Refrigeration A25

[Sunsetrider]

Willie - I am pretty sure my alternator is at least 60A, and as I said, it has a new look about it. But I am NOT sure what an external regulator is in this context. Could you expand on that a little bit? Just enough so that I could look it up, as it relates to this topic.

[Beta Don]

Keep this in mind as you move forward. I think right on top of larger than original alternator, you should try to understand what an external, tweakable regulator can accomplish so you get the most out of the alternator that your belt can drive. And carry extras. (Belts and alternators?)

Great advice!

With the little 3 cylinder, 30 HP Yanmar in my sailboat I used a 'smart' regulator for the alternator. Looking for a cheap, externally regulated alternator I found that the one from a 1973 Datsun 240Z bolted right up to my engine and rebuilt alternators from Autozone for that car were ridiculously cheap - Something like $30 or $35 each, so I always carried a spare and a couple belts too. An internally regulated 55 amp alternator might not output more than 25 or 30 amps, while the 'smart' external regulator can push a 55 amp alternator very near the 50 amp mark - Near double the output. The regulator provides the same Bulk, Absorption and Float stages that 'smart' battery chargers have which will greatly extend the life of your batteries and also reduce water consumption

Two set of T-105's is the *perfect* set-up for any small boat, IMO - Great choice. 400 AH, 200 usable. Keep in mind if you actually use those 200 AH's, it may take 8 or 10 hours of engine run time to fully recharge them with the stock alternator on your engine

Don

[Beta Don]

Alternator regulation discussion

http://www.cruisersforum.com/forums/f14/internal-alternator-regulator-or-external-155213.html

Don

[Sunsetrider]

I tried dipping into that thread. As a lawyer approaching retirement, it turns out I have already learned too much and my brain rebels at learning all that electrical info. It is already pretty much filled up with info that is no longer useful.

So what I need to know is what to buy and how to put it in so I can go boating.

The good news is, a lovely couple have a shop near my office called "Alternative Eco Energy", wouldn't you just know it, and they are also my clients and friends. I finally thought of dropping in to see if they could help me. Turns out they handle the Unique fridge I hanker for, at $50 less than list, and they stock Interstate GC batteries which they claim they prefer over the Trojans, and of course they are EEs and handle solar (obviously), so they are going to put together a proposal for my situation. I must ask them of they can advise me about regulators, but in any case I am looking for an answer rather than an understanding! To my shame.

[WillieC]

Just tell me what to do next!! Sunsetrider, I hear you! It sounds like you just found a treasure trove of information right at your fingertips. Whatever you end up with, make you sure you have accurate drawings and have a basic understanding of how it all works so when it goes kaput, you'll either have an idea what happened or some poor guy down the road can look at the purty pitchers and sort it out, quickly, one would hope.

[Beta Don]

Yes, you've found the perfect resource to help you set up your boat's electrical system! I'm sure they'll steer you right and probably save you some $$$ at the same time. I would ask them to keep it as simple as possible and trust their advice

The basic difference in alternator regulation is - Internal regulators lower the output amps as the battery voltage rises, so even though your batteries may need a hundred amps or more, once the voltage begins to rise, the alternator begins to cut back it's output so it takes much longer to charge them. An external regulator can hold the alternators output to max (the 'Bulk Charge Phase') until the batteries are nearly full and then switch it to an 'Absorption Phase' to finish the charge and then lower the charge to next to mothing to maintain the batteries in the Float Phase - Exactly the same way your 'Smart Charger' works. An internally regulated alternator will keep it's output voltage high even when the batteries are full . . . . usually around 14.5 volts, and that will cause your batteries to gas and use more water than if it had a lower float setting, usually around 13.25 volts

Net result is, with large battery banks you can fully charge the batteries in half as many engine running hours or maybe even less, subject to what can be generated using your little single alternator belt of course. At a bare minimum though if you do nothing else, you will want to put a much larger gauge wire between your alternator and your ACR - The small gauge wire in your OEM engine wiring harness was never meant to charge anything other than a small starting battery

Don

[Sunsetrider]

I am having an electrician review and renew my engine instrument wiring in the early spring. I will address the alternator wiring as you suggest. I will also look more into the regulator - no idea which would be the appropriate one to install.

[Sunsetrider]

Reviving: I have decided to go with 4 GC batteries (I need to get onto the boat to figure out where they can fit), solar panel on the upper bow deck (i need to get down to the marina storage barn to measure that area) an alternator regulator and an upgraded 20A 3-phase battery charger probably from promarine. I will look into upgrading the alternator charging wire. The DC load calculations from the sailing sites don't apply well because they have to account for such things as autohelm, VFR and instruments with the engine off for long periods. I don't go far with the engine off!

So I hope other A25 owners read this and those who have either a top loading fridge and/or a solar panel and/or 4 GC batteries will chime in with ideas as to where to put these things. Other than dkirsop who has already done so, which is is appreciated! My start and house battery are comfortably located below the helm seat per the pic below.

ALSO if another A25 has done a dc load calc and wanted to share, that would be a great help since it isn't so easy to be accurate when the boat is not available (and even when it is!)

