watt diference

[Ervin R Dilly]

I am having a watt problem,have 2 strings of 12/230w panels connected to the 4.2 inverter using vin 1 and 2 and each string .Here is my readings at 1430 hrs,clear and sunny.(Vin 1,412V,3.0A.Pin 1 150 watt.)( Vin2 398V,2.8A pin 2 1133W.)This difference is a daily thing and am wondering if this is in the panels or something other.Dont know where to start checking.Thanks for any help

[Dave Turpin]

Something is awry with the readings.

1412v at 3A = 4236W and 398V at 2.8A = 1114.4W.

The second set of readings makes sense. You are getting about 41% of rated output.

The first string is not making sense. The voltage is too high. No inverter in existance could take that much, for one thing. Probably it is more like 400V. Maybe it is actually reading 412V and the LCD is damaged such that the "1" in the first digit is erroniously illuminated?

If that were the case you would have 412V at 3.0A = 1236W = 45% of rated output.

[Ervin R Dilly]

You might of misread the vin1,then comes the V.Thanks for the reply

[Dave Turpin]

Ah, yes.

Then the only problem is the power reading of Vin 1 is wrong. It still leads to either a software display issue or an issue with the LCD, not the string itself. Maybe a burnt-out digit, and it is actually reading 1150W?

If that is the case I would watch the power as the sun starts to go down. You should see the power level go from 150-> 0 then jump to 900-ish and drop again. If that is it, just replace the faulty LCD screen.

[Ervin R Dilly]

Just went and checked the pin 1, 32W and pin2, 72W sun is ready to go down.Both were steady on there reading with maybe a little varience.Also right after I purchased this (less than a year ago) my backlight went out so I have to read this with a light as the unit is in my garage.Dont know if this also effected the LCD or not.

[Rob Beckers]

Ervin, if you call 1-877-261-1374 (Power-One's RMA phone number) they'll fix the backlight (likely they'll send you another inverter and you return yours in the box the new one comes in).

I regularly see a difference between inputs of the inverter, despite the same string length and panels (and orientation etc.). There may be a couple of reasons for this: First, what you're seeing is a 1.5% difference in Power. The sensors that read voltage and current are not that precise; Power-One doesn't give numbers though you can assume they are likely around +/-3% on the outside, which leads to errors that can even exceed 3% for power. Another possibility is that there's a small temperature difference between sections of panels. Those higher up on a roof could be a couple of degrees warmer on average vs. the bottom ones. Then there's variability between the panels, which may cause the MPPT tracker to run at a slightly different point.

As for the values at dusk, I wouldn't read too much into that. These are very low light levels where a tiny difference in light leads to a large difference (in % variation) of the power output. On top of that the light is changing, so the MPPT tracker has to constantly adjust.

In short, 1.5% in power difference between inputs is IMO normal and nothing to worry about.

-RoB-

[Ervin R Dilly]

Thanks Rob,will call the # and see what they say.Will keep you posted.

[Cor van Houtum]

just change the strings on the inputs
see if the problem goes with the string , or stay's with the inverter

or replace battery

[Ervin R Dilly]

Thanks,did that yesterday by the advise of the company,now waiting for some sun to see if it is the inverter.Didnt want to do to much without the replies from the maker.Now they say I am on hold till the enginerrs look the problem over.Seems like the 2 readings are close until I get to the 1000 reading and then I think it drops the 1.Will wait for the sun and see.

[Cor van Houtum]

I mean the smal 3032 battery that is insite the inverter
When it is empty it does strange things
also daily power is then wrong
it adds the daily power from the days together where the battery was empty
maybe other readings can do strange things to ?

[Rob Beckers]

It will tell you when the battery is empty (the little button-shaped battery that runs the clock in the inverter).

[Ervin R Dilly]

Understand this according to the directions,a symble will show up on the screen.Still waiting for a reply from the enginers.

[Ervin R Dilly]

Got a good sun yesterday and yes I suspect the reading is been damaged.Here is what I got,Pin#1, 1211W, Vin#1 382V,3.2A. Pin#2 213 W,Vin #2 404V, 0.5 A,So looks like the trouble is in the readings.This is with the lines reversed.

[Dave Turpin]

I would just write a "1" on a Post-it, put it in place on the LCD and call it good.;)

[Ervin R Dilly]

What do I do if it is only 600,duh

[Ervin R Dilly]

Good news,got the unit replaced on the 26th and Got a reading of 1005 watts(cloudy)So that proves it is working okay.It was a reconditioned unit but as long as it works,all is fine.Great company as they stand behind there products.:::amazed: