FYI, a cheap power meter, 12 bucks
 

NEW AC Digital LED power meter monitor Voltage KWh time watt energy Volt Ammeter
New AC Digital LED Power Meter Monitor Voltage kWh Time Watt Energy Volt Ammeter | eBay

Wow - I might just spend $12 just to see how this works. Sounds like there is no toroid core to put around AC main wires. "Measures up to 50 amps with larger gage wire" - direct feed with voltage drop across diode to sample current?

It looks like it is the display module for a larger unit. Sounds like part of a power alarm system from the description.

Good catch . . . maybe somebody has seen this in action.


Steve

This looks pretty exciting, and if it works, it will beat the pants off the $30 electric meters I have purchased to monitor my consumption. I would really like to hear from anyone who is using one.

That looks like a pretty good deal..
 

From what I can almost see, those wires look a bit small for 240vac at 20A (4.8kW)..
But, if they are 14 gauge, they are short enough not to matter..

These might be pretty neat for monitoring your ASHP..


Features :
AC Multifunction Power Meter :
1.Electric parameters measurement function : Energy Power Voltage Current Working Time
2.Power down data storage function : Keep off before the electric power,total operation time,display items,back light out state
3.Overload alarm function : More than power alarm threshold backlight flashing alarm
4.Power alarm threshold preset functions : Can set power alarm threshold
5.Electricity, operation time key reset function Backlight
6.Voltage Measuring Range : AC 80 - 270V
7.Current Measuring Range : 20A (The Current range can be increases up to 50A by use of heavier gage wire.)
8.Rated power: 30A/6600W
9.Operating frequency: 45-65 hz
10.Energy Measuring Range : 0-9999.99KWh
11.Power Measuring Range : 0 - 9000W
12.Working Time : 0 - 9999.59hours
Package
100% Brand New
1X AC Digital LED power meter monitor Voltage KWh time watt energy Volt Ammeter

I bought one, many on eBay for <$12. now, several Hong Kong sellers.
The wires are 12 gage at least.
IMO, this item would be best used as a panel meter built into the case of your hacked heat pump, inasmuch as its memory and accumulative features require power. It apparently has a battery backup but I don’t know how long it would last.
Could be cased and made a portable instrument, but IMO not worth the effort.
It is single phase, and only requires the hot load wire in and out, the ground wire only required to run the instrument.
The negative is that there is not a good English user manual for it. But should not be too difficult to figure out.

It would be pretty cool to have a meter for my tankless electric hot water heater. That thing pulls 40A and I haven't been able to find anything besides my TED that can measure and log.

The spec looks a little funny..

7.Current Measuring Range : 20A (The Current range can be increases up to 50A by use of heavier gage wire.)

8.Rated power: 30A/6600W


6600w/220v=30A

Contradictory/inconsistent?


50a x 220v = 11kw and that's a LOT more than 6.6kw..

Haha... yeah a little confusing.

So any word on further use of this item??

I think I'm going to try it for my solar panels. There are no cheap 220v metering options.

Only issue I see is if it can keep data during a power outage. I doubt they can include a battery or memory for that price; which means you lose data.

Seems to me, if you are using a GTI system, that puts out 220vac,
you will have to cut into both hot sides of the 220vac, between the GTI and the grid.
You would insert that meter into that cut. (In series like a Killavolt meter).

So, the meter would be powered by the grid 24/7..?.

One side is going to be just a pass-thru, and a common for the internal DC PS & an AC voltage measurement point.
The other side (red?) will be tapped for voltage measurement, and the internal DC PS.
That side will likely have a non-contact current sensor. (like a clamp sensor).
But it could have a plain old resistor sensor, like a Killavolt.



The only problem I see is your meter board would not have a ground or neutral. (floating).
And part of the board would be electrically 'hot', relative to ground.
If you put the meter in a metal box, you could ground it to neutral..

Not gonna be UL approved.. :eek: