Any Elctrical experts onboard?

[Ocnvoyager]

Have DC charging questions. Specifically related to multiple batteries and multiple charge inputs. AC Charger, Wind, Solar and alternator.

Thanks

[Phil Prater]

So, what may I ask is the question, or questions.

[Ocnvoyager]

With multiple batteries including house batterys and starting battery where is the optimum place for the alternator lead?

[Phil Prater]

While many believe in all the new fangled stuff, like echo chargers, and isolators and combination charger/inverters, I'm not one of these. I have a 450ah house bank, and a single group 29 start/emergency battery. I use a simple 1 - 2 - both battery switch, with the alternator lead going to the common side of it. So, if it is on 2, house bank is charged, or on 1 the start/emergency battery is charged. I never run it on both, and have never had a problem.

[Ocnvoyager]

Phil Thanks,

Before my boat went underwater it was set up just as you described with all the batteries in the house bank connected and start battery separated just by a switch.
Since everything is getting replaced and brought up to more modern standards I have been doing a lot of research on Isolators and combiners and charge relays.

From what I have read and been told by the people who make all that stuff is that the batteries will have a much shorter life overall if they are simply joined by a common bus and charged in that manner.

What kind of battery life are you seeing?
I am planning to use 4, 4D Gel cels for the house and small starting battery probably Group 27 for starting.

[Phil Prater]

Bill,
I think most of the shorter life stuff is primarily a sales pitch. Think about it for a minute. You do nothing different with the old way, except control where the charging voltage from the alternator goes. There is no voltage change, nothing any different. The echo chargers just take alternator voltage above a certain point and bleed it off into the start battery. I rarely put the battery switch on 1, as I start the engine off of the house bank normally. I also have 300 watts of solar, and here is how mine is set up. I have two 85 watt panels, and two 65 watt panels. This is, when it isn't cloudy for a couple of days, enough to handle all my charging needs. I use two controllers. Both wired directly to the house bank. One of the controllers is on a 65 watt panel, and is the cheaper type, which uses a dump, for when the batteries are fully charged. The dump goes direct to the start bank, and is enough to keep the start battery fully charged at all times. The other is a 30 Sunsaver controller, and it goes to a float mode when batteries are up. I recently returned to Slidell from a cruise to S. Fla. and this set up worked pretty good. Almost never had to run the engine to charge batteries. A couple of times when we had two or three cloudy days in a row.
I have the typical power users, including a small fridge, laptop, auto pilot, chartplotter, etc. The one minor problem I have found with my set up, is that I need to put a switch in the circuit to totally shut off the solar. What is happening is when running the engine, the alternator regulator senses the voltage from the solar panels, and cuts back the alternator output. When I do need to charge batteries with the engine, this slows down the process some. Not sure how much. Other than that, really like my set up, and it has been totally reliable and problem free.

[Veranda]

Hey Bill,

If I can make a suggestion. We're using 4 4D batteries as a house bank such as you propose. They each weigh in at about 125 pounds. When it comes time to replace them I think we'll be considering 6 volt batteries as an option. They weigh in at a lot less, around 65 pounds. Maybe even 12 volt group 31's, I dunno I haven't done the research yet. Handling those 4D's is a bitch.....

Bill

[Ocnvoyager]

Good advice. I was hoping my wife could do all the labor. She may think otherwise. How long have you had them in use? Just curious.

[Phil Prater]

Bill,
I have recently switched from Group 31 to the 6v golf cart batteries. Have only had them a year, but so far so good. I have the Sams Clubbers, which for 300 bucks gives me a 450 ah bank. About as much bang for the buck as is out there. I dont have the space for the 4 or 8 Ds, nor the desire to manhandle those big puppies into the boat. For my needs and budget the golf carts get it done.

[zeehag]

my formosa came to me with one d8--i call it a 2 men and a boy battery, and 4 of the golf cart ones.......my ericson has 1 of the 27s and 4 golf cart ones.....both both have had same batteries about 5 yrs now and still going well.......

[h]

Bill,

Pick up the July 2009 copy of Sail magazine. There you can see the Switch and combiner and the fuses required. I have a similar set up to the one discribed on the article minus the fuses. Which now I have to install to protect the conductors, and meet the ABYC standards.

With Gel Cell, the charge voltage is lower than the AGM or other wet cells. IE it is paramount that you use a charge controller, and set the charge voltage setting to Gel setting. I think it is 13.8 vs. 14.6V.

For wind generator the latest technology is the Air Breeze. Although the output is only rated at 200 W, it generate electricity starting at a lower wind speed. I the wash you get the same total per month as the Air-X (400W). Air Breeze is quieter, and has sophiticated electrical control etc.

On Solar, again, Sail Magazine July 2009. Nigel Calder wrote a good article on it. If you can wait, the prices and technology will be better soon. I know from my work there are many large companies in China setting up factories for making later technology solar panels with higher efficiencies. I am waiting in this department too. Since my cruising trip is not imminent.

h

[CommodoreSwab]

I plan on having 2 house banks tied together (possibly 1 8d and 2 6v golf car as space allows) along with a starting bank. The 2 house banks will be tied to a common buss which will allow disconecting 1 provided something happens by unbolting (I see no reason to place a switch that is always turned to both). As for charging I will have 2 wind generators, engine alternator (very small), a small solar panel, as well as a massive alternator on the engine.

The 1st wind generator is permantly mounted with the second able to be rigged while at anchor. One will go to the house bank and the other to the start bank. The small solar panel is tied into the starting battery, the small alternator is also tied into the starting battery. The large alternator will be tied into the house bank.

Both banks are tied together using a combiner so that when 1 battery is charged it spreads the charge to the others.

[Phil Prater]

CommodoreSwab,
That sure sounds like an overcomplicated set up. And as for using a common bus with the plan of unbolting one bank should something happen, I don't think you realize how quickly an electrical fire can spring up, should something happen. I would strongly recommend just tying them all together, and fusing them at the battery.