Solar Panels in storage

aweman · December 2014

Good day every one, amazing forums ya got here. I've been lurking and reading for the past 3 weeks and now it's time to ask questions.
I recently inherited a pallet of solar panels (20) from a family member who passed away, they were in dark storage for over 4.5 years. There also was an old inverter, Emmerson i think and it's from a data center because of the 18inch mounting distance and 4 to 8U's high, heavy boat anchor. he liked to patch up old tech and make it go.
So the first question is, does the dark storage take away from the lifetime of the panels. I don't think so but...
I don't think they are new, but they all output power and seem in good shape

The panels are rated at
peak power STC Pm 185W -+3%
Max power volts Vm 36.72V
Max power current Im 5.04A
open circuit volts Voc 44.0V
Short circuit current Isc 5.35A
Nom operating temp Noct 45°C -+2°C
Max power Pmax at Noct 166.5w
Current @ rated operating voltage Im @ Noct 5.06A
Max system voltage 1000V(TUV) 600(UL)
series fuse rating 10A
STC: E=1000W/M2 AM=1.5 T=25°C
Operating temp -40°C to +90°C

Not quite understanding all those numbers, but from my reading thru the forums.. I think these are 24V panels for a 24V setup, the old inverter is 24v also
Could these be used for a offgrid install? I have some land in northern Ontario, small cabin and we use propane for cooking and lights. Since it's a family cabin... I think that's where these PV's were intended to be installed, but he got sick and passed.

Any help would be great and thank you all

TTYL
Cameron

icarus · December 2014

Re: Solar Panels in storage

First...welcome to the forum. There are some very shape, vry helpful people here, present company not includied'

First,your panels shouldn't be harmed one whit by being in storeage.

Second, they would be fine for an off grid system, even a 12 vdc system assuming you use a MPPT controller.

I need more info on the inverter.

Once again, welcome and keep in touch,

Tony

BB. · December 2014

Re: Solar Panels in storage

aweman wrote: »

The panels are rated at
peak power STC Pm 185W -+3%
Max power volts Vm 36.72V
Max power current Im 5.04A
open circuit volts Voc 44.0V
Short circuit current Isc 5.35A
Nom operating temp Noct 45°C -+2°C
Max power Pmax at Noct 166.5w
Current @ rated operating voltage Im @ Noct 5.06A
Max system voltage 1000V(TUV) 600(UL)
series fuse rating 10A
STC: E=1000W/M2 AM=1.5 T=25°C
Operating temp -40°C to +90°C
Cameron

Hi Cameron,

As Tony says, as long as the glass is not broken and the backs of the panels are not torn/holes in the plastic, everything should be fine.

These are true "24 volt panels" for charging a 24 volt battery bank with a PWM (less expensive type) of solar charge controller. However, we today's modern controllers, you can take two of these panels and place them in series for a higher voltage array with an MPPT type solar charge controller (good for larger arrays and those arrays installed farther away from the battery shed/charge controller--You can use smaller diameter copper wire for the run).

20* 185 watt panels is a good size array. For an off grid system, we recommend a 5% to 13% or so rate of charge for the battery bank. For a weekend system, you can get away with a 5% rate of charge--However for a full time system (and one you don't have to constantly manage battery bank state of charge, amount of sun that day, and your loads), a 10% rate of charge or more is better.

In general, we don't want an over-sized battery battery bank. They are expensive, take maintenance, and have to be replaced every 3-8 years or so. For your array, I would suggest for a 24 volt battery bank:

20 * 185 Watt panels * 1/29 volt charging * 0.77 panel+controller derating * 1/0.05 rate of charge = 1,965 AH largest battery bank
20 * 185 Watt panels * 1/29 volt charging * 0.77 panel+controller derating * 1/0.10 rate of charge = 982 AH nominal battery bank
20 * 185 Watt panels * 1/29 volt charging * 0.77 panel+controller derating * 1/0.13 rate of charge = 755 AH minimum "cost effective" battery bank

Note that for many reasons, I would suggest avoiding a battery bank over ~800 AH if you can. In this case, I would look at a 48 volt battery bank. But, of course, that would mean a new AC inverter rated to run on 48 volts. Not cheap.

Also, larger battery banks need larger generators+AC chargers to keep the batteries up in poor weather (when you are using the system). Another reason to keep the battery bank as small as practical for your needs.

We need to know more about your loads, how far the array is from the battery charger+battery bank. You could use these panels to charge a 48 volt battery bank--But, as always, the devil is in the details.

Your array can supply:

20* 185 Watt * 0.52 end to end system eff * 4.0 hours of sun minimum for ~9 months of the year = 7,695 WH per day

That is more than enough to run an efficient cabin or small/energy efficient home (3.3 kWH per day will give you a Refrigerator, lights, laptop computer, clothes washer, well pump, etc.).

