You have just enlightened me M8. I had seen the term blocking diode and bypass diode and assumed the two were the same. Thank you. I have been messing with off grid power for ~10 years and you just set me strait.

@OffGridGarageAustralia

3 жыл бұрын

Thanks for the feedback, Michael!

Always know you got a bone to pick when you start it out this way. Good stuff Andy, clarification is always a good thing

That is a really nice way to describe how things work. I already knew the basis but still really enjoyed watching your video. Totally agree that in your scenario you’re unlikely to require a diode. I wonder if I might though, as I’ll be building a solar fence where at times many panels won’t be in the sunlight so maybe that would yield different results. I’ll certainly film a test against that and see if it also works just fine without diodes. I’ll then also compare the diodes with Tigo optimisers as I haven’t really seen such a test but I think they go hand in hand when you look at how those optimisers work. Thanks for another good video!

@user-wi5vk1zi2h

Жыл бұрын

Solar diode manufacturers, welcome to know

Your explanations are so clear ! As always. Thank you for that

thanks for the video. it explained the difference between the two types of diodes very well. thanks

You are right, in my first built east west 5KW unit I measured zero current running in the shaded part when the sun still was bright at the west side. Diodes produce losses, 0.7V siliciums

Very good experiment and explanation. That confirms what i had thought regarding diodes and back current. Earlier today, i found som facts about solar cell tecnique, and read that a solar cell is a type of diode. But the current created by sunlight flows in back- direction of the diode/solarcell. That should explain why the solarcell does not block ” back-current” Back current in the way we ar speaking about will flow in forward direction thru the diode/solarcell.

I would add only that a solar panel acts as diode ONLY in that when power is pushed to the panel it becomes an LED (light emitting diode), however the light emitted is not in the visible spectrum. Thanks for giving me some good laughs when you responded to people's comments though. Although I have a feeling those types of comments will never stop, lol. Great video, cheers. 😎

@OffGridGarageAustralia

2 жыл бұрын

Thanks for your feedback and additional comments.

Solar cells are like Zener diodes, when you exceed their avalanch voltage in the reverse direction, they will conduct.

@OffGridGarageAustralia

3 жыл бұрын

That is exactly right!

@Riddhi42069

2 жыл бұрын

I tried the same .. the solar panel works as a led .... Well its visible through a camera though

@Riddhi42069

2 жыл бұрын

Well its not from visable spectrum

@johnflower8384

Жыл бұрын

@@Riddhi42069 It is, with infrared camera!

Aim from Kenya Africa thanks you Soo much for your instructions

@OffGridGarageAustralia

6 ай бұрын

Thank you Adhan!

Thank you, it’s fantastic to find a You tube site that is easy to understand and is interested in teaching the facts about the subject. Question, is it best to use lithium iron sulphate batteries? I have no experience in solar energy I’m hoping to set it up in my outside work shed.

What blocking diode would you recommend for a 100watt 12 panel. I have shade problems currently and panels in different locations. A part number would be great. Great video.

Good vid. New subscriber earned! Keep up the great content! Cheers, Mate! - Jesse

@OffGridGarageAustralia

3 жыл бұрын

Thank you Jesse!

Great explanation. My double is cleared now 👍👍 thanks

Good video, very well explained re solar panels wired in series, but what about those wired in parallel? I have 3 panels (1x100W, plus 2x 160W) charging 12V AGM batteries for shed power. The 100W faces SSE, and both 160W panels face due South. One of the 160W panels is shaded each morning by a neighbours tree. Should I install a MC4 type blocking diode in the positive cable of each panel output?

Very clear explanation

I have some doubts: 1, The solar strings act like 2 battery cell connected parallel (remember top balance!). Until there is a big enough load the current flows MOSTLY to load. 2, Parallel resistors. The MPPT (and LiFePO4 cells behind it) have very low resistance. The Solar panels have high resistance. So current is flowing through the panels too, but few: R = R1×R2 / (R1+R2) 3, Voltage difference: where there is a potential difference there is current (and bigger makes higher) 4, MPPT is a high frequency DC/DC converter. So it pulsates very fast (open-close) in the solar side. And every time it is open there is an OC (only path through lower V string). 5, You can have a string in East and one on West roof (angle >20). The East is already producing in early morning where the West panels are totally in dark. 6, You can have more than 2 strings parallel. Like 2s6p config for some MPPT's. If one of the strings is in shade then 5 strings will push current through it. 7, Use fuses for the parallel strings. If a short occurs then all the parallel strings production will be going through THAT (lower resistance). Making a big shiny arc (DC so constant arc).

