A quick question about Owls

Usky

Since I can't easily get at my solar pv inverter to take readings I decided to invest in an Owl Energy Monitor; I opted for the wireless Owl +USB as it's the one Owl recommend for use with solar pv systems. Here's the thing though, the wiring diagram shows the monitor (Generation CT) attached between the inverter and the AC isolator (see below).
When I hooked my device up the monitor refused to register any activity at all so I moved the sensor to measure consumption just to test whether the monitor was working properly, which is was.

I tried connecting the sensor between the generation meter and the junction box and got generation readings that looked reasonable; the cables fitted by the installers are much more heavily insulated prior to the generation meter and I'm assuming the Owl sensor can't see through them.

So my question is: does anyone know whether connecting the sensor after the generation meter is giving me accurate readings, or do I need get a 'sparks' in to connect the sensor to the cable from the inverter to the AC isolator? Life is never straightforward is it? :huh:

TailSpin_2

I couldn't tell you exactly, but I can't see much wrong with what you've done already.

it's not going to help you, but I have a solo geo PV remote monitor and it's brilliant. It's really accurate on both instantaneous production and over periods of time. You can take the card out and stick it in your computer for your records.

Highly Recc if anyone is thinking of a remote meter.

grahamc2003

You'll be getting the same power in both locations, so theroetically the owl can go in both. Looks like due to shielding or interference, or possibly wiring configuraton (i.e. not getting at the single live wire), then in practice it doesn't work in one of the places.

You'll never get an 'accuarte' reading from the owl - they're pretty basic devices made just to give an indication of what's being used. Iirc, the specs say readings above 200W are +-5% (so an actual 4kW flow could read anywhere between 3.8kW and 4.2kW) and below 200W the accuracy is unspecified (i.e. it really means nothing when you see a reading below 200W - hence why you get some confused users asking why their standby TV is 75W when it's supposed to be 1W - you can't simply read off values off the owl and assume they're true!.

If you have the documentation of your owl available, perhaps you could post the actual accuracy specs just to see if I am remembering them correctly.

Usky

TailSpin wrote: »

I couldn't tell you exactly, but I can't see much wrong with what you've done already.

it's not going to help you, but I have a solo geo PV remote monitor and it's brilliant. It's really accurate on both instantaneous production and over periods of time. You can take the card out and stick it in your computer for your records.

Highly Recc if anyone is thinking of a remote meter.

Thanks for that TailSpin - I can't see what difference it makes either, but then I'm no sparks so am only really guessing. I've emailed Owl and will post their response here, assuming I get one of course.

As it goes the Owl monitor is wireless up to 30m so you can take the receiver with you wherever you are in the house and stores history up to 12 months. It also comes with a USB connector so can be plugged into a computer to download readings. The only drawback I've found so far is the software being Windows dependent and since I'm a Linux user I'll have to install third-party software to read it, which is a bit of a pain. Owl do say they're considering offering both Linux and Mac versions of the software if the demand is there, so hopefully in the future I'll be able to connect direct.

Just been looking at the Geo Solo on the web and it does look like the dog's wotsits... wish I seen that first.

don0301

If you want it to "read" generation, it can go on the cable anywhere between the inverter and the generation meter.

It must go on only the live wire or the return wire, if you have it clamped over both ie the whole cable it will read nothing, cos the 2 currents cancel each other.

the error specs for owl are:

<1A not specified
1<>3A with in 10%
3<>71A with in 5%

Fruit_and_Nut_Case

Usky wrote: »

...the cables fitted by the installers are much more heavily insulated prior to the generation meter and I'm assuming the Owl sensor can't see through them.

The insulating layer over the cable is just plastic so should have no bearing on the matter. Make sure that the clip is completely closed and that the two tips are touching otherwise it won't work properly. The clip is supposed to form a metal ring [O-shaped] around the cable; if it only forms partially [C-shaped] it's no good..

Usky

grahamc2003 wrote: »

You'll be getting the same power in both locations, so theroetically the owl can go in both. Looks like due to shielding or interference, or possibly wiring configuraton (i.e. not getting at the single live wire), then in practice it doesn't work in one of the places.

You'll never get an 'accuarte' reading from the owl - they're pretty basic devices made just to give an indication of what's being used. Iirc, the specs say readings above 200W are +-5% (so an actual 4kW flow could read anywhere between 3.8kW and 4.2kW) and below 200W the accuracy is unspecified (i.e. it really means nothing when you see a reading below 200W - hence why you get some confused users asking why their standby TV is 75W when it's supposed to be 1W - you can't simply read off values off the owl and assume they're true!.

If you have the documentation of your owl available, perhaps you could post the actual accuracy specs just to see if I am remembering them correctly.

Thanks Graham, that's helpful. I'm assuming it's a shielding issue as far as the sensor goes since the cable from the inverter down appears to be mighty heavy compared to everything else in the electrical system.

I take your point about the accuracy of the Owl and I guess used the wrong term in my original post. What I'd really meant to ask was whether the readings would be identical with the sensor attached before the AC isolator and after the generation meter.

With regards specs for the Owl CM160: they're not given in the very basic instructions that come with the monitor or in the 'User Guide' that I've just downloaded from Owl's web... looks as though I can't help to refresh your memory I'm afraid.

Usky

don0301 wrote: »

If you want it to "read" generation, it can go on the cable anywhere between the inverter and the generation meter.

It must go on only the live wire or the return wire, if you have it clamped over both ie the whole cable it will read nothing, cos the 2 currents cancel each other.

the error specs for owl are:

<1A not specified
1<>3A with in 10%
3<>71A with in 5%

Damn that's a pain... I'd have to strip the cable to get at the individual cores... not sure that's a good idea really.

Usky

Fruit_and_Nut_Case wrote: »

The insulating layer over the cable is just plastic so should have no bearing on the matter. Make sure that the clip is completely closed and that the two tips are touching otherwise it won't work properly. The clip is supposed to form a metal ring [O-shaped] around the cable; if it only forms partially [C-shaped] it's no good..

Yes I'd assumed as much, but no matter how I attach the sensor on the cable prior to the generation meter I can't get a reading. Don0301 has offered a probable explanation why that may be.

don0301

you don't have to strip all the plastic away, it's a magnet!


you just need it only clamping over one of the 2 wires


when set up it will look something like this

grahamc2003

Usky wrote: »

Thanks Graham, that's helpful. I'm assuming it's a shielding issue as far as the sensor goes since the cable from the inverter down appears to be mighty heavy compared to everything else in the electrical system.

.

I don't see why the ac out from the inverter should be a meaty cable at all.

But the dc in will be pretty thick to carry 4kW at 20 or 30V

Sure you're not clamping the owl on the dc input rather than the ac output?