How to Fuse a Solar Panel Array for a DIY Camper Electrical System

This video will teach you how to fuse a solar panel array for your DIY camper electrical system and explain why you MAY not even need to fuse your DIY camper solar array.
Blog Post w/ More Info: www.explorist.life/how-to-fus...
How to Calculate the Short Circuit Current of a Solar Array: • Solar Panel Wiring vs ...
➤Need additional & personalized help? Consider joining my private group: www.community.explorist.life
Here are some additional resources that you may find helpful with planning and installing your DIY Camper:
➤DIY Camper Solar Wiring Diagrams: www.explorist.life/solarwirin...
➤How to Perform a Power Audit: • How Much Solar Power D...
➤Basic Parts & Components of an Electrical System: • Basic Solar Parts Need...
➤How to Cut Wire: www.explorist.life/how-to-cut...
➤How to Strip Wire: • How to Strip Wire from...
➤How to Crimp Wire: • How To Crimp Wire Lugs...
➤How to Make MC4 Connectors: • How To Make MC4 Connec...
➤How to Wire Solar Panels in Series-Parallel: • How to Wire Solar Pane...
➤How to Crimp Wire Ferrules: • How to Crimp Ferrules ...
➤How to Wire an AC/DC Breaker/Fuse Box: www.explorist.life/how-to-wir...

[@WillProwse]

This is why I do single series string arrays haha I never put panels in parallel these days for this reason. I am too lazy to wire up a ton of breakers. Super good video! I will just direct my viewers to this video. Thanks

[@EXPLORISTlife]

Thanks, Will! Pure series makes things SOOOO much easier from a design, wiring, fusing, and nearly everything else standpoint. I 100% totally agree.

[@JjMn1000]

Ok!

[@jay-rus4437]

LOL....I ended up over here already because you didnt have a video on this Will. I watch all of your vids, and have your book, but you failed us all on this one 😂😂😂😂 Keep up the good work young man.

[@ziggystardog]

Sometimes you have to go parallel or series-parallel if you don’t have high enough voltage or current capability in the charge controller. Shading can be an issue in mobile applications. In these cases it doesn’t pay to be lazy.

[@gabakusa]

but in that case if you have connect them directly to the controller right?

[@Urge38]

I must say, (and this is NOT a brown nose exercise) I find your PV calculator the easiest to use BY FAR

[@LonnieWormley]

I just wanted to thank you for your efforts in explaining how to wire up a van. I have been watching your KZbin channel for about two years on how to build a van. I use to have a 5th wheel, but when I retired from being a higher education IT system admin and fix it all networking dude on 1/31/2020 my wife and I decided to get a van instead of another trailer. So in April 2021, we bought a 2017 Ford Transit 350 PowerStroke high-top extended. I downloaded your plans to add to my collection of two other van plans. I wanted to support folks who take the time to share accurate and easy-to-understand information. So anyway, I have a lot of van equipment in my dining room. I am working to get a minimal install in the van for our first trip in September. The van is not going to be completed, but I have a sliding bed and I installed two MaxAir fans. I told my wife that my goal was to get the fans installed, have a bed, and have batteries charging off of our van battery. When I was watching your Airstream build for the third or fourth time I realized that I had calculated my solar incorrectly and I had to order a different solar charge controller. I like the way you explain things in detail without glossing over what is important. Thanks again for all of your hard work.

[@ruralsolutions825]

OMG!!! Your presentation has just cleared one of the biggest confusion i have been having on PV module installation . Keep up the good work. Thank you friend

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@ewetoob6369]

If you are providing good content then you deserve all the ad revenue you receive.

[@outbackeddie]

Wow - I have been figuring this whole fuse issue wrong. Thanks so much for posting this information.

[@nomadicconquistador7-5-39]

Hey Nate, As I watch your videos to better my solar education, my girlfriend is listening in the background. She made a comment that should flatter you and your channel. She stated that your voice is soothing to the ear with good clearity and great vocalization of your words. Anyhow that tou should know. Love your channel

[@EXPLORISTlife]

Haha! I've heard that more than once.

[@dwighthapeman6590]

Your videos are so complete and so easy to follow! Thank you so much for all the time you spend making them.

[@billhooghuis6819]

Awesome! As an Electrical Engineer, I am quite impressed with your knowledge. Thank you!

[@Kevin_Aus]

Glad to see another video !! This gives me something else of yours that I can share when people ask me questions about setting up electrics/solar/wiring/etc.. in a van.

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@buildingourdaydream9804]

Excellent description explaining what was, at first, completely over my head. You are an excellent instructor sir! My journey through your series continues!

