using regular ac mini fridge with inverter

pjdaddo · Post by **pjdaddo** » Sun Apr 08, 2012 11:47 pm

Hello guys new guy here (been boating all my life 52yrs old and still learning) and I've already learned tons just browsing ,a lot of very experienced boaters here I've noticed.
My question,I'm thinking I want to use a mini fridge on the boat with an inverter is this a bad idea ? Its just collecting dust in the garage

k9th · Post by **k9th** » Mon Apr 09, 2012 5:14 am

First of all, welcome aboard.

I am assuming that you will be using shore power to run it while at the dock, and that you have no generator on-board to provide AC while anchored or stopped.

An inverter will work but you will need to make sure it is large enough for the load. It will put additional load on the alternator so you will want to make sure your alternator can handle the entire load also. It looks like you're set up for fishing so be aware of battery drain while drift fishing or at anchor if you have the fridge on. Also be aware of load on the alternator if you're trolling at or near idle with it on.

You may have to end up adding batteries to make sure you have enough DC current available to drive the inverter.

All things to consider, but in my opinion, it can work. To me, not the ideal situation, but workable. Others, I'm sure will be along with opinions soon.

g36 · Post by **g36** » Mon Apr 09, 2012 6:49 am

also welcome
i use an invertor for various things on my boat .i have a 12 v fridge but have also used a ac mini fridge off of my invertor at different times. i anchor out alot and do have a generator but dont want to hear it all day . i have set up my boat with golf cart batteries and have sized my set up for what i need. just as k9 said you may need additional batteries but if you are just out for the day and running the engines to go here and there trolling or whatever then you wouldnt need to do alot. a normal dc fridge pulls about 3-4 amps while running and your invertor and mini ac fridge will pull about 10-12 DC amps while running so it will use more power for sure but the set up will work great if you take this in to account. if your in doubt you could buy a seperate battery and use that to power your invertor and then there wouldnt be a concern about draining your main batteries. and if you want, hook up a battery charging relay or simiilar and it will charge when your motor is running.

boatsnbars · Post by **boatsnbars** » Mon Apr 09, 2012 8:58 am

I looked at doing this with my last boat. Marine ac/dc fridges are expensive. An electrican friend of mine suggested a large inverter, maybe 2000 watts, mounted in the galley and hardwired to the dc side of things. It could then be used to power other items if necessary. He said he could hook up a switch for the fridge to go between ac power and dc power manually. He also said to buy a new fridge, as current models are more energy efficient. Total cost was around $300, but I would also be able to watch tv, run a laptop, etc. I am currently looking at inverters for my Trojan, as I would like one for the bridge to run a laptop for navigation.

jordan · Post by **jordan** » Mon Apr 09, 2012 4:09 pm

When my 12/120v fridge quit I replaced it with a 120 volt only. Obviously I run it on shore power when at the dock but as soon as I unplug it runs off my inverter. I bought a 2000 watt that is hard wired in to one side of the boat, galley side. It knows when I unplug from shore power and starts doing its job. I use two deep cell batteries separate from the starting batteries, I also have a generator but use it very little. I have been out for 4-5 day trips and had no trouble running out of battery, but that being said, I run my gen in the morning when I'm making breakfast. ( coffee maker, electric cooktop, wife's hair dryer, hot water heater, etc.) So my batteries are being charged at that time.
This system works for me but might not for others!

Torcan · Post by **Torcan** » Mon Apr 09, 2012 6:41 pm

Don't mean to hijack someone else's thread...but
Wow!!
Fantastic info
I support this site, and the little I have paid has come back in Aces!!
You guys just saved me $1000
I looked into a new fridge for my little boat, and was discouraged by the pricing.
Here at Walmart...UGH...Yes, Walmart....I found one for
$148 !!!!

I'm going to go this route, along with the invertor, and shore power. I mostly want to keep things cool for a day, short trips. And when at dock will be plugged into shore power. I have no immediate intentions of anchoring in Lake Ontario overnight, scares the hell out of me. Lake is unpredictable. Will always overnight at one of our reciprocals. Also want to keep things cold on shore, if I don't end up drinking all the Pepsi...cough..cough..

Looking at this one

http://www.walmart.ca/canada-estore/cat ... d=10052191

alexander38 · Post by **alexander38** » Mon Apr 09, 2012 7:30 pm

how about this one, keep the the grey goose cold in the top..

http://www.homedepot.com/Appliances-Kit ... reId=10051

Big D · Post by **Big D** » Mon Apr 09, 2012 10:12 pm

Deffinitely doable. I did this years ago for my 120v fridge using an 800W inverter but every fridge is different, check the amperage draw and remember that start up spikes the amperage much higher. I have a genny, but when the little guy was born and we were warming bottles in the microwave for 10 seconds at a time, it was a waste to run the genny so I upgraded to an 1800W and now run the whole boat under certain conditions off the inverter. I say the whole boat only in that the main source switch is â€œINV â€“ SHORE â€“ GEN â€“ OFFâ€. The only way to do it in my opinion. This prevents any accidental chance of feeding 120 volts to the inverter...a no no, and extention cords everywhere, and keeps GFIs in the loop for safety. And as above, I`m on the hook a lot, and run the genny in the morning for breakfast, coffee, charging etc. When charged, fridge goes all night, anchor light, anchor alarm, interiors lights, exteriors etc.