@pau1phi11ips

3 жыл бұрын

The characteristics of the solar strings are very different to 2 batteries in parallel. They don't just try to balance each others voltage.

@rokask

2 жыл бұрын

That's what I feel is happening too! Andy is a great engineer and all, but not so hard on the science part.

Immer wieder gut!

@OffGridGarageAustralia

2 жыл бұрын

Danke Dir!

Thumbs up and subscribed! Definitely learned , good interesting 👍

Good subject!!!! Thanks👍👍👍 Buddy.

Thanku geezer 😜. Very informative.

Junction box diodes are bypass diodes that prevent shaded cells in series with unshaded cells from being heavily reverse biased under load.

I'm learning something. Thanks. So my questions is whether your observation regarding the blocking diode holds true between a full load and no load at the charge controller? Thanks again.

@OffGridGarageAustralia

3 жыл бұрын

That should make no difference, Harold.

Andy, all along, I think the diode inside the solar panel was blocking diodes. You corrected my misconception. Thanks. You said it was not necessary to add blocking diodes since the charge controller had the lowest impedance. Yes, I totally agree with you. But if the battery was fully charged, and the charge controller was in float mode, then the charge controller would not take in any current from the panel. Then panel with a higher voltage will push the current into the lower voltage panel. In this case, will it hurt the lower voltage panel?

great explanation

@OffGridGarageAustralia

Жыл бұрын

Thank you!

Hei Andy, have u tried to check the 5.5v mini solar power if it glows in the dark? If u feed it with 6v or over you'll have a little bit of surprise 😮😉...

Well done!

Thanks for your vids! It seems the solar panel works as a overpriced resistor in this instance?

Well now ill need a beer...after all these years being wrong.

@OffGridGarageAustralia

3 жыл бұрын

No problem, have a beer! 🍺

@eagz2898

10 күн бұрын

I was right, but I am having one too.

A video of Andy sluicing down a couple of beers... and oh yeah, some good information on by-pass vs blocking diodes :)

@OffGridGarageAustralia

3 жыл бұрын

After reading all the comments yesterday and repeating myself 100+ times, it was time for a 🍺

Love ur videos I've looked at a few my problem is my diodes are reading one way like they supposed to but my panels voltage is in reverse I'm getting a negative -00.1 when I test my panel

Simply superexcellent video ; )

@OffGridGarageAustralia

2 жыл бұрын

Thank you very much.

Don't know why you tube said to watch this video but it did. I did. I use a blocking diode between each string in parallel. I don't know what the failure mode is for a solar panel but if it is shorted, I don't want 50 amps feeding it.

Great video! Just with this one, I have become a fan. Question: Why are there specifications of junction boxes with 2, 3, 4, 6 diodes?

@TheRealMonnie

2 жыл бұрын

Diodes can only pass so much current without overheating, so putting more in parallel splits the current to reduce heat.

@damianroth4265

2 жыл бұрын

@@TheRealMonnie Thank you for the reply! : )

Thank you for this video. I'm loading up on research before building my first solar power system. So, then, the shading of one or two panels, will not decrease the output of the string, yes? And the same goes for two series strings connected in parallel?

@billallen275

2 жыл бұрын

The power out will be proportional to the sunlight falling on them. But unless you have a lot of lead resistance to the CC or inverter, then it will probably be negligible. Do the math.

The diode at the back of the solar panel's black box is a bypass diode. Its function is to bypass the panel in case it got damaged (open circuit damage to be exact).

God bless your patience.

well explained.

@OffGridGarageAustralia

2 жыл бұрын

Thank you!

Quite a bit of flickering...you might look into changing those lights...Maybe you get a LED driver (Power supply) and connect it to DC LED panels? The LED driver will make sure that you have a smooth DC Voltage without much ripple at the output. Alternatively you could use a DC-DC converter to dirve the LEDs with your battery bank directly.

You quite correct and thanks

I can see blocking diodes being necessary in an RV/campervan solar system where let's say you park and a tree branch blocks the front of the vehicle but not the back.

