Good Day Folks.
This spring I will be installing a solar system in my remote cabin in Northwestern Ontario Canada (about 1300 kWh/kW/yr). I have an electrical/electronics background but most of my experience is unrelated (but transferrable). I have done a lot of reading on designing an off grid system. But due to circumstances my design process differs and this is making it hard for me to find the information to figure out some key things.
Most system designs are based on the question what will the load be? In my case there is no electrical existing (all propane lights and fridge and stove) and everything will be added new. Also, I have access to some of the parts required for the system free of charge and plan to use them. I think this may dictate my maximum load I can output.
Here is what I have so far:
Batteries:
My work replaced a 10KVA UPS system that had the inverter unit fail on it. Its battery banks consisted of 48 12V batteries (HR 1234W) These are spec'd at 34 watts, and I calculated from the data sheet for the battery that they will put out 5.8 Ah each. Other specs for individual batteries:
I(short circuit) 349A
I(maximum charge) 3.4A
I(max discharge) 130A (5 secs)
Yes I think this is overkill for my 2 season cabin which only is used on the weekends and a few week long trips every summer. But they were free, and I have no other use for them.
Question1: what voltage configuration should I wire my batteries in? All my reading has pointed to the benefits of wiring up these batteries in a 48V x 4 bank configuration, which I calculate at 17.4 Ah per bank to a total of 69.6 Ah. This seems to limit the choices in charge controllers and inverters.
Solar panels:
At my residence I have a grid feed 10KW PV system. I have spare panels which I would like to use. My panels are Q-Cells QC-c05 230W with the following spec.
Nom Power : 230W
I(short circuit) - 8.3A
V(open Circuit) - 36.6V
I(at max power) - 7.75
V(at max Power) - 29.65V
I plan on bringing 4 of these units up to the cabin.
Question: how should these arrays be set up, 2 arrays of 2 panels each? Without knowing the load is it possible to tell how many panels I should be using?
Charge controller:
I am trying to size the controller, it seems I am not sure how to go about this. I think I need to figure out my battery bank voltage setup and how my solar array will be wired before I know what current rating I should have on a MPPT charge controller? Is that correct?
Inverter:
Again, without knowing the total load it is hard to size the Inverter. I also think that I need to know what the battery bank voltage is before I can select one. Based on the system described can I calculate the maximum Wattage unit I should install? I know this is backwards from how it is usually done but I was hoping we could think this through.
Load:
Currently I plan on installing about 250W of LED lighting.
L.P. on demand hot water heater rated 1.2A at 120V = 144 W
0.5 HP Electric water pump - currently my father powers this pump with a generator. It is located at the cabin(no winter access) and I don't know the specifications for it. It may stay Generator only, but would be interested in putting it on the Solar system. It likely only gets about an hour of use per day.
Thanks in advance for any insight you choose to share:
Tyson
This spring I will be installing a solar system in my remote cabin in Northwestern Ontario Canada (about 1300 kWh/kW/yr). I have an electrical/electronics background but most of my experience is unrelated (but transferrable). I have done a lot of reading on designing an off grid system. But due to circumstances my design process differs and this is making it hard for me to find the information to figure out some key things.
Most system designs are based on the question what will the load be? In my case there is no electrical existing (all propane lights and fridge and stove) and everything will be added new. Also, I have access to some of the parts required for the system free of charge and plan to use them. I think this may dictate my maximum load I can output.
Here is what I have so far:
Batteries:
My work replaced a 10KVA UPS system that had the inverter unit fail on it. Its battery banks consisted of 48 12V batteries (HR 1234W) These are spec'd at 34 watts, and I calculated from the data sheet for the battery that they will put out 5.8 Ah each. Other specs for individual batteries:
I(short circuit) 349A
I(maximum charge) 3.4A
I(max discharge) 130A (5 secs)
Yes I think this is overkill for my 2 season cabin which only is used on the weekends and a few week long trips every summer. But they were free, and I have no other use for them.
Question1: what voltage configuration should I wire my batteries in? All my reading has pointed to the benefits of wiring up these batteries in a 48V x 4 bank configuration, which I calculate at 17.4 Ah per bank to a total of 69.6 Ah. This seems to limit the choices in charge controllers and inverters.
Solar panels:
At my residence I have a grid feed 10KW PV system. I have spare panels which I would like to use. My panels are Q-Cells QC-c05 230W with the following spec.
Nom Power : 230W
I(short circuit) - 8.3A
V(open Circuit) - 36.6V
I(at max power) - 7.75
V(at max Power) - 29.65V
I plan on bringing 4 of these units up to the cabin.
Question: how should these arrays be set up, 2 arrays of 2 panels each? Without knowing the load is it possible to tell how many panels I should be using?
Charge controller:
I am trying to size the controller, it seems I am not sure how to go about this. I think I need to figure out my battery bank voltage setup and how my solar array will be wired before I know what current rating I should have on a MPPT charge controller? Is that correct?
Inverter:
Again, without knowing the total load it is hard to size the Inverter. I also think that I need to know what the battery bank voltage is before I can select one. Based on the system described can I calculate the maximum Wattage unit I should install? I know this is backwards from how it is usually done but I was hoping we could think this through.
Load:
Currently I plan on installing about 250W of LED lighting.
L.P. on demand hot water heater rated 1.2A at 120V = 144 W
0.5 HP Electric water pump - currently my father powers this pump with a generator. It is located at the cabin(no winter access) and I don't know the specifications for it. It may stay Generator only, but would be interested in putting it on the Solar system. It likely only gets about an hour of use per day.
Thanks in advance for any insight you choose to share:
Tyson
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