Starting battery vs. deep cycle for house power?

[tmh]

I recently bought a 1988 33' Cruisers Inc. express (not in the water yet - hopefully soon). The previous owner bought lots of "stuff" but never got around to hooking it up so I have three 1 year old, never used, trickle charged marine starting batteries. I have to start twin inboards and run house power - likely not overly power hog house power when engines off and not at slip. I have shore power and 3 bank charger system.

I have read a ton on how to manage the batteries - no agreement on anything it seems, but I think I know what I plan to do. I have two Perko 1.2.both, off switches installed, I need to check what is connected where. What I plan to do is have one starting battery for the port engine and two in parellel for starboard engine and house. Each switch would allow either bank to run the other if one bank died (in this case, port "bank" is just one battery).

After reading a ton, this seems to be easy, I have all the switches, etc. and at worst I have to start oth engines off one battery to get going (if 2-battery starboard bank dies).

Finally, my question. Being as I have three expensive starting batteries, do I need to replace one with a deep cycle for house power? or is the deep cycle not such an improvement to make it needed? When i have a battery fail, i will buy deep cycle for house and isolate differently, but for now, does starting battery provide decent house power? I'd actually be using two in parellel and TRY not to run any power hogs for long.

Thx.

 

[slia67]

Re: Starting battery vs. deep cycle for house power?

The reason you want a deep cycle battery as your house battery is because they are designed to be discharged to lower voltage levels without damaging them. Once you drop the voltage of a starting battery below a certain voltage (sorry, I can't remember the voltage) the battery's life is shortened dramatically. Imagine doing that over and over.

On the other hand, you already have the battery so what the heck. When one goes bad, replace it with a deep cycle.

 

[bruceb58]

Re: Starting battery vs. deep cycle for house power?

Plates are thinner on a start battery. This allows more surface area to allow more current to be delivered. This also means that as you discharge the battery more, you lose some of the metal and eventually the starter battery will fail. Discharge a start battery around 3 or 4 times completely and the battery is going to fail.

 

[raekmike]

Re: Starting battery vs. deep cycle for house power?

Just a word for the wise.
Don't always trust the sticker label.
Many deep cycle batteries will be labeled marine starting and are actually deep cycle and vise versa. Battery labeling is very confusing sometimes just to sell more and different types. what group size are they 24? 27? 31? and what amp hours or reserve capacity do they say on them. these things will tell ya more what got.

 

[tmh]

Re: Starting battery vs. deep cycle for house power?

thanks, mike and all. I'll check them more closely today.

 

[wellsc1]

Re: Starting battery vs. deep cycle for house power?

Two Perko switches and three batteries... What does the wiring diagram look like?

 

[tmh]

Re: Starting battery vs. deep cycle for house power?

Two Perko switches and three batteries... What does the wiring diagram look like?

Yeah...good question. I was sort of mapping it out myself on the boat today... It appears to go like this.

Battery 1 : positive to Switch "1" on both perkos, Battery 2 positive to both "2" on Perkos. One perko to starboard engine starter, etc., the other Perko to port engine starter. I need to find out where the alternators feed.

The 3rd battery is not hooked up yet. It is installed and fed a third Perko 1/2/all switch (I think, could be just on/off, need to check again) dedicated to the generator. The generator is not plumbed now and I am not sure I will ever do it, still a mental debate on that.

So, with no need for a generator battery, I will add it to one of the engine specific Perkos or just hook two batteries in parellel directly. (Ideas on this???) I need to determine which Perko(s) feed house power or if that comes direct from one or both batteries - next time on the boat I guess.

Ideally, the 3rd battery would be deep cycle for house power and charge off one or both alternators with an isolator type device to keep it from draining a starting battery. IF I ever remove the generator I will add a 4th battery for more house power. right now I'd need to find a mounting spot not in the engine bilge area for any more batteries.

 

[bruceb58]

Re: Starting battery vs. deep cycle for house power?