Blocking and Bypass Diodes in a Solar Panel Systems 

This has been the best and most informative piece on blocking and bypass diodes that I have seen, thanks!

Outstanding presentation -- particular with reference to partial shading on sailboat applications.

glad someone finally explained what to do to handle shaded panels.

I've been thinking and guessing a lot of things about solar panels and diodes, I'm glad I found this video confirming my ideas, thanks !

Nicely presented and clearly communicated - thanks

Thank you very much, i have some homemade panels an this was very concise and informative on the use of diodes!!!!

Thank you for the explanation

Best channel to understand solar panels

Good. Finally got some good video giving plain reasoning and avoiding "information bombardment"

This video help me out a lot I am a student becoming an electrician thank you

Very good lecture. Thank you so much for your time and knowledge

very good stuff, straight forward . Best way to say anything.

A lot of great info in a very digestible package. Many Thanks!

From Paklistan ...great thnx

Thanks, idea communicated in a proper way.

You have also "ideal diodes modules" on the market that perform as blocking diodes practically without voltage loss. A pair of them is ways cheaper than an additional controler.

I need a Renewable Doable Coffee Mug! With your AltE logo on the other side!

at a later date,, when i start building my home built micro camper i to tow behind my moped scooter,, i am going to be wanting to order some solar panels. i subscribed to your youtube cannel and i clicked on liked.

Always informative..thanks for this Alt-e.

Excellent info. Thanks, 2 thumbs up.

I'm convinced based on what you say here that my cheap USB charging panel does not have a blocking diode. My battery was almost full and leaving it connected overnight, by morning it's almost empty. What is weird is that the USB cable is hooked up to an "input" so I didn't think it possible for reverse current to flow.

What a great video.i am a big follower of your's.thanks mam for your information... thanks allot

Nicely explained.

Thanks for the diode class.

Absolutely easy explaination

Thanks for the information!

very help full with many thanks

The most excellent explanation. Thank you.

Very well explained. Thanks alot. Could you maybe make a video for using fuses instead of blocking diodes in the case of shading on parallel PV panels. Thanks again

Perfect video

Should mention the effect of PV cells shunt leakage. Different PV panels (quality) can have significant difference in shunt leakage of their individual cells. This shunt leakage of PV cells can interfere will ability to make in-circuit testing of bypass diodes. Sometimes it is necessary to unsolder at least one end of diode to check them. Number one failure cause of bypass diodes is excessive heating due to insufficient heat sinking of diodes. Leaded pellet diodes have poor ability to dissipate heat.

Thanks for the information bout diodes

Can you list bypass and blocking diodes with redundant capacity both amperage and voltage wise…? I plan to combine both fence style and panels that are close to solstice angles in parallel….best example is your sailboat solution. All strings are in 3s and approximately 80 to 100 volts…and between 5 and ten amps…..prefer using ideal style but have no track record on their failure rates….also higher efficiency ones…? Thank you.

I love your explanation....i have a question...the question is some of my solar panels had problems (voltage drop)in each of them(all).finds out the diodes are bad (changed all) while some work and others stil maintain voltage drop... please need your help..thanks from Nigeria.thanks.

Dear altE Store. I have seen some PV systems which use capacitors right after the DC breakers. It is claimed that these capacitors are used to make the fluctuation of the voltage and current from the PV panels to the controller more smooth. Please, explain this to us. Many thanks to your other videos.

You said who have quistion ask in comment section so I am asking and hope to find an answer. At 1:39 lets take the diodes , the anode of them is connected to the negative side and their cathode is connected to the positive side !!! so how they will work and pass current (they are now on reverse bias mode)!! you know to put a diode in forward biasing mode the anode should have higher voltage than the cathode!

I purchased Rich Solar Panels, 190 W. I tested it today using a Watt meter. The day was a clear sunny day, at approximately 12:00 hrs, and the sun at about 80 degrees off the horizon. I had a person angle the solar panel, to try and make it perpendicular to the angle of the sun. I got approximately 111 Watts, 8.5 amps, at 13.5 volts. And when partially shaded by one "Hand" of one person, the current dropped by a factor of 50% from 8.5amps to 4 amps. Under what conditions should I be getting an output of 190 watts? Should I check the diodes, or is there something else that I am doing wrong? I live in Boise, Idaho, and the skys were clear today at approximately 90 degrees outside temperature.

If a panel has bypass diodes in the junction box, why would we have to add a diode to bypass a panel in a series? The internal diodes would provide a current path of the panel for shaded, no?

