Refrigeration at anchor and underway

[CharlieO.]

So I am looking at this summit fridge.

https://s1.img-b.com/build.com/medi...NDAzZDctZTZjZi00ZGU1LWE2NDAtZDExMzAwNTZjZjUx~

My boat is not a power hungry boat. I have one set of 2 12v batteries that run the start and house. No solar (yet), no on board generator, we do have a Yamaha inverter generator 1000 watt.

My goal is to run this fridge while underway and at anchor.

If I powered an inverter from my current batteries would my alternator keep my batteries charged enough to keep the fridge running while underway?

What would you recommend for at anchor? I'm thinking a seperate house bank dedicated to powering the inverter for a fridge and outlet for electronics charging.

How much battery would I need to run say 24 hrs, what should I look for in an inverter with out busting the bank$$.

Currently we just have 110 old dorm fridge that we only run on shore power. Schlepping the coolers around is getting old and is one of the things my girlfriend requested we address this year and I agree.

Hope I explained my wants and needs clearly.

Thanks.

 

[ranger58sb]

My boat is not a power hungry boat. I have one set of 2 12v batteries that run the start and house.

My goal is to run this fridge while underway and at anchor.

If I powered an inverter from my current batteries would my alternator keep my batteries charged enough to keep the fridge running while underway?

What would you recommend for at anchor? I'm thinking a seperate house bank dedicated to powering the inverter for a fridge and outlet for electronics charging.

How much battery would I need to run say 24 hrs, what should I look for in an inverter with out busting the bank$$.

I'd guess an easy/fast solution would be to install another battery bank and an inverter to do nothing but service the new fridge. I suspect the self-defrosting feature increases your battery need.

So alternators might work for underway, depending on your current battery capacity, but wouldn't be great for at anchor.

And then maybe as a separate improvement, add capacity to your current house bank just 'cause 2x 12V batteries isn't much capacity if those are small-ish G31s or some such. (And swap out all your household lighting and especially your anchor light to LEDs if you haven't already.)

But...

You might consider potential mission creep, too, right up front. TV at anchor? Coffee maker at anchor? Microwave at anchor? Et cetera. If all that might gradually become attractive, larger bank, large inverter. At this point, it's maybe that larger house bank and an inverter big enough for everything except probably aircon and water heater. I'd guess this approach is likely better for the long run...

-Chris

 

[CharlieO.]

Chris, thanks for your input, I guess my thinking is running off the engine/alternator bank while underway but switching to the other possible new bank at anchor.

I'm trying not to be a power consuming boat and understand the concerns for mission creep. We do have propane for our kitchen needs, so coffee on the stove top. We had a dock neighbor that gave us his like new force 10 propane stove/oven when he removed it. I'll be removing my three burner stove top only to replace. But Tv at night is also nice for the family, me I'm usually wore out by dark thirty after a full day on the water.

We do have an led bulb in the anchor light and are slowly swapping out the cabin lights for led as needed.

So I guess I'd be looking for minimum requirements plus reserve on the equipment to power the fridge, then I could possibly upsize from there.

Would like to add solar in the future but that is not on this years schedule unless some great deal came along(like my new stove).

I'm not really good at numbers and calculations and such, definitely not my strongest quality. I'm good at picking up heavy things, well I used to be.:lol::lol:

 

[rslifkin]

I wouldn't put a self defrosting fridge on a boat (self defrost wastes a bunch of power) unless it's one of the really efficient models (usually not available in small sizes). The estimated consumption on that fridge is almost 900 wh/day. For such a small fridge, I'd say it's pretty inefficient. For comparison, my 9.1 cu ft DC powered fridge/freezer draws about 1kwh / day in moderately hot weather for a significantly larger fridge. And mine is not the most efficient setup I've heard of.

For solar, your boat should meet the requirements as a secondary home, so you can take the federal tax credit to get some of the cost back. Doesn't help with the initial hit, but it helps in the long turn. The credit just got renewed and is back up to 30%, so it's fairly significant.

 

[CharlieO.]

Interesting on the solar, I'm pretty sure here in VT we get credits and or compensation for energy efficient home upgrades. I am pretty limited on the space available to fit the fridge, this just happens to be one that fills the available space best. I am surely open to other fridge options but not really wanting to go much higher in price though and pretty size limited.

 

[rslifkin]

Interesting on the solar, I'm pretty sure here in VT we get credits and or compensation for energy efficient home upgrades. I am pretty limited on the space available to fit the fridge, this just happens to be one that fills the available space best. I am surely open to other fridge options but not really wanting to go much higher in price though and pretty size limited.