Keep up the educative content, Sir. I've learnt a lot from your channel.

All diodes and solar cells act like zener diodes when reverse biased. That includes all semiconductors acting like a solar cell to some degree when exposed to light. If you had thousands of LEDS you could make a solar panel. Although you would need many blocking diodes with one being in each small string, because they can only handle so much voltage before they try to conduct. That was some interesting trivia. Rectifying diodes also will have a much lower effective voltage drop if you put multiples in parallel. PN junctions are weird like that.

@billallen275

2 жыл бұрын

Hadn't heard that in general about diodes... too bad you can't parallel 10 of them and get 0.04 to 0.07Vf! Worth an experiment.

@dantronics1682

8 ай бұрын

you're slightly wrong about all diodes acting like zeners, a zener junction will recover but a normal diode either stays shorted after rv breakdown or burn out

11:00 Solar Panels can become a regular LED emitting light too (when it consumes current). We dont see it because the light is extremely faint.

@dantronics1682

8 ай бұрын

that may be true but show us a situation where one panel would be it total darkness while the other is in lighted area. even in shaded area the solar panel is still producing

Thanks Andy, didn’t know the difference between the two, but you were able to explain this “basic stuff” perfectly.

@OffGridGarageAustralia

3 жыл бұрын

Thanks, Tom.

Love your content! But please fix the flickering when you are in the garage :-) Have a look at 1 min 25 seconds for example. It looks like the fluorescent lights are the ones that make the flickering occur? 50 Hz compensation in the camera? Keep up the good work!!

@OffGridGarageAustralia

2 жыл бұрын

Thank you! You're bit behind with the videos. All fixed quite a while back 😊

Would it be a good idea to have a blocking diode if you have more than one string. It could help if one of the strings were hit with lighting or some other high voltage. It would blow the diode. What do you think?

@OffGridGarageAustralia

3 жыл бұрын

I did another video on this with a test. Blocking diodes are not necessary. kzread.info/dash/bejne/gJV3scaIlMvKhLw.html

So here is my question. If I have 2X 120 watt panels in parallel (on a sailboat - so one may have shade) - should I put a 10 amp blocking diode on each positive before the combiner? So in a boat situation it is not only possible, BUT very likely, that one panel in parallel may be totally blocked by a sail shade..

Great information . Thanks again 👍🏾

Thank you for taking the time to unconfuse the confused and to confuse the unconfused. Haha, SMILEY FACE

@OffGridGarageAustralia

3 жыл бұрын

Hahaha, which side are you on now?

@TheComputerGuyDR

3 жыл бұрын

@@OffGridGarageAustralia I'd reply with "Yes". Not giving you an answer to either but knowing that I'm on one side or the other (or possibly both sides). :: Chuckles ::

Thanks - I was wondering about both of those diodes... answered my question completely!! People should do a little real research in the literature, not U-Toob, before throwing scat.

a blocking diode is only needed if one is using a low wattage panel direct to a battery with out a controller lets say for long time vehicle storage to stop the battery discharging into the panel

@OffGridGarageAustralia

3 жыл бұрын

Yes, that would be a case for such a blocking diode. Great example.

Thank you

Hi! If you use the mppt, that is not giving back the power. It is my infomation. Haw a nice day!

I'm sorry if I'm a newbie, but the way i understood is, blocking diode and bypass diode is the same, it's just the way it is connected that makes it a bypass or blocking. if its connected in parallel in between the + and - in a pv array then it acts as a bypass diode. if it's connected only in the + of the PV in a one way strean of power flow then it wll act as a blocking diode. am i correct? please respond.

@OffGridGarageAustralia

Жыл бұрын

Physically, they are the same diodes, that is correct. Yes, you're correct. Bypass diodes are across the single strings in a panel to prevent total power loss during shading, while blocking diodes protect the panels from current flowing backwards.

@dantronics1682

8 ай бұрын

or in the -ve of the panel

Is the blocking diode needed if you occasionally feed a grid tie inverter with batteries? (Which puts your battery pack and panels in parallel.)