Great vid Amy

I had a back feed of voltage to one of my panels,and it broke two of the four diodes, It is a 12 volt (220 watt) panel, and the voltage read about 4.7 volts. I replaced the two bad diodes and the output voltage is still around 4.7 volts. Do I need to replace all of the diodes ? Any information will be of great help. Thank You.

At 4:13 unless I am going cross eyed you have the output from the PV panels going directly to positive battery output of the controller and the positive PV input of the controller connected to the battery positive!

WAOUH! You are the best! So I'm not saying: "EUREKA! EUREKA!", but: "UNDERSTOOD! UNDERSTOOD!". Now let me give you a homework (Smile, please!). Isn't it smarter to use a MOS or FET mounted a certain way, as there won't be any loss at all neither in current nor in voltage? As you really really master your thing, lady, pliz upload us a simple schematic of that sophisticated idea. Love you...r ...presentation. ABEGA FOUDA. PASSIONNATE HOBBYIST IN ELECTRONICS, YAOUNDE-CAMEROON.

I've been losing power from my battery even though I have a charge controller. Where should I put my blocking diode?

Please explain about batteries set points along with graphical representation

Could you do a demonstration of a 2S2P panel configuration with one panel shaded and show what the power out of the charge controller does before and after the panel is partially and fully shaded. My concern is with the Bypass diode when it bypasses the Shaded PV....? Does the power drop ~50% or ~75%?

very very help full

thank,s I am from pakistan .You have given good information .if we Do not use Solar Controller then How do we apply a blocking dioad With solar penal.

Does is matter were i put the solar controle battery wires on the battery bank if its more than one battery in parallel. Also great video learning alot.

If string a and b are matched in power but string a gets half power due to shade, then even with a diode won’t the total power be brought down in combiner since amperage is suffering?

AMY YOU ARE GREAT

Tq ma'am beautifully explained.

Thanks for the info. What are the pros vs cons on solar panels configured in Series vs Parallel for a 12v system?

How to check a 50A diode without multimeter?

Shaded sholar shells! Love ya!

when the cell is shaded, the current drops down, like pinching a garden hose. the cell will have static voltage but reduced current flow. the bypass diode completes the circuit in a loop for the panel. I understand just hard to put into words. If a seller says that these are blocking diodes when they are not, I have to wonder why. and there are many. Thanks

I have a Newpowa 70 watt panel that only has 1 diode in it. Can anyone give me an answer as to what Schottky diode I need to replace it with?

Many thanks for the informative videos , please tell us about pvsyst software tutorial?

MUITO BOA EXPLICAÇÃO.

how do i know if my charge controller has a blocking diode

i have a solar panels installed there and recently i have installed hybrid system with generator and now my question is that when there is bright sunshine the solar mppt modules get burned ? so what could be the reason ?

since glass envelope diodes are allowing uv or sun light to goes through in it and it has a p-n junction,is there way that i can use bunch of glass diodes as a photo voltaic and works like solar cell that procuce voltage?

Are in night with out solar controller charger solar panel connected directly in this case damages for solar panel or solar panel diodes please inform us or me

Awesome thank you so much!

Hi am from Nigeria..

I currently have this problem. One of the panels connected in parallel to other panels is partially shaded during the day, and as the day progresses the panel that is shaded changes during the course of the day. I thought of using an individual charge controller per panel, but this will not work for several reasons. First, the smallest charge controller that I thought off placing per panel has a higher activation voltage than the maximum voltage per panel. Second, even if the first problem was not an issue, the maximum power point would not be reached, and last but not least the charge controller that I need is part of a group of charge controllers connected as slaves and master. I thought of using optimizers, but the optimizers have an MPPT feature that conflicts with the MPPT of the charge controllers. So, far I have not found an ideal solution for this problem. Any suggestions?

I have a 265 watt 8 Amp what type of bypass diodes i need? .can i buy a 15 Amp bybass diode or 10 amp by diode.

Explain clearly with circuit where and how the diodes are connected across the solar panels

i have two 100w 12v solar panels. each panel has a imax of 5.72A. and diode rating of 12a. and 10A fuse rating. if i wire 3 of these together in parallel to try and create a 300w. 12v panel will they destroy themselves? seeing as how the current together could rise to over 15Amps which is higher than the diode and fuse rating?

Could you please state the increased module efficiency in using by pass module?

Is that a Genasun boost charge controller..? I have a question about the diodes. With a flexible solar panel rated at: 19v, 6.7a, 120w, how many OMS should the diode read if working properly..? (or does it matter how many amps the panel is rated at, do the diodes all read the same when tested..? (How do the amp rating affect reading the multimeter..?

