While the car isn’t running, that is. Will it drain the battery? For how many hours or days without restarting the car is it safe to leave this plugged in?
(We’re going camping for the weekend, and I need to refrigerate breast milk, so it’s important it stays cold, but it’s also important that the car starts up again when we need to leave.)
Will it drain the battery? Yes.
How long can you leave it plugged in? A car battery will have a capacity of at least 100 amp hours. This means it can supply, say, 1 amp for 100 hours, or , say, 100 amps for 1 hour. Your refrigerator uses 4.5 amps, so the battery will run it for at least 22 hours.
The problem is, after 22 hours, the car battery will be nearly flat. It’d really only be safe to run the refrigerator for about half that time. After that, the car’d need to driven around for a while (not just idled) to recharge the battery.
Damn, I was afraid of that. Sounds like dry ice in a cooler is a better bet - that keeps meat frozen for several days, so should hold milk really cold or frozen for a while.
Thanks for the info!
Just want to add here that on some cars the 12V socket is dead when the key is off. If you leave the key on the battery drain goes way up. I would suggest that you test your 12V socket before you leave, or you may be disapointed.
What is wrong with an ice chest? Doesn’t require any juice.
Do you mean having the key in the “accessory” position? Why would that use so much power? It just enables power to the car stereo and various electric controls (windows, wing mirrors, etc), most of which you can turn off manually.
One possibility is to carry a self-contained jump start battery and either use it to power the accessory, or use it to start the car once the car’s battery is drained. A jump start battery has a charger and 12V outlets built in, as well as a jump start cable - I just got a 22 amp-hour unit at Walmart for powering my telescope. But in your particular application, an ice chest is probably a better solution.
An ice chest with regular water ice doesn’t stay as cold as I need for keeping breast milk safe. I’m getting some dry ice today, which keeps things colder, and that should work. I just wondered if this little fridge that someone gave my husband could spare us the trip to the dry ice supply. Guess not.
Sorry, I realized this still isn’t clear. My milk is supposed to be frozen within an hour of pumping it and remain frozen until 24 hours before my daughter drinks it in the hospital. I’m “cheating” a bit by using a cold storage method that isn’t a freezer to begin with - so it has to be as cold as I can possibly get it to make sure no bacteria grows in the milk. She’s a premie, so can’t tolerate the normal bacteria load a “regular” baby can. Judging from the tepidness of my cooler by the afternoon of the second day camping, regular ice ain’t gonna cut it, and I’d have to throw out all that milk.