And a 755 AH @ 24 volt battery bank, assuming 2 days of storage and 50% maximum discharge:

755 AH * 24 volts * 1/2 days * 0.50 maximum discharge * 0.85 inverter eff = 3,851 Watt*hours per day

That would be a very effective system.

-Bill

aweman · December 2014

Re: Solar Panels in storage

Good day all and thank you for the quick response's.
I went out to check the Inverter, and my error it's a old UPS Emerson computer power 800watt
the batteries have been removed and the wires hang out the back , not sure whats doin there ? external batteries
it's probably free-recycled scrap , and not going to work the way I want it to.
I think it's probably best to start with the proper equipment for the proper job, like a pure sign inverter Outback or Magnum

Thank you

aweman · December 2014

Re: Solar Panels in storage

These are some photo's of the equipment
Attachment not found.
Attachment not found.

Photowhit · December 2014

Re: Solar Panels in storage

I would sort out what you want to do at the cabin, you could do a minimal system for cheap if you just wanted some lights and tunes when your there, You have the panels for a pretty good size system, but might not need that much system for what your needs are, 4 panels and 4 golf cart batteries(@$400), a cheap PWM charge controller($150-200) or a midnite Kid MPPT (@$350-400 with temp sensor possibly Whiz bang monitor module and shunt) and a 24 volt inverter like the Samlex or Exeltech ($200-800) Really don't need to go with a Magnum or Outback unless you need generator support. Might do a complete system for what you would spend on a high dollar inverter.

icarus · December 2014

Re: Solar Panels in storage

How many panels do you have.

The best rule of thumb is design around the loads. The loads define the battery requirements, the battery define the app regimen etc. any other process is working sideways or backwards. My venal rule of thumb is to take the rating of the PV, divide that by 2 to account for cumulative system loses, then multiply that number by 4 to account for the average hours of good sun one could expect per day, over the course of the year, taking into account weather , seasons etc. So 100 watts of PV might look like this, 100/2=50*4=200wh/day. This gives you a good place to start to design a system.

As a side note, we live off grid with 400 watts of PV' and routinely use ~5-800 WH/day, and very seldom have to run a genny, except in extended grey periods in the late fall before the is snow.

If you have extra PV that y wish to lose, let me know, I might be interested in picking up a few panels.*

Good luck and keep in touch.

tony

*This illustrates the second rule of PV dynamics! Loads always grow with time! Mine have, and now I am wishing for a few more watts of PV.

The first URL of PV dynamics is people always underestimate thier loading, while at the same time they over estimate thier charge ability from PV, leading to deficit charging.

T

aweman · December 2014

Re: Solar Panels in storage

I was just doing some off the sticker math, and I am not sure if I am thinking rite
20 pv panels at 5.05amps each, all in parallel would be around 101 amps @24v
101 amps if over the rating of any charge controller, so in that config I would need two strings of 10pv panels & two controllers ?
or 20 pv 2 in series or 10 times 5.05a = 50.5a @48volts
this seems like one charge controller could handle that
as it is rite now, all I own is the 20 pv panels
all I am doing is trying to figure out what I can build with this equipment I inherited.
I guess I have to get a kill-a-watt meter and figure out my power usage, but I all ready know I am a media whore and my ham radio equipment sucks power.
I was doing searching on charge controllers, and it seems the best ones for RF interference are Morningstar Advanced MPPT Charge Controllers. Has anyone else discovered this to be true, and how much noise do inverters usually make?
If we had power at the cabin, I know I would spend more time there.
I am always open to advice

Thanks again and take care
Cameron

CDN_VT · December 2014

Re: Solar Panels in storage

aweman , Any serial numbers or name plates on the panels ? storage of panels is what I have done . I bought extra to keep if something went wrong on my system , or to add if needed , if not I sell as required . 4.5 years in storage from new ? or used ?

I have 2009 panels 100W + , small 10-20 watt ones I've dated them & 2014 Canadian Solar winter load ones all noted on date built & position installed . some are spares for a replacement due to a golf/baseball or bullet

Sorry to hear about your Family member passing before he had a chance to use this for the cabin.

VT

Photowhit · December 2014

Re: Solar Panels in storage

aweman wrote: »

...20 pv panels at 5.05amps each, all in parallel would be around 101 amps @24v
101 amps if over the rating of any charge controller, so in that config I would need two strings of 10pv panels & two controllers ?
or 20 pv 2 in series or 10 times 5.05a = 50.5a @48volts
this seems like one charge controller could handle that...

Yep, you can spend a fortute making use of all the panels or figure out what you need and go from there.

Charge controller are rated on their output amps, MPPT type controller use most of the wattage and down convert to the needed voltage, but panels typically only output 75% of their panel rating...

