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Old 13-12-2017, 17:47   #1
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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
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Mo'orea
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Old 13-12-2017, 18:02   #2
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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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Old 13-12-2017, 18:09   #3
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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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Old 13-12-2017, 20:09   #4
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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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Old 13-12-2017, 20:12   #5
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Re: MPPT question using different voltage panels

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Originally Posted by smac999 View Post
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!!..,,


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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Old 13-12-2017, 20:14   #6
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Re: MPPT question using different voltage panels

Quote:
Originally Posted by chouliha View Post
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
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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Old 13-12-2017, 20:17   #7
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Re: MPPT question using different voltage panels

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Originally Posted by Mike OReilly View Post
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 Iíll 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.


Thanks that is just the info I am looking for. Thank you
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Old 13-12-2017, 20:27   #8
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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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Old 13-12-2017, 20:39   #9
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Re: MPPT question using different voltage panels

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Originally Posted by chouliha View Post
Thanks that is just the info I am looking for. Thank you
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 Iíve certainly seen a huge improvement. And it works very well with my two different voltage panel sets.
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Old 13-12-2017, 21:21   #10
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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.
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Old 13-12-2017, 23:14   #11
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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.
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Old 14-12-2017, 03:39   #12
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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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Old 14-12-2017, 23:13   #13
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Re: MPPT question using different voltage panels

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Originally Posted by Paul L View Post
........new controller will have smarter charge parameters.
Every parameter fully adjustable as well.
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Old 15-12-2017, 01:10   #14
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Re: MPPT question using different voltage panels

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Every parameter fully adjustable as well.
Yes, they are really good, but also expensive.
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Old 15-12-2017, 02:40   #15
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Re: MPPT question using different voltage panels

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Yes, they are really good, but also expensive.
Really?

https://www.amazon.com/Victron-BlueS.../dp/B00U3MK0CI @ $99

vs comparable Morningstar controller

https://www.wholesalesolar.com/36151...rge-controller @ $245
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