Boatsnbars, the switch used to go from ac to dc should have a middle off position or be of a break before make type from one on position to another or you will blow the inverter if it is on when you switch over.

aweimer · Post by **aweimer** » Mon Apr 09, 2012 10:33 pm

jordan wrote:When my 12/120v fridge quit I replaced it with a 120 volt only. Obviously I run it on shore power when at the dock but as soon as I unplug it runs off my inverter. I bought a 2000 watt that is hard wired in to one side of the boat, galley side. It knows when I unplug from shore power and starts doing its job. I use two deep cell batteries separate from the starting batteries, I also have a generator but use it very little. I have been out for 4-5 day trips and had no trouble running out of battery, but that being said, I run my gen in the morning when I'm making breakfast. ( coffee maker, electric cooktop, wife's hair dryer, hot water heater, etc.) So my batteries are being charged at that time.
This system works for me but might not for others!

How do you wire this up? I have a 120v fridge now, but away from the dock i have to run the genny or it thaws out. I was thinking about an inverter but how do you do this? Fridge has only one power plug? Where and how do you insert the inverter into the system to pick up the fridge when not on dock power?

Big D · Post by **Big D** » Mon Apr 09, 2012 10:41 pm

A lot of the newer inverters pass 120 volt shore power through them. When you disconnect shore power, they detect the absence of incoming AC and automatically switch over to invert mode. Personally, I like keeping the two systems completely separate. Have been called to too many failures. When these fail, you get no 120V shore power either!

aweimer · Post by **aweimer** » Mon Apr 09, 2012 10:42 pm

Interesting.

So reading up on Inverter/Chargers I see they are pretty cool. This looks like a 2012 project to me.

Question though, are they safe for Marine use? I mean exposion safe? The only space for installation in my boat would be under the salon and that is where the genny and both 80 gallon gas tanks are. I would want something that would be safe around fumes if they occured.

Thoughts /Suggestions? Thinking 2000watts is enough. Really would only run the fridge and maybe a TV for the kids.

alexander38 · Post by **alexander38** » Tue Apr 10, 2012 5:47 am

off subject but...For TV's get a 12v one there's some real good ones out there.

g36 · Post by **g36** » Tue Apr 10, 2012 7:00 am

aweimer wrote:Interesting.

Question though, are they safe for Marine use? I mean explosion safe? The only space for installation in my boat would be under the salon and that is where the genny and both 80 gallon gas tanks are.
.

Thoughts /Suggestions? Thinking 2000watts is enough. Really would only run the fridge and maybe a TV for the kids.

i would not put anything like this in the engine compartment. your only talking about the size of a shoe box a 2000 and for what you stated would be plenty. surely a locker or storage area somewhere on the boat is avaiable rather than the engine room. i wouldnt go crazy and buy the most expensive thing you can either. AIMS make good invertors (google them or others)and have a very high start up rating some models way more than comaparble units. i have a 2500 watt AIMS i run the tv, microwave, charge the computer, run my bipap at night. coffee maker, toaster etc.. and sometimes a 120 v mini fridge from time to time when we have a big raft up and need the extra food space. they are very nice things to have. btw my house bank consists of golf cart batteries

i have mine wired to the stbd side outlets and a dedicated receptacle in the galley and turn it on and off with a switch that isolates the receptacles (hot,neutral and ground)so they are only fed with power from one source at a time.
just fyi on most the ac generated from a invertor has power applied on both the neutral and hot legs unlike your house which is only on the hot side. so grounds cannot be tied to neutral. this is important if you ever consider tieing it into the existing wiring in the panel.

jddens · Post by **jddens** » Tue Apr 10, 2012 10:15 am

I have been doing this for several years. I have a dorm size refer and a 19" LCD HD TV. The refer draws about than 4-5 amps when running and the TV even less. I have a Heart 2K inverter and 2 group 29 deep cycle batts for house power. Starting battery is isolated. I also have a 120 amp alternator on the port engine. I usually overnight 1-2 night and this setup work great for me.......having said that, I also take a large ice chest when overnighting for food and such and primarily use the refer for beverages.............on shore power continuously when berthed................John

Commissionpoint · Post by **Commissionpoint** » Tue Apr 10, 2012 12:52 pm

g36 wrote: just fyi on most the ac generated from a invertor has power applied on both the neutral and hot legs unlike your house which is only on the hot side. so grounds cannot be tied to neutral. this is important if you ever consider tieing it into the existing wiring in the panel.

+1 No mixing the neutrals and the grounds in this application. Very important to remember.