Replacing 4D Batteries with 6-volt Golf Cart Batteries
My 4-year-old 4D house batteries were down to around 50 percent of their original 205-amp hour capacity. I looked around for sonic suitable replacements, but I wasn't thrilled with the selection out there. Most 4D's were either truck starting batteries or "dual purpose" and neither could handle a deep cycle installation without shortcomings. They made the real things, but the prices were higher than I was willing to spend.
You can use two 6-volt golf cart batteries in series to replace a large deep cycle 12 volt, as long as they will fit into the battery compartment. Golf cart batteries are famous for the number of cycles and abuse they can take. These things are run down just about every day of their lives, recharged overnight, and take 2 more golfers around 18 holes the next day month after month, year after year. 800+ cycles are possible for these workaholics - compared to maybe 400 cycles out of a normal marine 12-volt deep cycle, 250 out of a dual-purpose and no more than 20 out of a starter battery. They make really good marine deep cycles using other construction techniques or better design, but the prices are pretty steep. Compare this to the 4 Excide golf cart batteries that I picked up at Sam's Club for around $37.00 apiece. The other benefit is that they weigh only 60 pounds each, compared to 120+ for a 4D. They are a lot easier to lift out of the companionway. And capacity wise they are similar to marine deep cycles - some are better, some are worse.
It's a pretty simple installation. You'll need a few feet of heavy battery cable to connect each pair in series, and maybe some wood or foam blocks to stuff into the extra pace. The golf cart batteries are a little slimmer and a drop taller than most 4Ds, so you've got to prevent them from moving around in the battery well. Remember that you've got to hook up the negative to the positive within the set to be in series.
I also decided to replace the battery charger at the same time. The old Professional Mariner 50 amp unit (my 3rd after 10 years - replaced twice on warranty) was not doing a great job of prolonging battery life. I caught it going immediately to "float" a few times when the batteries were pretty far down. I also wanted to have a charger that had an "equalization mode" that can be initiated when needed. This heavier charging helps to get deposits off of the plates sort of like what a self-cleaning oven does when you invoke that cycle. I wound up selecting a Xantrex Truecharge 40 Plus with its optional battery temperature sensor. It will adjust the charge rate depending on the actual temperature of the batteries - another big plus.
I installed the batteries and charger a few months ago and it's working as intended. I can go out for 8 to 10 hours with ever\thing running on one of the 6volt pairs and easily have over 50 percent of capacity left. I'd like to talk about that too. There seems to be a question of whether running on both house cells (4 in my 6 volt case) is better than running each bank separately. In other words, should you have one house bank or two? Some of the boats were wired with the house bank (pair of 4D's) as "1" on the selector switch and the starter batter as "2". By the way - If you don't have a starter battery' maybe you should. It beats having to sail into your slip Columbus style. Been there, done that.
I think both methods have their place, and you should probably wire the boat with that in mind. That means being able to parallel both house cells or run them individually as the situation changes. Why should it change? It depends on how you are using the boat. There are two important things that you have to realize about a deep cycle battery - it has a finite number of cycles that it can deliver; and that you can't discharge it heavily and expect it to always recover. if you spend most of your time on the water day sailing or doing short cruises and will use less than 80 to 100 amp hours, then alternate the banks. Wire the switch to have battery one as "1" and two as "2" and alternate positions. You will be "saving a cycle" on one of them without bringing the other down to the point where it will hurt its long term performance. If you're going to be out for a longer time and you know that you will be using a lot of juice, then you should parallel them. You've burnt an "extra cycle", but that is less important than violating the other law about bringing either of them down too far. The only way to do this is to have the selector switch wired to allow it, and that may mean installing another switch to get the starter battery into the equation as needed.
You can also install an automatic relay or combiner system that monitors individual voltage levels and switches batteries in and out as conditions change - meaning that it will disconnect when the system is discharging and allow the manual selector switch to control usage. If any battery is getting a charge, then the relays close and they all do. Your alternator will then charge everything, which it is probably not doing now. I installed a 200 amp twin relay Xantrex "PathMaker" batterv combiner years ago to do this. Another benefit of this unit is that you can force all 3 batteries to go parallel to start the engine if needed - and do it from the navigation table if you get the optional remote panel.
Energy Arch for a C400
There are many types of cruisers: some are blue water, some coastal cruisers. Some cruisers are frugal. They adjust their lifestyle to make do with the minimum and enjoy it. Others take all the comforts of home with them when they leave the dock.
My wife and I fit closer to the latter. We are retired and in winter live aboard Agape, our C400 in St. Petersburg, FL. We sail the West Coast of Florida from Tampa Bay to the Dry Tortugas and have dreams of going to the Bahamas.
A liveaboard couple on our dock is working at living the frugal lifestyle aboard. They are using food stuffs that require no refrigeration so they will not have to maintain or provide power for a refrigerator. Not us! In addition to the refrigerator (hull #120), we installed a keel cooler freezer. Our expression is that we do not travel light. All this "living a normal" lifestyle requires mountains of energy.