You'd have to check into the VT credits. I know when I did solar on our boat I could take the federal credit, but not the NY one. The NY one only applied (at least at the time) to my primary residence, while the federal one is usable on a secondary residence (and a boat with a galley, head, etc. meets the requirements).

 

[Hippocampus]

If I was redoing frig/freezer I’d put a dedicated top loading freezer in the bilge and a sepeate efficient ac/dc frig/freezer in the galley.
You lose the cold when you open the door. You let in moisture (and the need to defrost) when you open the door. Top loading dedicated freezer will be more efficient and need less defrosting. You also have more opportunity to insulate around it and can put the compressor in a naturally cooler place in the boat.
I like refrigerator draws but they are so expensive but if you have a separate freezer you can get away with a smaller standard house unit. Overall think having two units means less electricity use. My current boat came with an ice maker. We repurposed it to serve as a freezer. Even gaining that small amount of freezer space is very helpful.

 

[SteveK]

Chris, thanks for your input, I guess my thinking is running off the engine/alternator bank while underway but switching to the other possible new bank at anchor.

I'm trying not to be a power consuming boat and understand the concerns for mission creep. We do have propane for our kitchen needs, so coffee on the stove top. We had a dock neighbor that gave us his like new force 10 propane stove/oven when he removed it. I'll be removing my three burner stove top only to replace. But Tv at night is also nice for the family, me I'm usually wore out by dark thirty after a full day on the water.

We do have an led bulb in the anchor light and are slowly swapping out the cabin lights for led as needed.

So I guess I'd be looking for minimum requirements plus reserve on the equipment to power the fridge, then I could possibly upsize from there.

Would like to add solar in the future but that is not on this years schedule unless some great deal came along(like my new stove).

I'm not really good at numbers and calculations and such, definitely not my strongest quality. I'm good at picking up heavy things, well I used to be.:lol::lol:

Do you have an inverter (not the genny one) to convert alternator to 110 power for fridge?
You need dedicated house bank of at least 2-6v deep cycle batteries (4-6v would be better) in series for 12v running a 1000 watt inverter which should run the fridge for 24 hrs approx before needing recharge.
Your Yamaha specs say "12 Volt DC output and cables for charging RV, auto and marine 12-volt batteries" but nothing on that output to know how long before it would recharge the batteries.
You should isolate house and start batteries, but have a way to join them to charge while underway.
The above suggestion is based on what I had on a sailboat. It also ran toaster, coffee maker, microwave (one at a time)

 

[O C Diver]

Unfortunately, most of the under 4 cuft. units aren't as well insulated. I would be shopping based on the Energy Star numbers.

Don't be afraid of the frost free units. My 10 cuft. frost free is under 1 KW per day which is very efficient. The other point to understand is that modern frost free units base the defrost cycle on hours of compressor operation. The point being is that the same unit in Florida will do the defrost cycle more times per month than in Vermont based on average daily air temperatures requiring more compressor time in Florida.

Ted

 

[rslifkin]

Unfortunately, most of the under 4 cuft. units aren't as well insulated. I would be shopping based on the Energy Star numbers.

Don't be afraid of the frost free units. My 10 cuft. frost free is under 1 KW per day which is very efficient. The other point to understand is that modern frost free units base the defrost cycle on hours of compressor operation. The point being is that the same unit in Florida will do the defrost cycle more times per month than in Vermont based on average daily air temperatures requiring more compressor time in Florida.

Ted

I agree that some of the newer frost free units are quite efficient. But unfortunately, as you noted, those efficiency improvements haven't trickled down to small fridges to the same extent.

 

[CharlieO.]

Steve, I don't have any inverter yet. I guess I wondering if I could have the inverter powered via the engine while underway then switch the source to my new bank. I was thinking I would do either the 4-6v or 2-12v.

Last seasons boat usage was going to other marinas or anchoring up for the day and swimming fishing ect, then either back to home slip or transient slip somewhere. This season will transition into being more comfortable at anchor for overnights.

My Yamaha generator says output for the battery charging leg is 8 amps. I only carry it in case I do need charge the batteries for some reason. It came with the boat when we bought it, but I've never used it except in the yard.

 

[rslifkin]

Would it not possibly make more sense to move all of the house loads to a new bank (including the inverter) and then adding a way for the engine alternator to charge that bank underway? Then you gain a separate house bank and don't have to worry about drawing down the starting batteries, plus no manual switching that could be forgotten. That architecture will also be easier to grow in the future if your power needs start to expand.

