Cheap Onzo Energy meter - £8

[PRTVR]

selym said:

saaby93 said:

This morning found the head had lost connection with the sensor
Pressed the power button on the sensor and no flashing LED

Last night with switching most things off the power was down to 20W
Since the power through the red wire generates the magnetic field to charge the sensor battery it looks like 20W is not enough to keep the sensor alive.
Has anyone seen a figure for minimum usage for the system to work?

Same. I came back yesterday and it had lost sync. I have non rechargeables in, surely they haven't died in a week?
(I've not checked yet, to be fair!)

They may not be designed to run on standard AAA batteries, think the power consumption on anything that has blue tooth would flatten them quickly, may need to look into replacement rechargeable battery pack, with 3 three fully working batteries, think the one that has leaked may be faulty or at least suspect.

[saaby93]

PRTVR said:

They may not be designed to run on standard AAA batteries, think the power consumption on anything that has blue tooth would flatten them quickly, may need to look into replacement rechargeable battery pack, with 3 three fully working batteries, think the one that has leaked may be faulty or at least suspect.

Is it Bluetooth or some other low power transmission system?
The unit is designed to hold either 3xAAA non rechargables or the charging pack
Mine is 1.6V again - waiting for it to charge
The power button causes the yellow led to flash 4 times I think if the battery is ok

[bazza white]

My was a bit funny yesterday with signal but seems to have settled.

[saaby93]

Just checked the sensor by pressing the power button - it flashed 4 times = I'm alive
However they units werent in sync
To get them to sync, put them right next to each other and pressed both blue buttons ( and let go)
Within about 5 seconds sync was achieved

It confirms that if the sensor battery runs low it loses sync

[megaphone]

saaby93 said:

PRTVR said:

They may not be designed to run on standard AAA batteries, think the power consumption on anything that has blue tooth would flatten them quickly, may need to look into replacement rechargeable battery pack, with 3 three fully working batteries, think the one that has leaked may be faulty or at least suspect.

Is it Bluetooth or some other low power transmission system?
The unit is designed to hold either 3xAAA non rechargables or the charging pack
Mine is 1.6V again - waiting for it to charge
The power button causes the yellow led to flash 4 times I think if the battery is ok

They are not Bluetooth, they are not WiFi, they run on 433Mhz according to the manual, same as garage door openers etc.

The battery indicator on the display is showing 3 bars after a week of use, not sure if that is the display batteries or the transmitter battery.

[TonyRPH]

I've had one of these since the end of August, and I was running both transmitter and receiver (base unit) off normal batteries.

The batteries in the base unit drained in less than a month, so I now have it plugged into a spare USB charger I had, and I've also fitted it with rechargeable batteries, so it can be unplugged if needs be.

I'm not sure about the status of the transmitter batteries, however it's still working after 7 weeks or so.

[saaby93]

megaphone said:

The battery indicator on the display is showing 3 bars after a week of use, not sure if that is the display batteries or the transmitter battery.

I'm pretty sure that's the state of the battery in the display. It disapperas when I plug the unit into a standard usb phone charger
All 3 bars are showing in the battery symbol when running stand alone. It warns in the manual that its not intended for long term battery use so I guess the battery bars would drop as the battery is used up?

[adsk]

I'm getting some strange readings on mine. When I turn on the kettle it indicates an uptick of 6kw. This is double what a kettle would draw. Is anyone else having this issue?

[saaby93]

adsk said:

I'm getting some strange readings on mine. When I turn on the kettle it indicates an uptick of 6kw. This is double what a kettle would draw. Is anyone else having this issue?

