# INA219 sensors and measure of the solar panel and lead acid battery #2 **URL:** \ **Category:** Sensors\ **Created:** [April 29, 2023, 3:07pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200 "2023-04-29T15:07:41Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 3:07pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/1 "2023-04-29T15:07:41Z")
A post here [INA219 sensors and measure of the solar panel and lead acid battery](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery/614453) has asked about using INA219's to monitor a solar charge controller using the following circuit: ![test_bb](https://europe1.discourse-cdn.com/arduino/original/4X/2/9/8/2985072f5c5a465a4586020555718640b63cb2db.png) To which the conclusion was "you can't do that as the controllers use common +". So if its not possible using ina219's, are there any similar to use sensors that can be used in that situation? ---
**Author:** ![paulpaulson](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/paulpaulson/32/363643_2.png) [@paulpaulson](https://forum.arduino.cc/u/paulpaulson)\ **Post date:** [April 29, 2023, 3:22pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/2 "2023-04-29T15:22:30Z")
Post a real schematic to see the system details. ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [April 29, 2023, 3:23pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/3 "2023-04-29T15:23:42Z")
The conclusion was that the INA219 cannot be used to measure the solar panel **voltage** , with that particular type of controller. As pointed out, the panel voltage is not needed. ---
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 4:00pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/4 "2023-04-29T16:00:35Z")
So, suppose, just for a moment that I DID want to be able to measure such a voltage, are there any sensors to do such a thing? ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [April 29, 2023, 4:01pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/5 "2023-04-29T16:01:16Z")
A voltmeter, connected across the panel terminals, comes to mind. ---
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 4:02pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/7 "2023-04-29T16:02:38Z")
And how would I connect that to an arduino, or are you just being awkward and obtuse? ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [April 29, 2023, 4:04pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/8 "2023-04-29T16:04:37Z")
That would depend on which voltmeter, and which Arduino you chose. For informed help with your project, please read and follow the instructions in the "How to get the best out of this forum" post, linked at the head of every forum category. ---
**Author:** ![EmilyJane](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/emilyjane/32/821537_2.png) [@EmilyJane](https://forum.arduino.cc/u/EmilyJane)\ **Post date:** [April 29, 2023, 4:38pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/9 "2023-04-29T16:38:03Z")
> [@paulpaulson](#): > > Post a real schematic @frank18 In addition to posting a real schematic of your project you need to post the link to your **positive ground charge controller**. Also post the model of your microcontroller and descriptions of any sensors and peripherals you intend to use. A charge controller like the one in the linked topic requires special attention if any measurements are to be made on it. ---
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 7:57pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/10 "2023-04-29T19:57:41Z")
` > real schematic of your project ` Impossible to do that when I don't know what sensor I could use to be able to do what I want. I guess I'm asking in the wrong place. ---
**Author:** ![EmilyJane](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/emilyjane/32/821537_2.png) [@EmilyJane](https://forum.arduino.cc/u/EmilyJane)\ **Post date:** [April 29, 2023, 8:06pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/11 "2023-04-29T20:06:14Z")
So you have no idea which charge controller you have or which microcontroller you have? If that’s the case you can start from scratch and use a charge controller that is not common positive. The correct way to start a project is to draw a schematic diagram of the parts you think you might need. You can put part numbers on them after a little discussion and thought about that. If you’ve come here without any idea at all just wanting the forum to hand you a complete project then you need to offer to pay someone to do it. ---
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 8:10pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/12 "2023-04-29T20:10:32Z")
I came here to simply ask if there is a sensor that can be used for low-side. Unfortunately everyone in this forum just jumps on their high horse and takes the {redacted} attitude to new users that is taken everywhere here. If I'd spent five minutes looking though the forum before asking that would of been obvious. moderator edit: language ---
**Author:** ![so-very-angry](https://avatars.discourse-cdn.com/v4/letter/s/7feea3/32.png) [@so-very-angry](https://forum.arduino.cc/u/so-very-angry)\ **Post date:** [April 29, 2023, 8:11pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/13 "2023-04-29T20:11:57Z")
Please delete this account as even that doesn't seem to be possible from my profile. ---
