UsbDP module to measure supplied voltage?

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1

UsbDP is a great little power-module. I am planing to use it to supply my Spider-based system with power, coming from a car-batteri, that is charged by a solar-panel through a regulator (just ensuring that no more than 12 volts are coming from the solar-panel).

But when the battery is not charged and the voltage is dropping, I need the system to alert me so I can come an swap the the battery - preferably before the system dies caused by missing power.

Is there a way to measure the supplied voltage, or should I add the voltage-measurement module?

Thanks

2

Use a divider and a analog input should do thrick

Edit: and connect the battery power to it…

3

Great, sounds like good news, what is a divider (sorry I am noob)!

Will this work?

       

AnalogInput batteryvoltagesensor = new AnalogInput((Cpu.AnalogChannel)Cpu.AnalogChannel.ANALOG_7);
         
double batteryvoltage = 0;
 
         while (true)
         {
            batteryvoltage = batteryvoltagesensor.Read();
            Debug.Print(batteryvoltage.ToString());
            Thread.Sleep(500);
          }
4

Just found the divider stuff on the http://www.ghielectronics.com/docs/8/analog-inputs

And tried calculating with Voltage divider - loaded and open-circuit dB calculator damping volts potentiometer circuit impedance damping pad decibel dB voltage attenuator impedance bridging matching - sengpielaudio Sengpiel Berlin

But I am still lost, which design to choose (type 1 or 2 in the calculator)? Based on the battery/solar-panel case?

5

In your case you need to know the soc value, But… based on voltage y8u can only get this in a unloaded state with a simple divider. Is there a soc output on the solar charger?

6

@ njbuch -

We are ALL ‘Noobs’ sometime. Maybe all the time for some things… I’m + 70 years old and still learning.

Great little application you can use. It is safe to download… I use it all the time!

But I am still lost, which design to choose …

I would say forget about you program for a moment. If you have some resistors, a power supply and any old volt meter… make up a few different resistor dividers and measure the node voltage. Maybe use a potentiometer at the positive and negative ends of the divider and ‘see’ what happens… Eyes and the meter tell you ALOT!

(Forget about the Z’s and whatever unless your a math wizard!) The drawing at the side tell you much more as I see it…

Hell, just poke around with you meter and SEE what changes and WHERE it changes.

AND most of all HAVE FUN DOING IT!

EDIT: I forgot to say… Change the Potentiometers while you are doing it.

7

This is the beast Midsummer Energy

But it might be feasible to upgrade for a soc?

8

Depends, you talk ab8ut a car (lead accid?) Battery?
And second, when do y need a allert? (critical point or some time left to act)

9

Yes its a car battery, and I need a few days before its not able to power The system.

10

Have a look at

But you will have to find the trigger level by testing, because you messure while loaded.