House Batteries in my Westsail 32

[Cheechako]

While 6 volt batteries tend to have thicker plates, dont minimize the trouble to connect them with good short cables and the cost etc. It can be a bit of a rat's nest and good thick cables dont bend easy etc. Every extra connection is a resistance or failure point. Just sayin.... maybe not worth the trouble to some people. I've done it before, not sure I would again.... KISS

[endoftheroad]

Originally Posted by oregonian

Ahoy endoftheroad,
This is an alternative to your suggestion and what I have been using in my W-32 for over 30 years. Most of that time was full time living aboard and long distance voyaging. I have all the stuff on my boat as you do.
I use two group 31, AGM's only (12V). No battery box. Both batteries are used separately and equally. No distinction is made for House or Start. I have one single solar panel that is not permanently mounted and only used at anchor or when convenient. All of this is less than 1/2 of your suggestion. I (and my wife), have been discribed as more minimalist than most - but- we have never needed more capacity.
Over the years, I have used wet cell, gel cell, and AGM's. I am most happy with the AGM's. The current 2 batteries are 9 years old and are just now showing signs of needing replacement. They have travelled far and wide.
You might consider using this "smaller" capacity. It will save money, weight, and volume. If it is not enough then just add another one.
Good luck, Hope to see you down the road.

Great info Oregonian!
Very interesting approach.
btw, thanks for your recent email regarding your boats rigging description. It was very informative and it eased many of my concerns.
I sure wish I lived on your side of the planet.
endoftheroad

[mcarling]

Like deckofficer and IceDog, I would not buy lead acid batteries again. Until something better becomes available, I will only buy LiFePO4 batteries. Since the OP was concerned about price and weight, LiFePO4 would be better for him than lead acid. The main caveat is that the charging regime is different.

[endoftheroad]

Originally Posted by IceDog

In order to install 4@6V batteries to provide 12V with double the capacity of one of them, you would need to install them as shown in the final drawing (series/parallel). Was the starter battery in one bay and the house batteries in the other bay or are there still two separate bays with cables laying in there? Do any of the cables go from one bay to the other or do you have a red and black running to each bay from a copper bus bar or terminal block near the alternator? Is the engine alternator the sole source of charging for the batteries at the moment?

The following excerpt is from How Lead Acid Batteries Work



Most marine, automotive, and RV applications use 12V DC. You have the choice to either buy a 12V battery or to create a 12V system by wiring several lower-voltage batteries/cells in Series.


When two 6V, 100Ah batteries are wired in Series, the voltage is doubled but the amp-hour capacity remains 100Ah (Total Power = 1200 Watt-hours).

You may decide to wire batteries in series because a single 12V battery with the right storage capacity is simply too heavy, unwieldy, or awkward to lift into place. Batteries consisting of fewer cells (and hence lower voltage) in series can provide the same storage capacity yet be portable. It is not unusual to see solar power installations where the battery bank consists of a sea of 2V batteries that have been wired in series.

Two 6V, 100Ah batteries wired in Parallel will have a total storage capacity of 200Ah at 6V (or 1200 Watt-hours).

Battery banks consisting of 12V batteries wired in parallel are often seen on OEM installations in boats and RVs alike. Such banks are simple to wire up and require a minimum of cabling. However, the wiring must have the capacity to deal with a full battery bank.

You should fuse each battery individually in such a bank to ensure that a battery gone bad will not affect the rest of the bank.

Battery banks wired in Series-Parallel are even more complicated. Here, four 6V cells are wired in two "strings" of 12VDC that were then wired in parallel. Using 6V, 100Ah batteries, this system will have a storage capacity of 200Ah at 12V or 2,400Wh.

Since such a system has more wiring, it is very important to group "strings" logically and to label everything. Furthermore, it is a very good idea to fuse every "string" of series-wired batteries to ensure that a problem in one part of the battery bank does not take the whole bank down.

Icedog,
Thanks so much, the diagrams helped greatly.

I'm confused how the previous owner of my boat used 4-12 volts batteries (2 in the port battery tray and the other 2 in the starboard tray) and maintained a 12 volt system. The start battery is seperate and at a different location.
And how/which diagram would I use for adapting 4-6 volt Trojan T-105's to my existing system (plug and play to the previous owners set up)?

endoftheroad

[Target9000]

Batteries can be wired in parallel or in series. When you wire in series it adds the voltage of the batteries, when you wire in parallel it adds the amp hours.

So the previous owner of your boat wired the 4 x 12v batteries in parallel to maintain a 12v system.

To accomplish the same thing (keeping batteries on two sides of the boat), you could do the following

[endoftheroad]

Target,
Thats awesome, thanks, I'm starting to follow.

Would the long wires crossing the centerline of the boat be an inneffecient layout?
Would the previous owner had to cross centerline with his 12 volts?

[Kettlewell]

Over the years, I have used wet cell, gel cell, and AGM's. I am most happy with the AGM's. The current 2 batteries are 9 years old and are just now showing signs of needing replacement. They have travelled far and wide.

Oregonian, that is one of the best results I have ever read using AGMs--most people report being very disappointed in their longevity. Could you let us know the brand and model? You aren't by any chance actually using gel cells and not AGMs? Gels have been known to last a very long time.

