Anchoring Amps/Day

2airishuman

The Loyal Opposition
1,004
478
Minneapolis area
I've found that there is no good time to run a generator in a quiet anchorage
Truth.

All lights are LED. The TV isn't on much. The refrigerators are the biggest factor. They account for 80% of the daily amperage draw.
This is typical. Although it is an expensive, disruptive project, rebuilding your freezer and fridge with vacuum-insulated panels would make a huge difference.

On the other hand, one of my FLA batteries shorted out after 5 years. The charger saw that as a low battery and just kept pumping. All 3 house batteries boiled over. It didn't cause a fire, but it seemed like it could have. Over the last several years the same thing happened to 3 other boats on my dock. In each case the FLA batteries were 5 years old.
Shorted cells in FLAs are a very common failure mode. As you describe the 6-cell, 12-volt battery becomes a 5-cell 10-volt battery. The charging sources that are present, blissfully unaware of the change in design voltage, try to bulk charge the shorted battery, which results in electrolysis -- with the battery giving off hydrogen and oxygen gas, and odoriferous sulfur gases. In rare cases the battery will explode when an adjoining cell shorts in the presence of hydrogen.

I replace FLAs after four years regardless of their apparent condition. Otherwise, it's like watching a bad movie where the ending is obvious.

AGMs are somewhat less prone to shorted cells.
 

accnick

Super Anarchist
3,555
2,556
May I suggest cribbage or backgammon in lieu of TV?
Reading works, too.

We do, however, have 4 TB of Britbox mysteries onboard. We treat ourselves to one of those episodes every few days when aboard, although last summer was primarily a reading summer, for some reason.
 

mckenzie.keith

Aspiring Anarchist
861
290
Santa Cruz
Based on past experience and some 3rd grade math, I calculate that I use about 140 amps/day at anchor. Does that seem about right to you? It assumes no major effort to conserve, so both reefers are running, and there is reasonable use of the stereo, TV, cabin fans, cabin lights, anchor light, etc. How does 140 amps/day compare to your calculations or experience on the hook?
I would like to encourage you to think and calculate amp-hours per day. Or even better, watt-hours or kW-hours per day. The whole amps/day thing drives me absolutely crazy with how wrong it is.
 

kent_island_sailor

Super Anarchist
27,684
5,530
Kent Island!
Based on past experience and some 3rd grade math, I calculate that I use about 140 amps/day at anchor. Does that seem about right to you? It assumes no major effort to conserve, so both reefers are running, and there is reasonable use of the stereo, TV, cabin fans, cabin lights, anchor light, etc. How does 140 amps/day compare to your calculations or experience on the hook?
More than me! I have no fridge and all LED lights. I am sure I am under 100. My biggest single thing right now is the anchor light, I need to climb up and swap it for LED. I think it draws about 2 amps, so that is say 16-20 AH right there. With 50 watts of solar and good sun I am through about 60-70 AH in a couple of days with all the fans cranking.
 

Bryanjb

Super Anarchist
4,464
274
Various
We're around 170 ah for the 12 volt system based on a Victron smart shunt. The 24 volt system we don't monitor other then SOC.
The 12 volt system runs a fridge and freezer plus house loads. The 24 volt system runs heavy loads and another fridge. All up we're probably around 220~250 ah daily? We charge with ~1,000 watts of solar and will add a couple of those whirly gigs this season. Plus we have a Northern Lights generator that we run every three days or so.
Batteries are just simple 6 & 8 volt golf cart batteries. $100 bucks a pop, we need 10, replaced every 5 years. We have zero interest in lithium because of the costs and problems associated with them
 
Really depends on ambient temp outside, your reefer load is directly related and the major consumer. I think someone above mentioned the AC go nowhere loads. They add up any power supplies chargers etc not in use plugged in will suck away. Other than reefer our biggest one was movie time watching the LCD TV, I think we probably averaged 100-200ah 24dc in the hottest wx being energy pigs. Usually charged every other day and never dropped below 50% capacity on a 400ah bank. We have a freezer but never ran down south.
 

JC522

Member
96
22
I would like to encourage you to think and calculate amp-hours per day. Or even better, watt-hours or kW-hours per day. The whole amps/day thing drives me absolutely crazy with how wrong it is.
I got to total amps/day by measuring the amperage draw from each device and multipying that by the amount of time I use each. For example one refrigerator uses 4.8amps with the compressor running. I figure the compressor runs 50% of the time. So, 2.4amps times 24 hours equals 57.6 amps in a day. The TV uses 1.5 amps and we might use it 4 hours. That's 6 amps/day. Add everything up and it comes to 140 amps/day. Not good enough?
 
