0

INA219
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

INA219

by FooManChoo on Sat Jan 12, 2019 8:10 am

I have a solar panel project where my Imax will be 3.3-amps (extremely unlikely to hit this unless I move to the equator and have a perfect day) and my Vmax is 35.1 (also unlikely to hit this, but want to protect the INA219 in case it happens).

I really, really want to use the INA219 as it reports voltage and current and I trust the Adafruit design versus the breakouts available elsewhere.

So, my question is: is there any downside with putting a 2:1 voltage divider in front of the INA219 to provide a voltage range of 0-52vdc and then adjust this in software?

FooManChoo
 
Posts: 10
Joined: Thu Feb 28, 2013 5:11 pm

Re: INA219

by adafruit_support_bill on Sat Jan 12, 2019 8:33 am

is there any downside with putting a 2:1 voltage divider in front of the INA219 to provide a voltage range of 0-52vdc and then adjust this in software?

A voltage divider will not work for this application. For a divider to work properly, the current through all of the resistors in the divider must be equal. That means you can't have any current load on the output of the divider. If you are feeding the output of the divider into the INA219, one of the resistors would be in parallel with your load and the other one in series.

One option would be to wire the INA219 on the low-side of your load to measure the current only.
Then you could use a voltage divider to scale down the panel voltage so you can measure it with one of your analog pins.

adafruit_support_bill
 
Posts: 73049
Joined: Sat Feb 07, 2009 10:11 am

Re: INA219

by FooManChoo on Sat Jan 12, 2019 8:42 am

Thanks, Bill. I realized the error of my ways after posting :)

I'm going to look at the INA226, which seems to be perfect for my application. If Adafruit were to produce a breakout based on this, that would be awesome!

Cheers.

FooManChoo
 
Posts: 10
Joined: Thu Feb 28, 2013 5:11 pm

Re: INA219

by adafruit_support_bill on Sat Jan 12, 2019 8:46 am

We also have the INA169. That will handle up to 60V @ 5A. https://www.adafruit.com/product/1164
But that is current-only with an analog output. You would still need additional circuitry to monitor the voltage.

adafruit_support_bill
 
Posts: 73049
Joined: Sat Feb 07, 2009 10:11 am

Re: INA219

by FooManChoo on Sat Jan 12, 2019 8:48 am

Alas, I'm using an ESP8266 and only have one analog port. I would prefer a completely I2C solution, too.

Thanks for your help.

FooManChoo
 
Posts: 10
Joined: Thu Feb 28, 2013 5:11 pm

Please be positive and constructive with your questions and comments.