My solar panel works fine in the morning hours, but falls off dramatically from mid-day on. Typically I will see 15a coming in at 10:30-11am, but around noon it falls down to 1-1.5a. I have checked all wiring, connectors and terminals and everything looks fine. I have one 250w panel connected to a Victron 100/20 MPPT feeding a 200ah LiFePo house bank on my boat. The MPPT was removed and bench tested by a shop and it passed. Do you think I may have bad diodes? Can I test the diodes without removing them from the black box? Thanks.

Gr8 video Would a blocking diode be required for each parallel string connected to a string combiner box ?

This is a well done informative video. Question- looks like I blew the diodes in 2x 100W panels. I am guessing by disconnecting them in full sun or an intermittent short I created when installing a transformer on the load side of my 2x Morningstar SunSaver controllers. Still seems odd as the controllers are full featured and I would have guessed they would protect in this scenario. If I replace the diodes is it possible the panels will still work?

Does it matter if the panel doesn't have any diode? Since my diodes are broken and I seemed to be difficult to find new one

Suggesting i have say 4 panels in series, say 100w 12v, and i wish to add bypass diodes for each, would each need to be rated the same, and how much, and why?

Specifications of blocking and bypass diodes?

Texas Instruments makes an "active diode" (FET) that has a very small forward voltage drop (0.026V) at 8A, and can handle up to 15A. www.ti.com/product/SM74611

Hi Amy, interesting that you bring up the two parallel system issue. I have a 600W wind turbine with a MPPT controller and will be adding the Renogy 600 W 6 panel system with the 60 amp MPPT controller going to the same 12 V battery bank. I would think that with two different MPPT charge controllers running in parallel to the batteries that each would have diodes blocking backflow, thus negating the need for additional blocking diodes. Am I doing the right thing or are there other precautions I should take ? Thanks Jim K RV Prepper

my name is Bobby. my profile picture here is of my girlfriend Patty who she sadly passed away from heart failure about 17 years ago. you did a very great job on your video on blocking diodes. i do have a question i like to ask you,, i understand that a blocking diode lets electricity travel one way but blocks it from going the other way,,,, i do understand that in the blocking mode that the diode blocks most of the electricity but there is a little voltage loss of some electricity passing through,,,,,,, now here is my question,,, could i use 2 diodes or better yet even 3 or even 4 diodes in series and have less of a voltage loss,,, or is that something that by using 2 diodes in series will be a bad idea.

You mentioned in your video, that it is best to install separete charge controllers for each string of panel, although it is more expensive. What do you mean by that? Do you have a video on this subject? Thanks.

..why not do bypass diodes on every single cells instead?

in a nutshell, for efficiency of panel then i should remove the diodes and run all panels through charge controller ?

May I ask what is the cause of reversing error on the scc during night, the connection of the panel is series, thanks

Some PV panel manufactures states the bypass diodes that is in their panels. how to select blocking diode for a given panel? for example for a 260W panel

Hi, do you mind tell how can I charge different type same voltage battery in parallel connected to Hybrid Inverter. when the batteries can also be charged by grid when solar is not enough.

hi, i am make my only solar panel and i want to know how to pick the right blocking diode? i am boosting the voltage from 7.5 to 13.0 volt with a boost converter. and i plan to increase the amperage from .2 Amp to 3.5 Amps. So how do i calculate to get the right diode to charge a 12 volt car battery without a charge controller ?

Is that become basic in all panels

In case of grid connected PV system, what might be security for backflow of higher grid voltages to inverter?

whats the best bypass diode dor a 50w solar panel 3.19amp?

Diode how is the shadow that know so how is it working ???

Hi..I have a panel output of 150 watt with 8.5 amp approx, also I have diode of 6amp and 3ampCan I use it both in order to save panel from reverse current

Fisher 30 Pacific Child says Thumbs Up..

but still rechargeable right

Hello ma'am, this was quite fruitful but i have a doubt as to where are the charge controllers placed in MW plants as there are no batteries there? And only the bypass diodes are present in the modules and not the blocking ones?

Thank you for your kind and well presented video. Yet, one question begs clarity. When 3 panels are connected in parallel not serial, would a blocking diode or better yet MOSFET on each panel be best to prevent a shaded panel from drawing current from the others ? I only heard you mention it is a good idea for serial panels... but what about parallel panels ?

Can solar panel run with out diode is I already got the regular charge?

Please advice on using solar panels to pump water

Blocking Voltage of bypass diode

Kindly send me one solar charge controller. Thanks

just checking because the the amps on the battery is high, and how do you what kind of battery do you use because in some battery doesn't show me the amps hour