[@EXPLORISTlife]

Glad it was helpful. Cheers!

[@treemaniscool]

Amazing videos, I've been looking at battleborn batteries and some local suppliers of panels to try and offgrid some appliances but there was so much information and much of it conflicting. This entire series puts it all together in easy clear ways with fantastic visuals!

[@fernandovicente8232]

Thank you for all information! Congrats from Brazil!🇧🇷

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@GeneralKP]

Ask far your videos are the most complete and simple to understand I’ve seen. Thank you!!!!

[@EXPLORISTlife]

No problem. Happy to help!

[@gohoop]

This was very helpful. Thanks!

[@waynehobbs5175]

You make so much sence. I really don't need another source of information. Thank you from South Australia.

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@evil17]

Enjoy ur vids, ur a great teacher, good info & content. Cheers

[@barbm.4301]

These videos are going to save me a lot of anxiety and trusting others who may or may not be competent. Thank you so much for producing all of these instructional videos and blogs.

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@witharebelyell2762]

Yes, but HOW do you know what your TOTAL short circuit current is of your entire array? Do you add up each one in series or parallel?

[@CharlesLangSamuel]

Very well explained thank you.

[@arecibo1974]

This information is awesome, thank you!

[@EXPLORISTlife]

Glad it was helpful. Cheers!

[@esliemarcelo2963]

most helpful tips.thnx..

[@Downgrader]

I think this answered the question I posed to your other video. 🙂

[@davidniquot6423]

Nice info, thanks.

[@iamnegan1515]

Excellent explanation.

[@EXPLORISTlife]

Glad it was helpful. Cheers!

[@christopherschulteshinesth1415]

Keep up the good work!

[@EXPLORISTlife]

Hey Christopher Michael, Thanks so much! Cheers!

[@memilanuk]

Great videos, they are very helpful. I especially like the way you break things down into appropriate bite-sized chunks 👍 That said... I think you may have wrong video linked in the show notes for determining short circuit current. The URL provided goes to the series-parallel video a couple of episodes back, not the one linked elsewhere from fall 2019. A minor quibble, otherwise you're doing great!

[@JohnSmith-qd8po]

Great explanation for a very confusing subject.

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@ttirrell]

Thanks Nate! I have 2 panels wired in series with no fuse. I THOUGHT that would be ok, but now I have the data to back it up.

[@EXPLORISTlife]

No problem! Good deal! Pure-series wired arrays RARELY (Never?) need fuses.

[@sailor7025]

Great to see you're back Nate! Your videos regarding solar anything are absolutely the best. Additionally, the interactive diagrams and associated ordering list are waaaaaay cool! Hope you and Steph are doing well.

[@EXPLORISTlife]

Hey Sailor70, Thanks so much! Doing good here. Just wrapping up some big projects that have pulled me away from KZbin for a bit, but doing good. Cheers!

[@MarkMettler]

Something I agree on. Thank you for enlightening the DIY group. I have yet to get serious about the 4S4P solution with my panels and inverter. I have a Growatt 80A with a 60-145V range. The panels are 260W 30.6V 8.5A and knowing the fuse solution leaves me cautious with a 3S2P. I could do 4s4P-5P even. 122.4V at 34A - 42.5A but then where goes the fuses? Brave men burn down their homes. I shall wait until I've absorbed more knowledge. Of course, there is always the wire to consider.

[@markhouse9570]

THANK YOU for these extremely instructive videos! They've given me enough knowledge to get most of the way into design on a motorhome roof 1200W 12V array. Panel: Newpowa 210S-12H. Vmp 16.77 V, Imp 12.48 A, Max Ser Fu rating 15A. Two 3-panel banks, S/P I see (2) series circuits producing 50.31V @ 12.48A. Paralleling them I calculate final out of 50.31V @ 24.96A (not adding for temp). Do I understand correctly that I need to fuse before or after the Y branch parallel cable(rated 30A) up on the roof, and if so, what fuse size in each leg? (figuring the Isc for the entire array is 39.27 x 1.25=49.1A and the Max Ser Fu rating is 15A) I'll be dropping to a breaker/disconnect before the Victron MPPT 150/85TR.