[dkirsop]

Before you commit to 4 GC batteries try using just 2. Based on my experience 2 is plenty. My boat came with 4 and I have just removed 2 to lighten the load, each battery weighs 60 lbs. which is a significant load. Instead of a second battery bank consider using the money saved and install a solar panel to keep the 2 GCs topped up. I used this rig on a two week cruise and had power to spare. i have a flexible 32watt solar panel that sits on top of the wheel house. Newer panels are more efficient and i have seen 100 watt panels that are the same size as mine.

Here is a picture of my current battery placement. Note that they sit over top of my holding tank.

Battery Box.jpg

If 2 GCs prove insufficient for your need you can always add 2 later. Good luck.

[Sunsetrider]

Actually I have anticipated you. On the advice of my off-grid supplier I have ordered 2 GC batteries and a 265W solar panel that will fit nicely on the coach roof, and a Midnite battery monitor. I am pretty sure this will work out but I can always increase if the need arises. I am happy to hear that you have found that to be sufficient. Now I can get to work and make minor adjustments to the battery area to fit the new batteries.

Not sure what to do with the 2-year-old house battery.

[Beta Don]

Before you commit to 4 GC batteries try using just 2. Based on my experience 2 is plenty. My boat came with 4 and I have just removed 2 to lighten the load, each battery weighs 60 lbs. which is a significant load.

But . . . . are you running DC refrigeration 24/7?

If you move every day and only anchor for one night, you can probably 'get by' with a single pair and a big solar panel, but if you plan on anchoring out several nights in a row or staying on a mooring ball (much cheaper than renting slips along the Atlantic Coast) then you're going to be running your engine just to charge the batteries pretty frequently. I just hate running a big diesel just to charge batteries!

We had 4 GC's and a pair of 160 watt panels and living on a mooring ball for a week or ten days we still had to run something to recharge. We had a 2.5 Kw diesel genset, so we didn't have top run the propulsion engine to charge. IMO, DC refrigeration is just too much load for a single pair unless you have some other plan for charging

Don

[Sunsetrider]

I am going to see how it works out with a pair, bearing in mind that the draw by these top-loading units are less than traditional upright fridges on bigger boats. What kind of fridge do you have Don?

[Beta Don]

The boat is long ago sold. I had an Isotherm refrigeration unit (about $1,000) meant to be built into an existing boat icebox compartment and I built it into a 3 cu ft high efficiency ice cooler ($400) which also served as our dining table, complete with fold out leaves. It was a fairly low amp draw, even when making ice - About 40 AH per 24 hours. We used it to make ice and in the first picture you can see the 4 trays in the freezer compartment and then there's a tray full of ice cubes directly underneath the freezer compartment. We made 4 trays of ice every single day. The freezer needed defrosting when the pictures were taken

The freezer was 1 cu ft and the fridge was 2 cu ft. I had digital temp probes in both the fridge and freezer so you could press a button and get a readout of the temp in the freezer and the fridge

You can't see it from the pictures, but the bottom of the fridge was a layer of glass beer bottles laying down, covered with a sheet of plexiglass and everything else in the fridge sat on that plexiglass shelf

In more than 30 years of boating, I never met a single boater who said "My battery bank is TOO BIG" . . . . until dkirsop posted here, that is. I had two banks of L16 batteries on my sailboat (400 AH each bank) and I wished a few times I had that sort of power on the A27. My sailboat only had 200 watts of solar and the A27 had 320 watts. A single pair of GC's gives you only 100 ah usable and with the fridge, lights, pumps, radio and TV you can easily go through 60 to 75 AH or so every day and my 320 watts of solar was capable of replacing about half of that on an average day. Your results will vary, of course

[dkirsop]

If I lived in Biloxi MS I would have 4 GCs too! The biggest driver of power demand for any refrigeration unit is climate. It affects both heat transfer efficiency and consumer load too. A quick look at your climate profile shows consistently high average day time temperatures and humidity levels. Where I live temperature and humidity levels are considerably lower. They are also considerably lower in Gananoque ON. I have about 30 years cruising experience in my waters and 2 GCs meet my needs. I seldom use shore power.

In my waters, if you fall overboard you will succumb to hypothermia in 15-20 minutes. This has a significant moderating effect on average daily temperatures and humidity levels.

[Beta Don]

I believe Sunsetrider I setting up his 25 for a trip south to Florida and possibly even further south than that, so what works in Ontario may not be the same as what works in Florida . . . . or Panama

At some point in his/her life, every cruiser should try to spend a winter in south Florida where you can find 80 degree days in January and February. We saw several Canadian boats semi-permanently moored in Boot Key Harbor on Marathon and their owners would fly in for a month or two in the winter and then they leave the boat there and fly home for the summers

Living on a mooring even for just a week or two will be the ultimate test of your electrical system - You can't always put your finger on exactly where the amps go, but even trying to be as conservative as possible, you'll find yourself needing to charge somehow more often than you would like. If you've ever experienced this, you won't be removing any batteries to save weight

Don