How to measure output of grid tie Micro Inverter

[Voltage Spike]

I have a Y&H 120 watt grid tie micro inverter that's installed and working. I tried to put my watt meter inline to see how much output I am actually getting but it just says overload. It's basically going the wrong direction. Maybe I can use my multimeter to measure ac amps? It would just be nice to see how much power it is producing periodically.

 

[markansas]

I have a Y&H 120 watt grid tie micro inverter that's installed and working. I tried to put my watt meter inline to see how much output I am actually getting but it just says overload. It's basically going the wrong direction. Maybe I can use my multimeter to measure ac amps? It would just be nice to see how much power it is producing periodically.

i use a kill a watt meter and read the line watts with out the microinverter . and then again with the microinverter. it easy

 

[Voltage Spike]

Thank you. What makes the Kill a Watt any different than this? I don't really want to spend any more because my ROI is about 2 years so far.

 

[MisterSandals]

i use a kill a watt meter and read the line watts with out the microinverter

How does the micro inverter function without sensing a grid? I do not see how a watt meter of this type would work.

My suggestion would be to use a clamp meter and measure the amps coming out of the micro inverter. I suspect that an individual line is not exposed so you may have to create an adapter to insert inline where you could clamp L1 and L2 wires individually.

 

[markansas]

i use a kill a watt meter and read the line watts with out the microinverter . and then again with the microinverter. it easy

Thank you. What makes the Kill a Watt any different than this? I don't really want to spend any more because my ROI is about 2 years so far. View attachment 75498

its what i use .. how do you have your microinverters hooked up a cut off ext cord or hardwired into the house? and yes the man below using a clamp meter is very correct. myself i do not have one. if you have a cord with multi outputs like this. i pluged my heater in to this and then into the killawatt meter.. measured . then my microinverters are ran into a ext cord . and i plug it into the multi output. it combined the two circuits and then read the meter again. on a good day 6 microinverters make just about 1k watt output for me. one day i will buy a clamp meter also. the multi output gets pluged into the kill a watt meter.

 

[Voltage Spike]

How does the micro inverter function without sensing a grid? I do not see how a watt meter of this type would work.

My suggestion would be to use a clamp meter and measure the amps coming out of the micro inverter. I suspect that an individual line is not exposed so you may have to create an adapter to insert inline where you could clamp L1 and L2 wires individually.

Thanks for the reply! The Micro inverter senses the grid just fine by connecting to the female end of a 50 foot extension cord to a GFI exterior plug on my house. I didn't know if the watt meter would work but wanted some way to see how many watts output of the 100 from the panels I'm actually getting inverted to ac. I know it is 92.5% Efficient. so max would be 92.5 Watts in full sun with no line loss, panel age, etc.

Can you point me to an adapter such as you are describing?

 

[Voltage Spike]

its what i use .. how do you have your microinverters hooked up a cut off ext cord or hardwired into the house? and yes the man below using a clamp meter is very correct. myself i do not have one. if you have a cord with multi outputs like this. i pluged my heater in to this and then into the killawatt meter.. measured . then my microinverters are ran into a ext cord . and i plug it into the multi output. it combined the two circuits and then read the meter again. on a good day 6 microinverters make just about 1k watt output for me. one day i will buy a clamp meter also. the multi output gets pluged into the kill a watt meter.

Thank you for this. Can't see the forest through the trees just yet but glad to know there a multiple ways to check.

 

[MisterSandals]

Can you point me to an adapter such as you are describing?

As i said, you would need to create an inline adaptor where each of the wires are exposes so you could put a clamp meter around them, individually. Think of it as a 1' extension cord with connectors (MC4?) on each end with all the wire cover removed. There is nothing special, it just provide access to individual wires for the clamp meter.

 

[MisterSandals]

but wanted some way to see how many watts output of the 100 from the panels I'm actually getting inverted to ac. I know it is 92.5% Efficient.

With this info, you could us a DC clamp meter and measure the amps coming from your panel(s) and multiply by the known micro inverter efficiency. If the amps are being pulled out of the panels, that's going to be used by your micro inverters (less heat generated in the amount of your inefficiency).

 

[markansas]

here it is in pictures.. sometime have a hard time describing ideas.
the orange cord is my micro-inverters coming in
the white cord is the heater
heater draws about 1200watts by itself with the panels added it 200 watts that is 900 watts if savings. if this helps you can you your meter for this

 

[Voltage Spike]

Very interesting. Basically you add a draw on the same ac circuit with and without the inverters power and then use the difference to correlate?

at 6 Mins, 50 seconds he uses a watt meter to measure the inverters output. I can't get that to work for me.