[@user-df7rd3ly8b]

Hi Nate, Do short circuit issues only apply when panels are in parallel? I read all (most) of the comments before asking and it is not explicitly stated, but implied by several messages and your graphs. This is my understanding so far; a) Panels in series - no issues since amps are not added (only voltage is added in series). b) Panels in parallel - fuses may be required since amps are added (in parallel) and total amps may exceed short circuit amperage rating of of the panel (fuse rating). c) Panels in series-parallel - fuses may be required for same reasons as above. It appears only the panels in parallel when the amps are added is where the fuse question becomes an issue. Can you clarify? BTW, you have the knack for educating people on complex topics. Strong work. Tim

[@winginitwithjohn8451]

Great timing. This video I hoped would clarify, but, maybe it went by me too fast? I'll read the blog post too. Thanks. I was in the process of fusing my Lynx distributer, I'll send those Q's to the EL private crew.

[@EXPLORISTlife]

Thanks! Yeah, downstream of the charge controller will be covered in an upcoming video

[@jobertpage-et1349]

Impressive...cool

[@EXPLORISTlife]

Hey Jobert Page-et, Thanks so much! Cheers!

[@lisarettig2740]

Thanks

[@gaborjakab3030]

Hi! Thanks for the video. I am far away not an electrician. What would be the functionnof the bypass diodes on the panels? Is there any additional protection from the inverter side? Thanks

[@lavaredwards3170]

are these concepts usable with home installation

[@sergioriveros5873]

Hey Nate... nice video... thank you for sharing. Speaking on sharing... would you share with us the excel spreadsheet ?

[@tomsweeney8433]

Your awesome

[@melaniecollins4045]

Hi Nate, we are wiring 840 watts of solar in series/ parallel and am wondering if our short circuit amp is 10.86 per series would we only need a 15 amp fuse or 20 amp fuse? our specs our for a 20 amp fuse. Thanks

[@WiSeNhEiMeR-1369]

HOWdy E-l-DIY-C, ... Thanks COOP the WiSeNhEiMeR from Richmond, INDIANA ...

[@izdats0]

Let's see if I understood correctly: I have two panels connected in parallel both with short circuit current = 10.269A, would short circuit current be added, too, for a total of 20.538A? Max series fuse on the panel is 20A, so would I need a 20A fuse on both panel's positive cable before they go to the parallel connector? Loving the videos btw, I'm learning a lot and found I did a couple things right on my starter system!

[@lucybirb]

Do the fuses in a combiner box pretty much do the same thing?

[@whitesamarrow733]

Hello, nice video. ISC of my solar array is 22.44A Maximum series fuse is 20A Must I put 20A fuse on each Double 2 in 1 MC4 combiner? Thanks in advance

[@MyGoogleYoutube]

So, my solar setup doesn't require fusing based on your video. Does it also not need a DC breaker? Could I just use a DC isolator? Love your content - thank you.

[@kingaspis]

Hi Nate, I"m having a hard time finding the max series fuse rating for my panel as it's not on the back sticker and can't find it on the manufacturer's website. Can you help? Newpowa model NPA180S-12H (180W mono). Thanks!

[@leoclarkin5944]

If Voc panel voltage is an issue, i.e., it exceeds solar charge controllers max input voltage, does it make some sense just to install an additional MPPT vice putting up to parallel wiring issues?

[@carrottop3454]

So I have 8-200 watt rich panels that I plan on wiring in 2 series strings then connecting those in parallel so I can max out my watts input for eco flow power station. The short circuit current for each panel is 10.2. So that would stay the same for each string but when I wire them in parallel it would then be 20.4. Would I need to fuse these at the Y branch connectors?

[@etibo6]

Hi, you make one of the best learning videos. Question for you, on the back of my panel, the max series fuse rating is not written, Do you know how to get it if it's not possible to talk with the fabricant?

[@chriscourtney5692]

*quick rundown* I have 4- 100w panels, p30L charge controller, 2- 200AH deep cell agm batteries, and a 1000w pure sine wave inverter charger, with 4 outlets run in parallel, that will be hardwired into the inverter charger. Do I need a breaker box anywhere? Or will properly placed fuses between components provide adequate protection.

[@shimpiden]

what about matching panel VOC to the controllers stated maximum VOC input ?

[@madcow3417]

You just saved me from doing it wrong. Thanks!

[@joecrockett7993]

Hey Nate, watched a lot of your video's your doing a great job. I have a 76 GMC RV the electrical is totally trashed doing a complete rebuild but don't want to do the solar quite yet but want to have a build that will be able to add it later I like the smart inverter (that uses battery power to top up when shore power is not enough) plan to go with 3 lithium batteries and have a 3000 watt inverter generator and like the idea of charging with the alternator too do you have a list going for a build that leaves the option of solar later?

[@EXPLORISTlife]

Hey Joe! Literally all of my diagrams and parts lists at www.explorist.life/solarwiringdiagrams can be used without solar by simply omitting the solar charging leg of the system.

