Outfitting vs. Cruise Ready Dilemma

[mitiempo]

Originally Posted by DDabs

Is it worth considering the price increase for going with AGM batteries over golf cart batteries? Or is that useless for my setup?

AGM batteries are available in a 6 volt golf cart type as well.

In my opinion, as long as you are able to install the batteries in a location that makes them easy to service - maybe 5 minutes a month at most - and do not need to install them in other than an upright position, flooded batteries are a much better value. They historically will outlast AGM batteries as well. While there are some that have had AGM batteries for many years, there are many with failed AGM batteries in a year or two. AGM batteries will cost about double the flooded batteries, if not more.

Here is a very interesting commentary on AGM batteries by MaineSail.

AGM Batteries - Making The Choice - SailboatOwners.com

[TacomaSailor]

"Is it worth considering the price increase for going with AGM batteries over golf cart batteries? Or is that useless for my setup?"

My understanding of AGM advantages are:

1. very high charge acceptance rate
2. do not leak when tipped over
3. no off gassing - particularly if overcharged
4. do not require periodic maintenance in form of water refill

1) If you are charging from a boat sized solar array or propulsion engine alternator then there will not be enough power available to really use the high acceptance rate. And, in any normal situation your house battery bank should not get pulled down low enough that even an AGM will accept high current flows for very long

2) I have our traditional flooded lead acid batteries contained in acid resistance boxes with pretty tightly fitting lids. Any minor spillage will be contained. Mirador layed on her side for over 8 hours, heeled at 45 degrees, and not a drop of acid spilled from the T-105 batteries. I do not think the lack of spillage is very important.

3) Mirador has had T-105 traditional flooded lead acid batteries since Dec 2002. Those six batteries are about eight inches below our electrical panel in the engine room. That panel holds the inverter/charger, the Trace C-40 solar controller, six big bus bars for connecting power cables, the really big fuse for the interverter, the Heart Echo charger. There is zero, as in none, sign of any corrosion due to fumes from the batteries on any electrical connection.

4) Not having to crawl down into the lazerette and over to the battery boxes to put water in the cells would be nice. But, that is a task I can manage once every three weeks in abut 15 minutes each time.

I really have very little AGM experience but can't see they are worth twice the price as a flooded lead acid battery. My only experience is with replacing them (AGM) on three different boats. In each case the batteries were only a few years old. It seems that the AGM battery type needs a little more careful management. In each case that I was involved - the battery manufacturer blamed the charge controller for the problem but they were all replaced on warranty.

AGM life expectancy is probably not a issue to consider.

Maybe someone call tell you why they are an advantage.

[TacomaSailor]

Originally Posted by nofacey

Tacoma......A couple solar questions
- Did you do any panel tracking to achieve your results, or just run them flat?
- I have a 24v main bank, eight 6v golf cart flooded cells in two groups of four. Like DDab, I'm setting up four 140W solar panels - planning to pair up the panels and run 24v into the MMPT controller. Question is weither I should put all 4 solar panels thru one controller, into the combined 8 batteries, or set up each pair of panels with it's own controller, with each feeding a group of four batteries.

Thinking that with a mast and boom there is always going some panel shadowing going on, and tying the four panels together will bring everything down to the lowest performing panel.....by running as two pairs, we should get higher output from two of the panels.

What do you think?

Our panels are mounted flat on top of the radar arch so lose some efficiency. But 30 amps at 14 V for a couple hours in the middle of the day was plenty of power and tracking did not seem important to me.

My brother mounted the same panels on his Tartan 42 so they could manually track the sun. After three months in Mexico, winter at about 20 degrees N, he decided, after a lot of measurements, that the incremental gain in current flow from tracking the sun was not worth the effort. In order to track the sun with the solar panels - he would have to return to his boat every 30 minutes in the middle of the day. Not practical.

Preventing shadows is the single biggest thing you can do and having two separate controllers will minimize the impact. However, after six months of worrying about such things and six months of seeing the batteries fully recharged by 1 or 2 PM - I kinda' quit thinking about shadows and efficiency.

As long as the batteries were charged fully at 14.4V I did not much care what else was going on. Here I am 12 years later and that strategy is still working.

[DDabs]

Tacoma, that is enough to justify going with T-105's. I have also read the thread that mitiempo provided and it seems like there are not enough pros with AGM.

Also, aft of the nav station in the Caliber, is that where your batteries are? Is that one big lazarette accessed from the cockpit?

[nofacey]

DDabs, we have two 140W panels set up to bolt on top of the radar arch, and plan for another two to pivot up off the stern rails - one each side.

[nofacey]

Thanks Tacoma - sounds like simple works - my favourite way!

[ranger58sb]

Originally Posted by DDabs

I

Here is what I plan to have on board in terms of what will cost me energy, and how I plan to generate power.

...

Anything else that will draw power please feel free to add that to the list.

The batteries I was considering were the Power-Tech AGM 12 Volt, 105 amp hours. Six of those? Or am I building too large of a system?

David

Add CO detectors. Consider sizing your system for some possible future added redudcancy (another VHF, another depthfinder, etc.), just in case you decide to do that.