...so the figures look like this;

20(panels) x 185 watts = 3700 watts x .75 (Normal Operating Cell Temperature) = 2775 watts available most of the time in direct sunlight.

With MPPT type charge controllers you can expect to max out available amps on a typical day as 2775 ÷ 24 = @115 amps or 57 amps at 48 volts.

If you choose to go to 48 volts their are less available in expensive inverters.

Do you reside in the US? You might do a grid tied system for your home, always the most productive use of solar panels. Just a few areas of Canada have grid tie as an option(from what little I know of Canada, heck they won't even let me visit your country!)

If the cabin is used a lot, you could look at a system there, but this would be a similar system to what I have at home, Total costs after panels might be $7000, Battery Bank $3000, Inverter $1500+, Charge controller(s) $600, Epanel, wiring, combiner box, breakers or fuses $1500, Back up generator(?),mounting system...

Grid tied system would just have mounting and inverter...

Photowhit · December 2014

Re: Solar Panels in storage

I see you have a NOCT value posted of 166.5 watts, that is nearly unbelievable 90%! Not sure I have ever seen anything above 80%, so a bit more power than what I was suggesting @3300watts.

There are some hams around here and some threads about rf problems, I'd search through the threads.

CDN_VT · December 2014

Re: Solar Panels in storage

Photowhit wrote: »

(from what little I know of Canada, heck they won't even let me visit your country!)

Whats that all about ? I get to visit all country's , & I wonder why they would let in a eye google .

Many myths are flowing
VT

Photowhit · December 2014

Re: Solar Panels in storage

CDN_VT wrote: »

Whats that all about ? I get to visit all country's , & I wonder why they would let in a eye google .

I was on a bicycle trip, and was in Vermont(maybe NH) and I was trying to go down hill. Down hill went through Canada. I had a Florida DL with a PO box and had no home address, actually was using my mom's, at that time you couldn't have a FDL with out a physical address. I had no 'job' and had camera gear, a midget mat cutter, with me... tools of two of my trades. I had no clear destination in Canada, I wanted to go down hill, I was on a bicycle! Even when they asked if I had any relatives in Canada my truthful answer seemed odd since my biological father lives there, though I hadn't communicated with him in 20 years... They wouldn't let me in... NO MYTH!

Attachment not found.

I really didn't want to have a home base I was 6 months into a 8+ month bicycle trip and had actually planned on 18+ months, but I wintered in Missouri and fell in love. 7000+ miles... lots of fun.

CDN_VT · December 2014

Re: Solar Panels in storage

SIR , Get a passport . If you were on the PNW side of North America , things might be slightly nicer.
Either Way , I have had a passport since the 60's since I do mark like a dog.

Friggin cool pix.

Oxford MS I spent some time, Either way , get a passport , some ID of such & let me know your plans ahead Of a transfer spot . I'll make sure you get the Queens Royal Cavity search 8)

Many of guests come and see frozen maple snow , it grows off tress.

Kidding (for those who don't know)

I wasn't allowed in USA @ at 11:00 pm due to curfew in 196X ,, (i had already fallin from the nest) , slept on the Peace Arch grounds , crossed next day @ 08:30 ..

Now I travel 360 around the 3rd rock . I'll meet ya , and show you Canukland ! It's your NSA that has their fruit of the looms in a bunch.

Scuba-Junky · December 2014

Re: Solar Panels in storage

WARNING: If you are using ham radio equipment please be aware that every MPPT charge controller I've played with produces EMI/RFI every 25hz or so. This interference will drive you crazy. I have tried all sorts of filters, toroids, extensive bonding/grounding and it just doesn't help much. There is also the possibility that adding chokes, capacitors, toroids to the PV array cable connections may even inhibit or interfere with the proper functioning of the controller.

The more separation you have between your antenna and your solar array does help, but most people due to logistics are forced to have both fairly close to their house. What happens is the controller uses 25khz as its pulse sampling frequency. This SIGNAL goes back out the PV cables to the PV array. The cables and array then act as a giant antenna broadcasting this signal. I can't believe this technology is allowed. Shoot, this can even be a problem if your the type to listen to over the air broadcasts on your stereo receiver.

Believe it or not, if you install a $40k PV system and it interferes with your ham radio neighbor, he can report it to the FCC. The FCC will come out with special equipment and if the PV system is in fact radiating interference, they will first issue a warning and if necessary followup with a citation to the owner of the PV system. This has actually happened with plasma TVs. They generate a huge amount of EMI/RFI. After 2015 plasma TVs will no longer be sold in the US.

We really need to get a thread going that HAM radio / Short wave enthusiasts can post what controllers, inverters etc., actually work and which ones cause interference.

Don't buy an expensive MPPT controller thinking you will be able to clean up the EMI/RFI. I can almost guarantee you won't be able to and you won't be able to return the controller and exchange it for a different one. Most suppliers will not take them back, or will charge you a restocking fee, etc.

