Combining differnt panels to the same Controller

Discussion about the FM100, FM80, and FM60 Charge Controllers

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FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

Hello People!

I have been using an underpowered system for about 10 years now.

I have 12 Kyocera KC120 panels on my container ... max i get out of them is typically 800 watts total,
according to the FlexMax 80 display. They are in 2 strings.

I want / need to add more panels.

I am looking at some used Trina TSM-340DE14A (II) panels - they are 340 watts max each. And Vmax is 48.x volts.

Someone told me when i bought all the panels and my first controller that i could put the kycera panels into 3 strings
and then add a 340 watt panel to each string and it would work .....

Do that work that way?
fcwlp
Forum Czar
Posts: 877
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Combining differnt panels to the same Controller

Post by fcwlp »

Combining 3 of the Kyocera and 1 of the Trina modules in a series string will result in the current being limited by the Kyocera module's current. In other words it is not a good strategy.

You would be better off buying 9 or 10 (depending on specs) for 3 strings of 3 or 5 strings of 2 and fully utilizing your FM80. The old Kyocera modules could be put on a different CC.
fcwlp
Forum Czar
Posts: 877
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Combining differnt panels to the same Controller

Post by fcwlp »

While it would be better to go with all Trina 340W modules and put the KC120s on a separate CC, the combination is not as bad as I first thought.

Kyocera KC120
- Vmp = 16.9Vdc
- Imp = 7.1A

Trina TSM-340DE14A
- Vmp = 38.2Vdc
- Imp = 8.9A

Three Kyocera and one Trina per string gives:
- Vmp = 3*16.9Vdc + 38.2Vdc = 88.9Vdc
- Imp = 7.1A
- Power 631W

Four strings gives 2525W
FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Re: Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

How about 4 Kycera panels and one Trina?

Four Kyocera and one Trina per string gives:
- Vmp = 4*16.9Vdc((/= 67.6Vdc + 38.2Vdc = 105.8Vdc - max
- Imp = 7.1A - max
- Power 751W - peak

does that sound correct?
fcwlp
Forum Czar
Posts: 877
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Combining differnt panels to the same Controller

Post by fcwlp »

Your math is correct.

One thing I just noticed is that you are on a 24V system, so the FM80 is limited to 2000W per spec. With your 4 Kyocera modules and 1 Trina, this will limit you to 3 strings.
FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Re: Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

Drat - I thought the FM80 could do 80 Amps!
raysun
Forum Emperor
Posts: 5623
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Combining differnt panels to the same Controller

Post by raysun »

FlyingDiscHawaii wrote: Fri Mar 06, 2020 5:27 pm Drat - I thought the FM80 could do 80 Amps!
The FM80 is rated at 80A charge current. Charging a nominal 24V battery, the rated panel power is 24V x 80A = 1920W.

If the battery were nominal 48V the rated panel power would be double - 3840W.

If the battery were nominal 12V the rated panel power would be half - 960W.

All the rated panel arrays would support 80A charging current.
pss
Forum Czar
Posts: 862
Joined: Mon Jul 24, 2017 8:40 am
My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.

Re: Combining differnt panels to the same Controller

Post by pss »

The FM 80 can handle 80 amps of current. But it is limited to an input voltage from the PV array of 150 volts. Above this voltage input can damage the charge controller components. I use 340 watt panels. You can only put 2 in series and this will produce a voltage of 80-95 depending on temperatures. I use 8 panels per a single FM60 in 2 arrays. A third array consists of 12 240 watt panels, 3 in a string on an FM60 and these three charge controllers get along better than kissing cousins at a square dance. In your case adding a third panel in series will come too close to the 150 voltage limit depending on ambient temperature. You will produce about 16-18 amps per 2 series string. If you are using a 24 volt battery bank, then you want a charge current voltage of about 30 volts (via the MPPT program of the charge controller) to be able to fully charge your system. An input voltage of 80 will work well with the charge controller's MPPT logic. 30 volts x 80 amps = 2400 watts of PV power is your limit. If you set up a 48 volt battery bank, then it would be 4800 watts of PV input on the same controller. Your old panels will not be compatible with the newer 340 watt panels on the same charge controller. The power outputs and voltages are just too different to mix to the same controller. The solution would be to locate a good used FM 60 or 80 and keep the old array on one charge controller and the second array (340 watt panels) on a second, separate charge controller and feed both of these into your battery bank. You will need to arrange the old panels in series to try and get the voltage up near 50 or higher (probably 3 or 4 in series for each string) so both charge controllers are looking a similar voltages to utilize MPPT properly.
FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Re: Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

I thought I could do up to 150 volts per string - not 50 volts.

Please explain:
raysun
Forum Emperor
Posts: 5623
Joined: Tue Jul 26, 2016 5:57 am
My RE system: Flexpower Two: (2) FXR3048A-01, (2) FM80, MATE3s, FlexNetDC
SimpliPhi 48-3.8 (6 @ 48v)
Outback IBR3 battery enclosure
REC Alpha 440W panels - 2 arrays: each of 4 strings of 2 in series
Honda EU7000is gas fuel generator

Re: Combining differnt panels to the same Controller

Post by raysun »

FlyingDiscHawaii wrote: Wed Mar 11, 2020 4:30 pm I thought I could do up to 150 volts per string - not 50 volts.

