86 Mariner 32 Battery question

Joined
May 24, 2009
RO Number
31301
Messages
543
I am hoping cmariner32 sees this, but wondering if anyone else knows...

Currently I have 2 batteries hooked up and the inside battery switch is for 2 batteries (1, 2, off, and all). But, inside the engine compartment it looks as though there was a place for a third battery. In fact there is a positive and negative cable for it but I can't figure out what they are for.

The previous owner said he had no clue and never had them attached either. He figured the original owner had them disconnected at some point.

Any clue what these are for? Not the engines as far as I can see. And I can't find anything that doesn't work without it.

I also have a third cable to run to the battery charger and was planning for next year to hook one up as a spare if we go on a weekend trip and we drain a battery.
 
Unless that is to hook one up and the cables send the power back to the circuit board etc.?
 
That's what I meant. The cables were put there for a genset. Do you think the boat had one at one time?
 
When I got my Mariner 9 yrs ago, it only had two batteries. Early on I installed a 3rd battery as there was room between the stringers and I felt more comfortable playing the radio, running the fridge, etc all day while on the hook. Two batteries are hooked in parallel and I use them as my house bank-the 3rd battery is my starting battery. My guess is that at one time there was a 3rd battery in your boat too. Follow the suspect cables and see where they go. If they connect with another set of cables from one of the other batteries, they were using 2 batteries for a house bank at one time in the past. If you don't use a lot of 12 volt systems while anchored, you can probably get along with one group 27 battery. Let us know what you find.
 
Not sure if it had one or not. The previous owner (#2 in the line of succession) said he noticed it to but never knew what they were for. So could be for a genset, not sure. When I get up there this weekend I will climb in there and see if I can figure out where they go and report back.

I am too thinking about setting up one bank of batteries when on the hook and then a separate one for starting the engines. While we haven't done any overnights or floating in the middle of the lake yet, we are planning to next year and I want to make sure I have enough juice to do so. cmariner32's setup is pretty much what I am thinking of doing. Question, is that a typo about one "group 27 battery"? If not, what do you mean by that?

The biggest thing that would draw on the batteries if we aren't plugged into shore power is the fridge. It switches from AC to DC when the shore power is disconnected. I am slowly going around and trying to replace things to reduce the draw. Spent 200 this spring and replaced the incandescent bulbs and put in LED's.
 
Battery size is categorized in groups-24, 27,31 and too damn expensive to even think about. Group 27 batteries will get you through most normal loads and usages and are reasonably priced from $80-120. I used 2 Sears Diehard gr. 27 deep cycle marine batteries hooked in parallel and a NAPA truck/bus battery for the starting battery. The 2 Gr. 27 batteries will give me a little over 100 amp hours of good power-enuff for a day or night on the hook without going below the 50% dishcharge. I only get 2-3 yrs out of the Sears batteries but they are cheap enough not to care. I got 6 yrs. out of the first NAPA battery and on year 3 of its replacment. It's one heavy-duty battery!
 
I have an 88 Mariner 32. It has 4 batteries (all deep cycle). 3 group 27 on switch position 2 which I use for the house, and a single group 27 on sw position 1 for back up, also attached to this battery is another switch in the engine compartment which connects the generator.

I also have a set of cable that are disconected. They run all the way to the bow and are dead ended under the forward birth. It appeares they were for a windless
 
Those 2 setups is what I am considering setting up. Thanks for the info on the group numbers, had no idea. So, when you fire up the engines, you switch to your starting battery and then back to the others when floating? Once you fire up the engines, do you switch to the house bank to charge them at all or do you leave it on the starter battery? As for using the batteries while at dock, yes they do get used for the radio, cabin lights, head flush pump, but we are hooked up to shore power and the battery charger is on then. The fridge flips from AC to DC depending on whether we are on shore power. While out floating, that isn't the case, everything uses battery. So how do you determine how many batteries to hook up?

As for the loose cables, from memory, I think they do run forward, just not sure where. NHBoatman, how did you follow those forward and find the ends? Seems there is an area that I won't be able to get to to see where they go. Where in the bow did you see then ends, I can check there first?
 
First question, I run with the switch in all position, this gives me the quickest recharge (I am a mooring boat with minimal access to shore power). Once back on the mooring I switch to bank 2, tha house bank.

Question 2. I can see the unused cables coiled on the subfloor by looking under the forward birth (lift the storage panel and look down and forward). Also look in the rope locker to if there any cables there.

As for how the cable route to the bow, I think it is majic, they just seam to appear from under the sub floor, and in the engine room, they are coiled just infront of the starbord gas tank.
 
I didn't get the chance to figure out where those cables run. Had a short stay this past weekend unfortunately. I would agree, there must be a little magic in how they run all sorts of things back under the floors.

As for running in the all position, I read that you shouldn't do this due to back flow on the power from one battery to another that has more of a charge than the other. So I have stayed away from that.
 
"As for running in the all position, I read that you shouldn't do this due to back flow on the power from one battery to another that has more of a charge than the other. So I have stayed away from that."

That is exactly why I do it. All of my batterys are the same size and type. I load test them monthly, so that I know all are in good condition.

By connecting them all together I have the single battery on sw position 1 which in fully charged trying to equilise with the 3 batterys on sw position 2, which are drained down quite a ways but I also have the output from 2 heavy duty altinators (67 amps each) pushing max charge into all 4 batteries. My total battery capacity is 420 amp hrs and at 50% discharge (about a weekeknd on the mooring) it takes a little under 2 hrs to fully recharge.

Works for me.
 
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