FM 80, 48 volt string to 24 volt batteries

Discussion about the FM100, FM80, and FM60 Charge Controllers

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TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Thu Nov 21, 2013 7:44 am

I have 4 Grape solar 250 watt panels wired for 48 volts, 8 6 volt batteries wired to be 24 volts. The FM 80 will convert the 48 to 24 needed for the batteries, correct?

dhamilton
OutBack Technical Service
Posts: 59
Joined: Tue Sep 13, 2011 9:42 am
My RE system: 2x VFXR3524A, FLEXmax80, 6x EnergyCell 106NC, Mate3

Re: FM 80, 48 volt string to 24 volt batteries

Post by dhamilton » Thu Nov 21, 2013 10:46 am

Hello,

The FM80 will step down the voltage from the 48vdc array to you 24vdc charge controller.

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Thu Nov 21, 2013 9:44 pm

Thank you!

blackswan555
Forum Emperor
Posts: 2637
Joined: Sat Aug 30, 2008 5:50 am
My RE system: Other peoples, VFX "E" versions, FLA`s, Generators.
Location: Ibiza Spain,

Re: FM 80, 48 volt string to 24 volt batteries

Post by blackswan555 » Sat Nov 23, 2013 3:15 am

you do not list battery temp sensor, Do you have one ? It is VERY important that you do on all charge sources,

Tim
My comments are based on my experience and research, They are not endorsed or checked by Outback.I am an independent British electrician living in Spain, So please take this into account when reading /acting on my post`s.

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Sat Nov 23, 2013 6:39 am

Yes I do have a battery sensor. Thank you for asking

WNY DAVE
Forum Member
Posts: 21
Joined: Mon Aug 12, 2013 3:14 am
My RE system: 2 x 230Watt Sharp Panels, FM60, Trace Inverters, 12 x 6volt Batteries, 24Volt system.

Re: FM 80, 48 volt string to 24 volt batteries

Post by WNY DAVE » Fri Dec 27, 2013 10:52 am

Just remember to hook the batteries up first to the controller and it should sense the battery bank voltage correctly. If not, you can set it in the menu.
The FM80 can handle up to 150VDC input. So, your 48 Volts input is fine.

How are you running your panels? All in Parallel? or series / Parallel configuration. Whats your panel VOC/Vimp ratings?

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Fri Dec 27, 2013 1:54 pm

WNY DAVE wrote:Just remember to hook the batteries up first to the controller and it should sense the battery bank voltage correctly. If not, you can set it in the menu.
The FM80 can handle up to 150VDC input. So, your 48 Volts input is fine.

How are you running your panels? All in Parallel? or series / Parallel configuration. Whats your panel VOC/Vimp ratings?
I have 4, 250 watt, 24 volt, Grape Solar Monocrystaline panels.
Wire in a series/parallel to produce 48 volts
Voltage @ maximum power point 30.7
Open circuit voltage of 37.7
Short circuit current of 8.72 amps
Current @ Max voltage of 8.15 amps

Yes I had the batteries connected before connecting the panels to the controller so the FlexMax80 auto adjusted and stepped down the voltage to 25.7.
Still on a big learning curve here.
The 240v and 120v work fine off the inverter.
On the DC side everything goes through a Midnight Solar 250v DC disconnect box with an 80 amp Ground fault, I drove an 8' ground rod in approx. 2' away from the DC box outside the house. I have a disconnect switch on the panels, inside and outside. Positive feed from the panels and the batteries are fused @ 80 amps ( I think the batteries should be higher, right?), also a disconnect switch on the battery side.
In the process of hooking up a sub panel to the inverter (240v), will run the 240v to a transfer switch located at the next to the Main panel.
In 2014 I want to add 4 more panels (same) through the same charge controller and add 4 more batteries.
What am I missing, beside lightning protection?

WNY DAVE
Forum Member
Posts: 21
Joined: Mon Aug 12, 2013 3:14 am
My RE system: 2 x 230Watt Sharp Panels, FM60, Trace Inverters, 12 x 6volt Batteries, 24Volt system.

Re: FM 80, 48 volt string to 24 volt batteries

Post by WNY DAVE » Sat Dec 28, 2013 1:31 pm

I assume 2 panels in series and each pair in parallel. So you should have like 60+ volts and about 16 amps coming into the Charge Controller.
do you have a pic of your data on the screen of your charge controller?

SOunds like you have everything you need.

Breaker should be about 1.25 x the max output, so 80 amps x 1.25 = 100amps. But 80 amp would work fine for now, you don;t have that much current going out to the batteries. If you get close the maximum on the controller, then you might update it. I;m running an 80 amp breaker on my FM60 output to the batteries.

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Sat Dec 28, 2013 3:54 pm

WNY DAVE wrote:I assume 2 panels in series and each pair in parallel. So you should have like 60+ volts and about 16 amps coming into the Charge Controller.
do you have a pic of your data on the screen of your charge controller?

