Visit our Popular Forums

barnakiel · 23-08-2011, 12:09

Quote:

Originally Posted by SV Demeter

Who is GP?

I believe back then GP made panels. It could be the GP, or the German PV company GP Solar.

In any case both the old thing and the new nonamechina product share these specs:

FS-M536 - FS-M536 Manufacturer & Supplier

We have the 75W model.

b.

SV Demeter · 23-08-2011, 12:27

These Solar Panel 100 Watt 12 Volt Multicrystalline

seem very appealing. I am having a hard time finding a reason not to use them and to spend a lot more $$. Maybe the thing to do is order one and see what shows up? I guess if it looks like junk I can always ship it back?

smallyachts · 23-08-2011, 13:20

They have a 24 volt in the same dimensions that with the proper MPPT and associated hardware you could pack more energy gathering into the same footprint.

You would also produce usable power for more hours per day.

IMHO

SV Demeter · 23-08-2011, 13:42

Had not thought about 24volt panels. Hmm. Im using an Outback Flexmax 60 which I think can handle something like 145volts IIRC. Most 24volt nominal panels have a max output of something like 35volts so even in a series parallel conficguration like I am planning I should be okay. Im not seeing however a 100 watt panel by UL Solar. Smallyachts were you suggesting someplace else?

smallyachts · 23-08-2011, 13:50

Quote:

Originally Posted by SV Demeter

Had not thought about 24volt panels. Hmm. Im using an Outback Flexmax 60 which I think can handle something like 145volts IIRC. Most 24volt nominal panels have a max output of something like 35volts so even in a series parallel conficguration like I am planning I should be okay. Im not seeing however a 100 watt panel by UL Solar. Smallyachts were you suggesting someplace else?

No, I was looking at the 85W panels. While total wattage is 15% less that is only during peak illumination. Since the sun moves as well as the boat you will only see that max during a relatively short window. You should actually see more usable wattage during the rest of the daylight hours.

If you are powering a 12 volt system via 24 volt panels and a 12V MPPT that will handle the max voltage/current from the panels you should be producing usable power earlier in the day and later in the evening.

Most systems we have been involved in have worked in this manner.

You would not need to do a series parallel, you would do all in parallel.

SV Demeter · 23-08-2011, 14:15

Quote:

Originally Posted by smallyachts

No, I was looking at the 85W panels. While total wattage is 15% less that is only during peak illumination. Since the sun moves as well as the boat you will only see that max during a relatively short window. You should actually see more usable wattage during the rest of the daylight hours.

If you are powering a 12 volt system via 24 volt panels and a 12V MPPT that will handle the max voltage/current from the panels you should be producing usable power earlier in the day and later in the evening.

Most systems we have been involved in have worked in this manner.

You would not need to do a series parallel, you would do all in parallel.

So are you suggesting then that I might make more power using an 85 watt 24 volt panel in a given day than I would with a 100 watt 12 volt panel? I understand there are gains to be had with MPPT but is it really that much better?

hellosailor · 23-08-2011, 17:48

"While total wattage is 15% less that is only during peak illumination. "
All things being equal, the 100W panels will simply have some 20% more surface area than the 85W panels, which means they will produce 20% more power ALL DAY LONG, not just during peak illumination. That's just how solar panels work, the more surface area, the more power. (Assuming the same technology in the panels.)

24V panels won't buy much over 12V panels, since an MPPT controller might claim a whole whopping 2%-4% more efficiency when run at maximum voltage instead of a nominal 12V. Going from 12v to 24v I doubt you'd see 2% more power, although even 2% is "money in the bank". The downside to that, is that if your MPPT controller fails, you can't just bypass it and run the panels to the batteries, the way you could with 12v panels.

Demeter-
UL Solar (and wait till Underwriter's Labs finds out someone else is using the name "UL" in an electrical field<G>) cleverly posts their warranty online and says it is subject to following their installation etc. procedures. Which they don't post online. Although they do offer separate "marine" panels and products. When in doubt, ask them directly and get it in writing.

