Time and Cost for converting dual 12v house bank to 4 6v's?

MitchM

.
Jan 20, 2005
1,011
Nauticat 321 pilothouse 32 Erie PA
can those who have done this project give me an idea of what the time involved and costs would be for this job ? I won't factor in battery cost , since th home batterie are done. So i have to replace my house bank with two 8Ds at 220 aH each, or my 2 31 XT Lifelines at 135 aH each, or 4 6v golf cart batteries which will require a re wire. (our primary issue is whether to replace the original 440 a H 8 D bank with another set of 8 Ds, to get enough aH to use the inverter which needs a 'recommended' 400 aH minimum bank. But we never use the inverter; all it runs is galley outlets and the microwave. ) So 4 years ago , we replaced the 8 Ds with 2 lifeline XT 135 Ah batteries . now we're contemplating the switch to 6 volts . thanks for all words of wisdom...
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Your Lifeline 31XT AGMs only lasted you 4 years? Either upgrade your battery charge management equipment or change over to FLA and save money on replacements. If you are sharing living space with your house battery, option 1, AGM + smart charger. Horsing an 8D battery into/out a boat is a hassle.
 
Jul 27, 2011
4,990
Bavaria 38E Alamitos Bay
Last summer, I replaced two 12-volt 4D's @ 125 ah each wired in parallel with four 6-volt deep-cycle Penn batteries @ 235 ah each, and wired in series-parallel to produce a 12-volt house bank of "theoretically" 470 ah. The four Penns fit into the same space as the two 4D's had. I bought new cable for the two series set-ups but used the existing cabling to connect them in parallel. So, if you do not figure the cost of the batteries then you're potentially talking only the cost of the new cable and ring terminals. I cut the cables to length and crimped on the terminals myself using the crimper at the store where I purchased the materials. So, it wasn't bad. As for time, figure a weekend and I'm only your very basic DIYer. However, if this had been more complex involving significant re-cabling I probably would have hired one of my electrician friends to install the new bank. My included advice is to follow your own notion; divest yourself of the inverter and remove your AC appliances.
 
Last edited:
Jan 4, 2010
1,037
Farr 30 San Francisco
Well if you never use your inverter, just chuck over the side and then you don't need such a big battery. You are welcome! The battery size suggested will be set by full load, if you never load it you don't need such a big battery.
 
Jan 11, 2014
11,323
Sabre 362 113 Fair Haven, NY
The 6v GC batteries have a few distinct advantages. First, for about the same Ah rating you get the batteries in 4 more easily managed packages of about 65 pounds each instead of 2 packages of 130 pounds each.

GC batteries are designed to be deeply discharged and recharged other batteries not as much. There is a huge market for GC batteries which has a positive effect on both cost and quality.

The only additional expense will be some new cabling for the series/parallel wiring and perhaps a new battery box. SBO sells a nice heavy duty battery box that will fit 4 GCs. I installed one on my boat. You'll need 2 short cables (~5 inches) to put pairs of batteries in series and 2 longer cables to parallel them.

While you're at this it would be a good time to clean up any wiring and add a marine battery terminal fuse to comply with the ABYC fuse within 7 inches standard.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
can those who have done this project give me an idea of what the time involved and costs would be for this job ? I won't factor in battery cost , since th home batterie are done. So i have to replace my house bank with two 8Ds at 220 aH each, or my 2 31 XT Lifelines at 135 aH each, or 4 6v golf cart batteries which will require a re wire. (our primary issue is whether to replace the original 440 a H 8 D bank with another set of 8 Ds, to get enough aH to use the inverter which needs a 'recommended' 400 aH minimum bank. But we never use the inverter; all it runs is galley outlets and the microwave. ) So 4 years ago , we replaced the 8 Ds with 2 lifeline XT 135 Ah batteries . now we're contemplating the switch to 6 volts . thanks for all words of wisdom...
Forget using 4D or 8D batteries. The only reason boat builders install them is because they look impressive at boat shows and require less labor & material cost to install. They are doing no one any favors by installing these batteries.

Beyond that, due to the square shape of the cells, there is no way to properly orient an 8D flooded battery on a sailboat so as to not expose the plates when heeled. Any manufacturer that installs flooded 8D batteries on a sailboat is simply not doing their job well.

