12v Solar battery monitor

mrc-core

Thanks for the reply, i'm going to make the changes tonight.
I'm getting readings from 8A to 18A this is not correct.

Boots33

How much current were you expecting to see

mrc-core

@Boots33 To be honest i just thought the values i was getting were too hight since the battery is 12V 20AH and i only have 4 arduino nano with some sensors using the power from the battery.

Today with one day having the changes made like you have said to do, i have value from the battery between hight 8.2A and 6.6A low, but the media value is almost always on 7.4A.

On the voltage side i'm getting high value 8.8V and low value 7.8V.
0_1466547276667_chart (1).png

Is this good values, correct values for a 12V battery ??

Boots33

I don't think those readings are correct. For a 12v battery it should be around 12.7v when full and not being charged. When it is being charged it should be up near 14v. Around 10.9v is considered fully discharged so your readings are way too low for a 12v battery. Your current readings seem too high as well for just a few arduino boards. Can you take some readings with a multimeter to cross check the data. Also check your 5v supply voltage, it is very important for this to be spot on 5v when taking analogue readings.

mrc-core

@Boots33 Have check the voltage from the battery and is on 12V at this time is discharging the current i couldn't get but tomorrow i'll make new readings and see the values.
The 5V supply voltage is set to 5.02V will have to reduce the 0.02V to get just 5V.

Thanks for your help.

Boots33

I should think 5.02v will be close enough. What value resistors are you using for your voltage divider.

Boots33

We appear to be operating in different time zones so have posted a couple of things to try.

The first thing to do is re-check all your wiring, I know you probably have done that already but best to make sure anyway.

Then you should try and isolate the cause of your problems.

lets start with the voltage readings.

This line of code in the sketch

int voltSenseMax = 25000;

is where you set the maximum input voltage of your voltage divider. If you are not using the 25v voltage sensor module you will need to change the 25000 to suit your voltage divider, by changing that value up or down you can also make adjustments in the voltage reading to fine tune the output. Your reading seems to be out by a few volts so i think you should take a look at the voltage divider first and see if you can locate the reason.

I will show the way to check the 25v module and you can use the same method to work out the values if you have used a different divider.

Because we are using a voltage divider to alter the 12v battery voltage into a 5 volt representation that the Arduino can use we will need to work out what voltage we are expecting to see at pin A0
the formula we need is

ArduinoIn = (BatVolts/voltsPerCount25)*voltsPerCount5

first we need the voltsPerCount25 for the 25v divider, so that will be 25/1024 which = .02441

then we need the voltsPerCount5 for the Arduino 5v input 5/1024 which = .00488

BatVolts is the actual battery voltage, you will need to measure this with your multimeter.

So as an example

If you measured your battery and it has 11.3v

(11.3/.02441)*.00488 = 2.26v

So if the voltage divider is working ok we would expect to see a voltage of around 2.3v at the arduino input. Which would = a count of (2.3/.00488) around 471

You can also remove the comments from the two Serial.print lines in this part of the sketch to see what the Arduino is producing

// ------------------ Start voltage readings --------------------
 

 sample_count = 0;
 sum = 0;
 while (sample_count < NUM_SAMPLES) {                                   // take a number of voltage samples  
  sum += analogRead(voltagePin);
  sample_count++;
  delay(10);
 }
//Serial.print("sum count..."); Serial.println((sum / NUM_SAMPLES));      // print the count result. will be between 0 and 1023
int voltageI = map(sum/NUM_SAMPLES,0,1023,0,voltSenseMax);              // map the reading and get our result in millivolts
//Serial.print("mapped volts..."); Serial.println(voltageI / 1000.0, 1);  // convert millivolts back to volts and print. the 1 at the end determines how many decimal places to show

Boots33

Here are what my graphs look like. You can see your voltage should be a bit higher if all is well

mrc-core

Hi. i have read the post's you have made, one problem i have found its on the voltage sensing module don't now why it's not workin, simply dead, i have already bought 3 other modules and now i'm waiting for them to arrieved hope to get them until friday.

