Need Advice

[rlwilson730]

I have 8 100 12v panels, all the same from Renogy, 4 12v 100aph Gell Battery's, 60amp MTTP. 2000W 24V Inverter. I'm going to run the battery's 24v, but the panels is were I some what get lost, running the panels in series. What do I expect to get at series? Is 8 panels enough or to much..
Thanks for any help...

 

[John Frum]

Please post a picture of the information placard on the back of one of the panels.
Also please post a link to your solar charge controller.
That way someone can work out the best configuration of your panels.

 

[snoobler]

With MPPT, config doesn't matter a lot as long as you have sufficient voltage and don't go over PV input voltage.

100W 12V panels are typically about 18-19Vmp and 21-22Voc. You could go 4S2P. That config would be fine with 12V or 24V provided your MPPT can handle Voc of 100V or more.

800W/12V = 67A. MPPT is limited to 60A.

60A is ideal for a 400Ah battery bank @ 12V, so you're pretty much there with 4X 12V/100Ah batteries. You'd get more out of your panels at 24V since:

800W/24V = 33A

The 24V will require less current from the MPPT.

With batteries in 2S2P/24V, you'd have 200Ah, and 33A is a good charge current for 200Ah.

 

[rlwilson730]

Please post a picture of the information placard on the back of one of the panels.
Also please post a link to your solar charge controller.
That way someone can work out the best configuration of your panels.

Thank I will do that, they all are from Renogy products. But I will get that picture ASAP... Thanks again

 

[rlwilson730]

With MPPT, config doesn't matter a lot as long as you have sufficient voltage and don't go over PV input voltage.

100W 12V panels are typically about 18-19Vmp and 21-22Voc. You could go 4S2P. That config would be fine with 12V or 24V provided your MPPT can handle Voc of 100V or more.

800W/12V = 67A. MPPT is limited to 60A.

60A is ideal for a 400Ah battery bank @ 12V, so you're pretty much there with 4X 12V/100Ah batteries. You'd get more out of your panels at 24V since:

800W/24V = 33A

The 24V will require less current from the MPPT.

With batteries in 2S2P/24V, you'd have 200Ah, and 33A is a good charge current for 200Ah.

So run the panels +-, +-, +-, so on take to + from the first panels and the - from the last panel and hook to the MTTP?

 

[rlwilson730]

With MPPT, config doesn't matter a lot as long as you have sufficient voltage and don't go over PV input voltage.

100W 12V panels are typically about 18-19Vmp and 21-22Voc. You could go 4S2P. That config would be fine with 12V or 24V provided your MPPT can handle Voc of 100V or more.

800W/12V = 67A. MPPT is limited to 60A.

60A is ideal for a 400Ah battery bank @ 12V, so you're pretty much there with 4X 12V/100Ah batteries. You'd get more out of your panels at 24V since:

800W/24V = 33A

The 24V will require less current from the MPPT.

With batteries in 2S2P/24V, you'd have 200Ah, and 33A is a good charge current for 200Ah.

So run the panels +-, +-, +-, so on take to + from the first panels and the - from the last panel and hook to the MTTP?

 

[Dzl]

I have 8 100 12v panels, all the same from Renogy, 4 12v 100aph Gell Battery's, 60amp MTTP. 2000W 24V Inverter. I'm going to run the battery's 24v, but the panels is were I some what get lost, running the panels in series. What do I expect to get at series? Is 8 panels enough or to much..
Thanks for any help...

Your MPPT charge controller will have a maximum input voltage (Volts) and a maximum input current (Amps) and possibly a maximum input power (Watts). The most important of these is the maximum input voltage. You need to make sure that you do not exceed this.

Your panels will have a specification called Overcurrent Voltage (Voc), to get a conservative ballpark estimate of how many panels you can connect in series multiply:

Voc x # of panels in series x 1.25

For example if the SCC max input voltage is 150V and panel Voc is 22.5V and you have 8 panels and a 25v battery bank your choices would be
8 in parallel, 2s4p, 4s2p, 8 in series. However if you do the math you will see 8 in series would exceed the voltage limit and 8 in parallel would be too low. The highest number of panels in series you could use (with 8 panels) is 4 and the lowest is 2 in series (4S2P or 2S4P)

22.5V x 4 x 1.25 = 112.5V
22.5V x 2 x 1.25 = 56V

 

[rlwilson730]

Your MPPT charge controller will have a maximum input voltage (Volts) and a maximum input current (Amps) and possibly a maximum input power (Watts). The most important of these is the maximum input voltage. You need to make sure that you do not exceed this.

Your panels will have a specification called Overcurrent Voltage (Voc), to get a conservative ballpark estimate of how many panels you can connect in series multiply:

Voc x # of panels in series x 1.25

For example if the SCC max input voltage is 150V and panel Voc is 22.5V and you have 8 panels your choices would be
8 in parallel, 2s4p, 4s2p, 8 in series. However if you do the math you will see 8 in series would exceed the voltage limit. The highest number of panels in series you could use (with 8 panels) is 4:

22.5V x 4 x 1.25 = 112.5V

Thank you

 

[Hedges]

Thank I will do that, they all are from Renogy products. But I will get that picture ASAP... Thanks again

Still waiting for picture of labels. Or link to data sheets.
Numbers matter, and we can double-check your math and which values you plugged in.

 

[rlwilson730]

Still waiting for picture of labels. Or link to data sheets.
Numbers matter, and we can double-check your math and which values you plugged in.

I drive for a living, So Monday is when I can put the pictures up,
Thanks

 

[rlwilson730]

Still waiting for picture of labels. Or link to data sheets.
Numbers matter, and we can double-check your math and which values you plugged in.

 

[rlwilson730]

I found this set up with 8 panels, but I was going to use 4- 12v battery and run them in series to get 24v and the parallel the two sets
to get the 200aph

 

[Hedges]

PV panel sticker shows 21.6 Voc and temperature coefficient of -0.33%/degree C

How about the charge controller data sheet?

What is the record coldest temperature for your location (or what is your zip code)?

 

[rlwilson730]

PV panel sticker shows 21.6 Voc and temperature coefficient of -0.33%/degree C

How about the charge controller data sheet?

What is the record coldest temperature for your location (or what is your zip code)?

Well I thought I had a MTTP 60, but its a 40i I live in North Texas 76052 zip... Thanks for your help

Rover Li 40 Amp MPPT Solar Charge Controller

Buy Renogy's Rover 40 Amp MPPT Solar Charge Controller. Pair it with our BT-1 the BT app through bluetooth and you can monitor and adjust your solar system directly from your phone. Our Rover also comes covered in a die-cast aluminum exterior. This allows for safe heat dissipation along with...

www.renogy.com

 

[Hedges]

100V max input for charge controller.
40A output.

Dallas, record cold -19 degrees C

Dallas TX Lowest Temperature Each Year - Current Results

List of the lowest temperature and coldest day for each year in Dallas.

www.currentresults.com

-19 - 25 (ambient) = -44 degrees
-0.33% x -44 = +14.5% (increase in Voc for cold.)
21.06V x (1 + 0.145) = 24.12Voc max.

100V/24.12V = 4 panels max in series

You can connect the 100W panels 4s2p
This might produce 800W under best conditions, usually less due to heat or less light.
800W/40A = 20V minimum to deliver full power.

24V battery is a good fit with these panels wired 4s2p (as Snoobler figured)
You could even put a 3rd string of 100W panels, more likely to clip output some of the time when battery below 30V.

 

[rlwilson730]

This is my set up 8 panels 100w
This how I hooked the panels up, I'm getting 80v