This is the first part of ABYC E-10 under "Installation". The FIRST THING YOU SEE!

"10.7
INSTALLATION
NOTE: When installing flooded batteries on a sailing vessel, consideration should be given so
that the orientation of the battery minimizes the uncovering of battery plates while heeling.
"

This fail, on top of the fact that they are not true deep-cycle batteries, leads to short life.

Even the trucking and agricultural industry are rapidly moving away from using 4D or 8D batteries. Some battery manufacturers have even stopped producing flooded 4D and 8D's altogether. This includes deep-cycle manufacturers such as US Battery Corp and Trojan.. Only in AGM or GEL will you regularly find a 4D or 8D battery that is actually a deep cycle battery. Both Dyno and Rolls do produce a deep-cycle version, in a flooded battery, but the rest are simply "starting" or "dual-purpose" batteries with a deep cycle sticker slapped onto them.

The Lifeline GPL-31XT is a 125 Ah battery not 135Ah so you actually have 20 Ah's leas than you think. Whether this matters or not would depend upon you actual daily -Ah consumption and ability to recharge. If you are looking at replacing Lifeline AGM's at year 4, your charging system and/or use are likely not working as they should. Flooded golf cart batteries are much less costly to chew through in short order than AGM's...

Sizing your bank should ideally be inclusive of your inverter, whether you use it much or not. When sizing a lead acid bank for cruising use, it should be sized based on 30-35% of its face value Ah rating as your usable capacity. With AGM's 35% is usually fine, they charge a bit faster, but with flooded deep cycle batteries sizing for 30% as usable capacity is safer.

When cruising you will usually cycle from 50% SOC to about 80-85% SOC, hence the 30-35% usable capacity figure. Once you're more than a day away from the dock, or a full charge, your usable capacity shrinks due to the rapidly declining charge acceptance above 80-85% SOC. If you continue this partial state of charge use (PSOC), each day, between full recharges, the usable capacity shrinks even further due to what is called PSOC walk-down..

In reality your 400Ah bank really only has a usable capacity when out cruising of about 120Ah's. A 250Ah bank only has about 75 usable Ah's. Also keep in mind that this sizing does not include for any aging, capacity loss due to age or PSOC walk-down. In short, a bigger bank, discharged shallower wins over the long haul....

Installing 6V batteries is a minimal cost difference so long as you have the available height in your battery box. A few series & parallel jumpers, battery box, some hold downs and re-programing your charge sources for optimal voltages are really the only differences.. If you really want to do it right some Water Miser caps or an automatic watering system can be installed too.

If you are in the market for deep cycle batteries this article can help shed some light on the buying process.

What is a Deep Cycle Battery?


.
 
Mar 29, 2017
576
Hunter 30t 9805 littlecreek
Don't forget to put them in battery boxes. Catches that acid during healing. And strap them down
 
Jan 30, 2012
1,123
Nor'Sea 27 "Kiwanda" Portland/ Anacortes
Even the trucking and agricultural industry are rapidly moving away from using 4D or 8D batteries. Some battery manufacturers have even stopped producing flooded 4D and 8D's altogether. This includes deep-cycle manufacturers such as US Battery Corp and Trojan..
https://marinehowto.com/what-is-a-deep-cycle-battery/
There are plenty of applications where FLA 4D and 8D are quite useful. But -- the NIOSH model lifting equations end up making an employee lifting safety limits about half the weight of a 4D. While OSHA itself does not have specific lifting limits the enforcement folks claim they are entitled to enforce NIOSH standards (or any others they deem appropriate) under the OSHA General Duty Clause.

In short the FLA version of 8 and 4D sizes are disfavored in large part because of workplace lifting rules coupled with the obvious spill hazard. Still these are useful - think big displacement diesel starting at half the price of Gel or AGM version
 
Jan 18, 2016
782
Catalina 387 Dana Point
As always, what Maine Sail said.

I'm a huge fan of GC batteries.
1. They're cheap.
2. They're widely available - you can get good ones at Sam's or Costco. GC places in bigger cities often have great prices too.
3. They are, by far, the best quality per dollar of any FLA battery. (If I can say that generically...)
4. Best AH/$$$ you can buy.
5. They'll outlast AGMs with the way most boaters treat their batteries.
6. Normal humans can lift em out of the companionway - that really can't be said for 8Ds.