[Paul Elliott]

Originally Posted by endoftheroad

BTW, I have refrigeration, ipads, anchor light, pressure water, bilge, propane solenoid, cell phones, some lighting usage, I'm a full time liveaboard on the hook. We're pretty minimal regarding electrical consumption but the Wife is a Vegetarian and the fridge (if it works) may save my marriage .

As you plan your electrical system, be sure to put together a realistic power budget (regardless of the type of batteries you eventually install).

You mention planning to install solar panels, and not needing to use much engine-charging. You may find that just the refrigerator alone may consume 100Ah per day, and you will probably need 300 Watts of solar panels to keep up with that (these numbers are approximate). Add in your other electrical loads and you can see how this adds up.

Solar panels are a good thing, but do be realistic about your power needs and how you're going to meet them.

[Target9000]

Originally Posted by endoftheroad

Target,
Thats awesome, thanks, I'm starting to follow.

Would the long wires crossing the centerline of the boat be an inneffecient layout?

Long wires are not the most efficient but it isn't going to make or break you. Just use large gauge wire with quality tinned connectors. As I mentioned, on our boat I chose to skip crossing the center by packing all the batteries on one side.

Originally Posted by endoftheroad

Would the previous owner had to cross centerline with his 12 volts?

The PO would have to connect the different sets of batteries, though there are several ways of doing that. So it may not look as simple as the diagram makes it out. The best thing to do is probably to follow all of the positive wires off the posts of the old batteries and trace where they all go. That would give you some good insight.

[Maine Sail]

A couple of shots of actual series parallel wired 6V battery banks.

This one was during the mock up of the battery box..


You could just picture the two parallel wires longer and the boxes on port & starboard. Note that the pos and neg takes offs for the system are at opposite sides of the bank.

[Paul Elliott]

Originally Posted by Kettlewell

Oregonian, that is one of the best results I have ever read using AGMs--most people report being very disappointed in their longevity. Could you let us know the brand and model? You aren't by any chance actually using gel cells and not AGMs? Gels have been known to last a very long time.

I've had a set of Lifeline AGMs in VALIS for over 10 years now, and when I do my semi-annual load-test they still deliver close to rated capacity. However, most of the time the boat is in her slip, with my solar panels keeping the batteries topped-off. The only hard usage they see is during my occasional 4-5 weeks at sea when I am sailing to and from Hawaii. No doubt they would be in poorer shape had I been cycling them heavily.

[onestepcsy37]

whatever you do, keep it simple, particularly if your knowledge of boat electrics is as basic as mine. golf cart batteries are best and if the boat was originally set up for them i would advise continuing to use them.

my boat came with four trojan t-105 golf cart batteries. they lasted about six years. i would have replaced them with same but when i checked around i found the prices way above my budget - about $140 each - so i bought four golf cart batteries at sams club - at $80 each. they're a year and a half old now and run like new.

like the diagram shows, you make a 12 volt battery out of a pair of 6 volt batteries by wiring a positive to a negative (use HEAVY wire). when you take power off the other positive and negative you're getting 12 volts.

i prefer the traditional wet cell lead acid battery. but my batteries are very easy to get to so i have no trouble checking their water level, something you must do regularly with plain garden variety wet cells.

i looked at the lifepo4 battery thread. too complicated.

[endoftheroad]

Originally Posted by Paul Elliott

As you plan your electrical system, be sure to put together a realistic power budget (regardless of the type of batteries you eventually install).

You mention planning to install solar panels, and not needing to use much engine-charging. You may find that just the refrigerator alone may consume 100Ah per day, and you will probably need 300 Watts of solar panels to keep up with that (these numbers are approximate). Add in your other electrical loads and you can see how this adds up.

Solar panels are a good thing, but do be realistic about your power needs and how you're going to meet them.

Thanks....
I don't plan to use the refrigeration until I put together a power budget and install the appropriate green charging systems. I told the wife we could buy ice for a month or so.

Coolmatic? The misses is sleeping so I better not open the engine room for the specs or model of the unit.

[Uncle Bob]

Originally Posted by endoftheroad

Thanks....
I don't plan to use the refrigeration until I put together a power budget and install the appropriate green charging systems. I told the wife we could buy ice for a month or so.

Coolmatic? The misses is sleeping so I better not open the engine room for the specs or model of the unit.

Hi that compressor looks remarkably like the danfoss 50 installed on my boat. Uses an insanely small ammount of power, 80 watts of solar runs everything and recharges the batts easily.

[oregonian]

Ahoy Kettlewell,
My batteries are Lifeline brand group 31's. I made an error in how old my current set is. I just checked my log. They were installed in Aug of 2002. That is 10 1/2 years. A few important notes regarding my installation: I do not have a high output alternator, or a smart regulator, or a combiner, or an isolator. I have a standard alternator with a built-in regulator. When at the dock, I never use my charger (10 amp) except when I am aboard. That is, I control all charging. The charger is never on Auto.
The reason I changed from Gel cells was because My charging voltage was a little high for Gel cells which do not tolerate the higher voltage so well. I did not have trouble with them but I was always a little nervous about it. AGM's are more tolerant of a higher voltage charge.
My system is not the most efficient by any means, but it is the most durable. I never have problems with it.