Distances and wiring

Hi,
I have a garden shed that I am playing with solar on.
I have a
Renogy Solar Charge Controller 12V/24V Auto MPPT
with two Renogy 100w solar panels wired up (positive wires into an adapter that will allow for you to wire two panels together into the same pair of wires) to my charge controller.
It is on top of my shed and the battery bank is two cheesy batteries from COSTCO in a toolbox in the back of the shed.
of course my neighbor planted a tree right against the fence and it is now shading my panels.
I am thinking of relocation of the panels, but I do not want to put them on my house.
How far do you think I could run the wires from the panels to the charge controller?
thanks.
Comments
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
Question. Are you running your two panels in series? If in series you double the VOC (voltage) number. Amps stay as listed on back of panel.
If you have the two panels wired in parallel you double the ISC (amps). Volts stay as listed on back of panel.
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
I have two 100 watt panels that I have in series. (positive from both into an adapter then out of one wire onward) then on to the solar charge controller
And Costco batteries are generally pretty good for the price. Need to know which batteries you got. Normal "car batteries" should not be deeply cycled as they will not last very many years.
6 volt @ 200 AH "golf cart" batteries are a good deal and will last 3-5+ years.
Assumptions:
- 2 x 100 Watt panels
- 100 Watts / 17.5 Vmp (voltage max power) = 5.71 Amps Imp current max power (close enough for most panels)
- 2 * 17.5 Vmp = 35 volts Vmp
- Imp = 5.71 amps
Normally, we aim for 1-3% voltage drop. In your case, you can have more drop (long runs with small diameter wire) if copper is "too expensive" for your project.For the calculator, lets say you are running 40 feet (one way run) on 10 AWG wire:
https://www.calculator.net/voltage-drop-calculator.html?necmaterial=copper&necwiresize=2&necconduit=steel&necpf=1&material=copper&wiresize=0.4066&resistance=1.2&resistanceunit=okm&voltage=35&phase=dc&noofconductor=1&distance=40&distanceunit=feet&eres=5.71&x=40&y=20&ctype=nec
Result
Voltage drop: 0.54
So, 2x panels in series, 40 feet one way run, on 10 AWG copper cable... Looks good (1.55% voltage drop).Voltage drop percentage: 1.55%
Voltage at the end: 34.46
Generally, tilt the panels to your latitude for best year round harvest. You can use a solar calculator to estimate your average hours of usn per day by month (nearest major city)
http://www.solarelectricityhandbook.com/solar-irradiance.html
For example, to calculate your daily harvest... Say 5 hours of sun (good summer number for most places):
- 200 Watt panels * 0.61 off grid DC solar system efficiency * 5.0 hours of sun = 610 WH per day
- 610 WH per day / 14.5 volts charging = 42 AH @ 12 volt battery bus
Some quick estimates (assuming NO SHADE on panels).-Bill
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
14 CS 370 watt modules. HZLA horizontal tracker. Schneider: XW6048, Mini PDP, MPPT 80-600, SCP. 3 - Discover AES 42-48-6650 48 volt 130ah LiFePO4 batteries
You can estimate your loads (Watts * Time; Amps * Time * Working Voltage) etc... Or you can measure the loads too using different types of meters...
DrSock. How familiar are you with Volts, Amperes (Amps), Amp*Hours, Watts, Watt*hours, and such? And are you OK with basic Math (simple algebra)?
I have no issue with helping you learn... But I do want to understand your level of electrical experience so I don't frustrate you with too simple or too advanced for you at this point.
-Bill