Do I need a "Smart" voltage regulator?

[TheThunderbird]

I want to break some eggs
I hate 3 things on board

Running a fridge
Disposing bottles of wine
Disposing bottles of water

Your fridge will cost you 4-500EUR per annum, a little bit less with solar.

Smart controls are a FAD. In the end, what you must do is to fire up the engine
Regularly
Everyday
Ah IN .... Ah OUT .....Ah IN ....

So, my answer is NO.
USE THE FRIDGE occasionally, live frugal

[Dockhead]

Originally Posted by TheThunderbird

I want to break some eggs
I hate 3 things on board

Running a fridge
Disposing bottles of wine
Disposing bottles of water

Your fridge will cost you 4-500EUR per annum, a little bit less with solar.

Smart controls are a FAD. In the end, what you must do is to fire up the engine
Regularly
Everyday
Ah IN .... Ah OUT .....Ah IN ....

So, my answer is NO.
USE THE FRIDGE occasionally, live frugal

Well, to each his own.

I certainly spend a lot less than that on my fridge (and separate freezer).

Doesn't cost me anything when I'm on shore power, which is now most of the time since I gave up my mooring.

The rest of the time, it costs me only the marginal cost of the cost of producing electrical power, since I produce power anyway for a multitude of other uses. So I doubt that I actually spend as much as 100 euros a year on powering my refrigeration.

And that small investment is probably recovered, probably many times over, in more efficient use of food -- less spoilage, less reliance on processed and packaged food. The separate freezer lets me buy fresh food where it's cheap (Germany, Estonia, Russia), and use it for up to months, avoiding being forced to buy so much of it where it's expensive (e.g. Sweden and Finland).

Even if the investment were not recovered in food costs, 100 euros per annum seems to me a luxury which I can afford, even in bad times. YMMV.

[Maine Sail]

Originally Posted by Scot McPherson

Do NOT top off your batteries in the AM as suggested however, that leaves absolutely nothing for your solar and wind to do. Get as much from the sun and wind as you can, then top off your batteries before you go to bed. This MAXIMIZES the amount of energy gained from solar and wind and MINIMIZES the amount of fuel you will need to burn.

The best practice is actually the opposite of this. You want to get your batteries to as high an SOC as you can in the AM using bulk charging, then let the solar take over. This uses your alternator in the most efficient manner possible.

You don't want to waste half your day under bulking your batteries when the quickest way to replenish over night losses is to fire up the high current engine or gen set for 30 minutes to an hour and quickly breeze through the constant current stage of charging. Because the acceptance taper is the longest part of the charge process this is best left to the low current PV system.

Solar, unless you have a massive array, simply can not produce the same bulk current an alternator can and you'll wind up at the end of the day at an overall lower SOC..

Solar is best left for the "finish charging" through the long, slow and arduous acceptance stage. The acceptance or CV (constant voltage) stage can take as long as 4-10 hours depending upon the battery bank type and state of health. This is ideal for solar when you start out the day at the highest SOC possible.

The alternator is best and most efficiently used to get you from 50% SOC to 80-85% SOC early in the day so the PV can handle the long, slow acceptance stage.

You can turn off Dino powered sources when at absorption voltage the current declines to what your solar can produce, minus DC system loads. Running the engine in the evening means the alternator is being used less efficiently and wasting fuel because the batteries will be at or close to absorption which means the alternator will be putting out low current, which is what the PV is best used for...

Reverse your practice and you will see a higher SOC by the end of the day, which is considerably more healthy for the batteries.



As to the original poster, two G-31 automotive type batteries are not going to be well suited for refrigeration plus typical house loads. Of course this all depends upon how you actually use the boat.

I have a number of customers who do one overnight per week and then tie to a dock for shore charging until the next weekend.. These customers still run the stock alternator and survive on automotive cased "light cycling" batteries.

If your boat is the early to mid eighties P-34 unfortunately the stock battery tray is horrible and can really only fit two G-31's. You'll want to find a location to fit more Ah's. Also the battery tray is oriented incorrectly for flooded batteries and causes the plates to come uncovered from electrolyte while heeled. Bad design by Pearson.. The only real suitable option, in that factory tray, are VRLA batteries (GEL or AGM) or you just burn through cheap G-31's rapidly and accept it.

If you start to push beyond a few days of use at a time and are on a mooring etc. then you'll likely want a considerably larger bank, better quality batteries, and improvements to the charging system usually including solar. A lot depends upon what your stock alternator already is. Any stock alternator can be converted to external regulation, though below about 50A you're really chasing fairy tales. If you use a Balmar regulator with adaptive alternator temp sensing, plus belt manager, it will charge better, charge faster and keep your batteries healthier. A Balmar ARS-5 can be had for about $300.00 plus the alt temp sensor and any competent alternator shop can convert your existing alt to external for a minimal fee....