ESP8266 Community Forum

- Sun Aug 20, 2017 10:42 am #69327

I would buy IN219 boards and set them for different addresses. If you need higher than 3 amps then change the shunt resistor. IN219 boards can be bought for $1.50 usd each.

I think is no way to find genuine INA219 with proper designed boards at that price. Might be some on ebay but I would not hold my breath about how precise and reliable they would be.
Also, would you go with more than 3Amps load with that thin traces? I don't think so, you are way too experienced for doing that.

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- Sun Aug 20, 2017 11:43 am #69329 trackerj I have used those boards. They are adequate. I'm sure you would rather sell your boards but there are acceptable less expensive alternatives.

Also, would you go with more than 3Amps load with that thin traces? I don't think so, you are way too experienced for doing that.

For higher currents I would remove the shunt resistor and use an external shunt. The current shunt could be left in place, it would just have to be included with the external shunt's resistance.

As far as my experience. I have been working designing commercial products for over 30 years.

- Sun Aug 20, 2017 3:31 pm #69338

trackerj I have used those boards. They are adequate. I'm sure you would rather sell your boards but there are acceptable less expensive alternatives.

Also, would you go with more than 3Amps load with that thin traces? I don't think so, you are way too experienced for doing that.

For higher currents I would remove the shunt resistor and use an external shunt. The current shunt could be left in place, it would just have to be included with the external shunt's resistance.

As far as my experience. I have been working designing commercial products for over 30 years.

I am really sorry and must apologize if somehow I was misunderstood. It was no sarcastic remark in the sentence : " I don't think so, you are way too experienced for doing that." Literally, I know you have enough experience to know that. And you probably also know also that I have also enough.

I am not trying to sell anything here. Everybody is free to buy/use whatever they want. I am just trying to help people less experienced to learn something in the right way. If you used such a beautiful board, how thick is the load trace? And how big was your load target? under or over 3Amps? What was the quality of the shut resistor? I don't expect a high quality, low TCO one for such a price.
Only with the Shenzen market "magic" you can have a brand new,genuine 1.5$ INA219 + a 5$ good quality shunt resistor and a well designed PCB for a complete device that will cost only 1.5$. yeah. magic. You know is no "magic" there. Just low quality, grey market or defective components.

And to know exactly what's the board we are talking about, it's about this one or similar?
http://www.ebay.com/itm/INA219-GY-219-B ... SwEzxYZxyk

If you use an external shunt resistor and also load circuit then the fancy 2$ Ebay board has just become somehow just a expensive smd adapter for the INA219 IC, isn't it correct? And by the way, don't you loose then also the the short lenght, balanced, kelvin current sensing traces connection to INA219 that will help you to have the best accuracy over the entire measurement domain?

Also, can you please elaborate a bit more the idea from here: "The current shunt could be left in place, it would just have to be included with the external shunt's resistance."

Let's help people to learn something about.

Happy breadboarding,
TJ.

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Available on Tindie: https://www.tindie.com/products/nEXT_EVO1/universal-ac-mains-dimmer-mpdmv41/

- Sun Aug 20, 2017 5:04 pm #69339

Also, can you please elaborate a bit more the idea from here: "The current shunt could be left in place, it would just have to be included with the external shunt's resistance."

I guess he is proposing to add an "external" shunt, in parallel with the "internal" one, and choose a proper value (accounting for the two resistors working in parallel) for the desired amperage.

Anyway, 3 amps seems like plenty for my projects, and I do not really need a great accuracy in the measurements; so these modules will probably do the job quite nicely. There are moments when you need a high quality product and can justify the cost, but this is not one of them.