Usefulness Of MPPT Technology
This isn't a trick question. I wish to take a "Short Course" in the reality versus hype of MPPT control... Users who have MPPT and can report real-life experience... Let's say I get a pair of panel...
Forum Discussion
More Ideas from AZ wind and solar. See post #8 or 9?
21 amps perhaps 22 or 23 at the elevation and latitude he is at, and to keep the losses closer to 1%, not 2 %, assuming a long electrical run. He is already losing a lot from 17.1 volts down to 12.7V with the batteries topped off.
NO mention of floor plan or how long his runs are, I am erring on the safe side for distances involved, DC current doesn't like to travel long distances.
Mex, you don't mention if your AC runs on 120 or 12 V, also, what will your inverter losses be if you run off of batteries to an inverter for 120V to get your 5000BTU AC running. How many amps at 120V does it draw running, and how many amps at freeze value start up of the compressor?
430 watts at 120V = 3.54 amps... and at 12V =35.4 amps, after the losses from an inverter.
Why don't you make up 120V with 60 cells, and go with panels that will run the A/C straight up from panels wired in series to give you 120V, while you have sunshine, with an inverter that will take it from 180vDC PWM at say 4amps to 120 AC PWM square wave or with a modified sine wave? What will your wattage losses be with that? Will your A/C run on a modified sine wave without issues?
Get 500 watts total of panel and wire them in series so you end up with 120 to 128 Volts. Use batteries to make up the excess or a big old capacitor to start up the compressor amperage draw.
Seems a huge waste do go down in voltage with your panels, if you could run the A/C straight off the panels during the day with 120V alternating current.
What time of day do you need to run the A/C? During daylight, or evening hours, or late in the afternoon when it's hottest and most humid and sunlight is fading?
Some ideas on how to do it.
120V DC to 120V AC converter, and voltages in between. 1000w
Have your looked into just a straight grid tie inverter at 2 or 3x the watt draw of your A/C, straight off the 28-30V panels to run the AC directly during daylight hours? What are the hours of usage of your A/C in relationship to sunlight hours?
pianotuna wrote:
Hi NinerBikes,
Why do you think large wire is needed with pwm between the panel and the controller?NinerBikes wrote:
The PWM will handle it. Size up to 6 gauge for the run to the controller, and to 2 gauge for the battery if you run 4 120 watt panels.
21 amps perhaps 22 or 23 at the elevation and latitude he is at, and to keep the losses closer to 1%, not 2 %, assuming a long electrical run. He is already losing a lot from 17.1 volts down to 12.7V with the batteries topped off.
NO mention of floor plan or how long his runs are, I am erring on the safe side for distances involved, DC current doesn't like to travel long distances.
Mex, you don't mention if your AC runs on 120 or 12 V, also, what will your inverter losses be if you run off of batteries to an inverter for 120V to get your 5000BTU AC running. How many amps at 120V does it draw running, and how many amps at freeze value start up of the compressor?
430 watts at 120V = 3.54 amps... and at 12V =35.4 amps, after the losses from an inverter.
Why don't you make up 120V with 60 cells, and go with panels that will run the A/C straight up from panels wired in series to give you 120V, while you have sunshine, with an inverter that will take it from 180vDC PWM at say 4amps to 120 AC PWM square wave or with a modified sine wave? What will your wattage losses be with that? Will your A/C run on a modified sine wave without issues?
Get 500 watts total of panel and wire them in series so you end up with 120 to 128 Volts. Use batteries to make up the excess or a big old capacitor to start up the compressor amperage draw.
Seems a huge waste do go down in voltage with your panels, if you could run the A/C straight off the panels during the day with 120V alternating current.
What time of day do you need to run the A/C? During daylight, or evening hours, or late in the afternoon when it's hottest and most humid and sunlight is fading?
Some ideas on how to do it.
120V DC to 120V AC converter, and voltages in between. 1000w
Have your looked into just a straight grid tie inverter at 2 or 3x the watt draw of your A/C, straight off the 28-30V panels to run the AC directly during daylight hours? What are the hours of usage of your A/C in relationship to sunlight hours?
