Autonomy with two 100w panels 54 amp-hour battery

[facciatosta]

Originally Posted by Scubaseas

1.4A usage may be optimistic as the unit is rated at 35W or 2.9A. But if it's sunny out 200W solar should run it fine. Really depends on how much you open it and what the ambient temperature is. A power pack/jumper box (12Ah to 18AH) might be an idea to supplement what you have and run the cooler off the USB cable. Then use it on your car in the winter.

I agree that 1.4A seems optimistic especially for fridge of that size. It could be OK for Canada.

Down in Florida we bought much smaller 45W Alpicool C12 Mini Car Refrigerator 12 Volt Portable Fridge Freezer 13 Quart.
I had 2x65AH flooded battery but decided to add the 3rd 60AH AGM Victron battery( small dimensions).
We have Sunpower 3 x 110 W solar panels that charge all 3 batteries. The 3rd AGM battery powers only 45W fridge and 1000W Renogy invertor. On the sunny day it is enough to boil 1.8L kettle 2 times a day( from inverter) using submersible 300W portable heater and to run the fridge for about approximately 12 hours depending on the set temperature.
The AGM battery handles the fridge fairly good, but not very good with the 300W heater.
We care 1lb propane thanks for the gas stove. Without solar panel we would use 1 tank in 3 days. With the solar panels 1 tank is good for 8 days.

[mawtty]

Do you have a starter motor on your engine?
Do you have an engine? If so, you will need a starter battery for it.
Anyway you will need an AGM 120 aH battery for your fridge alone.
With good sunshine. lithium is better.
Experience from living on a 26 ft sloop in Queensland.

[joelhemington]

Originally Posted by francois.lavoie

Last year I wanted to be completely autonomous in terms of energy consumption on my Catalina 250 sailboat.
https://www.cruisersforum.com/forums...ls-215877.html
It was concluded that I could meet my energy needs with one 100w panel thru a mmpt controller plugged to a unique 54 amp-hour battery. Also, I was better to go for a cooler and ice solution than to go for a compressor driven cooler and even worse with a peltier driven cooler. The latter system being even less energy efficient device:
For the next summer my conditions will change. I will always be at a marina, but might go for some lenghty sailing trips on the St-Laurence river east of Quebec city. This means that I might drop the anchor in a bay for a day or two.

My situation.
Two 100W solar panels with a mmpt controller (which could accomodate 4 panels)
54 amp-hour battery (1)
No generator, but the electricity provided at the marina most days.

I intend to buy an aspenora compressor driven 37 quarts cooler which depending on the ambient temperature could spend 1.4 amp-hour.

I am wondering how I could augment my autonomy. Would there be a better alternative to the Aspenora?

Comments are appreciated.
Thanks

Get two mmpt controllers so you can parallel wire each panel to it's own controller - in case you get shading issues.. Maybe look at a 100 amp hour LIFPo4 battery as they charge faster and can be safely drawn down lower than an AGM. I doubt you'll need much energy on a 25' boat, it's not like you'll be installing a washing machine. Don't know much about that Aspenora, but the popular choice seems to be the Dometic, frig freezer combo for smallish boats - who knows, you might get lucky and catch more fish than you can eat. Remember, the solar only works during the day so a little more battery capacity might come in handy over night.

[SURV69]

The only truly important "power mongers", are always the same ... heating, cooling, refrigeration, cooking and communication ...

Reduce your footprint on these and you're pretty much home free.

Expect as little as 10% power from your panels(unless you have some sort of dynamic tracking).

10% for three cloudy days in a row gets eaten up quickly and on the third day, you'll wish you had more batteries for those sunny days you had 4 days ago.

If a single sunny day will "realistically", give you x,xxxWh, or more, then plan your battery bank for that.

Then reduce your footprint in every way and manner possible.

[francois.lavoie]

I am positively surprised to read all of your propositions. For the battery life, I knew that I should never go under the 50% of the charge of the battery. Which is in volts and varie with the type of battery. I will come back on this topic if necessary.


Calculations according to the apenora cooler.
1.4 Ah x 24 =33.6 for a day out, which is alone more than 50% of my 54 Ah available.
However I can count on my solar panels.



In the following, I mention the pertinent information according to the questions asked. Also, I will summarize the information that is useful for my context or situation.



Electricity needs.
Outboard motor starter for a 9,9 hp honda extra long foot, however I could do without the starter, there is a crank pulley. The alternator serves as a generator. It does not seem very efficient though. To be evaluated.

The VHS-DSC radio
depth sounder
lochmeter
propane stove, gas security sensor
lights at night, but relying mainly on the frontal lamps for reading
Sentinel at the top of the mast at night
The river is the bath, no shower.Water is boiled on the gas stove and there a second stove that could be used outside in the open cockpit. I have no bimini.



Here is a photograph of a boat that looks like mine.


Additional electricity consumption over a first 100W solar panel.

