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01-27-2015, 03:03 PM
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#1
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Member
Thor Owners Club Ford Super Duty Owner
Join Date: Sep 2014
Location: Mount Laurel, N.J.
Posts: 75
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How to determine voltage for a solar panel
below I have specs on a solar panel. using a mppt-60 controller how many amps will it produce to charge a 12 volt battery at maximum charging rate?
Rated Maximum Power - Pmax 220w
Output Tolerance: 0/+3%
Current at Pmax -- Imp 7.41A
Voltage at Pmax -- Vmp 30.36V
Short-Circuit Current -- Isc 8.30A
Open-Circuit Voltage -- Voc 36.43V
Nominal Operating Cell Temp: 45°C / ± 2°C
Weight: 19.5kg / 43lb
Dimensions: 1640x992x45 (mm) - 64.5 x 39 x 2 (inches)
Maximum System Voltage 1000V IEC / 600V UL
Maximum Series Fuse Rating: 15A
Cell Technology: Multi-Si
__________________
2015 Thor Ace 30.2
1240 watts solar/batteries 1450AH
Sue and Tim Affourtit
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01-27-2015, 04:32 PM
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#2
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Senior Member
Join Date: Sep 2012
Posts: 1,177
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i would get one it well tell you all you need to know real time
Bogart Engineering Products | Bogart Engineering
guesing 20amps every hr x 5= 100 amp hrs every day give or take GUESSING
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01-27-2015, 04:42 PM
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#3
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Senior Member
Join Date: Jan 2015
Posts: 345
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Quote:
Originally Posted by tlaffourtit
below I have specs on a solar panel. using a mppt-60 controller how many amps will it produce to charge a 12 volt battery at maximum charging rate?
Rated Maximum Power - Pmax 220w
Output Tolerance: 0/+3%
Current at Pmax -- Imp 7.41A
Voltage at Pmax -- Vmp 30.36V
Short-Circuit Current -- Isc 8.30A
Open-Circuit Voltage -- Voc 36.43V
Nominal Operating Cell Temp: 45°C / ± 2°C
Weight: 19.5kg / 43lb
Dimensions: 1640x992x45 (mm) - 64.5 x 39 x 2 (inches)
Maximum System Voltage 1000V IEC / 600V UL
Maximum Series Fuse Rating: 15A
Cell Technology: Multi-Si
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Hi,
By dividing module wattage by your current battery voltage, you get the current that the module can produce with 1000W/m2 and perpendicular to the sun with air mass of 1.5 and cell temperature of 77° F if there were no losses. Because there are conversion losses and many other factors that affect the power, deduct 17% to get close to what it can do in the real world. If the cell temperature is hot, deduct up to 25%.
For example, your battery is charging at 13 volts. 220/13 = 16.92 x .83 = 14 amps. At 14.8 volts you will get about 12 amps.
Larry
__________________
I have a vast knowledge about PV solar, batteries and inverters. I'll try to provide the best answer if I know it and hopefully correct some "Campfire" talk. Full-time 1999-2004. Part time now. '92 Hawkins, 360AH Lithium Battery, 1480 Watts PV solar.
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01-27-2015, 04:46 PM
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#4
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Senior Member
Join Date: Jan 2015
Posts: 345
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Quote:
Originally Posted by terry735001
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The Bogart capacity meter will not tell you how much power the PV system is converting. It will tell you how much of that power is making it to the battery, though.
Larry
__________________
I have a vast knowledge about PV solar, batteries and inverters. I'll try to provide the best answer if I know it and hopefully correct some "Campfire" talk. Full-time 1999-2004. Part time now. '92 Hawkins, 360AH Lithium Battery, 1480 Watts PV solar.
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01-27-2015, 05:00 PM
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#5
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Member
Thor Owners Club Ford Super Duty Owner
Join Date: Sep 2014
Location: Mount Laurel, N.J.
Posts: 75
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then I would need 5 panels to fully use the mppt-60 controller to reach 60 amps charging?
__________________
2015 Thor Ace 30.2
1240 watts solar/batteries 1450AH
Sue and Tim Affourtit
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01-27-2015, 05:12 PM
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#6
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Senior Member
Join Date: Sep 2012
Posts: 1,177
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Quote:
Originally Posted by BatteryPro
The Bogart capacity meter will not tell you how much power the PV system is converting. It will tell you how much of that power is making it to the battery, though.
Larry
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is that not what he was asking was what was making it to the batterys and really in the long run thats all the matters is what the batterys are seeing and getting ???????
