Autoformer test a "back yard" report
Hi all,
The equipment:
Sola Basic 4000 autoformer PF 0.98
Magnum hybrid 3012 inverter PF corrected
1200 watt water heater
325 watt absorption fridge
13500 BTU Dometic ducted roof air with a manual thermostat. PR unknown.
A splendidly weak 15 amp shore power connection, with a 20 foot #12 cord to the RV and a dog bone adapter 15 to 30 amp. I know from previous visits that voltage drop is excessive.
The parameters:
The Magnum was set to limit the 15 amp circuit to 80% (12 amps).
At no load, the voltage was 118. Adding a load of 325 watts from the fridge caused this to drop down to 116.
Turning on the water heater (1200 watts), while running the fridge, without the autoformer resulted in 98 volts inside the RV. It did not "trigger" the load support feature of the Magnum. This, I thought, provided a "test bed" for the devices.
Adding the autoformer caused voltage inside the RV to bounce up to 114 volts. Wattage inside the RV was 1525. Demand on the shore power side of the autoformer was about 16.9 amps (measured with a kill-a-watt meter). Voltage on the shore side was a scant 95 volts. I reset the Magnum to only allow 11 amps to be drawn. Voltage inside the RV did not sag.
For the next part of the test I tried the roof air conditioner. The start up surge caused the Magnum to go into load support and knocked the shore power "off line".
The Magnum was running in inverter mode with a draw of 175 amps on the battery bank.
After the usual connection to shore power time delay, the Magnum then allowed the shore power to pass through. Even though the watt meter showed only 951 watts, the Magnum continued to do load support at 33 amps.
I deliberately moved the thermostat up until the air conditioner cycled off. I was taken by surprize when the air conditioner restarted after just over 1 minute.
Then I turned the load support feature of the Magnum off. When I tried to start the roof air, the Magnum disconnected the shore power and went into its time delay. Five minutes later, I tried a second time, turning on the fan on the air conditioner first. The Magnum again disconnected the shore power.
I have ordered a Micro Air to lower the start up surge. The MA starts the fan first and then has a 5 second delay. If the air conditioner "short cycles" the Micro Air forces the compressor to wait 4 minutes to avoid "high head" starts. This "wait" is enabled even when there is no shore power.
I don't understand why a "motor" load of 951 watts would cause load support to become active, while the water heater plus fridge totaling 1525 watts did not. Could this be a power factor issue?
I may continue this test tomorrow, by passing the Magnum and using just the Sola Basic. Obviously, I won't attempt to run the roof air on this weak shore power connection.
The equipment:
Sola Basic 4000 autoformer PF 0.98
Magnum hybrid 3012 inverter PF corrected
1200 watt water heater
325 watt absorption fridge
13500 BTU Dometic ducted roof air with a manual thermostat. PR unknown.
A splendidly weak 15 amp shore power connection, with a 20 foot #12 cord to the RV and a dog bone adapter 15 to 30 amp. I know from previous visits that voltage drop is excessive.
The parameters:
The Magnum was set to limit the 15 amp circuit to 80% (12 amps).
At no load, the voltage was 118. Adding a load of 325 watts from the fridge caused this to drop down to 116.
Turning on the water heater (1200 watts), while running the fridge, without the autoformer resulted in 98 volts inside the RV. It did not "trigger" the load support feature of the Magnum. This, I thought, provided a "test bed" for the devices.
Adding the autoformer caused voltage inside the RV to bounce up to 114 volts. Wattage inside the RV was 1525. Demand on the shore power side of the autoformer was about 16.9 amps (measured with a kill-a-watt meter). Voltage on the shore side was a scant 95 volts. I reset the Magnum to only allow 11 amps to be drawn. Voltage inside the RV did not sag.
For the next part of the test I tried the roof air conditioner. The start up surge caused the Magnum to go into load support and knocked the shore power "off line".
The Magnum was running in inverter mode with a draw of 175 amps on the battery bank.
After the usual connection to shore power time delay, the Magnum then allowed the shore power to pass through. Even though the watt meter showed only 951 watts, the Magnum continued to do load support at 33 amps.
I deliberately moved the thermostat up until the air conditioner cycled off. I was taken by surprize when the air conditioner restarted after just over 1 minute.
Then I turned the load support feature of the Magnum off. When I tried to start the roof air, the Magnum disconnected the shore power and went into its time delay. Five minutes later, I tried a second time, turning on the fan on the air conditioner first. The Magnum again disconnected the shore power.
I have ordered a Micro Air to lower the start up surge. The MA starts the fan first and then has a 5 second delay. If the air conditioner "short cycles" the Micro Air forces the compressor to wait 4 minutes to avoid "high head" starts. This "wait" is enabled even when there is no shore power.
I don't understand why a "motor" load of 951 watts would cause load support to become active, while the water heater plus fridge totaling 1525 watts did not. Could this be a power factor issue?
I may continue this test tomorrow, by passing the Magnum and using just the Sola Basic. Obviously, I won't attempt to run the roof air on this weak shore power connection.