**Author:** ![EmilyJane](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/emilyjane/32/821537_2.png) [@EmilyJane](https://forum.arduino.cc/u/EmilyJane)\ **Post date:** [April 29, 2023, 8:13pm UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/14 "2023-04-29T20:13:04Z")
The simple answer is “Yes you can do it with an ARDUINO programmed to be a voltmeter.” Happy? P.S. From your avatar, I can see why you’re so angry. ---
**Author:** ![EmilyJane](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/emilyjane/32/821537_2.png) [@EmilyJane](https://forum.arduino.cc/u/EmilyJane)\ **Post date:** [May 1, 2023, 1:52am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/15 "2023-05-01T01:52:05Z")
So I was wondering before so-very-angry left us if it wouldn't be possible to measure the "positive ground" referenced voltages by completely isolating the Arduino with relays and never having the Arduino ground common to more than one voltage source at a time. That wouldn't require a special sensor but would accomplish OPs initial requirement. Connecting sensors like the INA219 to measure current would be a different problem. I thought there might be a way to power a microcontroller off the positive ground system but didn't think that through. ![Screen Shot 2023-04-30 at 8.43.03 PM](https://europe1.discourse-cdn.com/arduino/original/4X/1/5/4/154459131a0308d4dbb25bf1a0211d97632bd996.png) ---
**Author:** ![anon94801460](https://avatars.discourse-cdn.com/v4/letter/a/278dde/32.png) [@anon94801460](https://forum.arduino.cc/u/anon94801460)\ **Post date:** [May 1, 2023, 2:13am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/16 "2023-05-01T02:13:36Z")
The basic problem with measuring the solar panel _voltage_ is that most charge controllers use PWM switching. So the measured "panel" voltage levels are either open circuit, which is uninformative because it doesn't depend strongly on illumination level, or the battery voltage, during alternate portions of the switching cycle. Either way you don't learn anything very useful about the solar panel performance. Only the current matters. Whether the ground is positive (true for many older controllers) or negative is a separate problem. ---
**Author:** ![EmilyJane](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/emilyjane/32/821537_2.png) [@EmilyJane](https://forum.arduino.cc/u/EmilyJane)\ **Post date:** [May 1, 2023, 2:25am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/17 "2023-05-01T02:25:42Z")
Okay, I get it. It doesn't particularly matter **how** one would do it then. ---
**Author:** ![racpi](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/racpi/32/1126829_2.png) [@racpi](https://forum.arduino.cc/u/racpi)\ **Post date:** [May 1, 2023, 3:04am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/18 "2023-05-01T03:04:36Z")
the amount of time and effort required makes these a no brainer imho > **[BlueSolar MPPT 75/10, 75/15 & 100/15 (12 / 24 Volt + load output) -...](https://www.victronenergy.com/solar-charge-controllers/mppt7510)** > > Maximize the energy-harvest, driving it intelligently to achieve full charge in the shortest possible time using the BlueSolar MPPT 75/10, 75/15 & 100/15. Find a dealer nearby. every stat under the sun at your finger tips ---
**Author:** ![Wawa](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/wawa/32/1211303_2.png) [@Wawa](https://forum.arduino.cc/u/Wawa)\ **Post date:** [May 1, 2023, 3:22am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/19 "2023-05-01T03:22:55Z")
Displaying generated **panel power** could be nice. The INA219 should be able to output power from it's measured battery voltage and panel current. Leo.. ---
**Author:** ![TomGeorge](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/tomgeorge/32/215261_2.png) [@TomGeorge](https://forum.arduino.cc/u/TomGeorge)\ **Post date:** [May 1, 2023, 7:32am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/20 "2023-05-01T07:32:02Z")
Hi, In your schematic. ![Screen Shot 2023-04-30 at 8.43.03 PM](https://europe1.discourse-cdn.com/arduino/original/4X/1/5/4/154459131a0308d4dbb25bf1a0211d97632bd996.png) If you common all the positives, what will happen to the gnd1, gnd2 and gnd3 when their respective relay is OPEN and isn't referenced to the controller gnd? You have the potential to apply more than the 5V or 3V3 that the A0, A1 or A2 is rated at. Can you please tell us your electronics, programming, arduino, hardware experience? Tom.. 😃 👍 ☕ 🇦🇺 ---
**Author:** ![theeccentricgenius](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/theeccentricgenius/32/993275_2.png) [@theeccentricgenius](https://forum.arduino.cc/u/theeccentricgenius)\ **Post date:** [May 1, 2023, 9:58am UTC](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200/21 "2023-05-01T09:58:43Z")
> [@TomGeorge](#): > > You have the potential to apply more than the 5V or 3V3 that the A0, A1 or A2 is rated at Way more. 🤣 😂 [Next page](https://forum.arduino.cc/t/ina219-sensors-and-measure-of-the-solar-panel-and-lead-acid-battery-2/1121200.md?page=2)