Starting Battery for a MK I (1/2)

[Rick Johnson]

I have the week off, so I'm trying to get a few projects done while I can.  The new Xantrex Truecharge 40+ has been ordered and is on the way.  I now need to move the starting battery to a new location.  From the projects page and other postings, it seems like the area behind the motor or else in front of the starboard water tank are the two areas described.  It also seems like under the aft berth would be hot/damp and not easy to get to...  In front of the water tank is cool/dry, easy to get to and would be a longer cable run...

Any suggestions?  Any pictures?  Any comments?

Thanks,

Rick

[Jon Schneider]

check out the projects section of this site for Mark Elkin's description (http://home.san.rr.com/heysailor/sailing/projects/index.html)

[Stu Jackson]

Yes, Rick, those are the two choices.  Why do you have to move the starting battery?  You could also put it where our two of three house bank batteries are lcoated - under the forward part of the settee in front of the table.

While discussed before in the numerous electrical system posts, here is my summary:

1.  Aft near motor
     Advantages: shorter wire runs to starter, could use AGM or gel for no servicing
     Disadvantages: out of sight out of mind, hard to get to, needs wiring to either the old switch or a new one, if mixed with wet cell house bank would require an ACR to deal with differing charging voltages between gel and wet cell types

2.  Forward of Starboard Water tank
     Advantages:  easy to get to, will be serviced, can use wet cells
     Disadvantages:  longer wire runs to starter, BUT you can simply extend the existing wiring that should be from your 1-2-B switch to somewhere in your original battery box

Do we hear a preference here?  Nope, just a list of considerations for you.

What our boat has: (see November 2006 Mainsheet Tech Notes, too)  House bank: 3 130 AH wet cells, two on a plywood shelf under the forward section of the settee, one in the battery compartment; start battery in the battery compartment; 1-2-B switch used for selecting source to starter from C post on the switch; alternator output wired to the house bank PDP; combiner between house and start bank; if combiner fails the 1-2-B switch can be used to parallel banks for charging; Freedom 15 Inverter Charger

We chose to keep the 1-2-B switch and not add extra switches as Mark described.

In addition to Jon's reference to Mark's Project, see the others on the projects page, and also back-review a lot of the battery discussions here.

[Rick Johnson]

Jon, thank's I read that one...  I thought there was another where the owner described pouring resin to level the spot for the battery box.  I cannot seem to locate that one now...

Stu, I'm going to add the second pair of golf cart batteries to the current location next week so I don't have much choice about moving the starting battery.  The starting battery I just bought is a wet cell, so I really don't like the idea of under the aft berth (unless someone talks me into it).  The cold plate condenser is under the forward section of the settee, so that's out.  It's looking like my only choice would be forward of the water tank.  I was adding a Blue Sea Mega fuse holder, so I could use that in the battery compartment and extend the #4 wire from there to the starting battery.  I could then use the Blue Sea Maxi bus on the neg side to do the same thing...

I've tried to look at everything in projects and under the forum, but I'm sure I'm missing some idea...

Thanks,

Rick

[Stu Jackson]

Rick

It sounds like you've done your homework, and your decision is sound and workable.  Go for it! 

Oh, BTW, take pictures...

[Ron Hill]

Rick : I believe that I was the first one to put the starting battery just fwd of the starboard water tank. 
The 2 PRIMARY reasons that I selected that area haven't been mentioned!! 
First, all of the storage seemed to be on the port side and I wanted to keep the boat in trim.  Second, I also noted that as I added items they were aft of the mast so I also wanted that battery in a froward area - knowing well that it's better electrically to have a shorter wire run.
I'd use #2 wire if you put that battery forward of the starboard water tank!!

[Rick Johnson]

Ron,

Damn, #2 is expensive...  And me on a school district salary!  Any idea how long that run is?  Did you write anything up for TechNotes?

Thanks,

Rick

[Stu Jackson]

Rick,

Yup, #2 IS expensive.  It also depends on how you're wiring it for the length of run.  Regardless of what the length is, remember that for the past 20 years #4 wiring has worked from the battery compartment to the switch, to the starter (and back).  If your connections are good, as Ron has posted in terms of crimping and soldering, then the extra length may (repeat may) be OK with that size. 

The length, based on the boat length and just looking at my notes, is 10 feet out and back, and five feet sideways and back if you go to the switch, so 10 * 2 + 5 * 2 = 30 (including the ground wiring).  I just don't think you'll need to do anything but extend what you have.

[Rick Johnson]

Stu,

I'm hoping you're right.  I'll see if I can get away with using new #2 for the short run from the new battery location forward of the water tank to the battery switch and neg bus bar location in the old battery location (I'd guess about 8 ft).  I'll use the existing #4 from there to the starter and the ground.  If I get poor performance, I'll switch the old #4 for #2 at a later date.  Thanks to you and Ron for the help with a plan of action....

Cheers,

Rick

[Ken Krawford]

Rick,

I've been buying wire from a guy on Ebay for a couple of years.  Great stuff and very good prices.  Right now he's selling Ancor 2 AWG tinned wire for $2.60/ft.   That's pretty good compared to West's $5.99.   He also has lugs, shrink wrap, etc.

http://search.stores.ebay.com/Genuinedealz_2-AWG-Marine-Battery-SAE_W0QQsaselZ779049QQsatitleZQ222Q20AWGQ22Q20MarineQ2cQ20BatteryQ20Q2dSAE

[karista]

I selected the starboard side space next to the engine. Easy to get to and provided the absolute shortest wire connection to the starter. Installed a separate switch next to it. Selected the Deka group 34M AGM battery which has a lower height than the group 24 but higher CCA. This battery easily fits into this space, you will have to glass-in a small mounting platform. No maintenance, short wire length and direct connection to the starter was my goal. Worked out great.

[Jon Schneider]

Karista, do you mean that you placed the battery in the engine cabinet?

[Ron Hill]

Rick : I looks to me like the cost between #2 and #4 marine wire is about 55 cents/ft. 
Try the new installation with #2 and if you have have problems you can always parallel the old #4 with a new #4 if you have space on the terminal lug.  A thought.   

[Stu Jackson]

Good idea to consider paralleling wiring instead of replacing, also discussed in my Nov. 2006 Mainsheet Tech Notes article.

[Susan Ray]

I have a 1987 so this may not apply...but my starting battery is in the port lazerette secured up against the forward wall and has a short run to the starter and panel.