Have seen your graphs and they are really differents from mine.

Once again today with the multimeter i've made some readings from the battery and i got values in 13,2V - 12,9V and this values were measured at 19:00

Once again Thanks for helping me

mrc-core

@Boots33 said:

30k for R1 and 7.5k for R2

I was going to try to build the voltage sensing but i don't have any 7.5K resistor.... i can put 3 10k Resistors in serie to get the 30k Resistor but i cant make the 7.5K.

Can i use one 10K resistor in the place of the 7.5K, will this work ?? or will the values i'll get be rong??

Boots33

Yes that would work. That would give you a maximum input of 20v so you will need to change relevant line in the sketch from 25000 to 20000

You can try different values on this web site. http://www.raltron.com/cust/tools/voltage_divider.asp

mrc-core

I'm going to try this way and see what values i'll get.
Once again thanks.

mrc-core

I really don't get this.
Has i can see i did everything correct but i'm still getting weard values.... In the charge regulator that i have the solar30 i'm connecting the ACS712 like you told.
The voltage dividir i had it connected also on the battery vcc for the 30K resistor and ground on the 10K resistor, over the code i ahd change the "voltSenseMax" to 20000.

With this changes the House battery went from 8.4V to 16.2V but when i make the reading off the battery with a multimeter i get 13V and also the charge regulator screen shows 13V...
The charge current is over 0A now but is night at my place ill wait until tomorrow to see if this values change over the morning and day.
The load current is 9.1A this one i dont get it...

0_1466710939397_chart (1).png
0_1466710946717_chart (2).png

0_1466711310363_Sem Título.jpg

Boots33

When you were measuring 13v at the battery what was the voltage at pin A0 on the arduino. You will need to compare the readings to see if the divider is working correctly. Have you removed the comments on the serial print lines , you can then check those results with your other measurements. Also check the resistance of the resistors in your voltage divider with your multimeter to make sure they are close to the values you expect.

From what I can see in the picture the asc712 looks to be hooked up OK. They are very sensitive to electromagnetic interference so you may want to try it further away from your regulator.

mrc-core

Hi.
Ok i did not measure the pin A0 when i was measuring de 13V over the battery but i can do that.I have removed the comments but i hook up the arduino in the battery box and did not look over the serie monitor on PC, once again i'll do that today.
I think the voltage divider i ok, i did a check using a 3,7V battery and the values ia had get with the voltage divider were 0,20% differente from the ones i was getting over the multimeter, 3.2V to 3.4V

I'm going to mak some changes over the place were the asc712 is, i have a box on the wall 40cm to 80cm distance off the batteryes. That's were the ACS712 is going to be.

Thanks.

mrc-core

Just took the readings from pin A0 and the values are 3.2V when the battery readins says 13V.
The house battery is fix at 16V or 16.2V but i could not move the acs712 to the box i wanted it's night now and i can't see well, sow this change will be done tomorrow. While i'm wainting let's see if this 16V changes during the day off tomorrow.

Well it's being dificult to get this project work like a charm but it's staring to get tune up thank's to your help Boots33.

mrc-core

I've a mistake when said 4 arduino nano with some sensors, correcting this mistake:
1º arduino nano with UV sensor;
1º arduino nano with lux sensor, pressure sensor, temp/hum sensor and one anemometer; "this is my meteo box sensor"
1º arduino nano with the acs712, voltage sensor and the dallas temperature sensor
1º arduino nano controling a rain gauge.

It's 4 arduino nano with 7 sensors, i don't believe that all this put together are draining 8.6A from the battery. Isn't this a too high value ?

Boots33

3.2v at A0 sounds about right for a 20v divider reading 13v at the battery. So your divider seems to be OK. you now need to check the results from those serial print statements and see how they compare.

The code for the voltage measurement is pretty simple with the map function doing most of the work. Not a lot to go wrong there I think. But we will know more when you get the above results.

