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13-12-2017, 16:47
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#1
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Registered User
Join Date: Nov 2012
Location: French Polynesia
Boat: Allied 39
Posts: 886
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MPPT question using different voltage panels
I'm looking at Victron BlueSolar 100/30 MPPT Charge Controller - 30 Amps / 100 Volts
I have the following
1ea Kyocera 12V 70W 17.9vmpp
2ea Shell 12V 80W 16.9vmpp
1ea Solosol 12V 150W 18.36vmpp
Total watts = 380
These panels are run parallel joining into a Blue Sea 12V breaker and then onto the ships buss. Currently not using a MPPT controller
I understand the unit would see all panels as 16.9V.
Would I see much improvement with a MPPT versus without?
Thanks
Chuck
Jacaranda
Mo'orea
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13-12-2017, 17:02
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#2
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Registered User
Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 14,131
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Re: MPPT question using different voltage panels
You will hopefully get much more detailed responses from the electrical whiz kids here on CF, but my experience closely relates to your situation, so I’ll chime in.
I have two different types of panels (~21v and ~19 volts), four panels in total, all run in parallel to a single junction box. Total of 400 watts.
My prior controller was a simple voltage cut off style. This season I installed your controller, a Victron 100/30 MPPT.
HUGE DIFFERENCE!
With the old charger batteries never got well charged. With new MPPT batteries are healthy and almost always fully charted by noonish. We have plenty of power.
ADD: I assume you have some sort of controller right now.
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13-12-2017, 17:09
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#3
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Registered User
Join Date: Jun 2013
Location: canada
Posts: 4,634
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Re: MPPT question using different voltage panels
You can't run 380w of solar to a battery without a controller. That is dangerous as f*ck. Anything over 10w needs a controller.
So to awsnwer your question. No. It will probably charge less. But your boat won't catch on fire.
To get the most proformance. You'll need 3 controllers. With one the panels will all run around 17.5v. And none will be producing peak power. But they will be close.
Now go disconnect those panels right now!!..,,
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13-12-2017, 19:09
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#4
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cruiser
Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
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Re: MPPT question using different voltage panels
Yes, crazy to even consider no SC.
You need three, or replace all with matching.
There are some very cheap PWM out there, but cheapest I'd go with is Victron 100/75 ~$100 each.
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13-12-2017, 19:12
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#5
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Registered User
Join Date: Nov 2012
Location: French Polynesia
Boat: Allied 39
Posts: 886
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by smac999
You can't run 380w of solar to a battery without a controller. That is dangerous as f*ck. Anything over 10w needs a controller.
So to awsnwer your question. No. It will probably charge less. But your boat won't catch on fire.
To get the most proformance. You'll need 3 controllers. With one the panels will all run around 17.5v. And none will be producing peak power. But they will be close.
Now go disconnect those panels right now!!..,,
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Been running this as a live aboard for 15-20 years. We have a trace c40 controller protecting the batteries. Thanks for your concern.
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13-12-2017, 19:14
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#6
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Registered User
Join Date: Oct 2015
Posts: 2,007
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by chouliha
I'm looking at Victron BlueSolar 100/30 MPPT Charge Controller - 30 Amps / 100 Volts
I have the following
1ea Kyocera 12V 70W 17.9vmpp
2ea Shell 12V 80W 16.9vmpp
1ea Solosol 12V 150W 18.36vmpp
Total watts = 380
These panels are run parallel joining into a Blue Sea 12V breaker and then onto the ships buss. Currently not using a MPPT controller
I understand the unit would see all panels as 16.9V.
Would I see much improvement with a MPPT versus without?
Thanks
Chuck
Jacaranda
Mo'orea
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With an buffet assortment of panels you have a problem. The power curve for each of them will be different, so the MPPT controller really can't get everything out of them it should.
You might seriously look at trying to work out a way to have a single flavor of panel and sell the others.
