Testing running roof air via inverter
Testing running roof air from the battery bank with minimal solar. Equipment: Magnum 3012 hybrid inverter powered from 556 amp-hours of telecom batteries Dometic 13500 BTU roof air from 2005...
Forum Discussion
Hi Itinerant1,
When the Magnum is set to load support and there is, for example, a 15 amp shore power supply @ 120 volts, then when more than 15 amps are needed the excess current is taken from the battery bank. I.E. running a 10 amp coffee pot while running a 16 amp microwave. However the output voltage will still sag as the load increases.
On the other hand, if a "weak" 15 amp shore power supply @ 96 volts is being used to attempt to run an air conditioner, then an autoformer can "boost" the voltage up to 108. Without the autoformer the air conditioner would be damaged pretty darn quickly.
One of the few design faults of the Magnum is that the cooling fans shut off when the inverter or generator are turned off. I had been using load support help with the surge from the roof air, and fridge from my Yamaha generator. It was a hot day and so the load was 1900 watts from the AC and 325 watts from the fridge. I decided to go shopping--and so I turned off the load support and then turned off the generator. When I came back an hour later the red fault light on the Magnum remote was on. When I started the generator, no power would pass the Magnum. I bypassed the unit, and I had power again. That is when I noticed the soot marks on the wall above the Magnum.
Earlier in the summer of 2016, I was in a campground and it was hot as Hades. I did not yet own an autoformer. The voltage was only 102 on a 30 shore power feed at the campground. I found out, more or less by accident, that I could force the Magnum to do "voltage support" by dialing down the input amperage to just 11 amps. I do have a modest solar system and that meant I was able to run only the roof air from the (low voltage) shore power supply, without totally draining the battery bank. It did cause the Magnum to become pretty hot (I don't remember the numbers).
I do not recommend forcing the Magnum to do voltage support.
One other oddity is that sometimes the Magnum will not function if there is a ground fault shore power supply. Some it will work just fine with. If I bypass the Magnum the ground fault does not trip--so the issue is something inside the Magnum.
When the Magnum is set to load support and there is, for example, a 15 amp shore power supply @ 120 volts, then when more than 15 amps are needed the excess current is taken from the battery bank. I.E. running a 10 amp coffee pot while running a 16 amp microwave. However the output voltage will still sag as the load increases.
On the other hand, if a "weak" 15 amp shore power supply @ 96 volts is being used to attempt to run an air conditioner, then an autoformer can "boost" the voltage up to 108. Without the autoformer the air conditioner would be damaged pretty darn quickly.
One of the few design faults of the Magnum is that the cooling fans shut off when the inverter or generator are turned off. I had been using load support help with the surge from the roof air, and fridge from my Yamaha generator. It was a hot day and so the load was 1900 watts from the AC and 325 watts from the fridge. I decided to go shopping--and so I turned off the load support and then turned off the generator. When I came back an hour later the red fault light on the Magnum remote was on. When I started the generator, no power would pass the Magnum. I bypassed the unit, and I had power again. That is when I noticed the soot marks on the wall above the Magnum.
Earlier in the summer of 2016, I was in a campground and it was hot as Hades. I did not yet own an autoformer. The voltage was only 102 on a 30 shore power feed at the campground. I found out, more or less by accident, that I could force the Magnum to do "voltage support" by dialing down the input amperage to just 11 amps. I do have a modest solar system and that meant I was able to run only the roof air from the (low voltage) shore power supply, without totally draining the battery bank. It did cause the Magnum to become pretty hot (I don't remember the numbers).
I do not recommend forcing the Magnum to do voltage support.
One other oddity is that sometimes the Magnum will not function if there is a ground fault shore power supply. Some it will work just fine with. If I bypass the Magnum the ground fault does not trip--so the issue is something inside the Magnum.
