question

k1dw1d avatar image

Streetlight Function MPPT 75/10

Hello, I have a setup of a MPPT 75/10, an 12V AGM battery 38Ah, a monocrystalline solar panel 30W/12V and a 12V DC Lamp.

I'm trying to simulate a streetlight system using the MPPT (lights on at night/ lights off at day). I'm using a VE.Direct USB cable to connect to my PC and to change the settings with the VictronConnect app. What I am trying to do now is to understand how the Streetlight function within the VictronConnect app works. I've understood that Load Output function serves as a "Protective Function" for the battery, in case it gets overdischarged or when the voltage goes below a specific value (conv. and user def. algorithms). Also I've read that the "Load Output" function has priority upon the "Street Light" one, which means that if the battery gets overdischarged at night, the lights will still go off and the "Streetlight function" won't work until the next cycle.

I've read the manual: https://www.victronenergy.com/live/victronconnect:mppt-solarchargers#streetlight_settings , but there are still things unclear for me.


1) How the MPPT gets the time of the sunset/sunrise if I choose the "Switch on till sunrise" and "Switch off" at sunrise options and what is actually happening behind the Applications Interface? Is the app accessing some API to get the sunrise and sunset time according to my geographical location? What happens if I change the time and geographical position of my PC?

2)How the "Night detection voltage level" and the "Day detection voltage level works"? It sais that it can be used to adjust the detection to match the panel configuration. As I understood it tracks the Solar Panel voltage and it turns on and off the light when the voltage is below or above the inserted values by the user. What I tried was inserting some values in these sections: (11.4V for night detection, 11.9V for day detection). During the day the panel gives apx. 12V so that means that at night the value will decrease below the 11.4V, the MPPT will understand that is night and the lights will turn on. I haven't tried it outside in real conditions, but in the room, if I flip over the solar panel and the voltage gets to 2-3V still nothing happens.

3) How these 2 options stated above work together?

Do they have the same priority in the code or the sunset/sunrise option has priority upon the voltage level detection. Because even if I flip over my panel in the room (trying to simulate night) nothing will happen. I've also tried plugging out the solar panel from MPPT to simulate pitch-black but still nothing happened. Does it mean that I won't be able to simulate the night since the night/day detection isn't working separately from the sunset/sunrise option?


For example I chose these settings:


At sunset: Switch on till sunrise

At sunrise: Switch off

Night detection voltage level: 11.4V (according to the min. detectable value from the manual)

Night detection delay: 0m

Day detection voltage level: 11.9V

Day detection delay: 0m

Gradual dimming speed: 0s/%

Mid-point shift: 0m


Should I expect that with these options, somehow at sunset time the DC lamp wil turn on and at sunset will turn off? What are the night/ day detection voltage level option used for if they can't work separately from the sunset/sunrise function.

Do you have any idea of how can I make it work?

VictronConnectStreetlight
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
wkirby avatar image
wkirby answered ·

1) It does not keep time. It does not have a real time clock.
It works out night and day by the PV Voltage.

2) You need to adjust the detection Voltages according to your own situation. You can play with the detection Voltages once your panel is set up outside and adjust to suit. Try lower Voltages to start with. Try night detection at 2V or 3V and then day detection at 8V or 10V and see how you get on.

3) Sunset means the Voltage level that you have chosen for night detection
Sunrise means the Voltage level that you have chosen for day detection.

2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

myansweris42 avatar image
myansweris42 answered ·

When I first setup Streetlight on 75/15, it wouldn't work regardless of how I configured the settings.

I finally was able to get it to work by connecting the load (a small load of two led light strips totalling 0.5A) and then factory resetting the controller. I tried this after seeing several other comments in the forums on having the load hooked-up first (even though the manual says connect battery first, solar panel second, and load third).


When setting voltage for night (sunset), any shading on the area you are lighting may effect how quickly (i.e., what voltage) you want the streetlight to trigger at, even though the panel may still be getting some sun. Also, due to the photo electric effect and the way photons are scattered by the atmosphere, you could be getting 12V on a 12V solar panel right up to sunset, even though you may want it to turn on at dusk.So, setting the threshhold to something above the nominal voltage of the panel would be necessary.Some trial and error will be needed to get those adjustments right.


Also, if you plan to use this by a roadway or as a driveway sign, you will want to setup a time delay on the day detection as car lights flashing against the panel will create a false "sunrise" and turn off the load briefly.

1 comment
2 |3000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Time delay does not work on mine... No matter what I put into the time delay the unit switched the load when voltage levels are met. Anyone know what in doing wrong..?