[@TechyBen]

I just bought 4 fuses... oh wait, I better watch the video first... last week... XD

[@frankt7769]

Hi I have 2 parallel solar panels running to my victron 100 20a than to my battery box the battery box has a 16a circuit breaker do I still need to put a fuse on my battery box

[@thomasansieta2639]

Good videos I have learn a lot question I am starting a system for my cabin have 4 panels 300watts each panel is better parallel or serial

[@EXPLORISTlife]

Hey, thomas ansieta! I appreciate you taking the time to ask your question, but unfortunately, I don't have enough info about your specific question to provide an accurate answer, but here is a playlist that, if you watch all of the videos start-to-finish (and take notes 😉), you'll have a REALLY good idea of how to design a solar array: kzbin.info/www/bejne/gJzFpGtqqKd7qck Alternatively, I have some of my most common solar array setups pre-built here: shop.explorist.life/product-category/all-products/camper-wiring-kits/solar-charging-wiring-kits/

[@loganreynolds4396]

Awesome information. Appreciate all the work you do. Quick question, I have 4 550w panels I plan on adding to the top of my bus. I need help determining between parallel or parallel series, and then sizing my fuses. IMP: 13.11 VMP: 41.96 ISC:14.01 VOC: 49.9 I cannot find max series fuse rating ANYWHERE, only maximum system voltage which is 1000 I calculated the short circuit (14.01) x 1.56= 21.86.. so if doing parallel I would need 30a inline fuse prior to the 4 to 1 mc4 connectors. What I then am getting confused about is after the 4 to 1, that would be (21.86 x4) 87.44 amps running thru that connector and would not be able to handle it, right? Or would a 100am pv isolator be after the 4 to 1? Any and all help would be appreciated.

[@5chips]

Hello Nate, I am a new subscriber and find your videos very informative. I have a question about fusing. Do two 160 watt solar panels connected in parallel have to be fused. Both have a short circuit current of 8.37 amps, optimum operating current of 7.92 amps and a max. series fuse rating of 15 amps? I think the answer is no, but not sure. Much appreciated, thank you.

[@EXPLORISTlife]

Does your array short circuit current exceed your max series fuse rating? Here's how to figure out your array amperage: kzbin.info/www/bejne/gXuYq3aPaqp1m7M

[@edwardbyrd7667]

Thank you. I don’t need my inline fuses then.

[@billm6852]

When is the "next video" coming out? I am looking for info on the breaker between the solar panels and the charge controller. I checked your web page but did not see an article there yet either. Looking forward to it !

[@EXPLORISTlife]

This Sunday if UPS gets here tomorrow with a few parts I'm waiting on! 😆

[@danielreger5463]

Great videos. Best help I have found. I cannot figure out the fuse between battery and controller. Manual of Renogy Rover 40 amp Mppt states to match the rating of the controller, so 40 amps. I am running two 160W renogy flex panels in parrallel. 8.88a short ciruit current. 20 amp Max Series fuse rating. Is it even possible to achieve 40 amps of current with that setup? Thanks for what you do!

[@EXPLORISTlife]

A 40A charge controller is indeed capable of putting out 40A. As for why Renogy recommends that; I cannot say. I know that Victron and most other quality charge controller brands recommend the fuse be somewhere in the ballpark of 125% of the capacity of the charge controller given proper wire sizing so the fuse won't blow under normal operating conditions.

[@leonelhernandez3618]

Hello, thanks for share this video. BTW how did you build that pretty diagrams, can suggest any software for do that?

[@EXPLORISTlife]

Glad it helped! I use Microsoft Visio to make all of my diagrams.

[@tonym2540]

You're presentation of what the current does when a short appears in 3 panels connected in parallel was very helpful. Thank you, thank you, thank you! But once I understood it, I tried to apply that reasoning to the 3 panels in series and got confused. I came to the conclusion fusing in any pure series arrangement would never be needed since the currents never add. Is that right? (Still learning...)

[@EXPLORISTlife]

Fusing in a purely series array is indeed never needed. Nice work!

[@wilfredomarino3413]

Idol how about in batery connection.parallel connection also need to fuse?if how.thanks

[@leemobai762]

Great video. Love the schematics. May I ask what do you use to draw them.

[@EXPLORISTlife]

I use Microsoft Video for my diagrams.

[@leemobai762]

@@EXPLORISTlife Thanks - you got to hate spellcheckers. I know you meant Visio.