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accnick

Super Anarchist
3,555
2,556
I got to total amps/day by measuring the amperage draw from each device and multipying that by the amount of time I use each. For example one refrigerator uses 4.8amps with the compressor running. I figure the compressor runs 50% of the time. So, 2.4amps times 24 hours equals 57.6 amps in a day. Not good enough?
It's just a question of nomenclature. Amp(ere) is a measure of current flow at a point in time. Amp hours are current over time. Five amps current draw for one hour is five amp hours. Five amps current draw over 24 hours equals 120 Ah per day.
 

Jud - s/v Sputnik

Super Anarchist
6,558
1,901
Canada
Reading works, too.

It’s relatively easy to fit Gibbon’s classic “Decline and Fall of the Roman Empire” on board - six dense volumes. (Essential reading for the Western/European intellectual history cannon.) Feynman’s classic lecture volumes on physics, also essential reading by the time-rich yachtsman, are similarly compact and carry-able on board in paper format.

However, John Stuart Mill’s collected works (on philosophy, history, politics, etc etc), another essential work, run to 33 volumes, so online/PDF is best here. But PDF/e-book then leads back to the thorny problems of power on board, a vicious circle...

FEB2DA18-6707-4CC5-B4A0-2A855DD1C7A3.jpeg
 

JC522

Member
96
22
It’s relatively easy to fit Gibbon’s classic “Decline and Fall of the Roman Empire” on board - six dense volumes. (Essential reading for the Western/European intellectual history cannon.) Feynman’s classic lecture volumes on physics, also essential reading by the time-rich yachtsman, are similarly compact and carry-able on board in paper format.

However, John Stuart Mill’s collected works (on philosophy, history, politics, etc etc), another essential work, run to 33 volumes, so online/PDF is best here. But PDF/e-book then leads back to the thorny problems of power on board, a vicious circle...
Essential for what? A good BM? Thanks but I don't need that kinda help.
 

2airishuman

The Loyal Opposition
1,004
478
Minneapolis area
So, when people speak of "amps per day," they ordinarily mean is "amp hours per day."

For example one refrigerator uses 4.8amps with the compressor running. I figure the compressor runs 50% of the time. So, 2.4amps times 24 hours equals 57.6 amps in a day. The TV uses 1.5 amps and we might use it 4 hours. That's 6 amps/day. Add everything up and it comes to 140 amps/day. Not good enough?
And that's exactly what you're doing here because you're multiplying the amp draw by the hours per day. That's fine. I know what you mean. Usually it's clear when all we're talking about is the total daily load.

But it becomes muddy when the voltage isn't constant, as when comparing 12v and 24v systems, or mixed 12v and 24v systems (as upthread), or when trying to adjust for efficiency (because batteries have higher Coulombic efficiency than energy efficiency, meaning that you get close to the same amp-hours out as the amp-hours in, but at a lower voltage).

The more precise way to talk about this is in terms of watt-hours or kilowatt-hours, although there again the daily total -- kilowatt-hours per day -- is usually the most interesting value.

I strive to understand. This isn't engineering class so I'm not going to be pedantic about units.
 

Jud - s/v Sputnik

Super Anarchist
6,558
1,901
Canada
Essential for what? A good BM? Thanks but I don't need that kinda help.
Essential to keep your mind alive. You’ll have more to talk about at the anchorages you visit (rather than just the weather, anchorage advice, fridge insulation, etc.)

If your tastes run less toward the practical, my list above, and more to the mystic, there’s always the ancient classic Hindu text, the Bhagavad Gita, the I-Ching, (and maybe even the Talmud), and the Chinese classical poets, various. YMMV.

Either way, electrons or paper.

Hope you’re not taking this too seriously...I’m just having a bit of fun...
 

JC522

Member
96
22
Essential to keep your mind alive. You’ll have more to talk about at the anchorages you visit (rather than just the weather, anchorage advice, fridge insulation, etc.)

If your tastes run less toward the practical, my list above, and more to the mystic, there’s always the ancient classic Hindu text, the Bhagavad Gita, the I-Ching, (and maybe even the Talmud), and the Chinese classical poets, various. YMMV.

Either way, electrons or paper.

Hope you’re not taking this too seriously...I’m just having a bit of fun...
Me too. Just trying to stay in character with the usual SA site banter except I omitted the customary foul language.
 

JC522

Member
96
22
I'm not going to be pedantic about units.
Oh, no? A lot of my friends are engineers and every one of them is a PITA. :)

So 5.8ah is 5.8 amps of current flow over an hours time. That would equal 139.2 amps in 24 hours. 140ah would be 140 amps of current flow over an hours time or 3360 amps in 24 hours. The textbooks need to be rewritten in plain english.
 
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