Please explain:
The absolute maximum input limit for FM80 controllers is 150V. The voltage out from a solar panel will vary with conditions. The published STC Voc of the solar panel is a static test voltage, not the "real world" voltage that can be driven higher than STC by conditions such as cold weather (not an issue in Hawaii), and cloud-edge effect (a very big issue in Hawaii). A 30% overvoltage from STC is not unexpected, so 70% of 150V is prudent, even that makes me nervous from experience.

The 24V nominal battery bank will not benefit from a very high nominal PV panel array voltage. A large delta between the two will only make the charge controller work harder. The benefit to high array voltage is the ability to use lower gauge wire to bring the PV harvest from the array. However, the cost savings in copper is not likely to offset the shorter service life of the charge controller.

I have a 48V battery, and run my arrays at approximately 90V.
FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Re: Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

Update:

I did not get those Trina panels.

Instead I got 6 of these:
SunPower® E-Series Commercial Solar Panels | E20-435-COM

https://us.sunpower.com/sites/default/f ... 6-revc.pdf

I put 2 in series and yet the FlexMax 80 charge controller displays "Voc"

Does that mean that it went over voltage?
Right now I have 3 of them hooked up thru a Midnite solar combiner box ....

the ants took over a 15 A breaker or 2 so I have to purchase some more of them.

Is there any reason why I can't put 2 of these in parallel ?
fcwlp
Forum Czar
Posts: 877
Joined: Wed Jan 22, 2020 9:40 am
My RE system: GS8048A, FM80 w/3,600W PV Fixed, FM80 w/2,700W on Zomeworks tracker, Mate3, 24 Trojan 2V L16 1100AH @ C20, Grid-Tied with Kohler 14RESA LPG Generator and MEP-803 Diesel if needed.

I install and maintain grid-tied and off-grid systems in my area and consult on solar system design/operation.
Location: 80 miles NE of Phoenix at 5500'

Re: Combining differnt panels to the same Controller

Post by fcwlp »

FlyingDiscHawaii wrote: Sun Aug 01, 2021 8:07 pm Instead I got 6 of these:
SunPower® E-Series Commercial Solar Panels | E20-435-COM
The Voc for these panels is 85.3V, so you can not put two of them in series and use a FM80 CC. Your FM80 for a 24V systems is specified to 2000W max PV input, with 6 panels you have 2,610W of PV input.

You can put the panels in parallel but you then need to be careful on your wire size coming out of the combiner. The Impp is 5.97A, so recommended five in parallel is ~30A. I would recommend a minimum of #8AWG wire from the combiner to the CCs.
pss
Forum Czar
Posts: 862
Joined: Mon Jul 24, 2017 8:40 am
My RE system: 8330 watts in three strings, Flexmax 60 x 3, Radian 8048A, GSLC load center, Mate 3S, Hub 10.3, FN-DC and 900 Amp, 48V Trojan T105-RE battery bank.

Re: Combining differnt panels to the same Controller

Post by pss »

Dear FlyingDiscHawaii:
I read your recent posts. Now, please know what I write next is for your own good. You need to stop now trying to work on your solar system. You need to hire a solar professional and pay them. This is because you can be killed by electricity, kill others, kill animals and start fires.

You started this thread and got accurate excellent advice. Despite your ability to ask more questions and look for approval of your panel purchase, you did not. Then you connected the panels incorrectly, being unable to watch a Youtube, ask a forum question or read the charge controller manual and understand what and how to do something.

Some people are good at art, auto mechanics, plumbing, doctoring, accounting, etc. Think of it like this: you are just not good at solar, yet need it to work. So please just hire someone before more equipment is either damaged or killed and maybe people too. I won't provide you any more help and I hope others on this forum agree with me.
FlyingDiscHawaii
Forum Whiz
Posts: 39
Joined: Wed Sep 02, 2015 3:27 pm
My RE system: PV panels:
Kyocera 120- 120 watt max - (x12)
2 strings of 6 - (36 cell units ? or watt?)
combiner in the E-panel / what breakers? - 15 AMP DC

Charge Controller:
OutBack FlexMax - 80 amp max

Batteries:
Hawker 2 volt used submarine batteries

Inverter:
OutBack FX2524 - sealed unit

OutBack Mate 2 Controller - no hub

Generator:
Honda EU3000is - not working under load
we now use that little Ryobi

Remainder of system:
Midnite Solar e-Panel thingy ..
looking for a desulfator - is this neccessary?
Location: Puna, Big Island of Hawai'i
Contact:

Re: Combining differnt panels to the same Controller

Post by FlyingDiscHawaii »

The Voc for these panels is 85.3V, so you can not put two of them in series and use a FM80 CC.

--> Thanks - I missed that line, as I did not look after the second voltage.
And when I first hooked up one the voltage only went to 45 volts after a few minutes of full Sun.
Now it goes up to 65 volts with full Sun.
--> maybe I don't really have full Sun yet.

Your FM80 for a 24V systems is specified to 2000W max PV input, with 6 panels you have 2,610W of PV input.

--> yes, thanks - I know and I and planning on only using 4 of them, yet I wanted to test all 6 while I am working
on things. And switch on the 5th panel during the morning and late afternoon when the Sun goes behind some
traveller's palm.


You can put the panels in parallel but you then need to be careful on your wire size coming out of the combiner. The Impp is 5.97A, so recommended five in parallel is ~30A. I would recommend a minimum of #8AWG wire from the combiner to the CCs.

---> thanks - I am using 8 gauge from the combiner box, and was considering 6 gauge as I normally like
to oversize parts.

And at some point I will get a larger charge controller. Yet first I want to get the Mate 3s and hub and FlexNetDC.

Thanks.
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