[@kevinmatthews2620]

question for you, i am finalising wiring this weekend for a friend of mine he has 2 identical longi panels installed on his shed roof both 445w rated max power,the have a max short circuit current each of of 11.53 a,, current @ pmax of of 10.78 amps, max system voltage of 1500v, max series fuse rating of 20 amps, we wish to wire both together to get the most watts/amps out of them (the voltage pmax is 41.3v ), they will be feeding to a string of 8 12v batteries and in turn the 12v power will be feeding to a victron quattro 12v 5kva system, what fuse do i need i am confused by the series/parellel and the info on the labels ?? pps , these are new current generation Longi panels about 3 months old, they are currently both seperate running 2 charge controllers,here in the uk dc isolaters are super expensive, i was going to use standard mcbs of the correct amperage on both lines to act as a dc isolation, is this right/wrong ??, i have the victron putting out 240v ac with no problem off of 2 rolls batteries that are currently contacted, the remaining 6 lead acid 220ah batteries will be wired for 12v this weekend on the second dc in line on the victron, the victron has a main off box(external to the unit) with 2 lines each already fused with mega fuses of 500 amp times 2, which according to the victron specs exceeds the 800 a min fuse rating, please help :) :)

[@joe84bmw]

I have one panel that’s 15a and came with the rv and adding two more that are 20a rated. All are renogy 200 watt panels, would I use a 15a and 2 20a fuses or make them all 15a? Im not very good at this 🥴

[@jonathanxing2843]

Great Video, Can I please ask what software do you use to make the diagrams? I would like to design my own system and looking for the software to do sketches.

[@davebenz8271]

They are great. I’d like to know, too.

[@mattr7229]

Thanks so much Nate for all the immensely helpful videos you have made... Question for you... in Case study #1 at 3:18, you show panels A, B, C where C is the right most panel and it has a failure causing it to short out. From Kirchoff's current law, you get the 20.4 amps (total from panels A and B) going through panel C. The part I am unclear on is you show the total potential current thought panel C at 30.6 amps. In a real world scenario, if though panel C has a failure (e.g. short), it is *possible* for it to still be operational to produce current? I have no knowledge of the mechanism of solar panels and hopefully I will learn something but it would seem if the panel fails, it wouldn't be capable of producing current. However, even if the 20.4 amps were the only current, based upon your example, the fusing would still be required. Thanks!

[@stevengiraldogarcia8117]

I have the same question!

[@powderdayallday]

It depends how the solar panels fails... they are basically made up of multiple smaller cells connected together. The "Maximum Series Fuse Rating" on the panel is the upper limit of what the internal connections between the solar cells INSIDE the panel can handle before failure. If one of these internal connections fails, the individual cells inside the panel are still capable of producing power (individually, just not exporting it from the solar panel). There is a chance that the fault could result in an internal short (and maybe an external return path? frame?), and when connected in parallel, the external fault current will contribute to the internal fault.

[@marklandry8706]

Nate....all great info...quick question on future solar expansion...any reason to not oversize solar controller with expansion of panels and batteries down the road...?

[@EXPLORISTlife]

That's a good idea. Set up an 'end goal' and work backwards from there.

[@kirbyspencer538]

Just keep an eye out for the possibility of over-currenting your battery during bulk charging.

[@walterschilling4512]

Hello Nate , Being consistant with your example of the panels in parallel , with those same specs can I use a 16a breaker on each panel .

[@EXPLORISTlife]

I'm not sure I follow... Are you asking if you can use a fuse size larger than the max series fuse size listed on the panel?

[@johnboling]

What do you use to make your wiring diagrams? Always so clean.

[@EXPLORISTlife]

Thanks! I use Microsoft Visio for all of my diagrams.

[@Kylosgrande]

The example you first showed if it was wired in series parallel what it need a fuse? - I am doing exactly that, 4 12v 100w panels in series parallel,

[@BurnProcessMedia]

I am using the same Rich Solar 200w 12v panels as shown above. They will be wired in 3S2P. Each sting will produce the 9.8a but the strings when parallel will be 19.6a exceeding the individual panels 15a max fuse rating at the combiner. Where (if at all) would I fuse this array and what fuse capacity would I use? This is an amazing video btw. Thanks for all you do. You and Will Prowse have become my Gurus.

[@andresjoubert]

I have the exact same array setup I am preparing to install. 6 Rich Solar 200W 12v panels in 3s2p configuration. Was this question ever answered, and if so, what was the verdict? Fuse required or not? If so, what rating fuse?

[@BurnProcessMedia]

@@andresjoubert nope, it wasn’t answered unfortunately.

[@EXPLORISTlife]

I didn't give this one a personal answer as the video answers the question. 🙂👍 If the array amperage exceeds the max series fuse rating, it needs fuses.