The only solution I know of so far is to use an older style PWM charge controller.

I'd love to have someone chime in and tell us EXACTLY what controllers actually work well without producing EMI/RFI. I'd like to know the details as to exactly how things are configured, separation distance between panels and antennas, types of antennas, system voltage, bands of operation checked, etc. If your out west, I'd want to stop by and actually witness the claim in person though.

Norm - W7CK

aweman wrote: »

I was just doing some off the sticker math, and I am not sure if I am thinking rite
20 pv panels at 5.05amps each, all in parallel would be around 101 amps @24v
101 amps if over the rating of any charge controller, so in that config I would need two strings of 10pv panels & two controllers ?
or 20 pv 2 in series or 10 times 5.05a = 50.5a @48volts
this seems like one charge controller could handle that
as it is rite now, all I own is the 20 pv panels
all I am doing is trying to figure out what I can build with this equipment I inherited.
I guess I have to get a kill-a-watt meter and figure out my power usage, but I all ready know I am a media whore and my ham radio equipment sucks power.
I was doing searching on charge controllers, and it seems the best ones for RF interference are Morningstar Advanced MPPT Charge Controllers. Has anyone else discovered this to be true, and how much noise do inverters usually make?
If we had power at the cabin, I know I would spend more time there.
I am always open to advice

Thanks again and take care
Cameron

westbranch · December 2014

Re: Solar Panels in storage

You might want to cross post this challenge on the MidNite site, boB is a ham operator K7IQ and he designed their Classic line of charge controllers...http://midniteforum.com/index.php?action=unread

Vic · December 2014

Re: Solar Panels in storage

Hi Norm,

Nice to see you on this Forum.

Well, essentially, all digital electronic devices emit some EMI/RFI. The more work that these devices do (generally) means more EMI/RFI.

Emissions are generally Conducted via the interconnecting wires/cables, and as you note, the PV leads are often the largest emitting antenna, even if the PV wires are in metal pipe, all of the way to the individual PV strings.

Often, the emissions can be REDUCED to tolerable levels with judicious use of Toroidal inductors (like Common-Mode chokes). And separation of the emitting conductors from the receiving antennas is often effective.

MPPT CCs are not the only system power electronics that do emit EMI/RFI. Inverters often do, as well. And seems that the cheaper the inverter, the greater the chance for large emissions. Try to shield all above ground AC power leads, and bury the feeders from the power electronics to the points of use. If one is doing new construction, try to use metal pipe for all AC runs in the home, shop, and other buildings with AC power.

Quality AC inverters should be tested to FCC Class B, at least for USA sales. For inverters, FCC B includes frequencies from 100 kHz to 30 MHz, for conducted emissions on the AC cables attached to the inverter. This is part of the Class B test.

For Charge Controllers, there is NO test for Conducted emissions, as there are NO AC cables connected to CCs, in general, so the emission tests begin at 30.00 MHz, IIRC. This leaves the entire LF, MF, and HF radio spectrum without conducted emissions, where, the RFI conducted/emitted is by far the greatest ... a bit unfortunate.

The MPPT CC with the lowest emissions, and the one that responded quite well to shielding and Common-Mode choke emission reduction is the venerable Outback MX-60 -- long out of production. Have not tested the OB FM line of CCs for emissions.

Some of the more feature-laden, complex MPPT CCs have quite strong emissions, which, when substituted for the MX-60, with all of the previous emission reduction items still in place have had emissions 30, or more dB greater then the MX, on the same (low HF) band, and with similar power levels.

Like to DX on the low bands, so, many times, the CC emissions (which are essentially ALL created when running the power-making Buck Converter) are absent while DXing, as there is no, or very little sun.

Much of this, and some more is covered on this site in this L O N G Thread:

http://forum.solar-electric.com/showthread.php?5887-Radio-Noise-from-PV-System

All FWIW ... separate, shield, CM Choke, and bury AC leads in the ground help LOTS. YMMV. 73 GL, Vic ... Kilo Six Italy Charlie.

Scuba-Junky wrote: »

WARNING: If you are using ham radio equipment please be aware that every MPPT charge controller I've played with produces EMI/RFI every 25hz or so ...The more separation you have between your antenna and your solar array does help, but most people due to logistics are forced to have both fairly close to their house ...

The only solution I know of so far is to use an older style PWM charge controller.

I'd love to have someone chime in and tell us EXACTLY what controllers actually work well without producing EMI/RFI. I'd like to know the details as to exactly how things are configured, separation distance between panels and antennas, types of antennas, system voltage, bands of operation checked, etc. If your out west, I'd want to stop by and actually witness the claim in person though.

Norm - W7CK

Solar Panels in storage

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