Need help regarding Solar Panel DIODES
samadniazi
Registered Users Posts: 9 ✭✭
Hi , I am new to Solar Energy.. I bought (1) 150w Solar Panel , the problem i am facing is that, i am getting volts 19v but after connecting load , i am unable to see AMP using Ampere Meter.. and Fan is also moving too slow.. so I have opened the Junction Box and see too many Diodes.. so i just checked every diodes it seems to be dead.. even Current is not passing from each .. I want to know why there is so many diodes in 1 solar panel.. Diodes (10a10) Pictures are attached for reference.. Should i have to buy all of these 15 diodes for my 1 solar panel... or i can use only 3 diodes???
waiting for your reply...
waiting for your reply...
Comments
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
His setup;
Normal panel wiring;
I just picked up the image, I believe you can ignore the added diode, it clearly shows 3 in the box.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
How have you measured the panel? How large a fan are you connecting? Watts and volts amps, type (brushed or brushless)... Panels in good direct sun will produce about 75% of their panel rating.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
The fan, particularly if used may have more resistance now than spec'd. you also don't have good connections with a wire just shoved into the MC4 connections, also a very thin wire, not sure about your distances.
You could check the short circuit current with a hand held meter to give you a better idea if there is a problem with the panel.
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
I am available for custom hardware/firmware development
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
I seriously doubt the panel is the problem. Hopefully you get all those diodes replaced in the correct orientation. Being that you are having difficulty operating and knowing you haven't got the correct meter for the task at hand it sounds like you really shouldn't be removing diodes. If you are trying to run the fan by just pushing those tiny wires into the MC-4 connectors you should expect things to not be working properly.
How far is the panel from the fan (how many feet of wire?) ? What gauge wire are you using?
2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric, 460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
Your meter, as Photowhit says, can only measure AC current. It cannot measure DC current. You need to get a DC capable current clamp meter like this one from Sears:
http://www.sears.com/craftsman-digital-clamp-on-ammeter/p-03482369000P
Next, the 5 diodes are in parallel--Equivalent of 1x larger diode (this may be a good thing--I have always worried that the 1x diodes would overheat if ran at rated current on a hot roof in a plastic J-Box).
And Photowhit's diagram is incorrect. Those are not blocking diodes, they are bypass diodes:
Modern solar panels used in systems these days do not use blocking diodes (older/smaller panels for direct battery charging without a charge controller is when blocking diodes are typically used).
Blocking diodes will have upwards of 10-12 volts or so "reverse voltage" (exact voltage will depend on specific panel wiring/configuration and loading+sun on panel). When you have a 60 cell panel (30 Volt Vmp) and 3 bypass diodes, you will have 20 cells or ~10 volts at Vmp across each diode. If a part of the panel is shaded, then the voltage will switch from "reverse" ~10 VDC to "forward" ~0.2-1.0 volts across a bypass diode (assuming full sun and a DC load on panel).
Solar cells are literately "giant" diodes. And they do not like much more than ~12 volts reverse voltage--If you have 10 amps in series (high voltage GT or MPPT charge controller), and shade one cell--That cell goes "high resistance" and could see close to 400+ VDC backwards across the cell (and destroy the cell/solar panel). With the bypass diode, instead, the bypass diode goes into forward conduction and "shunts" the current around the "dark"/high resistance cell and lets the current flow through the rest of the cells/strings in the panel+array.
Because you are seeing your DC fan run, there is current flowing (regardless of what your AC only meter says). We need to next look at the Vmp and Imp rating of the panel, and the current/voltage rating of your fan.
Also, we need to guess at the amount of sun (and position of sun) for your panel. More or less, your panel outputs current proportional to the amount of sun you have. If you have clear sky with full sun and the panel facing the sun directly, your panel can output near rated Imp. If the panel is not facing the sun square on--And/or you have clouds, or morning/evening sun, the panel will output much less than 100% Imp (just a little haze and not pointing panel at sun, you can get 50% or less of Imp very easily).
If the current requirements of your load is > Imp (or available Imp current), the voltage of the panel will "sag") and reduce the power available to your DC fan.
-Bill
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
-Bill
- Assorted other systems, pieces and to many panels in the closet to not do more projects.