@talentoytrabajo2880

2 ай бұрын

O sea q si lo va poner un inversor o va cargar una batería no es necesario el diodo pero una pregunta porque va el diodo en paralelo con el panel y no en linea recta en el positivo eso es loque yo no entiendo y ya investigue pero encuentro nada al topar puntas del cable del panel siempre se cae el volante así como trae el diodo y de antemano gracias espero me entiendas

Simply said, bypass diode is connected between the terminals, blocking diode is connected in series to prevent back-current. Use a diode with lowest voltage drop for best performance

@OffGridGarageAustralia

Жыл бұрын

The voltage drop or power loss is actually not much different between a normal diode or a Schottky for example.

@paveljelinek772

Жыл бұрын

@@OffGridGarageAustralia if we're talking bout bypass, voltage drop does not matter. If we're talking blocking diode, i always choose schottky. The differential between schottky and ceramic one is not marginal. The performance loss is 1W on my 20Wp (schottky vs ceramic) and progress more as you catch the sun on stronger panels

Hi. If I have only 3 panels, in parallel, the internal bypass diode act as a block diode. Correct? I understand Well?

What if you change the polarity on the solar cell and the bench power supply. How the cell will behave then?

Hey Andy. Good explanation on blocking diodes. I use three of them on my system, but it's very different than your setup. My system is on my Recreational Vehicle and i have three different sources of voltage/current to charge the batteries. I can use the onboard RV charger, i can charge from the tow vehicle, or i can charge from the Solar string. I found that i had to use a blocking diode for each of the three charging systems, as it was possible to be charging the batteries at night and the RV charger would pass current through the solar string. The biggest downside of the blocking diode is the .5v voltage drop that it creates, and the heat that has to be dissipated with the blocking diode. I have a large heat sink on the three blocking diodes to deal with the heat. Anyway, very different application that yours, and the blocking diodes allow me to use all three sources at the same time if i choose to quickly charge the system. Thanks Andy. Good stuff!

@OffGridGarageAustralia

3 жыл бұрын

Thanks James, very good point and a different scenario. If you have panels with different voltage, you need blocking diodes, that is correct. You can get Shottky diodes which have only a 0.2V voltage drop.

@robertgrant5895

3 жыл бұрын

Schottky diodes have a .4 volt drop. Use them for this purpose. Also, your solar charge controller should prevent current from going from your RV charger through the solar string but it depends on how you have it all connected. Seems to me you should only need one diode in the right place.

Blocking diode (function) will be in any good MPPT controller. Or ANY good controller, to prevent night loss. Installing directly in the panel array would be a waste, as they cause voltage loss, and extra expense.

@Believe30

2 жыл бұрын

I am hoping the video maker will address your comment. TY

@ThanosSustainable

Жыл бұрын

There is no night loss on ANY good solar charge controller. They don’t mix their input and outputs.

I have 4 panels 2x2 in series and both strings in paralel on both sides of my balcony. In the morning the sun is from one side than after 12 o clock fron the other. ON EACH SERIES strin one panel stoped working and I am wondering why. I do not haveb a blocking diode

Some brands has both blocking and bypass...you can see that on the connection...blocking diodes are in series and bypass diodes are in parrallel

Back in the early 90s i used 60 watt Solarex panels witch came with no diodes. I installed blocking diodes and ran straight to my batteries. No charge controller.

*Blocking* *Diodes* are recommended when you connect a Solar Panel directly to the battery, without any Charge Controller. This prevents the battery from discharging through the Solar Panel(s) at night ...

@petercamusojr1545

3 жыл бұрын

I hand an old HF charge controller that discharged the battery over night. This charge controller needed a blocking diode.

@OffGridGarageAustralia

3 жыл бұрын

Yes, that is a use case for a blocking diode.

@MrSummitville

3 жыл бұрын

@@petercamusojr1545 "Harbor Freight" for PV components? Well, that tells me all that I need to know ...

@petercamusojr1545

3 жыл бұрын

@@MrSummitville It was a gift 10 years ago from my daughter. Surprisingly well designed learning tool/toy for the time. I know a couple offgriders that used them for years as their main electrical power source. Yes, they are wayout dated now, but if it works no need to throw them away. It can run 1 light in a shed or outhouse. I did have to open the panels up after 7 years... break the corners of the glass to resolder the leads back on. Lot of fun, minimally useful.

@marioeduardocalfilneira378

2 жыл бұрын

And diode bypass?

