Need help

[Yen]

Happy new year to all. I have a 6 panel solar system that is connected to the grid line through 6 individual micro invertors. Each micro invertor produces 0.6 Amps at 240 acV and has its own LED monitor lights (green and yellow), but I want to be able to measure the ac current passing into the grid from each panel. This is to make sure that all the panels are producing at full capacity on the ac side at any one time. Can someone suggest a less expensive system? One that is non invasive if possible. I have an analog AVO meter which I use for antic radio repairs.

Yen

[jflorey2]

Happy new year to all. I have a 6 panel solar system that is connected to the grid line through 6 individual micro invertors. Each micro invertor produces 0.6 Amps at 240 acV and has its own LED monitor lights (green and yellow), but I want to be able to measure the ac current passing into the grid from each panel. This is to make sure that all the panels are producing at full capacity on the ac side at any one time. Can someone suggest a less expensive system? One that is non invasive if possible.

If individual conductors are accessible - an AC clamp meter. They are cheap and easy to use.

If they are not accessible (i.e. it's an Enphase system or equivalent) - then use a DC clamp meter on the DC leads to the panel. That will give you a rough measure of power being delivered to the inverter. They are more expensive but not too bad ($120 or so)

[Yen]

Thanks jflorey2. In my mind all AC clamp meters are expensive especially on low current . Can you suggest one that is not and where I can find it.

[inetdog]

Thanks jflorey2. In my mind all AC clamp meters are expensive especially on low current . Can you suggest one that is not and where I can find it.

If the precision of a low amp range is a problem for you, just run the AC through a ten turn coil of wire and clamp the ammeter through the center of that coil. All of your readings willl be ten times the actual current. (Note that doing this while staying compliant with the electrical code may involve some work.)

[jflorey2]

Thanks jflorey2. In my mind all AC clamp meters are expensive especially on low current . Can you suggest one that is not and where I can find it.

Home Depot has a clamp on meter for $43. It's called the "Auto Ranging 600 Amp AC Clamp Meter." Good down to .1 amp AC, so that would be a resolution of 24 watts - which should be sufficient for seeing if the inverter is running.

[solarix]

Amps are always a troublesome thing to measure. Get a "Kill-o-Watt" meter (about $35 at home depot) and just adapt your wiring to insert it into the current flow. Will nicely measure amps, watts, even kWh.

[dennis461]

Thanks jflorey2. In my mind all AC clamp meters are expensive especially on low current . Can you suggest one that is not and where I can find it.

You can find some small current transformers on ebay for around $2.00 each.
However, you need to be able to build some sort of junction box such that each hot conductor for the 6 inverters, passes through it.

The CT outputs can then be hard-wired to a suitable resistor (ohms and power rating) depending on the CT ratio and your 0.6 amps.
Then measure voltage drop across resistor,

This may be a bit more invasive than you intended.
But, I suspect right now you do not have individual conductors available.

My plan above allows you to measure quickly each of the outputs.
If you are able to spend more time taking readings, and do not want a permanent solution, take a look at this.
http://www.ebay.com/itm/25A-SCT-013-...UAAOSwI~VTx0KJ

[Yen]

Thanks solarix. Any method is worth trying.

Yen

[Yen]

This message is for solarix. The Kill-A-Watt electric monitor is not available here in Canada. I got on line with US Home Depot and found that I have to hot wire the AC end of each micro invertor which ends up with problems with the electrical code. I have 6 micro invertors in the system. Any other suggestions?

[Yen]

Thanks Dennis461. I shall add your suggestion to my experiment. Shall keep on trying until a reasonable solution is found.

[karrak]

I you want a cheap 100A AC/DC clamp meter with a maximum resolution of 1mA I would recommend the Uni-T UT210E. The build is a little flimsy and I wouldn't use it for high voltage work but it works well.

Simon

Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
BMS - Homemade Battery logger
Latronics 4kW Inverter, homemade MPPT controller

[jflorey2]

This message is for solarix. The Kill-A-Watt electric monitor is not available here in Canada. I got on line with US Home Depot and found that I have to hot wire the AC end of each micro invertor which ends up with problems with the electrical code. I have 6 micro invertors in the system. Any other suggestions?

Code shouldn't be an issue if you want to do this to just test the inverters to make sure they are producing. I once built a simple "cheater" cord to test Enphase inverters this way; it plugged between the cable and the inverter and allowed you to measure current/voltage directly.

[Yen]

Simon. Uni-T UT210E. Is Uni-T the name of the manufacturer? I guess I can find one in Ebay. Voltages in my system are 24Vdc from the solar panels and 240 acV, 0.6 Amps from each micro invertor.

[Yen]

jflorey2. Sounds interesting. Any chance you can send me a diagram/schematic of what you did? Email address is limyenheng@shaw.ca

[karrak]

Simon. Uni-T UT210E. Is Uni-T the name of the manufacturer? I guess I can find one in Ebay. Voltages in my system are 24Vdc from the solar panels and 240 acV, 0.6 Amps from each micro invertor.

Uni-T is the brand name. Just do a Google search "Uni-t 210E"

Simon

Off grid 24V system, 6x190W Solar Panels, 32x90ah Winston LiFeYPO4 batteries installed April 2013
BMS - Homemade Battery logger
Latronics 4kW Inverter, homemade MPPT controller