INA226 Module Current/Power Capacity - Page 1
Forum section: electronics / projects

author: flywire
author_rank: Contributor
timestamp: January 27, 2021, 03:43:10 am
content: How much current or power can anINA226 moduletake? I plan on putting an R004 current shunt on it which would measure 20A so 20A x 81.9175mV = 1.6W, ie a 2W shunt.How can I check if the module pcb can tolerate that much current at 36V (or say 40V)? I don't want to melt the tracks.INA226 chip datasheet

author: coromonadalix
author_rank: Super Contributor
timestamp: January 27, 2021, 03:23:16 pm
content: I have ordered ina226 boards, i did not push them over 10 amps with an adjusted value of the onboard shunt resistor, i removed the onboard resistor and instead used 2 wires going to the shunt resistor for bigger currents measurements, i did twist them to avoid noises / interferencesIn the page 10 you may have to write the calibration registers to suits your needsFor the ina226 boards you have to meausre the traces width and do calculations for the supported currents, i did not bother and switched to separate shunts

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 27, 2021, 03:35:42 pm
content: I recommend the following tool, which is pretty handy:https://saturnpcb.com/pcb_toolkit/Note that the current will only flow through the shunt resistor, the very short traces from shunt to plated holes, and the plated holes themselves. Of course you need to select your shunt resistor appropriately, but as to the rest, you can remove the solder mask over the short traces between the shunt and plated holes, and reflow some solder over them to increase current carrying capacity.As they are (so without this modification), those traces - from the pics - look like ~4 mm wide and according to the above tool, ~10 A would be the maximum reasonable. Tinning the traces as above should do the trick.Also beware of your external connections. Use proper wiring.

author: flywire
author_rank: Contributor
timestamp: January 28, 2021, 07:40:19 am
content: I appreciate the explanation. At least I don't have to worry about the power jumping the 1mm gap between the tracks.@coromonadalix I understand it needs recalibrating.@SiliconWizard that's the tool but it's way too complicated for a noob like me. Would you mind adding a screendump to help me understand the calculation? Calculating Via Current I assume.I understand:* hole diameter 2mm* pad diameter 4mm* Ref plane opening ??* Via height 1mm (generates error)* Via Plating thickness ?? default 0,025mm* trace width 4mm* trace length 5mm from centre of hole to centre of shuntUsage will be in a vehicle under the sun in Australia so it will get hot, even with heatsink and cooling fan.INA226 Power sensor - 20.5mm(W) x 19.4mm(L)

author: coromonadalix
author_rank: Super Contributor
timestamp: January 28, 2021, 11:22:07 am
content: Do you know the Allegro Acs xxx series of hall effect current sensors ? you have ones who go up to 100 ampsNo special shunt requiredMaybe they could suit your needs better, really easy to interface on Arduino and other platforms, tons of code available on google

author: Renate
author_rank: Super Contributor
timestamp: January 28, 2021, 11:42:01 am
content: Well, here's my setup using an INA226.I'm using the fuse as a shunt, so no extra resistance.I calibrated it as a 0.34 milliohm resistance.Have you considered an off-board shunt?

author: flywire
author_rank: Contributor
timestamp: January 28, 2021, 08:55:13 pm
content: @coromonadalix I read somewhere why hall sensors weren't a good idea compared to current shunts. Inaccurate with small DC loads iirc (??)Recap.* ina226 is distributed with a (black) R100 current shunt - 0.8A* ina226 is distributed with a (white) R010 current shunt - 8.3AQHow much current can that module take?A10A (R080) as explained by @SiliconWizard aboveConventional thinking is to use an external shunt for larger loadsQIf module board has to be modified to remove shunt what does it take to upgrade it at the same time?AUpgrade wire connection to shunt - solder (to be tested) or copper wire.Interestingly I was thinking of a fuse myself, especially since it is required anyway. (Noob clueless thinking has no bounds.) My concerns are the performance (accuracy) would likely change over different operating conditions and I suppose it would have to be recalibrated when it was replaced.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 28, 2021, 10:34:03 pm
content: Taking the shunt off the board, as Renate suggested, would be the easiest path IMO. 2W of dissipation is already something; even if you take care of the traces, the shunt resistor itself will heat up significantly on board, and as it is, it will be hard to put a heatsink on it, and the elevated temperature of the board could compromise the measurements.Then you could just connect small wires from shunt to the board - those will carry only negligible current, and if you keep them short, it should not compromise accuracy either or pick up noise.

author: Pineapple Dan
author_rank: Contributor
timestamp: January 29, 2021, 12:13:35 am
content: Quote from: flywire on January 28, 2021, 08:55:13 pmIve had good results with the ACS724 but using the fuse as shunt is interesting and the notion crossed my mind before. You could end up with a non-working device though if someone decides to bypass the fuse with a piece of tinfoilWhat kind of accuracy are ye getting from the INA? In theory I'm getting a resolution of ~20mA on a 10 bit ADC reading the ACS724-10AB but havn't done any detailed testing on that