Question please. What kind of diodes or how to know if what's fit to my 20w solar panels. Thank you. :)

@dantronics1682

8 ай бұрын

assuming the manufacturer of the panel knows what they are doing they would have fit the correct one

I have 2 X 150 W 22V oct voltage solar panels on each side of my boat. All panels are connected in parallel and charging is controlled via a voltage sensing relay, no charge controller. Would blocking diodes be beneficial for each 2 parallel panels?

@dantronics1682

8 ай бұрын

wouldnt it makes more sense to get a solar controller than worry about blocking diodes? I'm sure your batteries would benefit more

Great video, but I'm not sure why people are disputing this as blocking diodes are so cheap and they simply plug onto the end of a series string, so if you use them you simply eliminate any possibility of back feeding when shaded so I would rather know all of the power my panels are producing is flowing in the direction of my battery bank.

@dantronics1682

8 ай бұрын

a 50 amps diode is so cheap and its got zero forward resistance

Hey Andy I need some help with bypass diodes I was given some panels and one of them the center bypass diode was accidentally broken off any ideas how to find out what one I would need to replace it with I’m talking about the one on the back of the panel in the center junction box the whole box is gone but the terminal tabs are intact

@dantronics1682

8 ай бұрын

If you look at the label on the panel it should tell you the short cct current, ideally the diode should be able to handle that current

is blocking diode and bypass diode same type of diode ? ordo you have to buy two different diodes to make those connections ?

@OffGridGarageAustralia

3 жыл бұрын

Same type of diodes but different task.

I have a question sir. I have all in one off Grid solar inverter which supports 3.5 KW panels. So there are 3 strings os 3 panels each that make up 3.5Kw. all 3 strings are parallel. Will it Be a problem If I place 2 strings iñ south direction and 1 string in West direction? Your reply will be appreciated. The reason for this is to get some power and try to keep the batteries topped up untill the sun goes down. Thanks

@OffGridGarageAustralia

Жыл бұрын

That depends on how many solar inputs the inverter has. If it has only one solar input, I would not recommend mixing strings which point in different directions.

@eltonpereira875

Жыл бұрын

@@OffGridGarageAustralia thanks for quick reply sir. Inverter has only one input channel.

kindly guide me as my 150watt solar panel is showing 21volts but 1.2 amp. What should i do and what is the reason.?

How do u increase current in series arrangement of solar panel?

Does the charge controller act as blocking diode.?

Thanks for going over this, I like to hear the basics. I had not used any blocking diodes in my system and noticed that the combiner boxes that they sell come with them so always wondered if I should invest in one of those fancy boxes.

@OffGridGarageAustralia

3 жыл бұрын

I think they are good for marketing. It all depends a bit on your circumstances and location. If you have a lot of shading during the day, yes, maybe (can you not just install more solar?). If you only have shading in the morning or evening, don't worry about it...

@AQUATICSLIVE

3 жыл бұрын

@@OffGridGarageAustralia Thanks nice to see it tested in real life.

What happens at night in total darkness? Isn't it possible (due to a fault in the Solar Controller) that the battery storage voltage & high current can backfeed into the solar panels and destroy them? Isn't this the reason why every Solar Panel has a diode across the (+) and (-), with the cathode facing the (+) terminal? Also, talking about diodes, if you are drawing any inductive load directly from a Solar Controller, it is wiser to install a blocking diode of a suitable size - simply to protect from back EMF reaching the Solar Controller, with possible resultant damage. This is my understanding, and I hope it makes sense.

This is perfect and well done Bro !!!

@OffGridGarageAustralia

3 жыл бұрын

Thanks a lot!

Another fantastic video .. You are the man

@OffGridGarageAustralia

3 жыл бұрын

I appreciate that

I need to replace my junction box( diodes), do all cell use basically have the same diodes

@OffGridGarageAustralia

2 жыл бұрын

They have probably different diodes depending on the panel's voltage and current.

A panel of mine was shorted and now when I try to connect to battery it asks what should I do

You are mistaken. You do need blocking diodes for older panels, which have a single PV surface. However, modern panels, have blocking diodes included in their internal construction, since you can shade half the panel and still get half the power. I have a bunch of thin film panels (the black ones, where the PV cells are thin and run through their entire length), which DO need a blocking diodes to run in parallel. I found out by experimenting, just like you did.

