moving batteries forward

westward · Posted: Wed May 28, 2014 10:04 pm Post subject: moving batteries forward

I'm interested in moving the batteries forward in my boat for weight distribution purposes: to add to the bow and remove weight from the stern. Anyone have thoughts? What gauge of wire to use, which type of battery will resist the increased pounding and not outgas or need much ventilation? Pitfalls you've encountered? Thanks in advance, Mike.

Pat Anderson · Posted: Wed May 28, 2014 10:15 pm Post subject:

Great thought, I will be interested in the responses you receive!

Chester · Posted: Wed May 28, 2014 10:38 pm Post subject:

Subscribed.

16Pounder · Posted: Wed May 28, 2014 10:59 pm Post subject:

I have my house battery (deep cycle) in the cuddy just in front of the steering column and the starting battery in the rear on the same side of the boat. The kicker is on the opposite side of the boat (port). This seems to be balanced fairly well. You can see the house battery in one of the pictures in my album. I have run it like this for years. I used a wet cell battery for the house battery most of the time I have owned the boat (16' Angler) but I just replaced it with a glass mat battery. The wet cell worked OK but it seemed to want to expel fluid out the top which wasn't a big problem with it in a plastic battery box. They seemed to last about 4 years before I needed a new one. The glass mat was expensive but won't have any fluid to leak. It's smaller in size than the wet cell battery but weighs the same. I have two 8 gallon gas tanks and rarely use more than one on a trip. I have a switch on the tanks so I can use fuel out of the best one to keep the boat balanced depending on whether or not I have a passenger and depending on the size of the passenger.
The wire from the house battery to the stern of the boat goes to an electrical device (I forget what it is called) to prevent discharging it and then to a switch. I think I used 12 ga. wire. I also have wire running to the stern of the boat for one electric downrigger. I forget what size it is.

Al

thataway · Posted: Wed May 28, 2014 11:07 pm Post subject:

How far forward do you envision? The best battery for this application will be the AGM. It can be placed in the cabin, without much risk of toxic fumes. You really don't want to put the batteries all of the way forward, for several reasons, but mostly you like to keep weight out of the bow of the boat. It is better to trim the bow down, rather than put a lot of weight up there. Using trim, you can always bring the bow up going down wind and waves. If you put too much weight up there, then it is harder to get the bow up.

Wire size, depends on the length of the run and starting requirement of the engine. Most of the smaller engines, will start with a small battery. When you calculate the length of the run of the new cable, be sure and calculate a "round trip", not one way. If the battery is moved 6 feet, then you will need 12 feet of wire.

You will have to decide if you want to use the current cables, and establish a terminal (like a stud) for both positive and negative, or run new heavier cable. Mercury gives a table which will allow #2 wire for 30 to 115 hp outboards up to 20 feet. I probably would fuse near to the battery, with that long a run...

Sunbeam · Posted: Wed May 28, 2014 11:30 pm Post subject:

I've been thinking about this in my 22 Cruiser, if I get to the point where I want to add a second battery. Right now I don't really have the capability to re-charge more than my one (105 amp hour) Group 31 AGM, but I may add charging capability, and then I would want a second battery. My boat is already starboard/aft heavy (the current house battery is in the starboard lazarette) and there isn't room for a second house battery there anyway, never mind the weight.

I did a sort of "paper napkin" calculation for putting the two batteries under the forward/port seat box (two Group 31 AGM and then only the small start battery left in the lazarette), and I think I came up with #2 wire (calculating voltage drop over the two-way run). But then I'd have a longer run than you would in a 16). I would re-calculate of course before actually doing it. I thought "Well that's a lot of cable/weight, when I'm trying to improve things, not load them down more," but then I did the math and it really wasn't that much weight in cabling. Of course this would require proper fusing, etc., as Thataway mentions.