As I wrote in the first post, I had defined that without the refrigirator one 100W panel seemed to be sufficient for my basic needs except for the cooler with compressor. But even this pretention should be tested this summer. Actually the Aspenora coolet alone should use 1.4 Ah, so for a 24 hour trip, will spend 33.6 Ah. Which is more than I will have as a reserve which would be 27 Ah at best, and 22 Ah (if we use a 40% factor as the battery is not new).


Solar panels input.
Based on some calculations on the net, 200 W solar panels could charge a 50 Ah within about five hours in ideal conditions.



Already made suggestions.
Do without the cooler with the compressor (one sailed across the Atlantic without a fridge)
You do with what you have.Led bulbs everywhere.

Additional battery (many of you are advising).


Which size should be the additional battery?

[SURV69]

ideal means aimed at a bright Sun on a sunny day

[silkie]

For only 2-3 days away from the marina, you need only more battery, or no fridge.

[SURV69]

I have said it in the past and I will say it again ...

There is nothing wrong with using/making a PELTIER refrigerator.

Peltier is a poor choice for ICE CREAM, but I used to keep my milk very cold, running only at night and early in the morning.

The simplicity of a Peltier, is the beauty of a Peltier ... small, cheap costing parts that can be kept in a bag for repairs. A Peltier can be shaped to fit anywhere you want.

Depends very much on what you want to keep cool, keep cold or to freeze ...

4-6 amps per hour is not much, if it only runs a few hours a day ...

[Scubaseas]

Originally Posted by francois.lavoie

I am positively surprised to read all of your propositions. For the battery life, I knew that I should never go under the 50% of the charge of the battery. Which is in volts and varie with the type of battery. I will come back on this topic if necessary.


Calculations according to the apenora cooler.
1.4 Ah x 24 =33.6 for a day out, which is alone more than 50% of my 54 Ah available.
However I can count on my solar panels.



In the following, I mention the pertinent information according to the questions asked. Also, I will summarize the information that is useful for my context or situation.



Electricity needs.
Outboard motor starter for a 9,9 hp honda extra long foot, however I could do without the starter, there is a crank pulley. The alternator serves as a generator. It does not seem very efficient though. To be evaluated.

The VHS-DSC radio
depth sounder
lochmeter
propane stove, gas security sensor
lights at night, but relying mainly on the frontal lamps for reading
Sentinel at the top of the mast at night
The river is the bath, no shower.Water is boiled on the gas stove and there a second stove that could be used outside in the open cockpit. I have no bimini.



Here is a photograph of a boat that looks like mine.


Additional electricity consumption over a first 100W solar panel.

As I wrote in the first post, I had defined that without the refrigirator one 100W panel seemed to be sufficient for my basic needs except for the cooler with compressor. But even this pretention should be tested this summer. Actually the Aspenora coolet alone should use 1.4 Ah, so for a 24 hour trip, will spend 33.6 Ah. Which is more than I will have as a reserve which would be 27 Ah at best, and 22 Ah (if we use a 40% factor as the battery is not new).


Solar panels input.
Based on some calculations on the net, 200 W solar panels could charge a 50 Ah within about five hours in ideal conditions.


...

Which size should be the additional battery?

Are you spending 5 hours/day making sure the panels are not shaded and pointed in the optimal direction? And that you will have cloudless skies for all three days? I understand your math but my gut tells me your assumptions are a bit off.

Is your 54AH capacity 100% useable? Or only 50% or a usable capacity of 25AH?

Additional battery? 150AH for lead/acid maybe 100AH for lithium? For a reserve capacity more is better.

[francois.lavoie]

@Scubaseas

A usable capacity of 25 Ah with the battery, is that I have presently. If I devote two 100 W panels to keep on charge that battery, the first panel for the all the other electrical equipment, and the second panel for the cooler needs, will it be enough? I understand that adding a second 54 Ah battery would meet my needs for 24 hours.




From your point of view, I understand that I should calculate completely without the solar panel because of shade, orientation of the panels, clouds...



Is it the case?


@all:
Thanks for your numerous comments and suggestions. I will try to summarize them in my next intervention.

[Scubaseas]

Originally Posted by francois.lavoie

@Scubaseas

A usable capacity of 25 Ah with the battery, is that I have presently. If I devote two 100 W panels to keep on charge that battery, the first panel for the all the other electrical equipment, and the second panel for the cooler needs, will it be enough? I understand that adding a second 54 Ah battery would meet my needs for 24 hours.




From your point of view, I understand that I should calculate completely without the solar panel because of shade, orientation of the panels, clouds...



Is it the case?


@all:
Thanks for your numerous comments and suggestions. I will try to summarize them in my next intervention.

All the other electrical equipment? Add up your total usage and plan accordingly. I'd reduce your expectations of solar power by maybe 30% and up your usage to what it really may be. 33AH/day for a small cooler maybe fine but now you have other stuff to add?