To support these energy needs, we first installed a second alternator on our Westerbeke 42B. I left the original alternator as it was and use it to charge the engine battery and as a "spinning" reserve. The second alternator is a Balmar 70-90-amp model mounted on the port side of the engine. The original dual 4D batteries have been replaced with 8 T105 golf cart batteries. Six batteries are in the original but modified battery box. Two arc under the starboard side of the aft berth. I installed a Link 10 on the house bank to monitor energy usage.
This arrangement worked well as long as we were motoring. However, when anchoring or sailing, we still had to run the engine 1 to 1-1/2 hours a day.
The solution was solar panels and a wind generator. Before either of these could be considered, an "Energy Arch" would be required. I priced a stainless steel arch at some of the local fab shops in the Tampa Bay area - $6500 to $8500. A bit pricy. Aluminum arches would be somewhat cheaper, but the aluminum hardware I have seen on saltwater boats seems to have appearance problems after a few years.
However, I had an ace in the hole. One of my sons (whom I had fed and educated for some 20 years) is a professional stainless steel welder for a small firm in upstate New York. This firm makes stainless steel equipment for fat and fiber extraction from food stuffs.
I was able to secure permission to build the arch at this firm's shop on evenings and weekends.
To design the arch, I bought $11 of I-inch x 1-inch x 10-foot wood strips at Home Depot. I used tape and cord to "build" and modify the mockup arch on Agape.' I then measured the arch and ordered the stainless steel material. We used 316L stainless tubing. The main arch is 2-inch diameter tubing with the stringers and braces being 1-inch diameter. All the tubing was .065-inch wall.
The construction took about 2 months working 2 evenings and Saturday mornings most weeks.
The horizontal section slides into the vertical sections and is bolted. This was done so that the unit could be disassembled and shipped to Florida.
One photo shows the 3 Shell 80-watt panels mounted on the horizontal section with room for one more panel.
Another shows a Fourwinds II wind generator mounted on one of the welded vertical tubes. When I designed the arch, I did not know which generator I would use but figured that vertical tubes welded to the aft corners would be useful. They were.
Agape' also has a backstay-mounted radar. Originally, this unit was anchored to the deck on the port quarter. I had a pad welded on the rear arch about 30 inches above the deck for the radar pole. This allowed the radar to be raised and minimize the interference between the radar pole and the arch.
The arch makes a very convenient place to work on both the radar and the wind generator. The 1-inch stringers act as steps on a ladder and the flat arch top is a perfect platform. If I'm going to spend any time on top of the arch, I place a 1-foot by 2- foot piece of wood on the arch.
The mounting to a compound angle deck was tricky. In the design and construction of the arch, I was able to design for the athwart ship angle. The smaller nuisances were beyond my design and measuring ability. To make the fit at the deck, I cut sections of a polyethylene kitchen cutting board. I then faired this section with a Dremel tool and wood rasp so that I had even contact across the four mounting pads. The units were assembled with marine sealant on top and an aluminum plate underneath. The mounts have not leaked in the 9 months since assembly. I plan to glass in the polyethylene for cosmetic purposes.
The system does a very good job of providing energy for the boat both at anchor and Linder sail. In mid April, I was getting about 4S amp hours per day from the 3 solar panels plus booster. On an overcast day, the power output seems to be 20 to 25 amp hours.
The wind generator is more erratic. Sonic days, it produces virtually nothing. On three days, it fully charged the battery bank; we were under tornado watches on all three days. Yet, the two systems compliment each other. When there is little wind, the sun is normally shining. When sailing and at night, the solar panels have little or no output but often the wind generator is putting 8 to 10 amps into the batteries,
The arch cost me about $1200 including shipping. The solar panels and booster were $1500; the wind generator and mounting hardware together were $1450. It is interesting that the solar panel system and wind generator cost within a few dollars of each other. Yet I am getting 3 to 4 times as much energy from the solar panels. The wind generator does fill some energy holes, and it is much sexier.
One side note on the wind generator was the noise issue. Below 5 knots, it doesn't run and is, therefore, quiet. Above 10 knots it is a very quiet unit; the wind in the rigging makes more noise. But from 5 to 10 knots the system sounds like a threshing machine. The rear cabin was not habitable. I believe this is a function of the natural frequency of the total mounting structure. Other Fourwinds II units do not have this problem. Some KISS generators have had similar problems.
The solution was to go back to my welder and built an isolation unit. This unit can be seen in Photo 1, 2 and 3 at the base of the wind generator pole. This isolation unit cut the noise by 3 fold and sleeping in the rear cabin is no longer a problem.
Also added to the arch is a small swivel arm to be used to hoist the dinghy motor.
I also had the objective that the arch not stand out and become the focal point of the boat; as built, I believe the arch blends into the bimini.
I've had many compliments from folks on the dock on both the design and welding on the arch.
I may add the fourth solar panel, but so far the arch and energy system appear to be satisfying the needs of our complete home away-from-home.