Positive voltage from PV reads -18v when connected to charge controller??

[aaronfro]

Quick question:

I have a Meanwell tn-1500-112 solar inverter/charge controller
and when I tested the pos/neg leads coming from my panel... they read +18v
I then connected to wires to the solar DC input of the inverter
Places my alligator clips on the wires and my multimeter reads -18v
Does this sound right??
The flow of electrons is reversed when connected to the charge controller??
I'm sure my wires are all pos to pos... neg to neg... no crossing
Any ideas on why this is??

Thanks in advance!

-Aaron

[Sunking]

No polarity does not change. Assuming they are standard battery panels you should read about 22 volts open circuit. When connected to the controller and batteries taking charge will depend on what type of controller you have. If MPPT should be around 17 to 18 volts. If PWM about 1 volt higher than the battery.

[aaronfro]

A good friend of mine (who's an electrician)... just told me earlier that when sampling the current in parallel... the polarity will "reverse". It was very overcast and I was getting +18v from the panel.... so I expect it to go even higher when sunny. I'm still trying to visualize the flow of electrons and WHY it would "reverse" as such. I have a Meanwell tn-1500 inverter/charge controller... and if the PV input wires were reversed it would recognize.

[Mike90250]

A good friend of mine (who's an electrician)... just told me earlier that when sampling the current in parallel... the polarity will "reverse". ....

Your good friend is a great joker. Buy him a beer.

Nowhere in any PV system, does the polarity of anything magically reverse.

[Sunking]

A good friend of mine (who's an electrician)... just told me earlier that when sampling the current in parallel....

His license should be revoked. Do not listen to him, he does not know what he is talking about.

[SunEagle]

Your good friend is a great joker. Buy him a beer.

Nowhere in any PV system, does the polarity of anything magically reverse.

Maybe he was thinking about the Earth's magnetic field. It reverses polarity every once in a great while.

[aaronfro]

Ok I'm not trying to get y'all too excited.

I have the manual for the inverter... that I got from a friend.
The manual... and all the distributors for Meanwell tn-1500-122
Don't disclose the exact pin info on the PV DC solar input for the inverter
If you look at the manual... you will see that the pos and neg input on the inverter is labeled
And the solar input is on top... it's a 6 pin molex connector
When I connect the pos of the PV panel to the pos input on the inverter (and the neg respectively)
The wires then read -18v
Either the inverter has the solar input polarities reversed (as labeled)
Or something else is going on that I don't quite understand

I didn't want to hook up the panel in reverse because of obvious reasons
And I didn't get a "reversed polarity" warning beep or light

I'm curious to know if anyone with an offgrid system
When tapping into the pos and neg inputs of PV into charge controller/inverter
Have experienced the same thing??

If Meanwell (Taiwan) has the polarity of the input different as labeled... I wouldn't be suprised

[Mike90250]

I have wired up many inverters, charge controllers and batteries.

You have a miss-wire somewhere if you are seeing polarity changes.

All of mine, use individual wires to each terminal. Wire them + to a + and - to a -, and it's always worked right for me.

Never worked with Meanwell. Maybe they mean well, but it just doesn't work out ?

[Shockah]

I have wired up many inverters, charge controllers and batteries.

You have a miss-wire somewhere if you are seeing polarity changes.

All of mine, use individual wires to each terminal. Wire them + to a + and - to a -, and it's always worked right for me.

Never worked with Meanwell. Maybe they mean well, but it just doesn't work out ?

[Wy_White_Wolf]

I have to ask. Why are you wiring the panel to the back of the inverter?

It should be wired to a charge controller then to the battery.

WWW

[aaronfro]

It's a solar inverter (has a charge controller built in)

[Legacy]

According to the spec sheet from the companies site , the positive 3 terminals are on the side
of the plug with the rounded corners an the negative on the side with the square corners.

I take it you have your batteries hooked up to the DC input before you hook up the solar panels
to the six pin plug?

[Wy_White_Wolf]

It's a solar inverter (has a charge controller built in)

Never seen one like that. Mind sharing the make and model number.

WWW