[@Nuke553]

This might seem like a silly question.. I am getting ready to install my panels. I plan on adding tilt bars, does it matter when laying them out if they tilt lengthwise vs width? If I lay them out to tilt up lengthwise (taller vs wide) I can fit more panels in the future. I can still fit all 4 width wise but it leaves little room for expansion later on down the road.

[@EXPLORISTlife]

It shouldn't matter. :)

[@CountryBoyMoto]

It sounds like fusing in parallel is just a good thing (cost vs possible repercussion)

[@EXPLORISTlife]

The voltage of a parallel wired array is rarely high enough to properly charge the battery bank. Series parallel or series is generally the better option.

[@CountryBoyMoto]

@@EXPLORISTlife I will watch your instructional videos “again” once my components arrive

[@talentscout5135]

So if I am doing 5 panels that are 9 amps in series and doing two sets of those in parallel what do you recommend for fusing? Do I need to fuse if my wire is 6 gauge and can handle more amps and such. Curious anyone I’m setting up a lv6548 soon so I am researching proper fuses and wires to run 150 feet to batteries

[@sovereignsoultribe]

Question : I am installing 6 x 150w solar panels to my bus in parallel. each panel has a 15A rating. Am i right in saying I DO need individual fuses installed for each positive connector? Thank you in advanced :)

[@bertweeb1989]

I don't have an RV but solar power is quite interesting.

[@EXPLORISTlife]

Hey Bert weeb, No problem! Glad it helped! :)

[@nikolasdassis]

Hi I want to make a setup with 6 solar panels total. They will goi either in 2s3p or in 3s2p. The maximum series fuse rating for the 1 panel is 15A, my question is, if I go to the 2s3p configuration or the 3s2p what kind of fuses should I install? Thanks for any help.

[@evespower1]

Thank you Nate! I am actually learning this and I took the quiz on your blog and only missed one, the last one. This is my 4th time watching this video and it makes more and more sense each time I watch it. I am figuring this all out, however, my Newpowa 180w panel only has 5 of the specs on the back. It does not have the max fuse series rating. It says: Short circuit rating of one panel is 11.75A, exactly what is a short circuit? (the path of least resistance explained here?) Second, how do we figure that out if we have two panels(if wired in parallel short circuit is 11.75A +11.75A , if wired in series it is just 11.75)? That is where I think I am on the right track..btw I only have one panel for now so my 30A charge controller doesn't need to be fused. I want to purchase another, but not without being sure that short circuit means what I think it does. Am I on the right path?

[@EXPLORISTlife]

The 'Max Series Fuse Size' is generally the Isc (Short Circuit Amperage x 1.56.

[@evespower1]

@@EXPLORISTlife thank you!!!!

[@davebenz8271]

My Short-Circuit Current (Isc) says 5.86 A, and my Max Series Fuse Rating says 15 A. Maybe panels have gotten better since they came up with the 1.56 multiplier rule of thumb.​@@EXPLORISTlife

[@jeffdidit8740]

Question: when figuring out if you need fuses and also wire size, do you use the stc wattage, or the maximum wattage for calculation? I have renogy 115w bifacial panels that have a max power stc of 115w, but it has a capability of 149w under optimal conditions. So in my calculations do i calculate using the 115 or 149? Thank you and I'm glad i found your channel as I've been struggling getting a straightforward answer on many applications even from renogy customer service itself.

[@EXPLORISTlife]

Whatever the max stated wattage is.

[@jeffreyreck3867]

Great video as always. Sorry if I missed it but I didn't see how you compute the Short Circuit Current of one's solar array when there's more than one panel. I've got 4 panels, 2s2p. Each panel's ISC is 9.85A, with a max fuse rating of 20A. (Hightec 210W panels). Do I add the ISC for all four panels to compare to the max fuse rating or just for two panels (since we don't add Amps for the two sets of series panels)? Thanks!

[@EXPLORISTlife]

That array will have a short circuit current of 19.7A. Here's why: kzbin.info/www/bejne/gXuYq3aPaqp1m7M

[@jeffreyreck3867]

@@EXPLORISTlife Great, that's what I thought, and no fuse required. Thanks for the quick reply.

[@EXPLORISTlife]

No problem!

