve Capacity: 140 L: 11-1/16 W:6-3/4 H:9-1/8 Item:12851 Price:$61.99