-Bill
My Requirements: 3 Hours of backup @Night @LOAD 4amp
i want to connect a battery which can easily fully charge with solar panel .. in my city .. 7 hours of Full Sunshine is present @Day . plus i also want to use same load of 4a at day time for continuous when sunlight is present ..
http://www.solarelectricityhandbook.com/solar-irradiance.html
Multan Pakistan
Measured in kWh/m2/day onto a solar panel set at a 60° angle from vertical:Average Solar Insolation figures
(For best year-round performance)
And normally, we design for the load--Not "just" for the size of the available solar panel. For example a 4 amp @ 12 volt load when the sun is present--That is a 7 hour load?
- 12 volts * 4 amps * 7 hours = 336 Watt*Hours per day (DC system)
- 336 WH per day * 1/12 volts * 2 days of storage * 1/0.50 maximum discharge = 112 Amp*Hour battery bank
Now sizing the solar array--You want to power your load from solar and charge your system during the same time (day time). I would suggest a 13% minimum rate of charge (remember, if you discharge your battery bank because of no sun, your solar array has to both recharge the battery bank and run your load at the same time):- 112 AH * 14.5 volts charging * 1/0.77 panel+controller derating * 0.13 rate of charge = 274 Watt solar array
Now--If you do not need to run the loads when the sun is behind clouds--You could get away with a 1/2 size battery bank and 1/2 size solar array...And sizing the solar array based on amount of sun you get per day... A nominal worst case calculation might look like:
- 336 Watt DC load * 1/0.61 DC off grid system eff * 1/0.75 less than ideal weather derate * 1/4.62 hours of December sun = 159 Watt array minimum
That is pretty close to your 150 Watt array... So--You decided how much "back power" you need vs just trying to run a system when the sun is available.-Bill
THanks bill for detail answer... but i still dnt understand,,,, which battery should i buy..??? 12amp or bigger????
As for battery sizing, you really need to understand and work with the numbers and trade-offs in Bill's post. A bigger battery gives you more availability for loads and reduces the need to deeply discharge, but brings a need to have larger sources to properly recharge. These are choices only you can make.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
http://geoiplookup.net/
http://geobytes.com/iplocator/
But these are guesses and are not always correct.
Guessing at your location saves a round trip discussion of where you are at and I can at least have some sort of answer that will be helpful. 80% of the time or so...
Battery bank--As Estragon says--It depends on your needs and usage pattern. For a full time off grid system (charge during day, use at night) 4 amp * 7 hours * 2 days storage * 1/0.50 maximum discharge gives 112 AH
If you only want one day storage, then 56 Amp*Hour minimum.
If you will only use the loads when the sun is shining (9am to 3pm)--You might get away with a 40 AH battery or a bit less... Really depends on your needs.
-Bill
- 4amps * 8 hour discharge = 32 AH minimum
Assuming your solar panel is supplying current during the day when you are using the device.-Bill
2nd After some minutes the charging symbol starts blinking, i have read its manual .. its something Float Charging..?? what is float charging mode???
https://ibb.co/cHfro5
https://ibb.co/gYJ0gQ
- Bulk: This is the charger taking all available charging current (power) from the solar panels and dumping them into the battery bank (100% of available solar energy)
- Absorb: This is when the battery has reached the charging voltage set point (like 14.4 volts for your battery). The charge controller will limit charging current to 14.4 volts and eventually stop (either 2-4 hour typical timeout, or when the sun sets).
- Float: This is the charging voltage that the controller will hold after it decides the battery is full (after absorb cycle is complete). If you draw power from the battery bank, the charge controller will supply additional current to hold 13.6 volts (or whatever setpoint is). This is to prevent the battery from being over charged--Too much voltage/current will overheat the battery and "boil" (electrolysis--Generating hydrogen and oxygen gasses from water)--Once a Lead Acid battery is charged, the controller drops back to a lower voltage to keep the battery charged with a mnimum amount of ch
- No Current/Dark: When the sun has set, the charge controller generally "turns off" the solar panel circuit to prevent current flowing backwards from the battery bank to the solar array (reverse current protection to array).
-Bill