[@tullgutten]

I have 1 string and a fuse on both poles right before the DC over voltage shunt so if Lightning strikes and the over voltage gets tripped i hope the fuses blow BEFORE any fire starts or the inverter blows up. Grid tie Solar Edge inverter and panels. Don't "need" it but want it 😁

[@thomasansieta2639]

my solar controller is a renogy 100 Amps and pure inverter 2000w renogy have eight batteries 192 amps gel planning on installing them on 24 volts series batteries based on your knowledge is this ok or you suggest something different, thank for your input lived up north in Canada not much sun in the winter in ONTARIO

[@EXPLORISTlife]

Hey, thomas ansieta! I appreciate you taking the time to ask your question, but unfortunately, I don't have enough info about your specific question to provide an accurate answer, but here is a playlist that, if you watch all of the videos start-to-finish (and take notes 😉), you'll have a REALLY good idea of how to design a solar array: kzbin.info/www/bejne/gJzFpGtqqKd7qck Alternatively, I have some of my most common solar array setups pre-built here: shop.explorist.life/product-category/all-products/camper-wiring-kits/solar-charging-wiring-kits/

[@aysensvoboda2274]

Great video. May I ask which tool you use for those drawings? Thank you

[@EXPLORISTlife]

Microsoft Visio

[@aysensvoboda2274]

@@EXPLORISTlife Thank you for such a quick answer!!

[@cardinhamkilligrew9712]

I am looking at a 600 watt solar array. (sailboat with some shading possible) 100 watt panels. 2 x 100 watt panels in series. the the 3 sets in arrays. The panels have this rating: Open circuit voltage 21.6 V Maximum power point voltage 18 V Short-circuit current 6.11 A Maximum power point current 5.55 A Would I need a fuse in this scenario? the set up i believe would be: SERIES PARRALELL 3 solar banks (each 2x100 watt panels) 3 - 200 watt solar banks in series then parallel 600 watts (40 volts at 15 amps) 100/50 charge controller 10 Gauge Wire Am I correct on all this? These videos are AMAZING!!!!! Best Ive seen

[@VEChaplin]

What do you do if you have to parallel different panel models? Example, 3 40w with 1 50w? And what if the "maximum fuse rating" is not written on the panel?

[@EXPLORISTlife]

If the solar array short circuit current is larger than any of the 'max series fuse ratings', you need fuses for your panels. Each parallel connected panel would get a fuse equal to it's 'max series fuse rating'. If a 'max series fuse rating' is not available... you must contact the manufacturer to find out more information.

[@mikenkaried4543]

GREAT VIDEO! It seems very hard to really get that design conversation laid out for discussion... One Advanced Question I have on that "in-series" fuse layout Idea. Let's say you have two in-series banks, each bank is 3 panels and each panel has an open c. volt rating of 49.8v and a short c. amp rating of 10.36amp, and directly at each panel connection in the series you use an MC4 connector that contains a cheap replaceable 15amp fuse so that it is closest to the source and slightly greater than nominal just in case one panel has a short circuit problem preventing damage to the rest in that series, if one single fuse (6 total) blows I believe that shuts off that entire 3 panel series, but my question is.. since that series is parallel to another 3 panel set will it cause any issues using the remaining 3 panel series for charging at only 10 amps and 150v, vs 20amps at 150volts? I know some MPPT chargers want sufficient amps to even begin charging efficiently. I have periodically detected some volt fluctuations back fed up the wire when only charging 12 volt batteries using this array when only one series is switched on, so either its a MPPT charger issue or this tiny fuse "in line" in a series is a bad idea for some electrical current reason.

[@EXPLORISTlife]

I'm not sure I entirely follow, but if a fuse blows...I recommend replacing it as soon as possible after the problem that caused it to blow is fixed. I don't like playing the 'what if' game with halfway broken systems. I'd rather just fix it so it works as designed.

[@mikenkaried4543]

@@EXPLORISTlife was trying to decide proper fuse placement by looking at what happens if a fuse pops. Does it cause other things to break by imbalancing sets or just kill the series and if so what are the ramifications moments later if it takes hours or days to get a replacement fuse.

[@EXPLORISTlife]

@@mikenkaried4543 I see. If a fuse blows, it just disables that series string and isolates the fault to that series string which would then continue to operate (not connected to the charge controller) at it's short circuit current, which the panels are rated for without the other series strings adding to the problem. The other series strings would continue to provide power to the charge controller.

[@nwlady1844]

Plz help! I just received my two new acopower 120w foldable solar panals. there is no "max series fuse rating"... on the back of the panel.... on the website and... I have emailed the acopower requesting this information.... no response. Should I be sending back these panels? Are they missing something like a fuse that they should have? Thank you for any help

[@jaffasoft8976]

What size fuse is needed? Is the fuse for each panel the same size fuse as the max fuse desciption on the panel and then how do you size a fuse into an array ? I got Short Circuit Current 11.39amp and Maximum Series Fuse as 20 amp, 2s2p . Will i use 20amp fuse in each panel and 40amp fuse in each series fuse then into the charge controller??