Anyway, I haven't gotten down to brass tacks yet, since I don't currently have the charging capability anyway, but just figured I'd post since I have been thinking about it for future.

spuncopper · Posted: Thu May 29, 2014 9:45 am Post subject: Moving battery froward

Hello, I have a CD 16 cruiser. I've been playing with the location of a second battery for two seasons now. At present I have it in a battery case strapped on the centerline to the bunk supports. This weight distribution works, but it's located where the port-a-potty sits.

Placing it forward of this would require installing an access hatch for maintenance. I'm looking at this arrangement as there are other reasons to have an access hatch; there is a lot of storage space not being used due to inaccessibility.

I looked at placing it in the storage area under the passenger's seat. This however doesn't appear feasible due to access for maintenance and, as I'm getting older and have a few skeletal issues, makes it hard to install or remove.

As I haven't decided where I want to place it I haven't run any wiring. The second battery, at present, is only used for my hobby to power a 12v hookah compressor for u/w metal detecting. Since it hasn't been permanently installed it can be moved if it's needed as an emergency starting battery.

Good luck and I'll be watching this thread for other ideas. :)

thataway · Posted: Thu May 29, 2014 10:31 am Post subject:

One of the beauties of AGM batteries is no maintenance (other than keeping terminals clean, and avoiding over heating). Yes, the weight of the battery can be hard on the back, arms etc…as we age.

jerry97230 · Posted: Thu May 29, 2014 11:11 am Post subject:

I added a agm battery under the vberth on the port side. Then I moved the two engine battery's down to the floor between the fuel tanks.
I also moved the water tank to under the v berth. It is centered.
This all helped with trim and gave me a lot more storage.
Jerry C 22 C Nile

westward · Posted: Thu May 29, 2014 9:38 pm Post subject:

I guess I need to start researching the specific connections, wire size, maintaining the connection for my (electric start) kicker, etc. AGM is clearly the battery type of choice for this application. Does anyone have an opinion on AGM battery brands? Optima sure makes a convincing case in their marketing materials; how do they perform in real life? I like Bob's suggestion about not too far forward: it may create a bow steering problem of its own. I will place mine right under the helm. This will shift the weight of 2 batteries well forward, and help to balance out a baseline listing to Port on my boat due to the kicker location. I need to learn a lot more before I do this but it sounds like a fun winter project. Thanks, Mike

thataway · Posted: Thu May 29, 2014 10:41 pm Post subject:

I am not a big fan of the Optima, but have never owned one.--They are good for areas where there may be more abuse such as pounding etc--because of the spiral winding. The failure rate seems to be about the same, or perhaps more (?) than other AGM's. It is hard to tell from reading of other's experiences. This may not be a fair assessment.

I think that one of the current best buys is the Sam's Club Marine Duracell AGM made by Easts Penn (Deka). However they are only in group 34 and group 31 size, not in Group 24. I have used one of the group 31's to run my chest freezer for a number of weeks the summer before last, and the battery is holding up very well. I would run the freezer for 23 hours, and then charge with a 30 amp charger for 1 to 2 hours daily.

The Sear's Platinum DieHard Marine AGM on sale also has an excellent reputation, with a 3 or 4 year warrantee. They are also available in both group 31 and group 34. They made by EnerSys(Odyssey). None of these are cheap. I believe that these are both good batteries.

The group 31 is a large battery, but the group 34 is a smaller battery. The usual battery for the smaller boats is the group 24, but the group 34 also will work well--is is slightly smaller (volume) than the Group 24, and also a little less capacity, but more than adequate for most uses on the 16 C Dory.

Pat Anderson · Posted: Thu May 29, 2014 11:38 pm Post subject:

Timely topic. I am looking at my house batteries right now for our CD25 Cruiser. We have two NAPA Premium Deep Cycle Marine/RV flooded cell batteries, NAPA 8301, Reserve Capacity of 160 minutes, vintage 2011. Our son-in-law is the manager of a NAPA store, so we got the employee discount! The relationship between Reserve Capacity and Amp Hours is somewhat confusing when you try to figure it out from web information but as far as I can tell, Amp Hours are about 1/2 of Reserve Capacity, so these batteries may be about 80 AH. In parallel, that should be 160 AH. Our Norcold fridge drawing 5 amps intermittently sucks these guys dry overnight, voltage drops from 12.5 to right around 12.0. So conclusion #1 is the Norcold has to go. I am wondering if we need to replace the batteries or what. Fully charged, my volt meter shows 12.5 on one and 12.8 on the other. What is conclusion #2?