SOunds like you have everything you need.

Breaker should be about 1.25 x the max output, so 80 amps x 1.25 = 100amps. But 80 amp would work fine for now, you don;t have that much current going out to the batteries. If you get close the maximum on the controller, then you might update it. I;m running an 80 amp breaker on my FM60 output to the batteries.

Assumption correct,I need to adjust the angles of the panels yet, I have been as high as 69 volts I don't think my amps are that high, but then again I'm still learning and have not done any tweaking to the controller.
Not sure how to post a pic here, just took a pic of what I think is the screen you are referring too
For today (bright and sunny, little clouds)
074V 18.9A 1.0kWH
Max 29.6V ABS 01:00
Min 25.3V FLT 03:55
Today we ran the washer and dryer a couple of times, not much else.
Thank you for the feedback and recommendations, I appreciate all information I get.

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Mon Dec 01, 2014 3:47 pm

Now @ 16 panels, 4 250W, and 12 230w. Four Strings, series, parallel @ 48 volts, fead to midnite combiner box, 4 breakers @ 15A each.
My MNDC250 has 2, single 10Amp Breakers and the 63A GFI. (wired per their diagram)
I'm approaching 80 amps on many occasions so the 10A breaker (Batt +) is getting hot then blows. Using 6AWG wire from the controller to the breaker, the wire is very warm.

All was fine until I add the last four 230W panels, max Amps were around 60, and nothing even got warm.

I'm was going to up the 2 single Breakers to 15A, and use 4AWG, but now I'm thinking the breakers should be closer to 60A.

Thought on this?

NFG
Forum Member
Posts: 13
Joined: Sat Nov 29, 2014 12:18 pm
My RE system: Back-up system of: Outback FM60, Rolls 12V flooded, 4 *100W + 2 * 80w panels, 1000W inverter for our freezers also thermo tube system thermal store with Rayburn wood burner for winter.
Location: SW France

Re: FM 80, 48 volt string to 24 volt batteries

Post by NFG » Wed Dec 03, 2014 1:16 pm

TomSandy76 wrote:
I'm approaching 80 amps on many occasions so the 10A breaker (Batt +) is getting hot then blows. Using 6AWG wire from the controller to the breaker, the wire is very warm.
Hi,

Im not surprised, I think the minimum cable for the FM80 is 4 AWG,
Have you made a typo ? - 10A breaker - do you mean 100A breaker?

Use a minimum of #4 AWG (25 mm2) wire for the output between the FLEXmax 80 and the battery bus bar conductors.

Outback manual P10 states:

Use a minimum of #4 AWG (25 mm2) wire for the output between the FLEXmax 80 and the battery bus bar conductors.

4 AWG is in fact 21.2 mm sq so you could go thicker, I think the FM80 cable lugs will accept up to 2 AWG maximum

For other DC breakers use a trip current of about 125% of load, a clamp meter will confirm current flowing.

N

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Wed Dec 03, 2014 4:17 pm

Changed the wires to 4awg, just stuffs into the breakers which have been switched out to 60a. Thank you for your reply.

TomSandy76
Forum Member
Posts: 10
Joined: Thu Nov 21, 2013 7:16 am
My RE system: 4 Grape Solar 250 watt panels:
Max System Voltage 1000V / 600V
Max Peak Power Pmax
250 W (-2%, +2%)


CEC PTC Listed Power

222.1 W


Maximum Power Point Voltage Vmpp

30.7 V


Maximum Power Point Current Impp

8.15 A


Open Circuit Voltage Voc

37.7 V


Short Circuit Current Isc

8.72 A

Module Efficiency (%)
15.4%


Temperature Coefficient of Voc

-0.128 V/ºC (-0.34% /ºC)


Temperature Coefficient of Isc

3.49x10-3 A/ºC (0.04% /ºC)


Temperature Coefficient of Pmax

-1.20 W/ºC (-0.48% /ºC)


FM 80
Midnight solar MNDC 250
8 6volt batteries:
US RE GC2H XC - 6 Volt Deep Cycle

5 Hour Rate / 193
10 Hour Rate / NA
20 Hour Rate / 242
100 Hour Rate /266
Min @ 25 Amps / 493
Min @ 75 Amps / 128
Min @ 56 Amps / N/A
Plates Cell / N/A
Length / 10-1/4" (260mm)
Width / 7-1/8" (181mm)
Height / 11-7/8" (302mm)

Re: FM 80, 48 volt string to 24 volt batteries

Post by TomSandy76 » Tue Feb 17, 2015 9:36 am

Question,

I have changed the breakers to 80 amps in my midnight solar dc disconnect box.
Feeding 48 volts in from the panels at 4800 watts
24 volts battery bank

Would like to change to a 48 volt bank, but is there a way toe still run my 24 volt inverter? (6000 watt)
Do I have to change to a 48 volt inverter, or is there a safe way to step down the voltage from 48 to 24 to continue to use my current inverter?

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