@dantronics1682

8 ай бұрын

a diode have a p-n junction, a solar panel have a p-n junction regardless of whether its old or new, here is a challenge, show us one modern panel which have bloking diodes built in

Reckon i might drink some beers and play with my diodes 😁

solar panels are like a semiconductor, they will also produce a tiny amount of light when fed power like an LED.

It's not necessary to have a blocking diode on each string if you have very few parallel strings. You don't want to run 80*ISC through one string because its shaded and you have like 100 strings in parallel.

But... this is why one should fuse each panel in a parallel string (depending on how many panels in the string). This is because if a short were to develop in one of the panels, the remaining panels in the parallel string would dump all their amperage into the shorted panel and cause a fire. The fuse should go right on each individual panel that is connected in parallel.

@hooperwille

5 ай бұрын

short across 1 panel is very unlikely scenario.

Blocking diode and bypass Diode is the same diode?

Thx

I'm so happy you cleared that up

@OffGridGarageAustralia

3 жыл бұрын

It was necessary, right? Too many had the same 'knowledge' 🍻

@andrewshowland

3 жыл бұрын

@@OffGridGarageAustralia yeah honestly I was a little confused on the matter because I knew there is diodes in the junction box even though I know what a diode does I didn't know what bypass diode did until you very gracefully cleared that up. Im happy that I have a good understanding now that I watched this video. Thanks again! I honestly would of never figured that out if I didn't watch this video.

@OffGridGarageAustralia

3 жыл бұрын

@@andrewshowland Thank you!

i once used a 1n4007 as a fan switch, just glued the diode onto the heatsink, the heatsink heats up, diode conducts,, allah fan switch... it did create a high pitch noise ...lol but the fan run keeping the heatsink cool

I think you should add a weather report in terms of amps.

Now i got it, why not to Mount EM parallel but allways in a row.i guess you did know about the UV light

With an infrared camera when you pass current through a solar panel it emits IR light

@petercamusojr1545

3 жыл бұрын

Everything emits IR light even the darkest parts of space. The light emitted is proportional to it's temperature. This is called black body theory or more properly "The Stefan-Boltzmann law".

do not want to burn my 12v solar panel or battery up please help me

i read shading causes fires as it overheats panels

do you replace the diode with the same number as the old one like [10amp Diode Axial Schottky Blocking Diodes for Solar Cells Panel,15SQ045 Schottky] [BOJACK 10SQ050 Schottky diode 10 A 50 V axial 10SQ050 10 amps 50 Volts for Solar Panel Parallel reflow Protection diodes] [Bridgold 25pcs 3Types Silicon Rectifier diodes,Package Including:10pcs 6A10 10pcs 10A10 5pcs 20A10] ok which one what volts going on and on

Min. 8:35 , Can the solar panel produce heat ? If so ..., how much ?

@OffGridGarageAustralia

7 ай бұрын

They can produce heat if current goes through them. up to the point where they catch fire. That's why it is important to have the right safety equipment installed.

Please, anybody can help me to explain what is happening. I have a 24V setup with 16 lithium battery, a BMS balancer JKONG and a Powland Inver. My app show a 75% charge,432ah in the battery but the Voltage is down to 23v. ... The inverter is reading 22,1v and prepare to shoot down. Why??

Nice experiment. What are the voltages and current flows with the solar cell turned face down?

@OffGridGarageAustralia

3 жыл бұрын

That didn't make any difference. The LED light above did not had any effect on the PN layer. Not enough lumen I guess. Yeah, that would be another experiment to see what happens when lights hit the panel.

12:17 what happens if the input door, in the solar charger controller, is closed because battery is full?

@OffGridGarageAustralia

3 жыл бұрын

It does not turn off the charge controller, there is no switch or relay. When the battery gets full and the charge controller reduces power it just drives the panels away from the maximum power point, into an inefficient area of the solar panel curve so to speak. It will not disconnect the panels though.

@zarbonida

3 жыл бұрын

@@OffGridGarageAustralia thanks for the answer and for the time you spend to give us free learning content. You, Will Prowse, David Poz and Jehu Garcia are the best solar teacher in the globe!

But what size do I use i need one for my dump on my turbines can someone help me