220 Volt Panels. How to convert to 110 AC?

[Chevyjim]

Hi, I am new at configuring solar panels and could use some suggestions. I came across some 220 Volt solar panels at warehouse auction at a good price and would like to experiment with them. They are made by First Solar and have an open circuit voltage of 220 Volts and short circuit current of 2.55 amps. What options do I have to convert these to run something on 110 AC? Seems like the most popular panels have a much lower output voltage like 12 V DC.

 

[rmaddy]

Get an MPPT charge controller that can handle about 250-275V depending on your coldest temperatures, put a bunch of the panels in parallel, and hookup to a battery and inverter.

How many watts are the panels? How many do you have? That will determine what battery voltage you need.

 

[robby]

The Solar panel seem to be the FS-6440 or FS-6440A
You need an MPPT charge controller that can handle at least 250V and then you would put them in parallel with each other, each one adding 2.55 amps to the total. The total Amps cannot exceed what the charge controller can handle.
If you have the money this charge controller would work.
Victron 250V/60A
Probably overkill for your needs but it's a solid product.

After that you need some batteries for the charge controller to charge and lastly those batteries are connected to an Inverter that changes the batteries output to 120V AC.

 

[Chevyjim]

Thanks for the replies! They are model FS- 6640A and have a rating of 440 watts. I have 20 of these. So if I understand right, the MPPT controller reduces the voltage to 12 VDC and connects to back up batteries? Then I use an inverter to go from 12 VDC to 110 AC? I am familiar with the parallel amperage and wattage parts of the equation.

 

[rmaddy]

20 440W panels is 8800W. You do not want a 12V system with that many watts. You want a 48V system. But otherwise the general idea is correct. The SCC converts the panel power into battery voltage. Then the inverter converts battery power into 110VAC.

You would need 3 of the suggested Victron 250/60 charge controllers to handle 8800W at 48V.

This level of power is beyond my experience. You may want to look over in the residential solar sub-forum of this site to get info on systems that can handle that much solar.

 

[robby]

Thanks for the replies! They are model FS- 6640A and have a rating of 440 watts. I have 20 of these. So if I understand right, the MPPT controller reduces the voltage to 12 VDC and connects to back up batteries? Then I use an inverter to go from 12 VDC to 110 AC? I am familiar with the parallel amperage and wattage parts of the equation.

TWENTY!!
I thought you just picked up a few panels
Are you planning to use all of them? I assume you are and to be honest with you I have Zero experience with panels that have this high of a voltage and this low amount of current. If you break them into two parallel strings of 10 and use two Victron 250/85 Charge controllers one for each string then in theory would cover all your bases. The problem is I don't know if the panels will handle 25 Amps running through them, I doubt it! I would contact First Solar and get some advice on this. The manual has some conflicting info, implying that they should be used in a string series of 7 and fed into a 1500V inverter or lower sized strings into 1000V Inverters. It says do not connect them in parallel but later down says you can for battery charging. Please contact them and get some clarification or maybe someone on here with more experience can chime in.

 

[Zil]

Those panels are not compatible with a 12 or 24 volt system. Those panels are very dangerous. With your limited knowledge, you could electrocute yourself.

 

[Struc]

A couple of Growatt Inverters would work fine for 2S5P panel configuration. 440voc / 12.75A input into each.

Account Suspended

Account Suspended

There are all in one units. You can parallel 2 units and get 10kw of output. The transformer in the "kit" will turn the 240v output into 120v for you.

If you just want one unit, you could do 2s7p panel config (14 panels), and then use a charge controller with the other 6 for charging batteries.

edit: There are many YouTube videos on the SPF5000ES, so I would recommend watching those and see if it is a fit for your goals.

 

[rmaddy]

A couple of Growatt Inverters would work fine for 2S5P panel configuration. 440voc / 12.75A input into each.

What's the max input voltage on those? 450V? You do not want to put a panel with a Voc of 220V in 2S. The 440V would be over 450V at only a couple degrees below STC (25ºC/77ºF).

 

[Struc]

What's the max input voltage on those? 450V? You do not want to put a panel with a Voc of 220V in 2S. The 440V would be over 450V at only a couple degrees below STC (25ºC/77ºF).

Couple of degrees? unlikely. I don't have the spec sheets for the panels in front of me, though.

That said, depending on where he's from, you could be right. The MPP Solar 500v input would be a better fit in really cold climates.

Open Box ! PIP8048MAX 8kW- 240V Only Solar inverter 8kW -2 x 4kW 500V MPPT built in Wifi – Watts247 Wholesale

watts247.com

 

[rmaddy]

Most panels are typically -0.3%/ºC. 440V / 450V = 0.9777 which means you only need a 0.0222 (or 2.22%) drop in temperature to go from 440V to 450V. 2.22% / -0.3%/ºC = 7.4ºC drop. OK, slightly more than a couple. The panels will be over 450V at only 17.6ºC or 63.7ºF.

