How to Size a Solar Charge Controller for a DIY Camper Van Solar System

[@DCGULL01]

So, Nate. 2 years later, and- here I am sitting, watching & feeling incredibly grateful! Not only are you highly focused, right on stream & quick (thank you!) but, additionally, you use Victron equipment (mine's marine- Victron required-almost!) and explain detail (fitment, temp. ranges, max voltage). Finally, space restrictions, wire runs, proper contacts at equipment- all priceless details that PREVENT releasing the magic smoke inside the wires & charge controllers (That's my biggest worry, can't put the Genie back in the bottle once it's been freed!) Wow, I wonder how many people have been helped with you & your wife's channel? I bet it's up to tens of thousands? Free calculators, Excel spreadsheets... Thank you is certainly NOT enough.

[@ChaplainArthur]

This may be an older video but your calculator is a life saver, or at least a lifeline. Thanks for all you do.

[@EXPLORISTlife]

Glad it was helpful!

[@1989cranston]

How this video has so few likes is beyond me. This calculator is amazing! Thank you for putting it together.

[@EXPLORISTlife]

Hey Nick Cranston, Thanks so much! Cheers!

[@EXPLORISTlife]

@SOLDOZER We didn’t get to a quarter million subscribers for teaching garbage.

[@Ricardofromage]

And thank you once again for this, that's just taken the last of any doubt out of which mppt to size/buy, great channel, brilliant calculator too, thanks once again 😊🙏

[@EXPLORISTlife]

Hey @Ricardofromage, Thanks so much! Cheers!

[@Ricardofromage]

@EXPLORISTlife I've been recommending you to a couple of guys im doing lorry builds for, sadly none of us are in the U.S or I'd be recommending they come for a design package 🙏

[@EXPLORISTlife]

@@Ricardofromage We actually ship internationally and currently have customers in over 50 countries! Love to have you as a customer too.

[@Ricardofromage]

@EXPLORISTlife now that is interesting!! I'm soon to be emigrating, but a part of the new life is building Mercedes Varios, start to finish. Buy rotten, fabricate and repair as needed, then offer up either as a Base vehicle or do a full build, having a tame solar team on hand would not hurt at all!! I'll certainly recommend Rupert gets in touch, he's hardly started on his install !! To be continued 🙏

[@hjdhjd78]

I been looking for this kind of information without the bs glad I finally found you.

[@ipwee]

Your calculator saved me from making a grave mistake. A self-proclaimed solar nerd convinced me that his math was correct. It turns out that my amperage was WAY higher (42 amps) than I should be running. Thankfully, I had doubts. Liked and subscribed.

[@a64738]

Higher amps then the solar charge controller is rated for is not a problem, it is just wasted as potential energy from the panels not used (no damage but it is waste of solar energy to not use it all). What is a really a problem is if your solar panels is producing more voltage (V) then the charge controller can handle...

[@patricialyons7995]

You should thank yourself. This stuff is a bit complicated when someone like me has absolutely no knowledge to start with. I've saved your video and worked out some numbers just to follow your demo, but I know when I get ready I'm going to want someone like you to double check my numbers. This won't be for 3 years when I retire. So in the mean time I'm going to be the most informed as I can be from rooftop to floor. You have been a big help. So thank you, i appreciate you. Pattie

[@CarlosAnglada]

The diagrams are JAW DROPPING

[@JR-kk6ce]

Great video! Just the right amount of focus, math and repetition for me to learn it. We all learn differently, and after watching countless videos from other channels this is the fellow that explains it just right for me to understand and learn.

[@EXPLORISTlife]

Glad it was helpful. Cheers!

[@cvakfree]

he is really a nice guy, i ask him help and he answer, he offer to help, amazing i have not use his good will but i will!

[@DCGULL01]

Nate- that's HUGE!!! The price of peace of mind is priceless. I don't mind doing the background work (using your calculator, doing some hand math, etc..), but- would feel 1,000 times BETTER if I could convince you to eyeball my work. Additionally, I will reference all of your work for determining wire size, but- as long as we talking solar- maybe, I could convince you to check that as well? I'd rather do this work RIGHT once, and, get years of service from this expensive equipment, than burn out controllers, ruin batteries or burn down my truck camper! Yikes!

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@idunasorchard]

The calculator is awesome and might really save some people a lot of headache and money from unknowingly undersizing their charge controller! Not to mention a lot of RVrs may find themselves in high altitude situations where cold weather can come during times of the year when the sun is high in the sky!