 

[SteveK]

Steve, I don't have any inverter yet. I guess I wondering if I could have the inverter powered via the engine while underway then switch the source to my new bank. I was thinking I would do either the 4-6v or 2-12v.

Last seasons boat usage was going to other marinas or anchoring up for the day and swimming fishing ect, then either back to home slip or transient slip somewhere. This season will transition into being more comfortable at anchor for overnights.

My Yamaha generator says output for the battery charging leg is 8 amps. I only carry it in case I do need charge the batteries for some reason. It came with the boat when we bought it, but I've never used it except in the yard.

Your choice, 12v works, but the 6v system will last longer hours from full charge. something to do with larger plates.
An alternator for charging yes, for continuous supply to an inverter, not so much. Have not heard it being done without a battery inline to be charged.

 

[rslifkin]

If 6v batteries are in the cards, measure the height available. That'll determine if you're stuck with the shorter GC2 sized 6 volts or if you can use the taller L16 form factor (which means you might only need 2, leaving space open for future expansion if you have the footprint available for 4 of them).

 

[CharlieO.]

Rob, with this conversation and reading some of the other recent electrical threads, I think that is probably the best bet. Start with a new house bank and inverter and go from there. I guess I would just need to figure on the charging of the new bank.

Recommendations for sizing and equipment are still welcome.

I do have room enough for good batteries, that was one of my reason for the smaller fuel tanks.

Steve, I guess I would be running off the only bank I have right now, charged by the engine alternator, I wasn't planning on bypassing the battery.

 

[rslifkin]

For charging the new bank, the 2 easiest choices are either a DC-DC charger, or an ACR to feed power from the engine alternator and start bank to the house bank when the engine is running. When you add the inverter, use a model that's an inverter/charger and that will take care of charging the house bank on shore power. Any solar you add can go just to the house bank, the start bank will be fine without solar charging if there's nothing drawing from it when the engine is off.

 

[Lepke]

My old 12v inverter, 2200 watt, kept a large house reefer and freezer plus lights, etc., for 48+ hours. 4 8d batteries. Engine mounted alternator kept batteries charged when cruising.
Now use 48v inverter with alternators on both mains.

 

[mvweebles]

CharlieO - you asked for minimum requirements, here's my best shot: What you need is data. I didn't catch what size your two 12v batteries are, but it's possible your current setup will get you through the night. But how do you know? Without data, you can't.

For $130 you can purchase a Victron SmartShunt (HERE from PKYS). Installation is pretty straightforward - just interrupt the negative feed on the battery and cable it inline. Will give you power draw and battery voltage. It's a really useful device even if you expand your system. Will tell you what your energy draw is at any point in time. Will allow you to interpolate how far depleted your batteries are in the morning; and how quickly they absorb alternator energy underway. You don't even need a gauge - all this is delivered to your smartphone via the Victron app.

BTW - I've linked to PKYS. Word of advice - pick a vendor and stick with them. If you have any issues, the vendor is Victron's first line of support. Easier to have all kit from one place.

Good luck

Peter

 

[Benthic2]

https://www.alibaba.com/product-detail/500-Watts-Exercise-Bicycle-Pedal-Power_60780084569.html

Here's a stationary bike that generates 500 watts of electricity. Now your girlfriend can have her fridge and stay in shape at the same time!!

 

[alormaria]

I have 3 group 31 12v deep cycle batteries. One dedicated to engine starting. The other two in parallel to run the 12v needs of the boat and a 1500 watt inverter. The inverter runs a Haier 110v under counter fridge when underway and anchor. The fridge is usually plugged into 110v shore power at dock. Some times I leave it on the inverter and the battery charger keeps the batteries up. Underway the stock alternator handles all charging. It's been working for 22 years. Batteries usually last 7 to 9 years. They are regular wet cells. Available anywhere. After 28 years the battery charger seems weak and may be replaced this year.

 

[CharlieO.]

Peter, I do like the idea of the smart shunt, I like to know what is going on rather than guessing. That is one of my reasons for rewiring my bilge pumps and adding the switches and bilge counters and high-water alarm.

Ben, not sure I could live through that suggestion, it would be great for my son to keep his own electronics charged though. But if I did suggest it (and lived) that could put me on the fast track to solar.

Al, are you charging both your start battery and house batteries at the same time while underway off your alternator? Your method seems somewhat what I was thinking in my mind.

I do have a 20 amp Charles battery charger mounted for charging when plugged into shore power.

 

[Gdavid]

As you are looking to increase the load on your alternator, you want to look into a couple potential weak links.