Aurelia · Posted: Fri May 30, 2014 12:57 am Post subject:

I am happy with two sets of Deka AGMs and did have a Optima go 5+ years so that wasn't too bad. I bought another recent set of AGMs from a local Batteries and Bulbs store (used to be batteries plus) and they have some good units for reasonable prices as well.

I have moved batteries forward on three boats so far and have been happy each time. Pay careful attention to placement, wire running possibilities, and if you use AGMs, don't be afraid to get kinky with mounting. Remember, they can be mounted on their sides or backs or ends and at angles so that allows for real creativity. Read the specs on the specific units you buy to be sure of the options you have. I have used PVC lumber, starboard, plumbing HDPE straps, webbing, angled aluminum, and adhesives, to create mounting solutions and that is just the beginning.

You can always test weight with jugs of water if you want to
"sample" your boat's handling and resting position with various load positions. Hollowing out at least some of the underberth space for storage opens up great options.

If you keep the starting battery rearward, consider going smaller on that unit if possible to reduce weight and move it lower if feasible. The motors on a 16 do not really need the same spec unit as a 90hp would. How about a lawn tractor battery or larger motorcycle battery? Talk to a mechanic about the real cranking amp needs of your outboard and start there. If you can put all the other loads on the house battery, you don't have to overcompensate on the starting battery.

Moving a house battery forward does not necessarily require big cables because you are unlikely to be running big amps from that unit on a smaller boat. Also, I would consider group U1, through 31 when looking at mounting positions. If you have the space for the next size up, it may be work a few more pounds and dollars if your electrical needs or anxiety level is in question.

If you hook it up to helm gizmos and lights plus the rear bilge, you may only need about 15 amps of throughput depending on the specific items you are powering. That means about 10 (bilge) and 12 (helm) gauge wire could do the job for that forward battery and that size is easy to work with.

The charging can be worked out various ways but that is another discussion.

Pat, If you run that 5 amp draw overnight for 12+ hours and its running the whole time then your set going from full to 12 (about 50%), is not out of the ordinary, but I would question whether the fridge is really running that many hours over night. The different charged voltages would cause me to question the health of that under performing unit immediately and consider a new matched set or just one big 4D if you have a place for it. are you house batts still in the stern?

http://www.napaonline.com/Catalog/CatalogItemDetail.aspx/Battery-Marine-RV-Deep-Cycle-Universal-BCI-4D-NAPA-Batteries/_/R-NBE8274_0213555638

Greg

Molly Brown · Posted: Fri May 30, 2014 6:25 am Post subject:

We are very happy with Odyssey batteries. I just put all new ones on our boat. The Odysseys that came out were installed in September of 2006. They are not cheap but are maintenance free and can be oriented anyway except upside down.

thataway · Posted: Fri May 30, 2014 9:41 am Post subject:

50% discharge of a flooded lead Acid Battery is 12.2 volts (resting state). If you are taking the battery down to 12.0 volts that is hard on them, and will reduce the life.

The little refrigerators do use a lot of current and are not insulated all that well. You might consider a larger battery such as a group 31. Which will have about 105 to 110 amp hours.

Fully charged battery defined at 2.2 volts per cell.

Reserve capacity applies a 25A discharge until each of the 6 cells is 1.75 volts and measures the elapsed time in minutes.

Amp hours The RC to Ah conversion formula is: RC divided by 2 plus 16. Or the constant current that will discharge the battery in 20 hours at 20°C to 1.75 volts.