I've used Interstate batteries for more than twenty years with no problems.Currently,on my Tsunami,I'm running two batteries,one is a grp 24 marine cranking battery and the other is a grp 27 deep cycle.These are in conjunction with a perko switch.

God, I'm terrible with my batteries,I rarely check them,and I keep saying that I'll switch back and forth from day to day,or that I'll always run the deep cycle when I'm trolling with the elec.downriggers,vhf.radar, etc all on.The truth of the matter is I forget,so god only knows how many hours are on each one.
Been 6 years now,they still test good,but maybe one of these days it's going to be time for a couple new ones.
I think I'll have to put a big sticker next to the ignition switch that reads,

" HEY! STUPID, CHECK THE BATTERIES"

Deka and Universal Power make excellent AGMs. Get em anywhere you'd find RV, marine or construction machinery.

Group 27s and 31s about 150-175 clams, sometimes get blems for 120. Deka/East Penn is the best bang for the buck I've ever experienced in a battery. Well over 220 at west marine so dont go there unless you have a supply deal. Concorde, Rolls, Trojan also great but super pricey and rarely find bargain price. AGMs are great for northern boaters or anyone forced to neglect their boat a while. But but like No Bones said, dont mix the charging systems.

What he said.



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For this dummy, what does an automatic charging relay do? And where in the system is it installed?

It's in here......

https://www.bluesea.com/products/761...4V_DC_120A/FAQ

Basically the Automatic Charging Relay allows you to have two batteries, one for the engine and one for the house, and keep them isolated from each other (that way you cant accidentally kill the engine start) but also allow them to each charge independently from one charging source.
Throw away the 1-2-All battery switch and get an on-off-combine switch and the relay.

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This kit will do that for you.

https://www.bluesea.com/products/764...tery_Kit_-_65A

Another advocate of Blue Seas add a battery switch, and acr, w battery isolator. Very first thing I bought for my seafari.
Great product of real value, safety, and reliability.

Ditto that!

Attachment 10728

So, I am still confused. What battery group, and how many marine or regular cranking amps do I need for a 200 hp, if I have 2 batteries?

?????

You go to the battery store and you buy the highest CCA rated battery they have that fits in your battery tray, normally size 24 or 27 series, you install it and waala you're done. That battery will also crank 300 - 350 hp motors so you are good with your 200 hp.