Sun 90 solar panels

Horsefly76 · February 2009

Does anyone have info on these panels?

Sounds too good to be true?

Sun-90

$270.00 each ($3.00 a watt) no min order

These Sun modules have cells that are manufactured by SunPower that have the highest efficiency in the industry of 22%. Specifications

* 90 watts
* 21.4 Voc
* 17.6 Vmp
* 5.12 Imp
* 5.55 Ics

niel · February 2009

Re: Sun 90 solar panels

yes, we have and they are good as far as i know with a small quark in that they can't be used with a negative ground and must be positively grounded. we are also familiar with who is selling them at that price and i have not heard any complaints about them either. even though both have sun in their names, they aren't affiliated with one another.

BB. · February 2009

Re: Sun 90 solar panels

Here are some discussions from 2007 about Sunpower...

The big issue with SunPower has been that their panels require positive grounding for the electrical system or they will lose power output over a few days/weeks/months if negative grounded (or left floating).

For Grid Tied inverters, this is not a huge issue. Some inverters (like Xantrex) include a positive grounded model for these systems--and there is no other issue/problem with GT.

For off-grid systems, the normal assumption is that grid tied systems are negative grounded.

You may be able to positive ground with some charge controllers (like Outback family--see manual for details)--and it is done for telecom equipment where positive grounding is normal...

But, for the "standard" off-grid system, negative grounding may be an issue as it will cause the panels to lose output... And positive grounding may cause issues with some equipment that assumes a negative ground (like 12 volt automotive accessories).

Lastly, in the above thread, there was a limit on the 90 Watt SunPower panels of 120 VDC max. (probably a UL/NRTL limit). So, may not be "legal" to operate at higher voltage as allowed by some MPPT charging systems (like the Outback and Xantrex 140+ volt maximum systems).

I looked for the 90 watt panel specs... But the links I could find were dead. The above issues may be why the 90 watt panels are "on sale"--it could also be the result of the current world financial problems.

Do you have any new links to the product specifications?

By the way, the panel specs. (for the larger panels at least) do not mention the positive grounding issues... You have to read the following installation manuals to find this little fact out.

UL (US and Canada), (PDF)
IEC (Europe and Asia), (PDF)

Important! For optimal performance, SunPower PV modules
must only be used in configurations where the positive
polarity of the PV array is connected to ground. Failure to
comply with this requirement will reduce the
performance of the system and invalidate SunPower’s
Limited Power Warranty for PV Modules.

For more information on grounding the system correctly, visit
our website at www.sunpowercorp.com/inverters or contact
SunPower technical support at 1-877-SUN-0123.

-Bill

niel · February 2009

Re: Sun 90 solar panels

http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=234

BB. · February 2009

Re: Sun 90 solar panels

I found a PDF Link to the SPR-90 data sheet dated December 2004... Don't know if it is still current or not.

Nothing about pos/neg grounding...

-Bill

niel · February 2009

Re: Sun 90 solar panels

all of their pvs (correcting myself as it is both leads in the rear of the cells) i believe have both leads in the rear and it is these pvs that have that quark. they did address this a few years back, but i guess now that they insist on putting most systems together from their own people and they only use the equipment that will work that they don't need to post such information and possibly confuse or scare off any prospective customers. i have personnaly seen this on their site in the past and will look to see if i can find it again.

niel · February 2009

Re: Sun 90 solar panels

updated:
here they mention the positive ground when they show their inverters.
http://www.sunpowercorp.com/Products-and-Services/Inverters.aspx

"Grounding
SunPower high-efficiency systems must be installed with proper grounding and inverter configuration procedures in order to perform optimally to their specifications. This is to ensure SunPower panels only see negative voltage as referenced to ground.
For optimal performance in North American installations, SunPower solar panels should be used with SunPower positive ground inverters where the positive polarity of the array is connected to ground. The SunPower inverters listed above meet this requirement.
For optimal performance outside the United States, SunPower panels must only be used with transformer-based inverters where the positive (+) polarity of the array is connected to ground."

ps-i guess you saw that the sun 90s are good to 70v so you can series 3 of their pvs max.

Horsefly76 · February 2009

Re: Sun 90 solar panels

The wife has been griping about the electric bill and I have been wanting to do this sort of thing for a long time.

Im not a tree hugger I just like the independence of it all8)

Here is what I have gathered so far.

8 Trojan T-105"s 2 1/2 yr old sourced from work (I work on electric man lifts so I have to maintain 100's of them)

7 C&D tech 100 amp hr 12 volt AGM'S (Bought new for $160 from Interstate battery because they didn't sell after 6 months)

Have plenty of welding cable (If a 25ft section has more than 3 "cuts" in the insulation it is replaced) ( I love working for a rental company):cool:

60 watts of solar so far need a lot more:roll:

Need a good MPPT solar regulator.