8.6A is too high for the current. if you were drawing that much your 20ah battery would be flat in a couple of hours, so the reading is wrong. Can you check with your multimeter and see how much is being drawn. I would not think it would even be 1 amp with just 4 arduino's connected

Boots33

With a 3.2v at A0 you should have a count of around 656 from the serial print

mrc-core

Hi once again.
Today i had to dismount all the solar system my arduino nano just died... don't now why and also the repeater node also dead...

I had replaced the arduino for the solar system i had also put he battery inside my house to make all the tests.
here is the serial monitor log:

Requesting temperatures...
sum count...511
mapped volts...10.0
Milliamps...-95
Requesting temperatures...
sum count...522
mapped volts...10.2
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=ok:10.2
Milliamps...-95
Requesting temperatures...
sum count...506
mapped volts...9.9
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=ok:9.9
Milliamps...-95
Requesting temperatures...
sum count...511
mapped volts...10.0
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=ok:10.0
Milliamps...-95
Requesting temperatures...
sum count...511
mapped volts...10.0
Milliamps...-95
Requesting temperatures...
sum count...511
mapped volts...10.0
Milliamps...-95
Requesting temperatures...
sum count...511
mapped volts...10.0
Milliamps...-95
Requesting temperatures...

One thing i had notice now is that house voltage is 10V but solar regulator and multimeter says 13V, and i had moved the acs712 away from the battery.
The test i made was one CPU fan connect to the solar regulator load, this fan is 12A - 0.25A.
Running the fan the solar regulator shows a Load off 0.1A and the arduino shows values between 0A and 0.3A

send: 6-6-3-0 s=255,c=0,t=17,pt=0,l=5,sg=0,st=ok:1.5.1
send: 6-6-3-0 s=255,c=3,t=6,pt=1,l=1,sg=0,st=ok:3
sensor started, id=6, parent=3, distance=2
send: 6-6-3-0 s=255,c=3,t=11,pt=0,l=21,sg=0,st=ok:Battery Status Sensor
send: 6-6-3-0 s=255,c=3,t=12,pt=0,l=1,sg=0,st=ok:1
send: 6-6-3-0 s=0,c=0,t=6,pt=0,l=0,sg=0,st=fail:
send: 6-6-3-0 s=1,c=0,t=6,pt=0,l=0,sg=0,st=fail:
send: 6-6-3-0 s=3,c=0,t=38,pt=0,l=0,sg=0,st=fail:
send: 6-6-3-0 s=4,c=0,t=39,pt=0,l=0,sg=0,st=fail:
send: 6-6-3-0 s=5,c=0,t=39,pt=0,l=0,sg=0,st=fail:
sum count...511
mapped volts...10.0
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=fail:10.0
find parent
send: 6-6-255-255 s=255,c=3,t=7,pt=0,l=0,sg=0,st=bc:
Milliamps...52
send: 6-6-3-0 s=4,c=1,t=39,pt=7,l=5,sg=0,st=ok:0.1
send: 6-6-3-0 s=5,c=1,t=39,pt=2,l=2,sg=0,st=fail:0
Requesting temperatures...
send: 6-6-3-0 s=0,c=1,t=0,pt=7,l=5,sg=0,st=fail:30.3
send: 6-6-3-0 s=1,c=1,t=0,pt=7,l=5,sg=0,st=fail:-127.0
sum count...517
mapped volts...10.1
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=ok:10.1
Milliamps...200
send: 6-6-3-0 s=4,c=1,t=39,pt=7,l=5,sg=0,st=ok:0.2
send: 6-6-3-0 s=5,c=1,t=39,pt=2,l=2,sg=0,st=ok:0
Requesting temperatures...
send: 6-6-3-0 s=0,c=1,t=0,pt=7,l=5,sg=0,st=fail:29.9
sum count...511
mapped volts...10.0
send: 6-6-3-0 s=3,c=1,t=38,pt=7,l=5,sg=0,st=ok:10.0
Milliamps...126
send: 6-6-3-0 s=4,c=1,t=39,pt=7,l=5,sg=0,st=ok:0.1
send: 6-6-3-0 s=5,c=1,t=39,pt=2,l=2,sg=0,st=ok:0
Requesting temperatures...

12v Solar battery monitor

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