You are calculating assuming ideal conditions which don't happen often on a small boat. In NY area I ran two 100W panels unshaded and usually got about 30 to 35 AH/day on average. And that was if it was bright and sunny out in June/July. YMMV.

I would be very surprised if you can make it three das with what you have. I could be wrong.

[raahell]

Bonjour Francois,

I understand you'll be spending time E of Quebec City? Remember that the St Lawrence is often shrouded in fog for many hours of many days so your expectation of solar energy may be optimistic, esp, the further E you go.

200W of solar seems pretty good for a small boat like yours. Based on what I've read about your situation, the most logical thing to do, besides reducing your consumption to its practical/comfortable/safe minimum, is to add battery capacity. This will give you a greater buffer for those periods without sun or shore power.

I'm assuming, based on what I've read, that you're trying to minimize fossil fuel consumption? Otherwise a small quiet (Honda) generator can be carried on board and used in emergencies. I gather your boat's (gasoline?) engine is an outboard with a not so great alternator. So at least having a gas generator won't require you to bring on another fuel type, just an extra jerry can, perhaps, of gas.

Worst case, you go with what you have, maybe add another identical battery to what you have now and keep your budget open to purchase said generator while you're voyaging, if and when you determine that you need it.

Some have suggested switching out your battery to a LiFePo but be careful with this one. Lithium batteries are not meant to be a "plug & play" replacement of lead acid and AGMs. They have their own internal electronics that can react poorly (shut down unexpectedly, leaving you with no power) to typical sailboat set-ups. Read Nigel Calder on this or subscribe to Attainable Adventure Cruising (Canadian website with excellent articles on everything you'll ever need to know about sailing and sailboats).

BTW how are you cooking and heating the interior? It can be pretty chilly and damp in the St Lawrence even in mid summer, due to aforementioned fog/mist. While considering your electricity needs don't forget the comforts of a warm berth and hot food. Bring your fleeces, lots of layers and an arctic sleeping bag, just in case.

Bon voyage! Maybe we'll see you on the St Lawrence this summer. We're hoping to return there.

[thomm225]

With my two 90 ah "so called" deep cycle batteries that are connected in parallel and my 4 solar panels that total 155 watts, I can run everything for days on end and this includes running a fan all night every night.

Loads are lights, ac inverter, depth, VHF/GPS/AIS, computers hooked to inverter, HDTV, autopilot, phone charging, etc.

Sometimes by morning the voltage is down to 11.8- 12.1 volts but it will be totally charge by that night and I can sail off with autopilot immediately if necessary.

[dmkkeng]

Originally Posted by francois.lavoie

@Scubaseas

A usable capacity of 25 Ah with the battery, is that I have presently. If I devote two 100 W panels to keep on charge that battery, the first panel for the all the other electrical equipment, and the second panel for the cooler needs, will it be enough? I understand that adding a second 54 Ah battery would meet my needs for 24 hours.




From your point of view, I understand that I should calculate completely without the solar panel because of shade, orientation of the panels, clouds...



Is it the case?


@all:
Thanks for your numerous comments and suggestions. I will try to summarize them in my next intervention.

For flooded cell batteries useable capacity is typically 35% of total capacity, you don't want to discharge the batteries below 50% and without shore power other charging sources such as solar will not likely get your batteries much above 85%. Unless your battery is new you may not even have 54 Ah, I think you will find that you have less 20 Ah of useable capacity. You have sufficient solar charging capacity however you are seriously deficient in battery capacity. I'm not sure how your solar panels are configured or what type of solar charging system you have however maximum charging current for flooded cell batteries is typically 25% of capacity or in your case 13.5 amps for a 54 Ah battery. In determining battery capacity you need to take into consideration at least one day with no solar charging. Adding a second 54 Ah would be the bare minimum and may not be enough on a cloudy trip.

[LargeMarge]

Originally Posted by Greg K

Yes, skip the fridge altogether. You don't need it. Sailed across the Atlantic without a fridge and now cruise with my wife on a 28 ft boat in the Med for weeks at a time without one. Perfectly fine. Zero energy issues.

.
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[applause!]
.
Agreed.

2003, we converted a 1997 Ford CF8000 commercial truck to our concept of an ExpeditionVehicle.

A couple-three years ago, after never needing a fridge, another overlander throuple offered us their 12v fridge... because they never used it.
Shiny!

Within a couple-three weeks, our 'new' fridge joined the equivalent of a NordicTrack in the corner of the bedroom -- a horizontal area to collect junk.

*****

On our rig, we have six 305-Watt photovoltaic panels -- a total of 1,830-Watts feeding our ancient AGM bank.

Other than charging our battery-powered everything batteries, we use our juice for a single-burner hot-plate and a 'sous vide' circulation heater for hot water.
With nearly two decades full-time live-aboard, this's The Key to electricity management -- simplify, use less.

We hope this helps.