Portable panels wire size
Hey guys, I need some help. Would you consider giving me some advice please?
I’m putting together a portable solar panel setup. The panel’s will be the following.
Max Power: 140Wp
Open Circuit Voltage (Voc): 21.0V
Short Circuit Current (Isc): 8.40A
Maximum Power Voltage (Vmp): 17.0V
Maximum Power Current (Imp): 8.00A
Originally I was planning on paralleling 2 of them on the same wires and just jumpering directly to my batteries when I need to use them but several said don’t do it that way so I got scared and decided I will probably get a controller. It will probably be PWM Charge Controller big enough so I can use it when I do a permanent roof install.
I would like to be able to set the panels up at least 100 ft from my batteries / (PWM Controller) if necessary to find sunlight. I was planning on using a 2 conductor 10 ga stranded wire to accomplish this. But after reading all the discussion on wire size from solar panels to controller on the thread mena661 started “Panel to Solar Controller Wire Size” for his new solar build I’m wondering if I will have too much of a voltage drop at that distance. So I would appreciate your advice if you would consider it. Will 100 ft of 10 ga wire from 2 of these panels work or not?
It would not be a deal breaker if I need to add a 2nd cable or even a 3rd if I needed to as I can buy 100 ft of stranded 2 conductor 10 ga wire for $35.00. The problem is I don’t know what I need.
I’m not sure I’m using the calculator that was posted on mena661’s thread correctly but what I am entering is Wire Size: 10 AWG Voltage: 21.8 Phase: DC Number of conductors: Single set of conductors Distance: 100 Ft Load Current : 8.95 Amp. The RESULTS: Voltage drop: 1.79 Voltage drop percentage: 8.21% Voltage at the end: 20.01. Will it work but not efficiently??? I don’t know. Then when I increase Load Current for 2 panels to 17.9 Amps it doubles the losses which drops the Voltage at the end to 18.22 volts. But also I don’t know what the minimum voltage into the controller should be for it to achieve reasonable bulk & absorption charge when batteries are at 50 to 80% SOC.
My short term reason for solar is to supplement my generator when off grid where there is limited generator run time. I want to get the most out of the panels that I can with existing conditions but right now I do not need the panels for topping off or equalizing my batteries. I will have a 485 Amp battery bank, will be off grid no more than 4 days at a time & will be on back on grid afterwards long enough to top off & equalize batteries as necessary. My problem is I will be running a 5 cu ft residential freezer with an inverter. It pulls 1.4 amp AC & I anticipate it will run at a min 50% to a max 75% of the time. If 50% of the time it will take 180 of my 240 usable amps if 75% of the time it will use over my 240 usable amps. I have a 55 amp Iota converter with Q4 controller plus a portable 40 amp charger I will be running with a generator but concerned if I can only get 2 or 3 hours of gen run time. My goal is to get as much as possible but hopefully at least supplement enough amp hrs from the portable to keep from killing my batteries. I think I will need to have the controller set so it never has over a 14.9 or 15 volt temperature compensated output but I don’t know what the voltage from the solar panels need to be to accomplish this when my batteries are at say a 60% SOC. If you could advice me it would be greatly appreciated.
Thanks,
Alan
I’m putting together a portable solar panel setup. The panel’s will be the following.
Max Power: 140Wp
Open Circuit Voltage (Voc): 21.0V
Short Circuit Current (Isc): 8.40A
Maximum Power Voltage (Vmp): 17.0V
Maximum Power Current (Imp): 8.00A
Originally I was planning on paralleling 2 of them on the same wires and just jumpering directly to my batteries when I need to use them but several said don’t do it that way so I got scared and decided I will probably get a controller. It will probably be PWM Charge Controller big enough so I can use it when I do a permanent roof install.
I would like to be able to set the panels up at least 100 ft from my batteries / (PWM Controller) if necessary to find sunlight. I was planning on using a 2 conductor 10 ga stranded wire to accomplish this. But after reading all the discussion on wire size from solar panels to controller on the thread mena661 started “Panel to Solar Controller Wire Size” for his new solar build I’m wondering if I will have too much of a voltage drop at that distance. So I would appreciate your advice if you would consider it. Will 100 ft of 10 ga wire from 2 of these panels work or not?
It would not be a deal breaker if I need to add a 2nd cable or even a 3rd if I needed to as I can buy 100 ft of stranded 2 conductor 10 ga wire for $35.00. The problem is I don’t know what I need.
I’m not sure I’m using the calculator that was posted on mena661’s thread correctly but what I am entering is Wire Size: 10 AWG Voltage: 21.8 Phase: DC Number of conductors: Single set of conductors Distance: 100 Ft Load Current : 8.95 Amp. The RESULTS: Voltage drop: 1.79 Voltage drop percentage: 8.21% Voltage at the end: 20.01. Will it work but not efficiently??? I don’t know. Then when I increase Load Current for 2 panels to 17.9 Amps it doubles the losses which drops the Voltage at the end to 18.22 volts. But also I don’t know what the minimum voltage into the controller should be for it to achieve reasonable bulk & absorption charge when batteries are at 50 to 80% SOC.
My short term reason for solar is to supplement my generator when off grid where there is limited generator run time. I want to get the most out of the panels that I can with existing conditions but right now I do not need the panels for topping off or equalizing my batteries. I will have a 485 Amp battery bank, will be off grid no more than 4 days at a time & will be on back on grid afterwards long enough to top off & equalize batteries as necessary. My problem is I will be running a 5 cu ft residential freezer with an inverter. It pulls 1.4 amp AC & I anticipate it will run at a min 50% to a max 75% of the time. If 50% of the time it will take 180 of my 240 usable amps if 75% of the time it will use over my 240 usable amps. I have a 55 amp Iota converter with Q4 controller plus a portable 40 amp charger I will be running with a generator but concerned if I can only get 2 or 3 hours of gen run time. My goal is to get as much as possible but hopefully at least supplement enough amp hrs from the portable to keep from killing my batteries. I think I will need to have the controller set so it never has over a 14.9 or 15 volt temperature compensated output but I don’t know what the voltage from the solar panels need to be to accomplish this when my batteries are at say a 60% SOC. If you could advice me it would be greatly appreciated.
Thanks,
Alan
