voltage drop in hot weather
Hi, I'm currently in Peachland BC. The temperature today was as high as 41 C (105 f). I was running the air conditioner on a 15 amp shore power connection. I normally shut down at 109 volts but ...
Forum Discussion
Hi,
I don't mind running my A/C at 105 volts input. It will draw more amperage, but that is still OK. THe higher wattage was due to higher discharge pressure in the 105F heat. The compressor needs to get the Freon up to about 300 PSI where it will convert back to a liquid at about 130F. Then it will drop to about 80 PSI inside at 45F.
On a cooler day, normal high side pressure is about 200 - 225 PSI with low side pressure at 70 PSI (40F). This is only a 130 PSI differential, so easy on the compressor. On a hot day, it can be 220 PSI differential, and that is when you are drawing 1900 watts!
For kicks and giggles, here is my low voltage story. I was in the pits at a drag race in Bowling Green KY, over Father's day in 2006. I have a voltage booster with a pair of 12 volt coils in it, so I can boost 12 or 24 volts.
The plug is a pair of 15 amp receptacles with #10 wire coming down the pole from some overhead #2 wires, fused at who knows how many amps - probably 100 - 150? I plugged in my 50' long #14 gauge cord, then a #12 gauge 25' cord, then the 25' #10 cord, then the voltage booster, finally my 30' cord from my RV. It then goes through a 25' long #10 wire to the inverter and back, to the fuse panel, then 10' or so to the A/C unit. I was reading about 128 volts while only the TV was on. My inverter/charger was off. I was at 12 volts boost, so input must have been around 115.
When the A/C was running, I was getting down near 105 volts, so I changed to the +24 boost, and kept it on! This gave me about 115 inside. And probably about 95 volts before the booster?
Anyway that is the extreme use of #14 wire to run a A/C unit, and can only be done with a voltage booster! If I had been drawing 1900 watts (just using your example) then I would have had about 19 amps going through the #14 gauge wire, and it would explain why the 15 to 30 amp adapter melted to the 25' extension cord. . . .
Fred.
I don't mind running my A/C at 105 volts input. It will draw more amperage, but that is still OK. THe higher wattage was due to higher discharge pressure in the 105F heat. The compressor needs to get the Freon up to about 300 PSI where it will convert back to a liquid at about 130F. Then it will drop to about 80 PSI inside at 45F.
On a cooler day, normal high side pressure is about 200 - 225 PSI with low side pressure at 70 PSI (40F). This is only a 130 PSI differential, so easy on the compressor. On a hot day, it can be 220 PSI differential, and that is when you are drawing 1900 watts!
For kicks and giggles, here is my low voltage story. I was in the pits at a drag race in Bowling Green KY, over Father's day in 2006. I have a voltage booster with a pair of 12 volt coils in it, so I can boost 12 or 24 volts.
The plug is a pair of 15 amp receptacles with #10 wire coming down the pole from some overhead #2 wires, fused at who knows how many amps - probably 100 - 150? I plugged in my 50' long #14 gauge cord, then a #12 gauge 25' cord, then the 25' #10 cord, then the voltage booster, finally my 30' cord from my RV. It then goes through a 25' long #10 wire to the inverter and back, to the fuse panel, then 10' or so to the A/C unit. I was reading about 128 volts while only the TV was on. My inverter/charger was off. I was at 12 volts boost, so input must have been around 115.
When the A/C was running, I was getting down near 105 volts, so I changed to the +24 boost, and kept it on! This gave me about 115 inside. And probably about 95 volts before the booster?
Anyway that is the extreme use of #14 wire to run a A/C unit, and can only be done with a voltage booster! If I had been drawing 1900 watts (just using your example) then I would have had about 19 amps going through the #14 gauge wire, and it would explain why the 15 to 30 amp adapter melted to the 25' extension cord. . . .
Fred.
