SMIC Solar Electric System

&

Military P3-62 Foldable Panel

Brooke Clarke 2009
SMIC System
P3-62 Panel

SMIC System


SMIC Solar Panel
              Front
SMIC Battery Box
              & Charge Controler
SMIC Calibration
              Kit
SMIC Solar Panel
              Rear
SMIC Charge
              Controler PCB

21 Aug 2013 - Sun 250G 250W Utility Intertie Inverter
Sun 250G Utility
                Intertie Inverter

Sun 250G Utility
                Intertie Inverter
22 Aug 2013 - around noon the panel was producing about 70 Watts.  By moving the panel to point more West and Up the power increased to 98 Watts.  A tracking mount would consume less than 30 Watts so should result in more captured power even after subtracting the power needed for the tracking motor.

I tried a couple of times to video the sequencing green LEDs, but they are very hard to see in the sunlight.

The fan in the inverter only runs when the temperature goes above some set point.  That happen around noon when I repositioned the panel and again the fan was on about about 1:30 when the outside temperature in the sun was well over 100 degrees.

Cooling the panel to increase the voltage (power) output may work.
2:30pm 27 Aug 2013 partial shade Ipanel about 1 amp
Sun 250G Utility Intertie Inverter
2:40pm 27 Aug 2013 partial shade Ipanel about4 Amps
Sun 250G Utility Intertie Inverter
Kill A Watt reading reverse (Solar) power.
The screen on the Watts Up (blue DC power measurement device) goes blank after some time.  Why?  So it can not be left connected all the time.  The panel puts out a few watts when there's light but no direct Sun.
Kill A Watt
                reading utility interite invertor power back into grid

Background

A friend mentioned that he had this in his garage and would I like to have it.  Here it is.

Components

Solar Panel

Parameter
Spec
Voc
30.96 V
Isc
8.81 A
Vpmax
22.84
Ipmax
7.67
Ppmax1
175 W
# of Cells
6 * 8 = 48
1000 x 1314 x 50 mm (39 1/4 W x 51 3/4 H x 2" T)
Note 1 - Ppmax is Vpmax * Ipmax, not an actual power.  The actual power will be less than this value.

On the back of the solar panel are a couple of wires, one with a socket termination and the other with a plug termination.  Looks as if you could have gotten ready made cables with matching terminating connectors to make it easier to install the system.  It's probable that when two panels are arranged side by side that you can connect them in series using just the cables on the back of the panel.

Need to find a place where it will not be shaded by all the trees.

The rated output only applies when the panel is getting full summer Sun.  At other times of the year the output will be lower, even when the panel is aimed directly at the Sun because the path through the atmosphere is longer and so less light gets to the panel.

Note that the current into a short circuit is directly proportional to the intensity of the light falling on a Silicon diode.  One of the things that can be done by a power point tracking controller is to short the panel and measure the current.  This is done for some number of micro seconds to get an idea of how bright the Sun is.  Knowing the short current current the controller knows what amount of power is available.  Some controllers do this very often so that they can track as clouds reduce the light to the panel.

13 Feb 2009 - It's been raining for a number of days.  Checked current output from main panel while raining, facing the house in near vertical position and got 200 ma into Fluke 87 DMM in Amps mode.
24 Feb 2009 - 11:45 am 63 F = 7.45 Amps seems to be the peak by manually tilting and pointing the panel.  Need to get the Electronic Load connected and plot the I-V curve next.
13 Mar 2009 - 12:20 am 63.3 F  = 7.83 Amps.  Weston 594 Photronic light meter into ma current mode of Fluke DMM = 163 ma.

