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# how many watts for two freezers will i need to make solar panel?

im trying to power two 4 amp 115 v 60 hz freezers for an icecream truck by using a solar panel but am having trouble figuring out how many solar cells i am going to need or watts i will need so i can figure out how many cells. i dont know if the voltage is right on the cells when they produce the right watts. any one know how i can figure this out?

## Discussions

5 years ago

Because of your change in Amp info our 3 100 watt 24 volt panel system with 2 / 30 amp mppt Battery controllers with 4 200ah batteries and a 300/600 dc/ac and a 500 watt Gridti inverter

should do the job.

5 years ago

Because of your change in Apm info our 3 100 watt 24 volt panel system with 2 / 30 amp mppt Battery controllers with 4 200ah batteries and a 300/600 dc/ac and a 500 watt Gridti inverter

should do the job.

5 years ago

our 5 100 watt panel system with 2 / 30 amp mppt controllers with 4 200ah batteries and a 300/600 dc/ac and a 500 watt Tigrid inverter

should do the job.

7 years ago

Get a Sundanzer freezer with a ice cream therostat in it! They run off solar panels Can run on 12 volts or 24 volt. Run a battery in the system . Panels charge battery and freezer runs 24/7.

9 years ago

You are going to want a solar panel that charges

batteriespowering an inverter, which powers the freezers. The freezers themselves will run more or less off-and-on. When the freezers are not running, all that solar energy coming into the panels has to go somewhere. Why not put it into some beefy batteries, and have your inverter run off the batteries? Then your cloudy day problem is kicked in the pants.And yes, 460 watts should do the trick. But, looking on eBay, do you have that much room on top of the truck? (2 panels, each 65 x 37.5 inches, you'd need 5'5" x 6'3".)

Answer 9 years ago

thank you very much for your response!!

^{.}you've been the most helpful and um actually looking at the truck agian one freezer is 4 amps and there is a smaller one that is 1.7 amps so a total of 5.7 sorry for the other info lol sitll helpfull though now i might have just enough room for the panel and if not, the freezers are only unplugged from the house power for about 8 hours plenty of time i think for them both to run off batteries and the panels or am i figuring this wrong?Answer 9 years ago

Total power = 5.7 A x 110 Volts, so 627 watts + 10% minimum for inverter losses, say 700W, not 460 W - can't see where that ever came from. NOW you only want THAT for 8 hours, so you need to store around 5kWh....Do you have to have this lot on the vehicle - you're going to struggle to have the area you need.

Steve

Answer 9 years ago

well theres two freezers one is 4 amps and the smaller one is 1.7 at least thats their rating hmm but i see where your going. the ice cream truck used to be an ambulance its a 1990 ford E350 with alot of room up top for about one panel. right now they are useing a generator but its a small one 120 volts 60 hz dc i believe 3200 rpm and it keeps overheating which is why i was looking at alternative and thought why not a solar panel.

Answer 9 years ago

There are some exotic insulation panels you can get made (not cheap), which are literally 10X better than the usual polyurethane insulation - so 1" of material looks like 10" of foam. Imagine what THAT does to power consumption !

Answer 9 years ago

24 USD / square foot !

9 years ago

I think, as others have said, you're going to struggle with mains compressors and solar. Can you measure how much power you are ACTUALLY consuming in use before you buy anything ? Can you beef up your insulation first ?

Answer 9 years ago

um how do you suppose i do this? i dont have a megger

Answer 9 years ago

Can you run them off house current ? If you can, there are cheap power meters available everywhere these days. Run the things off that for a bit and see how many kWh they are drawing.

Answer 9 years ago

for the other 16 hours of the day they run off house current so ill see about the meter thanks for the advice

Answer 9 years ago

I don't know where you are., but cheap power meters are available all over the place these days. Measure the total energy consumption over a day or so.

9 years ago

460 is just what's needed to run the freezers. To actually run the system you need a safety factor for those days when it's cloudy, early in the morning and late at night. I would increase the number to 690 watts.

Answer 9 years ago

um well cloudy days arent much of a problem since i am in a desert i mean right now its just why like .5 degrees of a 100 degrees. blaring sun all the time which is why i want to try this on the ice cream truck and hopefully it being succesfull post it for someone elses use

^{.}im hopeing to try this project on my house too i just need to find the time out of the navy and out of leave lol thank you very much for your helpAnswer 9 years ago

If you try this, take photos along the way and publish an instructable on it so others can learn from your work.

9 years ago

460 Watts according to this calculator I used. I don't think you're going to be able to do this practically with a vehicle-mounted solar panel.

Answer 9 years ago

Oops: This calculator

Answer 9 years ago

thank you!!

^{.}Answer 9 years ago

hmm well try only a 4 amp freezer and a 1.7 amp i forgot to look at the size lol but even then i dont know if i have all the room unless i alternate the freezers throughtout the 8 hour work day they go through

Answer 9 years ago

...and that's not allowing for inverter losses. Steve

9 years ago

Yes, amps times volt = watts, so 460W plus whatever safety margin you're comfortable with. Usually at least 10% is a good idea (460+46=506) but with something not that stable in terms of how much power comes out probably a bit more wouldn't hurt. Solar panel specs will tell you what they expect to put out, though I'd assume you're aiming to run via deep charge battery (or battery bank depending on what kind of Watt-hours you're expecting it to pull) with the "normal" power source firing otherwise so it depends a lot on the setup in general.