n3qik wrote: »
With 1KW of panels, look at using an MPPT controller. Wire the panels for 24V to the charge controller. Then use an 12V battery(ies). Will cost more up front, but will have a better system in the end.
tallgirl wrote: »
Disagree -- go as high as possible on the DC voltages if there are any AC loads. Higher DC voltages means much smaller cables and power lossage.
Solar Guppy wrote: »
Losses on DC side is purely based on the wire size. This is something an owner/installer can configure to suit their needs or budget. Further most of the loss is only at the peak production, 2/3rd of the day the losses would be less than half as the peak hour or so of the day. The loss is current squared times resistance for the power loss.
One can over look what can be a significant loss in the charge controllers, which can easily be 2-3% more losses and thermal stresses on the charge controller, The higher Voltage In, Voltage out differential, the less efficient the charge controller will operate at, regardless of which brand.
So while using smaller wire for higher voltages can have less wire loss, its almost always negated by charge controller decrease in efficiency were as a larger wire with lower loss allows the charge controller to have a smaller Vin and operate more efficiently.
n3qik wrote: »
I think TallGirl was looking at the battery voltage, not the array voltage. This is a valid point. At 1KW with a 12 volt system, it will work and gives the OP ability to use 12 volt devices. If OP is going to be using only 120 AC volts, then a 24/48 volt battery bank would be better.
I have lots of stuff that run off of 12VDC, so that is my mindset when working/typing on this stuff.
Plus, I agree to disagree
john p wrote: »
As its only a 1000w system it would seem he does NOT have any heavy loads to power.. My guess is if he was using an inverter it would be well below 1000w so 12v is ok. not really much loss in 3ft of #4 wire from batteries to inverter.. also you have the advantage of using many available things that are cheap to buy on 12v.. ie lights..not too many LED ones work on 48v ??
And there are quite often problems with series batteries as well .they not perfect solution and nor are parallel..
and really using a MPPT controller is not very cost effective on a small system.
Beware of 48 volt You will be forced to buy in larger quantities to meet battery voltage.
And there are quite often problems with series batteries as well .they not perfect solution