Funny you should say that.
Yesterday it was working fine and showed an uptick of 3kW
Following on from the seemingly run out of power in the sensor overnight, it now upticks by 6kW
It also seemed to be running 1kW high earlier so I switched off the whole house ( unit goes to zero) switched house on and the extra 1kW disappeared

[saaby93]

Trying to find 'calibrate' found more about battery issue in the comments
https://littlegreenblog.com/green-technology/energ...
Battery voltage now 3.8V
If its going to read double the power values - its a wasted £6.39

Edited by saaby93 on Friday 9th November 23:34

[megaphone]

saaby93 said:

megaphone said:

The battery indicator on the display is showing 3 bars after a week of use, not sure if that is the display batteries or the transmitter battery.

I'm pretty sure that's the state of the battery in the display. It disapperas when I plug the unit into a standard usb phone charger
All 3 bars are showing in the battery symbol when running stand alone. It warns in the manual that its not intended for long term battery use so I guess the battery bars would drop as the battery is used up?

Thanks, am going to try a USB supply and see what happens.

[megaphone]

Thought I'd try a 'dead house' and see exactly what I'm using when stuff is in standby.

Switched everything off and got a zero reading which was reassuring.

Alarm and boiler on in 'standby'. Still got a zero reading, so I doubt the accuracy or sensitivity of the Onzo.

SkyHD box, BT Vision and Apple TV on in standby, 36 Watts.

BB router, Wifi AP, HDD Back-up. 72 Watts

Computer and printer in standby, 92 Watts.

CCTV, 101 Watts

I've noticed the reading does fluctuate a bit but hovers around 95-110 Watts when everything is in standby. Would like to reduce this a bit but without actually switching stuff off I don't think I can.

[TonyRPH]

megaphone said:

<snip>

Alarm and boiler on in 'standby'. Still got a zero reading, so I doubt the accuracy or sensitivity of the Onzo.

<snip>

All the alarm will be doing is powering the LCD display on the control panel (micro amps for that) and trickle charging the battery - less than 50mA probably.

The boiler in standby? Probably also a few mA to power the control panel.

Add those two together, and it's likely that the Onzo cannot even resolve (or display) such low currents.

I've compared my Onzo with a proper AC clamp meter, and it compares quite favourably.

However, measuring AC current is a bit of a science, as each item will have a different power factor, which will also influence the apparent current drawn.

It's not as simple as measuring DC current.

[Scrump]

Today I noticed that the reading on the Onzo was fluctuating a lot and sometimes went to zero even though I had the coffee machine on. Wondering what was wrong with the sensor, I realised this is the first opportunity I have had to look at the readings during daylight.

As I have solar panels and it is cloudy day the output from the panels is fluctuating and causing the big changes in power drawn from the grid.

I now have the Onzo unit sat next to the display unit from the solar install and can see how as one reading goes down the other goes up.

[saaby93]

Can anyone try the kettle test?
Depending on kettle it should go up 2-3kW not 6kW

[Mr Pointy]

saaby93 said:

Can anyone try the kettle test?
Depending on kettle it should go up 2-3kW not 6kW

Yes mine shows about 2400W

[Scrump]

Mr Pointy said:

Yes mine shows about 2400W

Me too.
I also tested with a few large light fittings and the reading changed by the same amount as the bulb wattage (or near enough).

[saaby93]

Ive got it measuring properly again by putting the paper part of a fruit club biscuit wrapper between the two halves of the case that make a clamp over the red wire
You can get a packet of 6 for £1 at tesco.
So thats £7.39 now

Did anyone else peel off the clear plastic covering over the metal bits inside the two halves of the sensor case?

Edited by saaby93 on Saturday 10th November 14:53

[Scrump]

saaby93 said:

Did anyone else peel off the clear plastic covering over the metal bits inside the two halves of the sensor case?

Edited by saaby93 on Saturday 10th November 14:53

I did. Mine still seems to be reading correctly.

[saaby93]

Scrump said:

saaby93 said:

Did anyone else peel off the clear plastic covering over the metal bits inside the two halves of the sensor case?

I did. Mine still seems to be reading correctly.

the manual says to remove them too
https://www.manualslib.com/manual/932716/Southern-...
when I first ran it they were still there
I remembered I removed them on day 2

Maybe it's remembered somehow