Device to measure high amp dc current

Hardware
1

Hi all,

I’m wanting a esphome power monitor for:

  1. solar panels (2 separate strings of 6 panels each. They are 555w panels, I think 33v)
  2. 200A 51v inverter battery

I want to track how much power I get from solar panels, and also how much power is pulled from my battery.

I take it CT clamps are only for AC current measure?
I therefore have been looking for high current DC devices on the esphome components page.

2 devices seem like they could fit the need:
PZEM-017 (Peacefair PZEM-00X DC Energy Monitor — ESPHome)
Eastron devices (Eastron SDM Energy Monitor — ESPHome)

Which device might be ideal?
Eastron has these two

Are these supported by esphome, and would they work for my needs?
The spec does say “100-1000V DC” which I wonder might be a problem with the battery since it is a 52V battery?

The PZEM-017 says "supply voltage: 0.05-300V, so maybe this is better for the battery side?

Any input and advice appreciated, thanks.

2

Hello hiren1771,

CT clamps will pick up using AC or DC.
Well i thought it did, I can’t always be right…

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3

A couple clarifications, first —

  1. Are you sure it’s not a 200Ah battery, rather than a 200A battery? Big difference, so just checking.
  2. What kind of MPPT charge controller are you using? Does it have a separate dc load connection to the inverter? If so, this is often the easiest place to measure as many charge controllers, like the Victron, have built-in power meters.

Just to clarify, CT clamps that are actual “current transformer” clamps i.e. with a ferrite-wrapped core do not work with dc current. Current clamps that use Hall Effect sensors, like in handheld multimeter clamps, do work with dc current.

You already linked to the esphome support, though note that both sensors output a serial stream over rs485 so you also need a proper uart converter for that. I wouldn’t recommend the 100-1000v unit with a 52v battery, however. There are a few topics on this forum about using the PZEM with esphome for solar monitoring.

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4

Hi,

Thanks so much for the info, I will look at the link regarding PZEM.

  1. Yup it’s a dyness power brick rated for 200A max output. It’s a 14.3kwh battery.
  2. The inverter has a built in mppt, it will be a deye 12kw inverter.

I’m aware there are some HA plugins for deye etc, my worry is that only some models might be supported not all, and if the deye ever updates its firmware and decides to break the integration, I would have another way to get power readings which cannot be bricked (due to esphome firmware)

Thanks for clarity on CT clamps, I have a sonoff POWCT on my mains currently, but it is rated for 100A only, and I’m not sure if it has a ferrite core or hall effect in it.

Is there a 200A or 300A CT hall effect that would work on DC which supports esphome firmware that you might be aware of? I will look again through the esphome components page to see if I can spot any. They’d be ideal then as installation is very easy.

Thanks again for the info, appreciate your help.

5

HSTS016L (±200A Rated output 1.65V±0.625V/+3.3V)
could be option together with ESP32. Output voltage is nicely around 2V, so it could be usable even without additional ADC (ESP32 adc is not one of the bests).

1 Like
6

I will take a look, thanks so much.

If hall effect CT clamps can work on DC, why would the esphome docs be listing clamps as AC only?
Eg here under electricity - ct clamp it specifically says AC alternating current. ESPHome Docs — ESPHome
Then in the ct clamp page, it also says to measured single phase AC current CT Clamp Current Sensor — ESPHome

Are the pages incorrect or am I missing something?
Thanks.

7

Clamp is clamp.
CT is Current Transformer. It outputs AC sine wave.
Hall effect current sensor is not CT.

You only need adc component to read the voltage output. No need for CT-component.

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