Fuse them correctly. Charge them to full as much as possible, don't draw too deep, and you'll get more than 5 years out of em.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
In short the FLA version of 8 and 4D sizes are disfavored in large part because of workplace lifting rules coupled with the obvious spill hazard. Still these are useful - think big displacement diesel starting at half the price of Gel or AGM version
Sure for starting big boats, boats we are not really discussing here, they can work. However two G-27's or G-31's, as many of the trucking fleets are using these days, will work equally as well and in most cases can deliver more cranking capability than an 8D can.

For example I install a lot of Crown batteries. The 8D 1400CCA Crown runs about $230.00 at my Crown distributor. The next smaller 8D can only deliver 1100 CCA but Crown also makes an 1100 CCA Group-31.

The Crown G-31 950CCA battery runs $93.00 and two of those would give me 1900 CCA (0F) for less money than the single 8D. That's 600CCA more in two G-31's, or nearly an entire batteries worth of extra cranking amps for less than the cost of a single 8D..

I can also drop down to two G-27's and still have more cranking amps than a single 8D and for even less money.. Crown also makes a Group 31 1100 CCA battery. This would be 2200 CCA vs. just 1400CCA using their biggest 8D. My sport fishing customers are often shocked at how well the engines starts on two G-27's or G-31's vs the old 8D hogs they used to have......

For the customer with the 8D battery I need to additionally hire a couple of high school football players to get the 8D off the boat. With two G-27's or G-31's delivering more CA than a single 8D, and costing less, not including the extra labor, I see no need to ever install an 8D for starting purposes even on my customers with a 750+ horsepower MAN's, Deer's, Detroits, Cummins or Cats. Even on the large Cat C-18, one of my customers has in a custom Wesmac, Cat specifies two G-31's in series for starting at 24V...
 
Dec 19, 2006
5,809
Hunter 36 Punta Gorda
I changed from my 2-4D's years ago and now have 4-6volt's since 2010,for me was a big change where
i had the 2-4D's in my big cockpit locker and moved them to under my salon table seat on my 2007 H-36.
All the cables from factory were used and made some small cables and and 2 new battery boxes 4 Tronjon T-105's and love them.
I did also add solar 2-190 watt panels and when at home dock and anchored my solar does all my charging needs and still have the stock alternator.
Nick
 

MitchM

.
Jan 20, 2005
1,011
Nauticat 321 pilothouse 32 Erie PA
thanks to all for the thoughts. the boat has a heavily-built OEM fiberglass integral battery box with latchable lid and interior hold downs. there is room for the 6 vs both in height and width. The required large fuse is right next to the box. the boat originally came with 2 massive flooded 8 Ds, which needed a strong crew to remove.t the original flooded 8Ds lasted 8 years . ; the 8D engine s tart lasted till spring 2016. as for the observation : " If you are looking at replacing Lifeline AGM's at year 4, your charging system and/or use are likely not working as they should..." : the 31 XT lifelines were charged since install off a top of the line Master volt 3 stage inverter/charger which was functioning perfectly in all 3 phases per my fluke and per the onboard diagnostic Mastervolt panel which reads aH charge, allows the Peukert to be set and provides % remaining voltage. There was only one unfortunate incident when someone left the refrigerator on and the house batteries drained down to 11.2 volts. ( we don't leave the shore power charger on when we're away . The only 12v connected to the system if we are away is the bilge pump. ) the Lifelines needed an equalization charge last spring 2016 at haul in. IMHO the lifelines are now shot, as they did not pass a load test at fall haul out...
 

MitchM

.
Jan 20, 2005
1,011
Nauticat 321 pilothouse 32 Erie PA
Just a FYI- Lifeline recently advised that their AGMs require equalization charges when installed in sailboats. Here's their post:
"...At Lifeline we understand that some applications, especially sailing vessels, cannot always fully recharge every day. As a result you will need to equalize. Your equalizing routine will depend on a lot of factors. We are here to help you custom design a custom equalizing routine based on your application and habits to make your batteries last as long as possible. We personally worked with John Harries, which owns and operated a sailing website www.morganscloud.com. After two rounds of AGM batteries failing within two years, John called us for advice. We provided John with two new batteries and a custom equalizing routine. His new batteries lasted him 5+ years in the same vessel...: "
since mine are shot at 4 years, and since it's possible that happened because i did not realize the need for equalization, that is a factor to be taken into account. To equalize the lifelines last spring , i needed my portable 3 phase Schumacher charger , as the on - board master volt did not have the capacity to do an equalization charge.
 