 

[markansas]

Very interesting. Basically you add a draw on the same ac circuit with and without the inverters power and then use the difference to correlate?

at 6 Mins, 50 seconds he uses a watt meter to measure the inverters output. I can't get that to work for me.

yes and it was easy. and my kill a watt meter also does what in that video.. that video is feeding it to the grid. and mine was offseting the high wattage of the space heater during the day. measuring it by the hour to get a curve of the wattage. . play with it those are simple and easy to use it will read watts going in and going out. if done right have fun

 

[Texas-Mark]

How does the micro inverter function without sensing a grid? I do not see how a watt meter of this type would work.

Maybe already answered, but the kill-o-watt (and similar) meters are bi-directional and will read the current/watts in either direction. They work well for small grid-tie inverters.

 

[12VoltInstalls]

They work well for small grid-tie inverters.

I was confused at the microinverter word

“Small grid tie inverter” >= guerrilla solar

In the vid is that a suicide cord?

 

[Texas-Mark]

I was confused at the microinverter word

“Small grid tie inverter” >= guerrilla solar

In the vid is that a suicide cord?

No, the grid-tied inverter outputs nothing unless plugged into the grid.

But the point was that any small grid tie can be connected to one of those meters without issue to check output.

Small system of four I was running for a while.

 

[12VoltInstalls]

any small grid tie can

Hi, Jack!
Do these require solar panel input only?
Or can I use my battery bank?

Most days are cloudy. I most often won’t fully charge by solar so I’m replacing with an adjustable 10A battery charger.
On sunny days even this time of year, however, I make excess/surplus watts that I can’t really use once the batteries are full. Like today; tons of sun, but the batteries were full.

My battery charger is powered by a long run from my friends’ barn. Since I saw this thread yesterday I’ve been thinking on this. It seems I could put way more power into his ‘grid’ than I use for the charger, and in a couple months with longer days and warmer weather I won’t even need the charger. But I could still reduce his bill even now on sunny days…I’d want to only gridfeed above 12.9 or 13V battery volts (way in excess of that on sunny days)

 

[Texas-Mark]

Do these require solar panel input only?
Or can I use my battery bank?

It depends. The stand alone grid-tie inverters come in different input panel voltage ratings (i.e. 12v, 24v). So if you connect a 12v battery bank to a 12V input grid-tie inverter it will work, but give very poor performance because the MPPT needs a higher voltage than a battery provides for optimal output. .

 

[12VoltInstalls]

give very poor performance because the MPPT needs a higher voltage than a battery provides for optimal output

That was why I asked the question!
Thanks

There’s other methods. I’ll have to think through a good low-buck solution but right now I can’t think of one I like. Maybe a low trigger / high switched voltage control relay to cut out the input? I also have two unused 100W panels still in the box.

 

[12VoltInstalls]

The stand alone grid-tie inverters come in different input panel voltage ratings

I’ve got two unused panels (attachment) that I could use with 600W version but figuring for -20*F that puts me at almost 25V.
The unit header states 20-24VOC so am I safe to assume their 24VOC nomenclature accommodates that? Then their ‘about’ field states, “Solar Grid Tie Inverter - Fit For 12V Solar Panel 21V(Voc) 18V (Vmp)” but my VOC is 21.45 which is more than 21 but less than 24…

My assumption is everything will be fine but in reading the ambiguity is annoying.

A second method would be a manual A/off/B switch and use one string of my 800W 4S2P but I can’t because each string is 88VOC(nominal). So the ‘spare’ panels it will be.
I briefly searched but couldn’t find another guerrilla/cheapo gridtie inverter with higher VOC - or in the description of one identical but different ’brand’ unit it mentioned battery charging and “low battery voltage”but of course these do not charge batteries… >rolleyes<

 

[markansas]

I’ve got two unused panels (attachment) that I could use with 600W version but figuring for -20*F that puts me at almost 25V.
The unit header states 20-24VOC so am I safe to assume their 24VOC nomenclature accommodates that? Then their ‘about’ field states, “Solar Grid Tie Inverter - Fit For 12V Solar Panel 21V(Voc) 18V (Vmp)” but my VOC is 21.45 which is more than 21 but less than 24…

My assumption is everything will be fine but in reading the ambiguity is annoying.

A second method would be a manual A/off/B switch and use one string of my 800W 4S2P but I can’t because each string is 88VOC(nominal). So the ‘spare’ panels it will be.
I briefly searched but couldn’t find another guerrilla/cheapo gridtie inverter with higher VOC - or in the description of one identical but different ’brand’ unit it mentioned battery charging and “low battery voltage”but of course these do not charge batteries… >rolleyes<

i used .. and use still. they are not ul 1741 approved .. and they do great