[@robertharding5553]

You just saved me a bunch a digging around. I was searching for the right size charger to connect to a 540W panel. Thankyou Thankyou Thankyou.

[@tracystewart1026]

Thank you for so much information. How do I get the following: 1) Temperature coefficient VOC and 2) Temperature coefficient of PMAX if this is not listed on my panel or my specifications sheet? Any help you can offer is rally appreciated.

[@WandersOfficial]

yea...i agree... i dont know how to get those exact things aswell..good question...] help.>!>>! ultimately video left me confused on those 2 points

[@David_Mash]

@@jamieshakeshaft5468 my spec sheet has the Voltage Temperature Coefficient in mV, but it is not clear if he used mV or V in his calculator

[@mattr7229]

I will be upgrading my truck camper to a Lithium system and came across your videos. They are helpful beyond words!!! Thank you!

[@jeepguylv80]

just sad. i just happened to run across your channel while researching solar set ups for travel trailers ( glad i did by the way ) and i can't believe the dislikes !! why?, it seems the more information you give, the free resources, the time it takes to make videos of this caliber, everything short of doing it for them, people still have the nerve to thumbs down videos. you even take the math ( which is complicated for some ) and break it down to make it a heck of a lot easier. i just don't get it. thanks for all your hard work ( i know i appreciate it ) , read a few articles on your site as well... added to my favorites!!!

[@Meanie010]

Can I plug the flux capacitor directly into the orgonne generator or do I need to modulate the carrier wave output with a cascading field zener diode?

[@EXPLORISTlife]

As long as the marshal vane is below the Voc, you'll be good.

[@markyes2041]

But Captain Explorist . The Marshall Vane should always be calibrated against the Warp Drive -ve BUS differential with k-factor to maintain the hall effect constant at 0.02 % of sine magnitude ! I know because my nanna told me ~

[@ChatGPT1111]

Mark Yes my momma told me dat foosball is for the devil

[@idahomountainelk]

Fascinating video and your calculator is amazing. I only have a small teardrop camper with 100 W solar but I want to upgrade my batteries to lithium and the charge controller too.

[@wonghuiyien6446]

thanks for the info, but for total amp calculation, I suppose it refers to 5 panels connected in parallel? As current of panel suppose to be the same if they are connected in series.

[@marvinhillAllthrwaytolife]

I am so grateful you choose not to talk so fast. There is another person who teaches about solar who does speak fast, while he has good content, his fast speech makes it difficult for me to keep up. I found your videos for the first time today. Thank you for speaking slower. If been studying solar God 4 months now and did not know I can use 24v pannels on a 12 system providing I don't go above the voltage threshold of my charge control. Ty 4 that 2 :-)

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@GuitarDudeSean]

Your content is simply amazing!! I stumbled upon your channel trying to learn more about a solar install into a skoolie, and every video you've posted is so far invaluable to me. Cannot thank you enough for making all of this so accessible

[@Hermod_Hermit]

Just learned that I need a way bigger controller for my set up than I ever imagined. This saved me money in the long run, as I will not blow the puny one on an over voltage/amperage. With those 4x65W panels x 2 series it turns out I will have to go for a 150/60 controller.

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@notfound-qe1uo]

Sorry, but on the current calculation you multiplied by 5 at moment "6:04" but you should take into account that the maximum current is only 9.22A as the panels are connected in series. Thanks for the video!

[@MikeJones-pn3fl]

He's calculating the Amperage that would be supplied from the charge controller in the lowest temperature conditions. The current would be ca. 9.22A going into the controller, and ca. 46.14A coming out of it.

[@Marley-ii6ls]

@Mike Jones unless the voltage changes you can't just produce more amps. Watts in has to equal watts out minus losses just like a transformer.

[@a64738]

@@Marley-ii6ls Solar panels needs to be more volt going in to the charger then the volt going out. It is quite typical with 40 to 80 or 160v in, and 12 - 24 or 48v out. So it is always more amps going out then in...

[@danstreight2529]

Thanks for providing this information and calculator Nate!

[@alanblyde8502]

Thanks for the info, we are off grid “Victron gear” I constantly monitor our usage and as you say the difference in winter / summer is easy to see when looking live on the VRM, we have a duel axis array setup, consists of 6 x 335watt LG panels in 2 strings, (2010 watts total) it’s looking at the sun all day sun up - sun down, I have seen in colder days it reach 2430 watts, on real hot days eg: 39c it only pumps out 1700 watts, big difference, MPPT is 150/100. Inverter charger Mulitiplus 48VA - 35Amp. Batteries agm 12 volt -220AH x two banks (48volts) It gets us by no problems, il be using your method when upgrading later. Thanks again👍🇦🇺

[@EXPLORISTlife]

Sounds like a great setup! Glad it's working well for you. VRM portal is a great tool for sure.