Metro 6/1 Listeroid diesel engine with a 2600 watt gen head.

160 Amp presto light heavy truck alternator (On the Metro diesel) converted to use external regulator. Regulator is a xantrex 3 stage digital unit that has all the bells and what-not.

Kubota EB300 D 6.5 Hp water cooled diesel with 140 amp GM alternator for backup charging.

Need a 1500 watt sign wave inverter (Have a little 300 watt pure sign now)

I want to have at least 450 watts of solar plus a small wind generator.

I have been looking at the sun 90's to fill in the gap on the solar end.

I know this is a lot of BS just wanted to get some input on the solar end of it as it will cost me the most money.

Horsefly76 · February 2009

Re: Sun 90 solar panels

niel wrote: »

all of their pvs (correcting myself as it is both leads in the rear of the cells) i believe have both leads in the rear and it is these pvs that have that quark. they did address this a few years back, but i guess now that they insist on putting most systems together from their own people and they only use the equipment that will work that they don't need to post such information and possibly confuse or scare off any prospective customers. i have personnaly seen this on their site in the past and will look to see if i can find it again.

Neil thanks for all your help/info!

I just signed up here because another forum I was on was full of A** H***s that didn't want to share/discuss info but only pull out a stick and beat people when a question was posted/asked.

Aaron.

niel · February 2009

Re: Sun 90 solar panels

horsefly76,
for your own versatility and wider choices of equipment the sun 90s may be a bad choice, but that is up to you.
nice that you have much stuff accessible to you at reasonable costs and it gives you a big jump on things. is it your intention to use this in conjunction with the grid either to sell or just as a backup or as off grid? in fact, let us know more specifically if you can what all it is you wish to do. for example do you intend to use all of the batteries and what battery system voltage are you considering? i am going to advise you to not use different batteries together.
we encourage questions, but we also encourage reading as much as you can to get a better idea of what you are doing and what you may want to do. you do want to figure on conservative efforts on your part so as to reduce your need for power too.
we aren't into sticks btw.:D

icarus · February 2009

Re: Sun 90 solar panels

I don't think that the Sun 90's are UL listed however.

Tony

Horsefly76 · February 2009

Re: Sun 90 solar panels

niel wrote: »

horsefly76,
for your own versatility and wider choices of equipment the sun 90s may be a bad choice, but that is up to you.
nice that you have much stuff accessible to you at reasonable costs and it gives you a big jump on things. is it your intention to use this in conjunction with the grid either to sell or just as a backup or as off grid? in fact, let us know more specifically if you can what all it is you wish to do. for example do you intend to use all of the batteries and what battery system voltage are you considering? i am going to advise you to not use different batteries together.
we encourage questions, but we also encourage reading as much as you can to get a better idea of what you are doing and what you may want to do. you do want to figure on conservative efforts on your part so as to reduce your need for power too.
we aren't into sticks btw.:D

The batteries will be set up in two different 12 volt banks.

(Yes I keep the AGM'S separate from the flooded cells)

I wanted 12 volt for the simplicity as I do not plan on more than 80 amps current flow at any point and I have a lot of heavy welding cable already.

The plan is to supply power for the lights, computers, entertainment center and a portable evap cooler that is in the living room.

We are renting right now so there is not much I can do till we get a house bought in the near future.

I have changed all the lights to compact florescent.

Down the road I see a sundanzer fridge/freezer in the home to take that out of the pool also.:roll:

For the solar I was thinking 24 volt strings in to a MPPT controler

Again for now it is to reduce my energy bill/usage and become more Independent.

What do ya think?

BB. · February 2009

Re: Sun 90 solar panels

Conserve, conserve, conserve.

Then look at solar hot water and solar Grid Tied.

Since you have access to "free batteries"--you certainly can make, basically, a solar powered whole house UPS. Very cool.

However, unless you have frequent and/or long power outages--it is really difficult to justify off-grid in a home that is on grid.

Also, whatever you choose to do--at least do a back of the envelope / spread sheet of the costs/benefits of the various solutions.

For example, you mention looking at a Sundanzer fridge--frequently, an EnergyStar fridge uses almost the same mount of power and is 1/3 the cost--spend the savings on a off-grid TSW inverter and a couple extra panels... You will gain frost free, auto ice maker, and through the door water.

-Bill

icarus · February 2009

Re: Sun 90 solar panels

OK,, now you've gone and got me worried.

