I have (8) 300w solar panels. How do I size the micro inverters and the power pure sine inverter?
I want to tie the system into my house power and reduce my bill. I also want to use the array as a back up when the grid is down (often in my area). What size battery bank do I need to run a computer, refrigerator and a few lights?
Comments
Here are the steps:
Confirm that the Micro inverter will work with the 300W panel.
You are probably better off going with a grid-tied battery backup system, also know as a hybrid or multi-mode system. If you go with micro-inverters you will still need to buy a DC inverter / battery charger to operate your AC loads when the grid is down and charge your batteries. If you want your PV to keep producing when the grid is down then you need a special DC inverter that can control the operation of the micro-inverters, an AC coupled system, so it can be shut down the micro-inverters when the load is less than the PV system production. It gets complicated fast, if it were me I would go with the one inverter that will do it all option of the grid-tied battery backup system. It's impossible to size a system without knowing the size of the loads, the amount of time each one is on in 24 hours and how long you need the batteries to support the load. It would be worth your time to learn about all this and get it right the first time. Increasing the size of your battery bank will cost you more in total than sizing it correctly in the first place. You might want to track down a copy of the Dunlop book Photovoltaic Systems. It has a good section on off grid and grid-tied backup systems that goes into this in depth.
Hi,
We have installed few systems that generate pv power and send back to the grid and in case of grid failure it transfer to backup power, in this case "battery bank" and when grid power comes back, it will transfer to AC grid mode and continue generate power and sending back to the utility company.
For this kind of hybrid system you need On/Off Grid inverter or called Hybrid inverter.
I used Schneider Electric 4048 Grid tied back up inverters. Outback also carry these systems.
I can design for you if you want, I am in southern California.
By the way, micro inverter not gonna work for your need.
Yes, you may well find that 8 micro inverters, plus the special connectors and cabling may be more expensive than just getting a grid tied inverter. Be careful about the Voc values as MPPT devices vary greatly as to when they start and stop working ( cut in and overvoltage) especially with very low temperatures (the voltage can easily rise 10 Volts). Try using the Advanced Energy Corporate Website worksheet .It does support most panels made (I used Evergreen for Sovello) and will put most of the variables in for you.It then gives you it's recommendations for the inverter you picked, I chose the PVP 2000, the 2500 may be fine for you with 8 panels in a string as the voltage will be slightly higher). I already have a Xantrex 6048 but the installation is easily 25 X more complicated, I bought the PVP2000 to be able to get going without spending another $6000 on accessories (Control panel, distribution box,charge controller, conduit box, breakers, battery cables and expensive batteries [at least 100ah @48 Volts]). Off-grid is way more complicated, but there are suppliers who will sell you equipment to turn your grid tied panel/inverter into an off-grid unit.I am finding out these things AFTER the fact (the sellers of hybrid systems fail to tell you that they don't include MPPT, you have to buy a charge controller for that, and they are almost the price of, if not morethan a grid tie inverter). Happy reading and searching!
Comments
Here are the steps:
If you go with micro-inverters you will still need to buy a DC inverter / battery charger to operate your AC loads when the grid is down and charge your batteries. If you want your PV to keep producing when the grid is down then you need a special DC inverter that can control the operation of the micro-inverters, an AC coupled system, so it can be shut down the micro-inverters when the load is less than the PV system production. It gets complicated fast, if it were me I would go with the one inverter that will do it all option of the grid-tied battery backup system.
It's impossible to size a system without knowing the size of the loads, the amount of time each one is on in 24 hours and how long you need the batteries to support the load. It would be worth your time to learn about all this and get it right the first time. Increasing the size of your battery bank will cost you more in total than sizing it correctly in the first place. You might want to track down a copy of the Dunlop book Photovoltaic Systems. It has a good section on off grid and grid-tied backup systems that goes into this in depth.
Hi,
We have installed few systems that generate pv power and send back to the grid and in case of grid failure it transfer to backup power, in this case "battery bank" and when grid power comes back, it will transfer to AC grid mode and continue generate power and sending back to the utility company.
For this kind of hybrid system you need On/Off Grid inverter or called Hybrid inverter.
I used Schneider Electric 4048 Grid tied back up inverters. Outback also carry these systems.
I can design for you if you want, I am in southern California.
By the way, micro inverter not gonna work for your need.
Yes, you may well find that 8 micro inverters, plus the special connectors and cabling may be more expensive than just getting a grid tied inverter. Be careful about the Voc values as MPPT devices vary greatly as to when they start and stop working ( cut in and overvoltage) especially with very low temperatures (the voltage can easily rise 10 Volts). Try using the Advanced Energy Corporate Website worksheet .It does support most panels made (I used Evergreen for Sovello) and will put most of the variables in for you.It then gives you it's recommendations for the inverter you picked, I chose the PVP 2000, the 2500 may be fine for you with 8 panels in a string as the voltage will be slightly higher). I already have a Xantrex 6048 but the installation is easily 25 X more complicated, I bought the PVP2000 to be able to get going without spending another $6000 on accessories (Control panel, distribution box,charge controller, conduit box, breakers, battery cables and expensive batteries [at least 100ah @48 Volts]). Off-grid is way more complicated, but there are suppliers who will sell you equipment to turn your grid tied panel/inverter into an off-grid unit.I am finding out these things AFTER the fact (the sellers of hybrid systems fail to tell you that they don't include MPPT, you have to buy a charge controller for that, and they are almost the price of, if not morethan a grid tie inverter). Happy reading and searching!