[@chrisbroom8418]

Hi. I have 4 X 100w renology solar panels wired in series parrallel.I have a renology 60A mttp. do i need to use fuses and if so what size do you suggest.

[@EXPLORISTlife]

Hey, Chris Broom! I appreciate you taking the time to ask your question, but the video you just watched will teach you how to determine if your solar array needs fuses and what size. I've provided the information; now you need to put my information to use. 🙂👍 Alternatively, I have some of my most common solar array setups pre-built here: shop.explorist.life/product-category/all-products/camper-wiring-kits/solar-charging-wiring-kits/

[@chrisbroom8418]

@@EXPLORISTlife Thank you for your help.

[@lauriecarley4339]

I have 4 photovoltaic module panels ET-P660235 Max power 235v, VOC 36.96v , Isc 8.40a , Vmpp 29.90v , Impp 7.86a , and Max System voltage DC 1000 , Series fuse 20amp , fire rating Class C , Max field wiring 14 AWG.. MY Question is are these panels suitable to fit to my RV motorhome, if they are ok what type/size of controller do I need? I've read that the best way is to wire 2 panels in series and 2 panels in parallel, then 1 pair if wires through the roof to an isolator switch - a 40amp MTTP control unit - a MT50 display -20amp fuse going to 2 batteries ( lithium batteries, hopefully budget permitting) or the next best , I've been give a new 3000w inverter ( hopefully it's Ok ). The 30ft long Tiffin American RV is 12v, it has 2 Leisure lead batteries (age & condition not known), a starter battery, it has mains hook up and a 110v generator via a three way switch GEN/OFF/MAINS. I'm looking to buy all the remaining parts in one go and connect it all together

[@chandleraustin8500]

can i do this set up but just get a normal inverter and converter instead of the inverter charger you use? would i then have to change where my shore power runs to??

[@EXPLORISTlife]

Ultimately, you can do whatever you like, but I do not recommend separate Inverters and chargers. They are too complex to set up and more expensive by the time the additional transfer switches and wiring is all taken into account.

[@chandleraustin8500]

what is it i would be missing getting this one thats half price. this brand has one in the 1,200 dollar range too i just dont know where the price difference is coming from, Thank you

[@robertpeyton5534]

First of all, thank you for your videos. I have eight 400 watt Solar panels, the Voc is 49.3 volts. my charge controller is a tracer 4215 BN maximum voltage 150 input. I am running an off grid 12 V inverter to make my 120 v. My question is, will I need 4 charge controllers like this one to handle the solar panels and stay with 10 gauge wire. I think that’s what I have to do..I’m just double checking. Thanks, Rob

[@EXPLORISTlife]

There is indeed a pretty strong chance you'd need 4x charge controllers.

[@adventure_onthedaily9851]

Hi there, might be a silly question but my solar panels don't have the maximum series fuse rating on the sticker. I'm in Australia and purchased them here, if that matters at all. i'm using 2 x 200w panels wired in parallel, with a short circuit current for the array at 22A. If it's not listed on my panels, how do I know if I need inline fuses? thanks so much for any advice!

[@EXPLORISTlife]

If the Max Series Fuse Size isn't listed, you can take the short circuit current x 1.25 and then round up to the nearest interval of 5.

[@maninavan.2043]

Please, help I have three 100wt solar panels and keep being told to fuse them independently. And some say I don't. I have the three going into one and a breaker leading from that (+) cable. And a circuit breaker on it leading to my charge controller.

[@lawrencelovett3466]

Fusing is confusing! Thanks for everything you do to teach us what we don't know. I've learned so much. 2 quick questions: 1. If I have 5 panes in series and each has a fuse rating of 15amp then I don't need a fuse. However if these panels are 20amp fuse rating then I need a fuse? 2. How about between the MPPT Charge Controller and the batteries, do I need a fuse between them?

[@minceym]

Hey Nate I'm still a beginner and some of this went right over my head 😳 Any who can you tell me if I need to fuse these two panels for my solar generator in parallel? JA SOLAR JAM54S31-395/MR RATED MAXIMUM POWER (Pmax) [W] 395 OPEN CIRCUIT VOLTAGE (VOC) [V] 36.98 MAXIMUM POWER VOLTAGE (Vmp) [V] 30.84 SHORT CIRCUIT CURRENT (lsc) [A] 13.70 MAXIMUM POWER CURRENT (lmp) [A] 12.81 MODULE EFFCIENCY 20.2 The specs reads as: Maximum Series Fuse Rating 25A not sure if this is what you were referring to. Thx!