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01-27-2015, 05:27 PM
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#7
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Member
Thor Owners Club Ford Super Duty Owner
Join Date: Sep 2014
Location: Mount Laurel, N.J.
Posts: 75
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just trying to determine how many panels I would need in every day use to maximize the mppt-60 controller knowing of the multiple variables involved. I have a large bank of batteries to charge and rather waste some watts then not have enough.
__________________
2015 Thor Ace 30.2
1240 watts solar/batteries 1450AH
Sue and Tim Affourtit
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01-27-2015, 05:58 PM
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#8
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Senior Member
Join Date: Jul 2014
Posts: 35,438
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Watts / 13.5 is rule of thumb amp output.
13.5 is charging voltage
220/13.5=16.3 amps
3 panels will keep you under 60 amps, where 4 will put you a bit over.
Some use 5.5 hours a day for charging time, it works with my setup.
3, 225 watt 36 volt panels into a MPPT - 60 amp controller, Bogart 2020 TriMetric and 8 gc2 batteries.
In use 4 years
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01-27-2015, 06:00 PM
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#9
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Community Moderator
Join Date: Aug 2011
Posts: 6,200
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Quote:
Originally Posted by tlaffourtit
below I have specs on a solar panel. using a mppt-60 controller how many amps will it produce to charge a 12 volt battery at maximum charging rate?
Rated Maximum Power - Pmax 220w
Output Tolerance: 0/+3%
Current at Pmax -- Imp 7.41A
Voltage at Pmax -- Vmp 30.36V
Short-Circuit Current -- Isc 8.30A
Open-Circuit Voltage -- Voc 36.43V
Nominal Operating Cell Temp: 45°C / ± 2°C
Weight: 19.5kg / 43lb
Dimensions: 1640x992x45 (mm) - 64.5 x 39 x 2 (inches)
Maximum System Voltage 1000V IEC / 600V UL
Maximum Series Fuse Rating: 15A
Cell Technology: Multi-Si
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Use the online calculator here
http://www.morningstarcorp.com/string-calculator
Click the link which says "manually enter values"
When I did it I got the following results....it says 3 panels wired in series is optimal.
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01-27-2015, 06:17 PM
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#10
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Member
Thor Owners Club Ford Super Duty Owner
Join Date: Sep 2014
Location: Mount Laurel, N.J.
Posts: 75
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thank you all. chart is great. ty
__________________
2015 Thor Ace 30.2
1240 watts solar/batteries 1450AH
Sue and Tim Affourtit
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01-27-2015, 08:28 PM
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#11
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Senior Member
Winnebago Owners Club
Join Date: Sep 2013
Location: FTer Class of 2015 Origin: Evergreen, Colorado
Posts: 1,565
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Yea, cool website. Thanks, pasdad1. \ken
__________________
Ken, Deb, & Gadget (WIT Club, FMCA, SKP, and grateful volunteers with Habitat for Humanity and SOWERs), traveling in a well-behaved 2005 Winnebago Vectra 40FD w/1100w solar, some gee-golly-whizbang, and a TRAILERED 2015 Cherokee TrailHawk toad.
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01-27-2015, 09:08 PM
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#12
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Senior Member
Fleetwood Owners Club Ford Super Duty Owner
Join Date: Jun 2012
Location: SoCal
Posts: 15,749
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Are you going to tilt or have the panels flat? If tilt will you always have the Motorhome positioned optimally? Usage in the low angle winter sun?
Max solar generation only occurs at the peak of the day allowing for peak over subscription if the controller will handle it.
All factors that have a big impact on solar power generation and can impact the reality of sizing system components.
__________________
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
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01-28-2015, 06:43 AM
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#13
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Member
Thor Owners Club Ford Super Duty Owner
Join Date: Sep 2014
Location: Mount Laurel, N.J.
Posts: 75
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Thinking flat
__________________
2015 Thor Ace 30.2
1240 watts solar/batteries 1450AH
Sue and Tim Affourtit
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01-28-2015, 01:10 PM
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#14
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Senior Member
Fleetwood Owners Club Ford Super Duty Owner
Join Date: Jun 2012
Location: SoCal
Posts: 15,749
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If installed flat your solar output will be less, so can probably go an additional panel. I would not wire in series due to shading. Use PVWATTS to play what if with more realistic scenarios.
__________________
Vince and Susan
2011 Tiffin Phaeton 40QTH (Cummins ISC/Freightliner)
Flat towing a modified 2005 Jeep (Rubicon Wrangler)
Previously a 2002 Fleetwood Pace Arrow 37A and a 1995 Safari Trek 2830.
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