I just last week ordered a Sun 90, because added to my existing string, would put me just at the Max of my controller,,, and the price was right. I really don't need the extra wh/day but you can never have enough,,,, and if I start to run my fridge on the system a bit the extra would help. (off grid application!)

In looking over the spec sheet, no where that I can find does it mention positive grounding! http://sunelec.com/index.php?main_page=product_info&cPath=5&products_id=234

The question is,, what are the ramifications of a panel spec'ed for positive ground in a string of negative ground panels? It was mentioned earlier in the the thread that "performance will degrade" or something like that. Question is,, will I just get a slightly different performance curve, or will I risk damaging either the Sun panel or my other Siemens or BP panels?

To admit my own ignorance,,, I know that the negative side of my 12vdc system is grounded,, but I didn't know that the panels themselves cared one way or another. In my mind, it was just as if I had an old International truck with positive ground. The radio cared, but the light bulbs didn't.

What should I care about in this?

Thanks for the advice,

Tony

BB. · February 2009

Re: Sun 90 solar panels

Follow the link to another thread here in the #3 post from me--or here it is again:

some discussions from 2007 about Sunpower

Basically, because of the way the panels are designed/constructed, the panels trap charge internally if the panel is biased "incorrectly" against the ground plane (i.e., positively with regard to earth/dirt ground). The trapped charge reduces the overall output of the panel by a relatively large amount within hours or days (?).

In one example, a panel with a -160 volt charge went from 200 watt output to 140 watt output because of the charge/polarization.

It is temporary and can be reversed by changing the grounding polarity.

Read the old thread, there is a lot of data and details there.... I am wondering if these are leftover 90 watt panels that did not sell well from several years ago.

-Bill

icarus · February 2009

Re: Sun 90 solar panels

Bill,

As always thanks for the help,

After reading through the links provided, and realizing that they are way over my head,,,, I think I got the gist of the problem. The links also reference a 2006 date after which the problem should be resolved, such that the polarization issue goes away. Since there is no reference in any current Sun documents I wonder if it is safe to assume that the issue has been resolved?

Next, What,, in your (or Neil's, or Jim's, or any of your's) learned opinion of the following idea.

Assume that you have a number of panels connected in parallel. Some of these panels are "negative ground " panels, and some are "positive ground". If the battery and charge controller were left un-grounded what would the potential problem(s) be. (assume for this discussion 12 volt battery bank). Lets assume that battery bank feeds a grounded neutral inverter, and the house wiring is grounded. The batteries don't see "ground".

I have heard that there is no real reason to 'ground ' a small battery bank to earth ground, so would this solve the problem?

Tony

Horsefly76 · February 2009

Re: Sun 90 solar panels

BB. wrote: »

Conserve, conserve, conserve.

Then look at solar hot water and solar Grid Tied.

Since you have access to "free batteries"--you certainly can make, basically, a solar powered whole house UPS. Very cool.

However, unless you have frequent and/or long power outages--it is really difficult to justify off-grid in a home that is on grid.

Also, whatever you choose to do--at least do a back of the envelope / spread sheet of the costs/benefits of the various solutions.

For example, you mention looking at a Sundanzer fridge--frequently, an EnergyStar fridge uses almost the same mount of power and is 1/3 the cost--spend the savings on a off-grid TSW inverter and a couple extra panels... You will gain frost free, auto ice maker, and through the door water.

-Bill

Yes that is what I would like. Basically a large UPS.

No plans to go "off grid" for now.

The hole thing is what I like to call a practical hobby. I'm not too concerned about return of investment.

I like the idea of an ice maker too:cool: I see how much the wife and kids are getting in and out of the fridge & constantly leaving all the lights/ tv's on and I cringe

Have not been able to get them trained yet:roll:

BB. · February 2009

Re: Sun 90 solar panels

Putting on my Mr. Repetitive Hat--again... :roll:

Really, get a Kill-A-Watt meter to measure your 120 VAC 15 amp (max) loads. It is the only way to go for small appliances. Believe me, there is nothing better, for the price, out there.

Kill-A-Watt AC Power Monitor Meter
P4400 Cumulative Killowatt-Hour Monitor

There is another version that contains a backup battery... Probably nice to use for those Off-Grid situations where you turn off your inverter (or the inverter goes into standby/sleep/search mode). WindSun does not have it in their store, but you can search around for it using "P3 International P4460 Kill A Watt EZ Electricity Usage Monitor".

Run all of your major appliances AC loads on the meter--about 1 week each--and you will know where your energy wasters are. And some of them may surprise you... I have an old CD Stereo (my first somewhat nice--for me--stereo that I purchased 20 years ago). Found that "turned off" it used over 20 watts (more than I was using for my laptop computer in every day).