With a proper MPPT device you can run them in series. I have a pair of 37V panels when connected in series run over 75 volts in full sun into my Victron MPPT controller that feed my 24 volt batteries. Keeps wire size down, and I^2R losses low. It also helps reduce the impact of partial shading.
And the comments about the dangers of running these panels all directly connected without a controller to a battery are spot on! You are setting yourself up for a serious overcharge and even possible thermal runaway for the batteries. That would seriously ruin your whole day.
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13-12-2017, 19:17
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#7
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Registered User
Join Date: Nov 2012
Location: French Polynesia
Boat: Allied 39
Posts: 886
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by Mike OReilly
You will hopefully get much more detailed responses from the electrical whiz kids here on CF, but my experience closely relates to your situation, so I’ll chime in.
I have two different types of panels (~21v and ~19 volts), four panels in total, all run in parallel to a single junction box. Total of 400 watts.
My prior controller was a simple voltage cut off style. This season I installed your controller, a Victron 100/30 MPPT.
HUGE DIFFERENCE!
With the old charger batteries never got well charged. With new MPPT batteries are healthy and almost always fully charted by noonish. We have plenty of power.
ADD: I assume you have some sort of controller right now.
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Thanks that is just the info I am looking for. Thank you
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13-12-2017, 19:27
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#8
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cruiser
Join Date: Jan 2017
Boat: Retired from CF
Posts: 13,317
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Re: MPPT question using different voltage panels
He did correct himself, been using a pwm epsolar SC.
These are a bit less fussy about matching panels
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13-12-2017, 19:39
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#9
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Registered User
Join Date: Sep 2011
Location: Good question
Boat: Rafiki 37
Posts: 14,131
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by chouliha
Thanks that is just the info I am looking for. Thank you
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Glad to help. It was a big improvement for my setup. I suspect your current controller is not nearly as bad as my old one was, but I’ve certainly seen a huge improvement. And it works very well with my two different voltage panel sets.
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13-12-2017, 20:21
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#10
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Registered User
Join Date: Aug 2003
Boat: Dragonfly 1000 trimaran
Posts: 7,141
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Re: MPPT question using different voltage panels
The controller will take an average power output and will charge your battery bank.
Enjoy.
__________________
The question is not, "Who will let me?"
The question is,"Who is going to stop me?"
Ayn Rand
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13-12-2017, 22:14
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#11
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Registered User
Join Date: Jul 2005
Location: Bellingham
Boat: Outbound 44
Posts: 9,319
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Re: MPPT question using different voltage panels
I would consider breaking the panels into two banks and use two MPPT controllers. The matched Shell panels should see a good improvement. The other panels should be no worse than the your old PWM controller and probably better, as the basic new controller will have smarter charge parameters.
__________________
Paul
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14-12-2017, 02:39
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#12
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Registered User
Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 3,755
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Re: MPPT question using different voltage panels
It is not ideal, but it will work. The MPPT controller will find a compromise of the 3 panels and transform the power to a 14.4V output with a charging IUoU regime according to the settings on the controller.
I would suggest to add inline-Schottky protection diodes to prevent reverse-currents into the modules since the voltages differ a lot between the strings and can cause damage to a module - especially if shaded.
It is a good practice anyway to add string protection diodes when having more than two strings in parallel. They are cheap and reduce the voltage of the panel only by 0.2..0.3V, look at the spec for the Voltage / Amps of the diodes before buying, so they can handle the peak currents of your modules easily.
Serial connection is not an option, the currents of the modules are way too different.
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14-12-2017, 22:13
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#13
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Marine Service Provider
Join Date: Sep 2008
Location: Victoria B.C.
Boat: Wauquiez Centurion 32
Posts: 2,874
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by Paul L
........new controller will have smarter charge parameters.
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Every parameter fully adjustable as well.
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15-12-2017, 00:10
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#14
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Registered User
Join Date: Aug 2017
Boat: Lagoon 400S2
Posts: 3,755
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Re: MPPT question using different voltage panels
Quote:
Originally Posted by mitiempo
Every parameter fully adjustable as well.
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Yes, they are really good, but also expensive.
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