Hi, i have a plan to build a scale for racing cars. 4 load cells from bosch. To get readings +- 10g i need a good adc. What do you recommend?
10g/5000000g is 1/500000 or 19 bits of ADC resolution. Good luck.
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What if I go down to 2000kg, +- 250g?
Do a adc whitin resonable price exist?
If not, any advice?
The ubiquitous HX711 has a 24 bit ADC.
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... with about 16 bit real-world resolution.
Not counting for the drift of the load cell itself.
Leo..
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You are looking for a professional device. A professional device is tested with high and low temperatures and with high and low humidity.
If you build something yourself, it is not as accurate and might not be reliable outdoors. I have had Arduino clones where the crystal stops working with freezing temperatures.
A normal kitchen scale can be 1 gram accurate for up to 3 kg.
That is about 12-bits accurate. That is a reasonable number that can be achieved with an Arduino and normal hardware.
250 gram up to 2000 kg requires 13-bits accuracy. That is possible.
The ADS1115 is accurate: https://www.adafruit.com/product/1085, but I don't know how it is doing in combination with strain gauges.
The HX711 is for every day common indoor use, such as a bathroom scale or a kitchen scale.
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By the above, if we mean Arduino UNO/NANO/MEGA, then there are 10-bit ADC.
I have built with hx711, but i need more accuracy
Not good, because a Wheatstone bridge needs a ratiometric A/D, which the ADS1115 is not.
Excitation voltage and Aref must come from the same point, and Aref of the ADS is not accessable.
Maybe OP can try a Wheatstone bridge chip from Texas Instruments, like the ADS1231 (and others).
That one seems to be a HX710 (not 711), but not from the far east.
Leo..
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I'm afraid that is why a good set of scales is expensive.
You will have to build it to be mechanically rigid and sound to preserve accuracy (calibration) and consistent readings.
Tom... 
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No, you don't.
So which load cells from BOSCHE do you have ?
Never mind my nitpicking. You are asking for more accuracy, so be more accurate 
What do you consider a "resonable price"?
Code?
Schematic?
Datasheets?
Pictures?
Accuracy data?
It might not be the ADC holding you back.
I have built a scale for bee hive, 1x no name load cell 150 kg.
For this project Im not shure what to use, but 4x bosch load cells can be a possibility. This tread is more for me to ask and learn more because I have struggled a lot to make a good scale,
Pict is from the scale, welded stainless steel.
Can you at least give a link to the non-existing load cells from bosch ?
Hi
Single point load cell H40A
Or 4x
The AD7190 would work for your application
You are asking for 10 gm accuracy on a 5000Kg range. That is 0.0002%. The load cell you reference is a Class C which has an accuracy rating of 0.023%.
An ultra precise (super expensive) load cell in the range you are talking about may have an accuracy of 0.005% and that would be a cell designed for calibration/reference standard purposes not routine measurement use.
You need to rethink your entire concept.
Yes, I totally understand. Thanks for precise info.
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