A/C power draw

[TD4FREEW/CTD]

i noticed that a few peeps round here are running smaller out the window style air conditioning units that are selling in the home improvement stores in the summer time.

how much power are they drawing? does anyone run them off a battery/inverter setup for any long periods of time?

[madjack]

TD, they draw about 5A+ with the compressor running...about double that on start up and will kill a battery in 5r6 hours, maybe a little longer...battery power is not a viable means of running an AC unit
madjack

[TD4FREEW/CTD]

dang, you quick mad man! thanks for the reply.

5 amps is actually less than i thought it would be. @ 120 volts thats only 600 watts. not too bad.

lets say hypothetically, if i were to use a couple of 6v golf cart batteries with a 200Ah rating i could run a 5 amp appliance for approx. 40 hours before i ran the battery completely flat. of course that number would be slighty lower because of inverter losses. also, i do not want to drain the battery completely flat, so.. if i use the no less than %40 charge rule and subtract another %10 for inverter losses im down to 21 hours of run time. that is, IF i were to use ONLY the A/C and no other battery powered electrical items in my TD, which of course is not gonna happen. however, i dont think it would be unfeasable to get a good 15-18 hours of runtime out of the system. with my style of camping i wouldnt spend that much time in the TD anyway.

am i right? is there a flaw in my logic? can anyone object?

all input is as always, greatly appreciated!

Karsten.

[madjack]

sounds essentially correct...going your theoretical way, you should get a couple of nights theoretical usage........

[TD4FREEW/CTD]

alas, i have found the flaw in my logic.

watts is watts and in order to get 600 watts out of a battery i will need to pull 60 amps. that will kill my 200Ah battery in a little over 3 hours.

oh well, back to the drawing board.

[Artificer]

i noticed that a few peeps round here are running smaller out the window style air conditioning units that are selling in the home improvement stores in the summer time.

how much power are they drawing? does anyone run them off a battery/inverter setup for any long periods of time?

I tried running my 5000btu window AC with a Vector 750watt inverter. Started it, and ran for a few minutes. Inverter kicked out, and I couldn't restart again. If you do get something to work (bigger inverter) you would have to have a restart delay timer/relay to make sure the refrigerant had time to equalize before a restart atempt.

Sonetpro has a Pet Cool, and was going to try running that with a battery. Too high of a current draw for him, even with only 2000btu. thread

[GeorgeTelford]

Hi there

There is another flaw in the maths, You should never run batteries down to Flat 50% should be the max you are aiming for Ergo 100 Amps from 200, but the usual chargers/Converters will not charge fully if left for 4 weeks they may get 90% in, but if you use alternator charging too that brings the battery down to around 70% full which would only leave 40 Amps out of the 200 useable (remember we should not use the last 100 Ah)

Lets say its fully charged though 100 AH available.

Via an invertor the 600 watt would require about 660 Watts input ( invertors are not 100% efficient)

660/12 = 55 Amps If we had 100 Amps to start with thats less than 2 hours, but due to it being a high load peukerts law would lower the time dramatically.

If there were only 40 Ah due to vehicle charging 1/2 hour would be an amazing feat before the drain lowered the terminal voltage and cut out the invertor

[mikeschn]

Wouldn't you be better off running your car all night long to power the air conditioner?

That's not something that I would do, but I'm just trying to put it in context... (a Honda 2000i generator is a far better choice) But either way you will have angry neighbors...

Mike...

[GeorgeTelford]

Hi Mike

That would be possible, with diesel though it will soon kill the engine, with petrol motor you might get away with it.


Cheap 2 stroke genny, most will run 8-10 easy without a full load, over here they cost around £50