[@paulrosa6762]

Thanks!

[@EXPLORISTlife]

Hey Paul Rosa, No problem! Glad it helped! :)

[@adetoroayodejisaheed4549]

Why multiply the amps by 5 (number of panels) when it is connected in series?

[@paulmarshall3370]

Amps in serious stay the same

[@ForGood828]

I know this comment is super old but in case someone else sees it. The amperage that he is calculating is the output amperage from the charge controller to the battery. If he was calculating the amperage that the solar panels would deliver to the charge controller then your question is totally valid.

[@JorgeSanchez-je4bt]

@@ForGood828 I was confused by how the charge controller output is dependent on the sum of the all the amperage of the panels. In this case by 5 panels. What I think the question is if the output amps of the charge controller is affected by the array set up in terms of in series or in parallel.

[@ForGood828]

@@JorgeSanchez-je4bt Basically, you can calculate the output amps by dividing the max combined output wattage of the panels by the battery charging voltage(in this case 14.4V.

[@VinceBadovinatz88]

@LIV828 I never knew this part. I have mine set up for adding the amps and the volts in their respective spots. Because that's how I thought we were supposed to do it that's probably why my solar panels are not getting the proper output I'm barely getting half and they're mounted correctly according to being in the series and adding the voc. N the amps. I'm going to have to recalculate my whole system

[@teddy8080]

Correction needed Hey Nate. I would like to thank you for your time and effort to upload all those informative videos, keep it up. When it comes to calculating the Max Amps coming out from the MPPT solar charge controller the answer in your video references the max wattage you calculated with the formula divided by charging voltage pushed, where as in the calculator on the website it references the Max Voltage Per Panel at Estimated Low Temperature x Solar Panel Maximum Power Current (Imp) / Charging Voltage Pushed the two approaches are different and lead to different answers… I think something needs to be fixed.

[@bryandemerath6812]

Noticed that same thing.

[@rogerviets3150]

This is a great calculator. However, one thing to be aware of is that Victron charge controllers require a 5 volt difference between the voltage of the battery and the incoming voltage from the solar panels to turn on. For example, lets say your battery is at 12.4 volts, the incoming voltage must be 12.4 volts + 5 volts or 17.4 volts. This is important in selecting your panel. In my case, I was looking at setting up a single solar panel with charge controller to maintain my batteries while my RV is in storage. This is on a truck camper with limited space on the roof. I plan on an eventual expansion to 300 to 400 watts but initially I figured a 100 watt panel would be adequate to maintain my batteries. I bought the panel and a Victron 100/20 charge controller for future expansion. As it turns out the output voltage of the panel is only 16.77 volts. The charge controller will not turn until the battery voltage drops to11.77 volts. Not acceptable in my opinion. There are lot of panels on the market with higher output voltages and this wouldn't have been an issue. My solution is to buy another panel and run in series to double the voltage output. The charge controller should work fine after that. Just be aware of the 5 volt requirement to turn on your Victron charge controller (not sure how this affects other brand charge controllers) when sizing and choosing your solar panels.

[@matikaevur6299]

yeah, living quite far north i can agree .. when 24V panel produces enough voltage to charge 12V battery only 3-4 hours per day .. added second panel few weeks ago .. but its late spring / early summer. I'll see what happens in late october. Also using Victron controller, amazing stuff. Wide range of input V, different battery chemistries and voltages .. but the price .. ;) Still worth it

[@perpelle]

@@matikaevur6299 I'm in the same boat and need to start my build asap. Are there any cons in running a 24v panel in a 12v battery system when using a mppt controller? I can't decide between a 12v 200W panel and a 24v 200w panel. My location is in Europe where it can be incredibly warm but also cloudy and quite cold.

[@EXPLORISTlife]

Perhaps just choose from the systems I've already got designed and available to take the guesswork out of it? shop.explorist.life/product-category/all-products/camper-wiring-kits/solar-charging-wiring-kits/

[@perpelle]

@@EXPLORISTlife If your answer is for me then we have a problem with shipping/vat/import duties. It's just that a 24v panel with the same wattage as a 12v carry the same price. If my calculations are correct a 24v panel will send more charge amps to a 12v battery compared to a 12v panel with the same wattage.