If your alternator is a single V-belt, it can only handle about 80 amps and it will wear through belts faster as you are approaching this limit. The stock alternators are also limited on how much heat they can dissipate when heavily loaded continuously. The belt limitation is best solved by going to a serpentine (multi-groove) belt style, like your car uses. Youl need to retrofit your pulley's, the cost and effort required depends on your engine. The next best approach is a double V-Belt which may require less work, especially if your crank pulley already has a double pulley. An external voltage regulator with a temperature sensor on the alternator can address the overheating concern, it will limit the output based on the temp of the alternator. Improving engine room ventilation would help a lot as well but this may be difficult based on your boat.

 

[DavidM]

That is a residential, 120V AC powered fridge. Those, even Energy Star rated, are inherently less efficient than boat or RV specific 12V fridges. A Dometic 4 cu ft DC fridge should use less than 50 Ahs daily vs the 72 that the specs show this one to use. You might be able to improve that 72 Ah number if you can disable the defrosting.

I prefer a single, large house bank not split as you are suggesting. Your alternator will probably need to be upgraded to a high output, externally regulated one in order to recharge your battery bank in a decent time. A 1,000 watt inverter should work fine to power this fridge, but make sure it is a pure sine wave type.

At 72 Ahs daily plus other house loads which should increase your usage to maybe 100 Ah daily, you are going to need 200 Ahs of LA battery capacity or 100 Ahs of Li capacity for each 24 hrs you want to hang out at anchor. Installing solar can significantly extend your days at anchor.

David

 

[CharlieO.]

Thanks David, I don't really have any house bank yet. Just 2 12v batteries that are for start and house. So I would like to keep that for my start and electronics and nav. anchor/deck lights. Then start with a new house bank and ability to charge with main focus/power consumption being refrigeration. I think.

 

[rslifkin]

Thanks David, I don't really have any house bank yet. Just 2 12v batteries that are for start and house. So I would like to keep that for my start and electronics and nav. anchor/deck lights. Then start with a new house bank and ability to charge with main focus/power consumption being refrigeration. I think.

Personally, I wouldn't keep anything but engine start on the starting batteries. That way you only have to worry about solar charging for 1 bank when you add solar at some point, and there's no risk of running down the start batteries if you keep some electronics powered up at anchor.

 

[HeadedToTexas]

https://www.alibaba.com/product-detail/500-Watts-Exercise-Bicycle-Pedal-Power_60780084569.html

Here's a stationary bike that generates 500 watts of electricity. Now your girlfriend can have her fridge and stay in shape at the same time!!

Haha, outstanding!

 

[Olteppich]

Although I do have substantial solar input, I’m using an inexpensive 7cf chest freezer, and it consumes far less power than my fridge did.
I keep the bottom of the freezer lined with ice packs, and programmed the load setting on my solar charge controller to trigger a relay, which then powers up my inverter, and freezer, for an hour, every three hours.
At this cycle rate, drinks are kept on the verge of being slushy. Running the freezer for an hour, every two hours, keeps things frozen.
Without solar, you might have to keep the engine or generator running, but regardless, I’d use a chest style freezer/fridge

 

[ranger58sb]

That is a residential, 120V AC powered fridge. Those, even Energy Star rated, are inherently less efficient than boat or RV specific 12V fridges.

I think I'd quibble (minorly) with that wording. I expect we could say the fridges themselves are probably more efficient (that whole Energy Star thing, probably better insulation, etc.)...

But the additional costs associated with boat installation is that reverses that. Inverter, including it's losses. Additional electricity load (self-defrost). Et cetera.

Result is probably the same as what you said, of course. OTOH, it might actually be close in some cases, depending on specific fridge specific installation, specific inverter, etc etc etc.

-Chris

 

[Tator]

"If your alternator is a single V-belt, it can only handle about 80 amps and it will wear through belts faster as you are approaching this limit."

I have been using a 5/8 Gates Green Stripe single belt powering my 150 amp alternators for thousands of hours and 16 years. I normally pull 120 amps at cruising rpms for probably an average of 3 hours. I'm still on my original belt and it's looking fine.
Tator

 

[plittle2005]

Charlie, the easiest way to isolate the start from the house battery set is to use a FET battery isolator. Just connect the alternator output wire to the isolator and each battery to each isolator output terminal.


The FET voltage drop is so low that an external voltage sensing wire is not necessary.


This unit https://shop.pkys.com/Victron-ARG20...MIusfW56H3_AIV05FbCh2DqQQSEAQYASABEgKXDfD_BwE
Allows you to later add a 3rd isolated battery and charge all 3 independently.


That's why God gave us li'l inverter gensets!


Btw, met you up at Chipman last summer. Handsome boat!