# Battery Help - Starting VS Deep Cycle VS Hybrid



## LowTideFly (Apr 8, 2016)

My boat has 3 batteries. They're wired to a Perko switch with "1" "2" or "all" settings (not sure if this is wired correctly as I always have it set to "1") and a MinnKota 3 bank on board charger.

The batteries are bad and needing replacement, all 3 currently are hybrid deep cycle/starting.

My question is would it be ok to buy 1 starting battery and 2 deep cycle batteries in place of the hybrid dual purpose ones? I would like a true starting battery for the motor and true deep cycle batteries for the trolling motor and electronics. Would the starting battery be negatively affected by being charged alongside the 2 deep cycle batteries via the minnkota charger?

FYI electronics on-board are Trolling Motor, GPS, Lights and Bilge/Livewell pumps.


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## fishnpreacher (Jul 28, 2018)

Is your trolling motor 24volt?


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## LowTideFly (Apr 8, 2016)

fishnpreacher said:


> Is your trolling motor 24volt?


Yes 24v


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## topnative2 (Feb 22, 2009)

I have a promarine charger and each battery gets its' own charging bank.......should not make a difference.

I would get 2 straight deep cycles and keep a combo for the starter. I do not remember what the differences are but it is minimal...something to do w/ plate diameter.


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## RaspberryPatch (Dec 17, 2016)

Deep discharge battery does not necessitate cycling battery, and the amount of energy at then end of the discharge is low, so focus on cycle life. Cycle life is a function of plate design, and you can find long cycle life is AGM and Gel, but you will notice the Ahr (kwhr) rating of a cycle battery is a little lower than a high pack AGM. The exception will be TPPL AGMs.

Starter battery, all about cranking amps, also involves plate design, but the associate design principles will vary. 

It is best, these are on separate circuits, especially, as you have 24 circuit on another.

There are other reasons to ... charging voltage, temperature compensation and possibly addressing a equalization charge on the cyclic batteries to get a longer life.

Aside for commercial designs, I monitor and alarm low voltage low SOC (statenof charge), and use a low voltage disconnect to prevent deep discharge. There are other reasons on life to.


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## mwolaver (Feb 6, 2014)

I'm thinking his TM has two of the batteries, wired in series, on a dedicated breaker. The battery switch is probably for house use. In other words, he can select 1,2, or both for starting and house uses....and the '2' and both involve one of his TM batteries. This is how Master Repair configured a past boat of mine. So, I totally agree. Position '1' battery should be a starter battery and the others should be designed with the TM in mind.


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## LowTideFly (Apr 8, 2016)

mwolaver said:


> I'm thinking his TM has two of the batteries, wired in series, on a dedicated breaker. The battery switch is probably for house use. In other words, he can select 1,2, or both for starting and house uses....and the '2' and both involve one of his TM batteries. This is how Master Repair configured a past boat of mine. So, I totally agree. Position '1' battery should be a starter battery and the others should be designed with the TM in mind.


Spot on


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## RaspberryPatch (Dec 17, 2016)

Remember if you get a break before make switch - breaker make sure it is rated for the Interupt current of the battery. The interrupt is not the same as the normal continuous current, but the surge current under a short, and tells you the internal parts will not fuse during a fault.


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