The new Energy Star rated TVs seem to "run in standby" at 1 watt or less... There have been major improvements in energy efficiency for many appliances/electronic devices.

For major loads (i.e., 240 volt such as A/C, Electric Stove, Hot Water heater, etc.)--you can probably monitor your daily power use with the utility meter.

For my own use on larger loads, I got a used utility meter and socket--and wired it up with cords to patch into large equipment... Accurate and easy to do. Plus it can be done cheap. :cool:

On those with the mechanical rotor, you can measure how many seconds per revolution, and back calculate the Watt draw (stop watch and calculator). Very handy.

-Bill

niel · February 2009

Re: Sun 90 solar panels

horsefly76,
as was said, conserve. there is nothing wrong in wanting a whole house ups and you will need to figure what inverter to go for. solar you can worry about later when you get your place on a more permanent basis. this also gives you plenty of time to educate yourself on the subject and make a good decision as to what to go with.

tony,
if i remember rightly, i believe i brought up that very question in the past and i think the answer is it should work if the panels see + ground or no ground.
there would be no such thing as mixing + and - ground as that is called a short circuit.

BB. · February 2009

Re: Sun 90 solar panels

Tony,

I forgot to add, nothing in SunPower's current documentation states that the problem has been "fixed".

Their installation and inverter instructions still call out the positive grounding requirement for their larger, current production panels.

-Bill

PS: From everything I read--I believe the panels must be positive grounded. If ungrounded/floating--and one or more series connected panels floats "positive" with respect to ground--you will get an output reduction. I don't see anyway around the problem that does not positive ground the panel strings--unless one does not care about the documented power loss.

icarus · February 2009

Re: Sun 90 solar panels

Niel, Bill,

With my limited knowledge of sparks, I do understand that if you wired one panel Pos grd, and one neg ground, you create a direct short! :grr

On the other hand, is there any reason that I can't wire the other panels in the array, and the batteries to Pos. Grd?

Tony

BB. · February 2009

Re: Sun 90 solar panels

As long as you understand the issue (such as with the old IH truck and old British/American cars) with positive ground and DC appliances/applications--there should not be a problem.

-Bill

icarus · February 2009

Re: Sun 90 solar panels

All my 12vdc wiring is home runned using #12 romex, so that nothing is using ground for one leg of the circuit. Come to think of it, I'm no sure that the batteries, controller are grounded.

Tony

BB. · February 2009

Re: Sun 90 solar panels

Tony,

One thing to double check is that your charge controller is not negative grounded through the mounting/metal box of the controller... You may need to explicitly isolate it on a (dry) plywood panel (if it is not already).

-Bill

icarus · February 2009

Re: Sun 90 solar panels

I will have to check to make sure nothing in the system is negatively grounded.

If so,, I'll consider rewiring after doing a bit more researching....

If everything is negatively grounded, I might see what happens when I wire the Sun 90 negatively grounded,, to see how the output is over time.

I'll post here when I get some meaningful results.

Tony

mike95490 · February 2009

Re: Sun 90 solar panels

If you wire that panel in series with the others, when it gets "poisoned" it will reduce all the power in the string.

icarus · February 2009

Re: Sun 90 solar panels

Thanks Mike,

but no series,, only parallel. 12vdc nominal system,, panels, controller, battery, inverter etc.

Tony

BB. · February 2009

Re: Sun 90 solar panels

I "re-found" a link to an original PDF Sunpower paper (short version?) on the issue:

[PDF] SunPower Discovers the “Surface Polarization” Effect in High ...

Basically, the Vmp output voltage drops by ~4% and Imp output current falls by ~9%.

Before => after (Vmp and Imp may shift, so Pmp may not equal Vmp*Imp)
* 90 watts => 62-78 watts
* 21.4 Voc => 20.54 volts
* 17.6 Vmp => 16.90 volts
* 5.12 Imp => 4.66 amps
* 5.55 Ics

-Bill

icarus · February 2009

Re: Sun 90 solar panels

It will be curious to see how this works in the field. I will keep everyone posted.

It looks like in a string, the biggest risk is drawing down the string Vmp from ~17.4 to ~16.9 , a not insignificant amount.

Now, the question is,,with an off grid system, does that really matter, as the voltage is really controlled by the battery voltage. Might change the mppt boost a tiny bit.

Any thoughts,

Tony

mike95490 · February 2009

Re: Sun 90 solar panels

Just on a hot day, coming up short of a full charge.

icarus · February 2009

Re: Sun 90 solar panels

Mike,

I'm not sure what you are saying.

Are you suggesting the only time it would matter to me is on a hot day, when my batteries are nearly full?

Tony

Sun 90 solar panels

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