Load Testing

Using EL1132 Electronic Load
Outside air temp 81 deg F
Weston 594 about 50 ma
Amprobe LM631A 10940 foot candels
21 July 2010 10:15 am
Not pointed at Sun
Volts
Amps
Watts
25.08
0
0
24.57
0.505
12.4
24.06
1.014
24.4
22.92
2.012
46.1
21.5
3.005
64.6
18.86
3.997
75.4
10.44
4.511
47.0
0.072
4.95
00.4
 Aimed at Sun
Volts Amps Watts
25.44
0
0
24.52
1.012
21.8
23.58
2.011
47.4
22.54
3.005
67.7
21.35
3.997
85.3
19.87
4.997
99.3
17.22
6.121
105.4
10.5
7.1
74.6

10:30 am aimed at Sun, resistor load mode of EL1132
Ohms
Volts
Amps
Watts
11.6
27.27
2.351
64.1
7.7
21.76
2.842
61.8
5.9
20.97
3.553
74.5
4.9
20.26
4.136
83.8
3.9
19.21
4.901
94.1
3.0
17.41
5.866
102.1
2.0
13.71
6.922
94.9
You can see that the load for maximum power changes quite a bit so any fixed load will waste some power.  Hence the need for a Maximum Power Point Tracking (MPPT) electronics package.

12:00 noon PDT
104 deg F
Volts Amps Watts
24.07
0
0
23.16
1.012
23.4
22.22
2.011
44.7
21.19
3.003
63.6
20.01
3.995
79.9
18.51
4.995
92.5
15.64
6.103
95.5
5.3
7.105
37.7

1:00 pm PDT
103 deg F
Volts
Amps
Watts
23.8
0
0
22.92
1.012
46.1
21.94
2.011
44.1
20.87
3.005
62.7
19.62
3.995
78.4
17.64
4.995
88.1
9.212
6.103
56.2

Battery Box & Charge Controller

Uses couple of 14 V automotive relays and has an 8 pin IC marked HA17393 which is a dual voltage comparator.  There are three LEDs (Yellow, Red & Green) but they can not be seen when the lid is on the box.  There may be a transistor and diodes, but no switching mode charge controller.  So the function seems to be disconnecting the panel from the batteries at night or when the panel voltage is below the battery voltage.

A modern charge controller will adjust the load on the panel so that it's near the maximum power point even though that is not the actual load it is supplying.
Maximum Power Point controllers come in many flavors that have different capabilities, it's a subject of many patents.
This may be the same as the YY-12-12.
350 x 380 x 300 mm (14 x 15 x 12")

Enphase Energy  - makes a small Maximum Power Point Tracking Utility Intertie Inverter designed for use on a single solar panel.  About $200 per unit.  Intended for use with many panels where each panel does not need to be oriented the same and where there can be differences between panels or light falling on the panels.  The controller is about $1400 that's required if you want to sell the electricity back to the utility.  This also may require a minimum of 1600 Watts system capacity.  Wiki: Solar micro-inverter

Two each 65 AH Gel Cell type batteries are recommended wired in parallel ( i.e. a 130 AH 12 V battery).

DMM & Calibrated Solar Cell

The idea is to measure the incoming flux at the user's location and time of year and at the same time measure the panel short current output.
The Date, Time and temperature for each measurement are also requested.

Cables

SMIC Solar System
        CablesA couple of cables are supplied that have connectors on one end that match those on the back of the panel.

The other end of the cables has banana plug connectors that will plug into the DMM to allow measuring the panel output voltage and current (although not at the same time).
 The female connector (lower left) is marked:
+
ZJRH
05-1
TUV

The Male connector is marked:
-
ZJRH
05-1
TUV

The wire is marked:
TUV  2  PIG  1169  1x4.0mm2 ZJRH  Cixi   Renhe Photovolaic Electrical Appliance Co. Ltd.

