Not really, you need the right tool for the job.
hi Stuart, what do you think about this rs485 200v shunt would that be good for the high voltage folk (and everyone else)? Cheap too.
You have to worry when the device says it will damage your PC if you plug it in!
Shows its not electrically isolated from the signals it’s measuring.
in the manual it is supposed to be isolated
the warning is to not power the unit with the pc (mini usb) when under 7v on the battery,
comunication port is passive and optoisolated.
I read that as just the opposite. i.e. use the PC’s USB port if the voltage is <7V.
Even though the maual does say when the test voltage is <7V, please use the independent power supply mode.
The manual also says the instrument is capable of reading frequency, but the register address table says otherwise. Why would a module that reads DC need a frequency function anyway?!
Seems to make more sense grouping the words on the left side of the USB connector symbol together
as well as grouping the words on the right side of said symbol together.
Reading them as one long string from left to right as Forbid to use PC’s USB port When the input test voltage is <7V please may damage the PC use USB port to be the power supply (5V) doesn’t quite read right.
That said, with things made in China, it’s definitely a WTH?! moment when it comes to figuring out
their broken English and datasheets/instructions. Seems like there’s always something lost in the translation.
Surely that - or a similar unit - has been looked at before here? IIRC, our much respected contributor dBC had an input.
[Edit]
It was the PZEM-016: PZEM-016 single phase modbus energy meter - #4 by Bill.Thomson
sry i meant to say never use a pc to power the pzem on the usb port, only a power supply.
the pzem needs external power if main battery is under 7v.
It looks like the rs485 output has two optoisolators on it, which is good.
The code/intelligence if the existing diybms shunt is all contained on the board, it does all the amp hour counting and soc calculations.
This and similar shunts seem to be dumb in that they need an external controller to do that work.
could be a job for the watchdog?
I’ve ordered one from Aliexpress to have a play with, at its most basic, it should be possible to read the power, current and voltage from it.
It uses 9600 baud which is a bit slow for RS485, so that will limit the amount of readings you could ever read from it.
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This looks very interesting! I just ordered one to play with!
Yeah it’s a bummer that it doesn’t report Ah’s!! I guess if one could poll fast enough you could calculate the amp hours and determine SOC… But, like you said, that needs a controller…
hello stuart
The INA228 component is no longer available from JLCPCB and LCSC. Is there an alternative that I can use?
Hi Andy,
Where are you located?
Germany, lowersaxonia
Mouser has the part you’re looking for and has distributors in Europe.
Here’s a link to the INA228
https://eu.mouser.com/Search/Refine?Keyword=ina228
Price ranges from 3,47 to 5,90 € for 1 device.
HTH
yeah 20€ shipping for one peace 
but ok mouser have the ina822 in stock.
Is there a reason why the ESP32 controller can’t be used to program the shunt? I used the controller’s AVR programmer with my modules, but am scratching my head about programming the shunt as I only have a regular USB serial adapter, not a USB ASP adapter. There’s very little info about this step, just a brief section of the intro video where Stuart is using an Arduino Uno to program the shunt.
Hi, as i had the same issue a few weeks ago, i can tell you: “Relax”.
On the Shunt Stuard uses a new ATtyni which have to be programmed over UPDI.
after some investigation i found the easyest and cheapest solution (as Stuard did) was to buy an Arduino Uno and installed this Software on it: GitHub - ElTangas/jtag2updi: UPDI programmer software for Arduino (targets Tiny AVR-0/1/2, Mega AVR-0 and AVR-DA/DB MCUs).
The installation is than more/less like an Arduino sketch.
This!