60 cell 33 volt panel, 24 volt nominal?

littleharbor2 · July 2016

Just out of curiosity, Where would you draw the line, voltage wise, in calling a panel 24 volt nominal ? shown here is a 60 cell panel with a Vmp of 33.01 and Voc of 40.39. Even under typical sunny warm conditions wouldn't this panel produce enough voltage to properly charge and equalize a 24 volt battery bank? Now that 60 cell panels have reached the 300 watt range and put out this kind of voltage it seems they could be used in a pwm charging scenario to charge 24 volt banks. As I said just wondering about this , I don't need to be lectured on all the benefits of MPPT, I already know.

Image: https://us.v-cdn.net/6024911/uploads/editor/2r/u6dt60afqq4k.jpg

Vic · July 2016

littleharbor2 said:

Just out of curiosity, Where would you draw the line, voltage wise, in calling a panel 24 volt nominal ? shown here is a 60 cell panel with a Vmp of 33.01 and Voc of 40.39. Even under typical sunny warm conditions wouldn't this panel produce enough voltage to properly charge and equalize a 24 volt battery bank? Now that 60 cell panels have reached the 300 watt range and put out this kind of voltage it seems they could be used in a pwm charging scenario to charge 24 volt banks. As I said just wondering about this , I don't need to be lectured on all the benefits of MPPT, I already know.

Hi littleharbor2,

That is the highest Vmp of a 60-cell that I've ever seen.

BUT, to me, this is NOT a 24 V module. My limit is a bit above 35 V ... Am still using some Shell 72 cell PVs, which have a Vmp of 35.4 V STC. These Shells date from 2004 - 2005, and are Monos. Vmps, especially for Monos have risen to about 31.3-ish from the latest 60 cell Solarworld.

A number of 72 cell Mono PVs are now running at about 36.5 Vmp, as you probably know.

Could not find a data sheet for your candidate 300 PV, but in hot ambient temps, they would not have quite enough voltage, IMO. And they appear to be "frameless", but inexpensive. May be a hassle to mount, however.

Just a drive-by comment. Vic

vtmaps · July 2016

One other thing... if it is capable (I'm not saying it is) of charging a 24 volt battery with a PWM controller, that doesn't mean it will work with a MPPT controller. MPPT controllers need more headroom than PWM controllers.

--vtMaps

littleharbor2 · July 2016

J

Image: https://us.v-cdn.net/6024911/uploads/editor/fs/03sgkiy1li8n.jpg

Thanks for your input. I would be reluctant to promote these as "24 volt" myself but they are darn close.

Just a little more info, These are true American made panels, with frames and sold on ebay by a guy named Fred 480 V. For anybody who wants a true American product. Feeling patriotic on this Independence day weekend.

They are here American made solar panels made with 100% American labor with American made materials, the glass, cells framing and all wire is made in America, new cells new raw power 300 watt we have added a copy of the flash test we did, this is where our label data comes from we have A calibrated factory flash testers, where is your flash test sheet or are the numbers just falling from the sky? ask to see a updated copy of your panel test, good luck!! @not all panels without frames are frameless panels@ some are panels with no frames@ these are 60 cell panels with frames that they need

these are 300 watt 24 volt solar panels ready for all your needs, they can be used for commercial or residential settings, these are not flimsy panels no they are hardy with 3.2mm tempered glass fronts, the 3 buss bar american made, mono crystalline cells make these panels perfect for low light areas, heavy duty frames that can be used in a bolt down or clamp system, this panel has A transferable 25 yr. limited output warranty, a copy will be sent with every panel,

Panel Specifications 300 watt

Voltage Maximum Power	33.01
Current Maximum Power	9.06
Voltage Open Circuit	40.3

Photowhit · July 2016

I take it the last 2 paragraphs are cut and paste from the manufacturer?

"...can be used in a bolt down or clamp system..."

They have no holes for bolt down, so clamp down only it appears.

I'd put the cut off at 35 volts, with short wire runs and little drop across the charge controller, you might get away with lower, but, I'd like to see NOCT values for these.

Johann · July 2016

littleharbor2 said:

J
Thanks for your input. I would be reluctant to promote these as "24 volt" myself but they are darn close.

Just a little more info, These are true American made panels, with frames and sold on ebay by a guy named Fred 480 V. For anybody who wants a true American product. Feeling patriotic on this Independence day weekend.

They are here American made solar panels made with 100% American labor with American made materials, the glass, cells framing and all wire is made in America, new cells new raw power 300 watt we have added a copy of the flash test we did, this is where our label data comes from we have A calibrated factory flash testers, where is your flash test sheet or are the numbers just falling from the sky? ask to see a updated copy of your panel test, good luck!! @not all panels without frames are frameless panels@ some are panels with no frames@ these are 60 cell panels with frames that they need
these are 300 watt 24 volt solar panels ready for all your needs, they can be used for commercial or residential settings, these are not flimsy panels no they are hardy with 3.2mm tempered glass fronts, the 3 buss bar american made, mono crystalline cells make these panels perfect for low light areas, heavy duty frames that can be used in a bolt down or clamp system, this panel has A transferable 25 yr. limited output warranty, a copy will be sent with every panel,
Panel Specifications 300 watt
Voltage Maximum Power 33.01
Current Maximum Power 9.06
Voltage Open Circuit 40.3

This is just a advertisement disguised as question or comment.

Vic · July 2016

Ok littleharbor,

Sorry, just Googled that name and part number, and came up with several references to that product number being frameless.

The very high Vmp is just a bit curious, and had wanted to look at the Temp Coefficients, etc, thinking about the temperature effects on the Vmp.

With a PWN CC, this PV would probably work much of the time. High ambient temps, especially with cool Flooded batteries might be a bit of a push. But you know all of this ...

Vic

littleharbor2 · July 2016

Vic, Thank you for your input. I highly appreciate your knowledge and patience
Johann, As to this being an advertisement, NO WRONG, Get a life. You obviously haven't got anything constructive to add.

Photowhit · July 2016

littleharbor2 said:

Vic, Thank you for your input. I highly appreciate your knowledge and patience
Johann, As to this being an advertisement, NO WRONG, Get a life. You obviously haven't got anything constructive to add.

As I noted, the last 2 paragraphs look like they were cut and pasted from the manufacturer. Hence seeming to appear as an advertisement. I think if you go back and read, you might see what he's seeing.

zoneblue · July 2016

We try to keep things friendly around here, folk are just trying to help. Thus your comment is out of line.

littleharbor2 said:

Vic, Thank you for your input. I highly appreciate your knowledge and patience
Johann, As to this being an advertisement, NO WRONG, Get a life. You obviously haven't got anything constructive to add.

60 cell 33 volt panel, 24 volt nominal?

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