Integrate ampere measurement over time? 2

[SolarTrap]

Hello,
I am looking for an I2C device that can help with accurate measurement of amps (+/- 50A @30VDC) flowing in 2 directions (in and out of batteries). I am currently using an Arduino to do this but accuracy is low in terms of available bits at the ADC but especially with the sampling rate I am able to do the measurements (10Hz) with. Is there a chip that is able to integrate the amps over time until I read it?

Thanks
Markus

 

[zappedagain]

"in a very dynamic load pattern I might miss a few peaks." - Add an analog peak detector circuit. Or if you can sample the A/D faster in your interrupt service routine you can implement a digital peak detector.

Z

 

[jimkirk]

You'll have to provide a power supply for it (it draws very little current, 100 uA or so, 1.5 uA in shutdown). Since you've got a battery, you could probably power it by 2 or 3 cells closest to ground with no ill effect and put the shunt in series with that and the more positive cells, something like this:

[gnd]--[2 or 3 cells]-+-[Rshunt]-+-[cell]--[cell]-- ... --[Batt+]

The current range is set by the shunt resistor. +/-50 amps full scale would be 1 milliOhm. Plenty of options there:

http://www.digikey.com/product-sear...t=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25

I did something similar for a 15 Amp-Hour 48 volt battery pack.

 

[crshears]

Hmmm...all this is way out of my league; no matter what type of uC I was looking @, I don't think I would recognize 1 were I2C1...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]

 

[zappedagain]

CR, are you not fluent in over 6,000,000 forms of communication?

Z

 

[crshears]

Hey zappedagain, actually, I don't believe I am...

CR

"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]