Switching Mode Power Supply (SMPS)

DC IN 10-32 OUT 12-35V
          adjustable converter Module Z
There was a problem in getting a Maximum Power Point Tracking (MPPT) unit for this particular panel because it's output voltage exceeds the spec on the unit I wanted to get.  A way around this is to feed the panel output to a SMPS that's rated to take the possible range of panel voltages and then use it's output to feed a MPPT unit.  That was my motivation for buying this unit which was listed on eBay (seller: wholesell-aa) as:
DC IN 10-32 OUT 12-35V adjustable converter Module Z
and specified:
Module Properties: Non-isolated step-up module (BOOST)
Solar battery charger for electric vehicle
Size: 65 x 33 x 23.5 mm ( L*W*H )
Input voltage :10-32V
Output voltage:DC 12V-35V (adjustable)
Output current: 10A (MAX)
Input current 16A (MAX) (more than 10A please strengthen heat sink)
Output power: natural cooling 100W (MAX), strengthening cooling 150W (MAX) real power
Conversion efficiency: 94% (Under Input  19V 2.5A  output 16V)  For reference only

These specs are for a higher power than my panel can generate (about 100 Watts) at my location (it might make more power at the equator).

Note that as the Sun angle & brightness (clouds) cause the panel output to fluctuate, this module will try to maintain the output voltage constant.  Although not the same aa power tracking I expect it's much better than making a direct connection between the panel and a load.  It's now summer and an interesting load may be a 12 VDC fan, like those attached directly to automotive radiators.

2015 Update
The Moringstar SunSaver MPPT should work with this panel.  Unfortunately these cost over $200.

Summer Attic Fan

These are available as integrated units in the $200 to $400 range.  But it may be possible to use a 12 Volt automotive fan designed to be zip tied to the back of a radiator.  These come in different sizes (diameters) and have different current requirements.  The data from eBay sellers is mostly missing or inconsistant between sellers, but this table gives an idea.
Dia.
Amps
Watts
CFM
SFP=1
Watts
Calc
SPF
6"
4.8
58
300
14
0.19
7"
6.7
80
850
40
0.09
9"
6.7
80
1000
47
0.08
10"
6.7
80
1200
57
0.07
12"
6.7
80
1250
59
0.06
14"
12
144
1200
57
0.12
16"
14
168
1600
76
0.48
The 7, 9, 10 & 12" fans all seem to draw the same power, but a larger diameter fan moves more air.
The 12" fan running seems to be specified at 12V & 6.7 Amps or 80 Watts

Theory

The Specific Fan Power (Wiki: SFP) varies between 0.8 (probably these fans) and 2.5 Watts/litre/second (commercial air handling systems).
1 W/L/S = 0.353 Watts/Cubic Foott/second = 21.18 Watts/CF/Minute = 21.18 Watts per CFM.
These seem to be very inefficient fans.  There may be a better choice of fan type.  If you know of one let me know what it is.

Economics

Suppose this panel, rated at 200 Watts, got the Sun for five hours a day, i.e. generated one kilowatt per day.  If the electric utility charges 11 cents per kWH, then the panel earns 11 cents per day, $40 per year or to pay for it assuming a $1,000 price tag would take 25 years.

If it takes some hours in a oven at something like 1600 deg C to make a Silicon photo cell then there's a cost associated with that furnace time.  This may be the basis for the saying that solar panels (as we know them as of year 2010) probably will not make enough electricity during their lifetime to pay back for the energy used in their creation.  If that's the case then they are not a new source of energy.


P3-62 Panel

Fig 1
P3-62
                  Foldable Solar Panel

Maybe made by Global Solar Energy P3-62.

 Got this in June 2015 as a demiled foldable solar panel.  It's had the label cut off and the output wires cut off back in the fabric.  The wires are plastic coated and laminated into the fabric so it is not a simple matter to make a good electrical connection.  By using a large soldering iron to heat up the plastic that surrounds the wire I think I have remade the electrical connections.

Near the end of the day with the Sun low in the sky the open circuit voltage is 43 VDC, but when I try to measure the short circuit current do not get any current.  It's as if there's a very high resistance in the circuit, maybe my wire splice is not very good?  Need to check some resistances along the wires.



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