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Lwiddis

El Pueblo de Señora la Reina de los Ángeles

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Posted: 02/12/18 01:39pm Link  |  Quote  |  Print  |  Notify Moderator

"just know they are all 12 volt"

Gary, "12 volt panel" is just a name. If all they produced was 12 volts nothing would get stuffed into the batteries. My WindyNation 12 volt panels can produce 17.4 volts. Remember the volt reading is the "pressure" reading.

* This post was edited 02/12/18 01:49pm by Lwiddis *


2015 Winnebago 2101DS TT & Chevy Tahoe LTZ, 300 watts WindyNation solar - parallel & MPPT, Trojan T-125s. TALL flagpole for USC & historical flags. Prefer USFS, COE, BLM, NPS, TVA, USF&WS, state & county campgrounds. 14 year Army vet. Bicyclist!

Almot

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Posted: 02/12/18 05:43pm Link  |  Quote  |  Print  |  Notify Moderator

Wire them in series with existing #10 cable and see if shaded panel bothers you too much.
You have nothing to lose, just a short piece of MC4 extension cable, $10 worth.
You only need big amps until it goes into Absorb stage.

Lwiddis

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Posted: 02/12/18 06:23pm Link  |  Quote  |  Print  |  Notify Moderator

“You only need big amps until it goes into Absorb stage.”

Yes, Almot. A fact not understood by many RVers.

Lwiddis

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Posted: 02/12/18 07:01pm Link  |  Quote  |  Print  |  Notify Moderator

Almot, recommending #10 wire other than from one panel directly to a controller or to a combiner box just isn’t right.

mike-s

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Posted: 02/12/18 07:12pm Link  |  Quote  |  Print  |  Notify Moderator

The bypass rectifiers (a diode is a vacuum tube, why are they still called diodes - we don't call transistors triodes?) will take care of any shading issues, with only very minor power loss. Just wire them in series and don't worry, be happy.

full_mosey

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Posted: 02/12/18 07:36pm Link  |  Quote  |  Print  |  Notify Moderator

GaryS1953 wrote:

2oldman wrote:

GaryS1953 wrote:

Controller is a 40 AMP Renogy Tracer MPPT.
According to what I find, that controller should be good to near 100v.

Yeah,I knew the controller was adequate, just trying to prevent possible shading problems by maybe finding a way to isolate shaded panels.


You only guessed! 12V panels are usually below 24Voc. Three panels in series is less than 72Voc.

The MPPT will be good to go in series.

I have 12V panels in parallel on my TT and in series on the van.

HTH;
John

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Posted: 02/12/18 07:42pm Link  |  Quote  |  Print  |  Notify Moderator

Series will be the most shade tolerant, due to the bypass diodes. Installation is a slam dunk since you just add the third panel to the other two.

Recommend you run the Morningstar String Calculator to make sure of your VOC at your low Michigan temps. But I suspect you'll be OK.


2009 Holiday Rambler 42 Scepter with ISL 400 Cummins
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Bob


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