SV Demeter · 23-08-2011, 18:26

Quote:

Originally Posted by hellosailor

"While total wattage is 15% less that is only during peak illumination. "
All things being equal, the 100W panels will simply have some 20% more surface area than the 85W panels, which means they will produce 20% more power ALL DAY LONG, not just during peak illumination. That's just how solar panels work, the more surface area, the more power. (Assuming the same technology in the panels.)

24V panels won't buy much over 12V panels, since an MPPT controller might claim a whole whopping 2%-4% more efficiency when run at maximum voltage instead of a nominal 12V. Going from 12v to 24v I doubt you'd see 2% more power, although even 2% is "money in the bank". The downside to that, is that if your MPPT controller fails, you can't just bypass it and run the panels to the batteries, the way you could with 12v panels.

Demeter-
UL Solar (and wait till Underwriter's Labs finds out someone else is using the name "UL" in an electrical field<G>) cleverly posts their warranty online and says it is subject to following their installation etc. procedures. Which they don't post online. Although they do offer separate "marine" panels and products. When in doubt, ask them directly and get it in writing.

Hello that was my next stop. Im going to contact them and see if the panels are waranteed for use in a marine environment. I was thinking the 12 volt panels vs 24 volt should not really matter as watts is watts afterall. Thanks

smallyachts · 24-08-2011, 07:42

Well, I did say in IMHO

I also agree that in the event the controller fails you can not connect directly to your twelve volt bank, but then there are ways around that as well in a pinch.

Panels, (unless you have them mounted on a solar tracking array) rarely put out rated power except for a finite amount of time when they are receiving maximum vertical illumination. Put them on a boat, or some other object that moves around at will and you will see that finite period of time become much less, unless of course it is a dead calm and no current or tide effects.

So the object is to capture more usable power for a greater period of time and the tradeoff is the less usable power created during the period of maximum vertical illumination.

In theory given an equal amount of off angle illumination the 24 volt panel will exceed the 12 volts necessary to drive the controller sooner than a comparable 12 volt panel, at the other end of the day, it should also extend the period out.

Not that I am an expert in Solar Power, my training was in advanced electonics and nuclear propulsion for the US Navy, but I have been manipulating solar energy for quite a while on various projects.

The photo below is of a solar powered emergency radio system I designed and deployed on some of the coastal islands in Connecticut, if you look closely you will see the date of Aug 2, 85 in the lower corner.

It has been an exciting ride so far.

70AMX · 28-08-2011, 13:07

Wouldn't this be a good value for a 60" x 30" panel?
Kyocera 210 Watt 24 Volt Solar Panel KD210GX-LFBS
only $346.50
Solar Cell, Solar Panel, Solar PV, Solar Products, Charge Controllers, Solar Trackers

hellosailor · 28-08-2011, 13:19

"In theory given an equal amount of off angle illumination the 24 volt panel will exceed the 12 volts necessary to drive the controller sooner than a comparable 12 volt panel,"
Perhaps a good point, but with an MPPT controller that wouldn't matter. As soon as there is "power" available from the panel, regardless of voltage, an MPPT controller would be optimizing the power to the batteries, no?

**noelex 77** · 28-08-2011, 17:59

Quote:

Originally Posted by hellosailor

"In theory given an equal amount of off angle illumination the 24 volt panel will exceed the 12 volts necessary to drive the controller sooner than a comparable 12 volt panel,"
Perhaps a good point, but with an MPPT controller that wouldn't matter. As soon as there is "power" available from the panel, regardless of voltage, an MPPT controller would be optimizing the power to the batteries, no?

No! Most MPPT controllers cannot boost voltage, only reduce it. If the panel voltage is below the battery voltage no current will be produced.
Having a higher panel voltage is therefore helpful, but the amount of extra power produced early or late in the day is only slight

SV Demeter · 01-09-2011, 10:11

The folks at UL Solar emailed me back saying thier panels warranty would not be violated by using on a boat in a marine environment and that they sold "marine kits".

I installed the Outback Flexmax 60 controller yesterday and hope to order these panels in the next week. They are offering free shipping these days.

Solar Panel 100 Watt 12 Volt Multicrystalline

For all those who have suggested larger panels, yes that would be nice but due to mounting constraints I need to stay with a 26 x 40 inch frame. All panels over 100 watts I have seen are on larger frames.