 

[Struc]

Most panels are typically -0.3%/ºC. 440V / 450V = 0.9777 which means you only need a 0.0222 (or 2.22%) drop in temperature to go from 440V to 450V. 2.22% / -0.3%/ºC = 7.4ºC drop. OK, slightly more than a couple. The panels will be over 450V at only 17.6ºC or 63.7ºF.

Yeah, more than a couple, but you were right. That's not much of a window to work in. The small percentages really add up on these high voltage panels.

I looked up the spec sheet and it's -0.28%/C - so very close to your calculations.

 

[sunshine]

I came across some 220 Volt solar panels at warehouse auction at a good price and would like to experiment with them.

The spec sheet shows 2 junction boxes, + & - . A look inside, and tracing the tapes to work out if you can split the V may make them more diy.
I have never seen one of this type but with older modules splitting the V can be simple but 200v could be dangerous!!

 

[Pierre]

A couple of Growatt Inverters would work fine for 2S5P panel configuration. 440voc / 12.75A input into each.

Account Suspended

Account Suspended

There are all in one units. You can parallel 2 units and get 10kw of output. The transformer in the "kit" will turn the 240v output into 120v for you.

If you just want one unit, you could do 2s7p panel config (14 panels), and then use a charge controller with the other 6 for charging batteries.

edit: There are many YouTube videos on the SPF5000ES, so I would recommend watching those and see if it is a fit for your goals.

Your basic concept is sound and good value for money - as mentioned just make sure that your PV array does not exceed the MPPT specifications under all conditions.

 

[robby]

Most panels are typically -0.3%/ºC. 440V / 450V = 0.9777 which means you only need a 0.0222 (or 2.22%) drop in temperature to go from 440V to 450V. 2.22% / -0.3%/ºC = 7.4ºC drop. OK, slightly more than a couple. The panels will be over 450V at only 17.6ºC or 63.7ºF.

That is way to close for comfort. There are not many places that don't see 64F at certain times of the year.
I think those panels where probably bought to be used with some SMA commercial equipment. I think they are meant to be run in strings at 1KV or higher at low amperage.

 

[Chevyjim]

Thanks again for all the replies and concerns! I'm no stranger to 220 volts but am reluctant to start dealing with voltage higher than that. All the information that has been posted shows me there are many variables involved with configuring a system. I am gong to research the products that have been recommended and study the terminology that is being discussed. My main goal at first is to put maybe 2 or 3 panels in parallel if possible and eventually have the ability to produce 110 VAC at 10 amps. I want to say that I have learned more in this forum in 24 hours than I have poking around on Google for the last 4 weeks! One surprising observation I made was that these panels appear to produce around 170V even in the shade.

 

[Hedges]

Those panels are not compatible with a 12 or 24 volt system. Those panels are very dangerous. With your limited knowledge, you could electrocute yourself.

Thanks again for all the replies and concerns! I'm no stranger to 220 volts but am reluctant to start dealing with voltage higher than that. All the information that has been posted shows me there are many variables involved with configuring a system. I am gong to research the products that have been recommended and study the terminology that is being discussed. My main goal at first is to put maybe 2 or 3 panels in parallel if possible and eventually have the ability to produce 110 VAC at 10 amps. I want to say that I have learned more in this forum in 24 hours than I have poking around on Google for the last 4 weeks! One surprising observation I made was that these panels appear to produce around 170V even in the shade.

Do the panels have MC connectors?

220VDC panels are no more dangerous than 10 of my "12V" panels connected in series. I use 24 in series for 380 Vmp, 480 Voc under nominal conditions, < 600 Voc in coldest conditions.

So long as you never touch wires or screw terminals with PV panels connected (even in the shade as you have observed), not dangerous to work with.
I open the circuit with DC disconnect switch, disconnect MC cables for both (+) and (-) end of PV string, then work on the circuit.

Do you want 110VAC off-grid, or grid tie?
If grid tie (Net metering is dead! Long live net metering), all you need is a suitable grid-tie inverter. Some can be set up for "zero export" so they offset household loads, but aren't seen by utility as putting power into the grid.

If off-grid, then the 48V charge controllers and inverters (or AIO systems) recommended by others are worth considering.

With 3 or more panels (or series strings of panels) in parallel, you should have fuses for each, to protect against a short circuit getting backfed by the others.

Try to find out of the panels are subject to "PID", Potential Induced Degradation. If so, they should either be used positive grounded (all panels biased negative with respect to ground), or negative grounded (all panels biased positive), depending on how they are made. Most scc use negative grounding. Newer grid-tie inverters are ungrounded (half the panels biased each way), while many older ones are negative grounded but some can be positive grounded.

 

[Zil]

Yep. "so long as you never _" Let me hold your beer.

 

[AZdiywannabe]

Could you share where you found these, and if there are any more available? Having no luck finding these for sale in small quantities.

 

[sunshine]

Try to find out of the panels are subject to "PID", Potential Induced Degradation. If so, they should either be used positive grounded (all panels biased negative with respect to ground), or negative grounded (all panels biased positive), depending on how they are made. Most scc use negative grounding.

TIL : PID !