Six 225-Ah 6v batteries wired in series/parallel would likely fit in the same space and would give you 675-Ah. And they're designed to be deep cycle, whereas the 12v Group 31s are more of a dual-purpose battery.

If you might eventually run an inverter for some AC stuff appliances... more Ah is better.

It may be useful to consider putting the windlass one its own separate battery bank, too, partly depending on potential length of wire run. This is a place where a 24v windlass with two nearby Group 31 AGMs in parallel would be a good thing. Big time cranking amps, little voltage drop, and no (very little) off-gassing if the batteries are located underneath a V-berth (for example).

-Chris

[mitiempo]

Originally Posted by ranger42c

... more Ah is better.

It may be useful to consider putting the windlass one its own separate battery bank, too, partly depending on potential length of wire run. This is a place where a 24v windlass with two nearby Group 31 AGMs in parallel would be a good thing. Big time cranking amps, little voltage drop, and no (very little) off-gassing if the batteries are located underneath a V-berth (for example).

-Chris

I favor wiring the windlass from the house bank aft. The reasons are several. A forward bank means more maintenance as well as the ongoing expense of their replacement. The cables required to run the windlass from aft are a one time expense without maintenance. To charge the forward bank effectively requires large cables from the aft charging source. Charging cables should be sized for zero voltage drop - impossible with a run of 70' or so there and back.In many cases to even try to accomplish this the charging cables required are as large or larger than those needed to run the windlass from aft. A windlass is used with the engine running - so starting with 14.4 or higher at the alt the windlass is quite happy with the voltage it receives even after voltage drop. With chain forward there is enouigh weight in the bow without adding batteries there.

And as posted more AH is better. The addition of batteries to the house bank will gain a great deal more than batteries forward - a larger house bank will be not be cycled as low and all the batteries will last longer if batteries are added to it. Especially considering the few minutes a windlass is run on a daily or weekly basis.

[goboatingnow]

I would concur keep all the batteries together in one bigger bank , except starting ( for security )

Dave

[Sailorman Ed]

David - while cruising in the Bahamas, we got by very well with 270w of Kyocera panels running a good size Dometic stand alone fridge. We used a single low cost solar controller, not the fancy one. Always plenty of power on about 400 ah of battery (older gel cells) . I plan to go 50% more of each on the new boat.
+1 on the battery monitor - really good to see how much power each item on the boat uses. I had one solar panel on the aft davits and one on the SB side of the rigid bimini (faces south while you are at anchor in the prevailing wind) Remember most of the time you will be at anchor and I never had a problem with shading. I loved seeing the batteries at 100% just after noon each day. We had an outboard so ALL of the power generation came from 270 w of solar.

BTW, are you going to Long Cove Marina in Rock Hall?
Ed

[DDabs]

Ed, good to know, makes me feel comfortable about my estimated battery bank/solar array.

I am not quite sure where exactly in Rock Hall that the Caliber is located, however the photos on Yachtworld are definitely taken from a marina. It is listed through Salt Yacht Brokerage. I plan on getting into Maryland on Friday evening and looking at the boat on Saturday or Sunday.

David

[ranger58sb]

Originally Posted by mitiempo

I favor wiring the windlass from the house bank aft. The reasons are several....

Heh... good points... and I have to admit to a brain phart, 'cause I was really mostly thinking about a possible bow thruster in OP's future...



-Chris

[mitiempo]

Originally Posted by ranger42c

Heh... good points... and I have to admit to a brain phart, 'cause I was really mostly thinking about a possible bow thruster in OP's future...



-Chris

Unlike the few minutes a windlass runs at a time, a thruster is only used for seconds at a time - always when the engine is running. I would keep the batteries aft for a thruster as well in the size of boat being discussed.

[DDabs]

No thruster will ever be installed. The boat doesn't have a full keel, rather a longer fin keel similar to the Valiant 40 and a skeg hung rudder. While it's probably not the most maneuverable boat in a small marina, I'd prefer not to have any unnecessary thru-hulls.

[TacomaSailor]

A Caliber 40 is quite easy to manage around docks and hard stuff. Especially if you have a Maxprop

The only negative handling quality I have found in the boat when trying to dock is that the bow blows off down wind very quickly when backing when the wind is within 45 degrees of the bow. The bow has a lot of windage and the center of lateral resistance is a long ways aft so the boat will try to pivot rather quickly.

when backing under those conditions you need to carry a bit of speed to keep the rudder effective.

Backing to port with a head wind from port can be very difficult because the bow will swing quickly to starboard. When trying to back to starboard in a head wind the port prop walk will cancel almost any wind effective and the boat will be very slow to turn. Most backing with any kind of head wind has to be done by getting the boat speed up and putting the transmission into neutral so there is no prop walk to port

I thought long and hard about bow thruster the first year, particularly when single handing in the wind, but learned to manage the boat quite easily. I did practice maneuvering, particularly backing, into and out of slips for two to three hours a day, several days a week in all kinds of conditions for several months to get to the point of feeling very confident. (All of that practice was single handed)

This is a whole 'nother topic that probably deserves a PM or it's own topic.