May 20, 2016
3,014
Catalina 36 MK1 94 Everett, WA
I need to additionally hire a couple of high school football players to get the 8D off the boat..
.

I was working as a deck hand on a troller in the early 70's, about 50 miles off the coast of Washington and one morning an associate of the skipper calls on the radio that his battery died on him. We un-cable one of our 8D's and with both boats in close proximity hand the battery between the boats both of us rolling and not in sync. I'm still amazed we only broke one window. Bad enough to lug those things onto a boat and down into the bilge when tied up. Quite another rocking and rolling 50 miles out

Les
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
Just a FYI- Lifeline recently advised that their AGMs require equalization charges when installed in sailboats.
Mitch,

The need to EQ is not necessarily new with Lifeline batteries.. IIRC this goes back as far as the late 90's or early 2000's. If you treat Lifeline AGM's well, get back to 100% SOC regularly, use good quality charge equipment, and use temp compensated charging (a MUST), you'll get good life from them.
 
Feb 6, 1998
11,667
Canadian Sailcraft 36T Casco Bay, ME
IMHO the lifelines are now shot, as they did not pass a load test at fall haul out...
What type of load test was performed? Depending upon the test used you may be getting rid of batteries that are not yet dead and could still be revived.
 

Gunni

.
Mar 16, 2010
5,937
Beneteau 411 Oceanis Annapolis
Equilization:
I also have a Mastervolt charger (12/100-3) and run Lifeline XT31 batteries (4). The manual describes how to drop the charger into equalization mode from Float, but then ads this caveat:
Incorrect use of the equalize mode may lead
to hazardous situations.
Do not smoke; use any naked flame or other
sources of ignition due to risk of explosion.
Always ventilate the room were the batteries
are located and equalized to clear the air.
Equalization is ONLY applicable for wet type
batteries and will damage gel and AGM type
batteries

So my question is "what is incorrect use of the equalize mode"? I really don't want to explode my AGM's.
What am I monitoring and how do I stay left of boom?
 

MitchM

.
Jan 20, 2005
1,011
Nauticat 321 pilothouse 32 Erie PA
well Gunni, i was very frustrated with master volt for 'referring me to my dealer' over several install questions , (particularly involving the 'slave' lead install which was not clearly specified on the install directions. ) as to the equalization question: i have a fine 3 stage portable schumacher charger with equalize mode, and that is what i'll use . i'll disconnect the leads to the house batteries, and equalize each one separately. after reading the equalization directions from lifeline, (duh) i now realize the equalization must be done several times to work properly.. so i will start on this job when i haul in ----instead of ditching the lifeline XT house batteries... thanks to all as usual for very valuable suggestions. 'strange how much you've got to know before you know how little you know...'
 
Jan 22, 2008
8,050
Beneteau 323 Annapolis MD
MitchM said:
... 'strange how much you've got to know before you know how little you know. QUOTE]

"There has been an alarming increase in the number of things I know nothing about".
 
Oct 22, 2014
20,995
CAL 35 Cruiser #21 moored EVERETT WA
I for one am thankful to benefit from MaineSail's insight on the nature and upkeep and cost of batteries. Years of professional experience shared.

The decision I made was the typical compromise decision all boat owners face. I do not have a team of Footballers to help me load or unload batteries. I didn't not want to be 50 miles out and discover one of my batteries was dead and affecting the other good ones let alone try to wrestle a 100 plus behemoth boat to boat. Room for battery banks is limited and 4 CG6V was not an option at the present. Then I found a 30TMX from Dyno in Seattle WA. 135ahr, True Deep cycle, designed for the sweeper and aerial lift industry 12 volt battery weighing in at 65 lbs. 2 of these gives me 12 volts with 270 Ahr as compared to 2 6 volts at 225 Ahr. If one goes bad I still have an operating 12 volt battery. If a 6 volt goes bad your sailing or rowing. That's why folks buy 4 6 volt batteries.
http://www.dynobattery.com/products/sweeper-and-aerial-lifts/30tmx.php

And they fit the space designed on my boat.
It worked for me.