[@matikaevur6299]

@@perpelle Hello, i run 2x24V in series to charge 12V battery. It's ok in summer .. after that 2 weeks (ha joke :) not much. Tallinn, Estonia. Usually those MPPT controllers need battery voltage +2V to start charging. So in case of low light you get volts up faster and MPPT takes care about amps. My 2 panels are 24V, 240W, 10A, connected in series. So mid-sized victron is quite ok. No controller can give you power if you haven't seen sun for 3 weeks ..

[@76ram1]

I’ve just found your channel and it’s gold dust. Please keep up the fantastic work.

[@EXPLORISTlife]

Hey Roland Maraldo, Thanks so much! Cheers!

[@mrlincxg397]

can I have the reference of the equations used in this video? Thanks really need it in present time. EXPLORIST life - DIY Campers

[@charleslock6432]

I will probably not watch another video because I got everything I needed from this brilliant video, you just deserve a sub anyway. Top content lad

[@rogelioespinoza7852]

Way awesome, THANK YOU SO MUCH FOR WHAT YOU DO! giant help

[@mountainconstructions]

Finally found the info I was looking for regarding multi panels and the Victron MPPT 100/20. Thank you

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@francishagen8508]

Nice start 😂😂

[@EXPLORISTlife]

Haha, thanks!

[@Saint696Anger]

Lol that's exactly what I've been avoiding and it's like that on so many channels

[@Mriozo1]

On series, the amps still the same.. so 4 solar panels connected on series (the Voc x4, but the amps still the same 5.2 for example) or I’m wrong?

[@Five0Music]

Great stuff, and thanks for the calculator. With a 250/100 in the my setup, I’m apparently as cool as I can be. 😊 Your work is much appreciated!

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@recoreef1371]

you calculator is fantastic ! THANK YOU !

[@EXPLORISTlife]

Glad it was helpful!

[@CheapRVliving]

I applaud you for your awareness of the impact of temperature on a solar controller, but there is a flaw in your logic in relating to the impact of cold weather. You are only going to see those extreme low temperatures a few months of the year, and during all those months the sun will never go very high on the horizon. That’s easily proved by comparing the elevation of the sun on June 21 to December 21 at the same location. As volts go up with the colder temperature, they go down with a lower sun. Beyond that, cold air is much denser than the warm air of summer and by being low on the horizon, sunlight must travel further through much more dense atmosphere as well as a much denser atmosphere. A far more realistic example is to imagine driving at 12,000 feet at noon in Colorado on a very cold day on June 21 and it is 50 degrees F. That is going to be a large spike in voltage and you will be very glad you added that extra headroom for a big spike in voltage and amps. A friend blew his controller in just that situation-even though he had sized it right for “normal” temperatures. Your conclusions are helpful because other than spending too much you won’t regret buying a bigger better controller than you need, but choosing a more realistic example increases your credibility.

[@EXPLORISTlife]

With all due respect... my example is accurate. :) It's important to take into account the lowest morning temperature ever expected because before the charge controller comes out of it's sleep mode for the morning, the solar panels could potentially reach their full rated open circuit voltage (Voc) AS SOON AS the sun peeks over the horizon. Your example with the mid-day high elevation, cold weather in the summer would only be for the operating voltage (Vmp), which is inherently lower than the Voc anyway, so if we account for the morning time low temperature for the Voc, the high Vmp would always be covered. Sources: Where do we get the expected lowest temperature? Normally, this temperature occurs in the very early morning hours just before sunrise on cold winter mornings. The PV modules are, in many cases, a few degrees colder than the air temperature due to night-sky radiation effects. The illumination at dawn and dusk are sufficient to produce high Voc, even when the sun is not shining directly on the PV array and has not produced any solar heating of the modules. - iaeimagazine.org/features/pv-math/ PV modules will “wake-up” every morning with very little sunlight. Because the PV array is sitting outside, the temperatures of the modules will be the exact same value as the night air. Because the sun isn’t actually hitting the array immediately, the modules will not immediately produce any current, which means they will immediately go to open circuit voltage. If the temperature of the module is less than the STC value of 25°C, the module’s Voc value will actually be greater than the value listed on the module’s listing label. For our discussion, we will consider the temperature of the module to be equal to ambient temperature at daybreak. - www.ecmweb.com/renewables/article/20896643/the-highs-and-lows-of-photovoltaic-system-calculations "Voc will potentially be briefly produced in the morning when the sun first comes up and the panels are at their coolest, but the connected electronics haven’t woken up out of sleep mode yet." - www.altestore.com/blog/2016/04/how-do-i-read-specifications-of-my-solar-panel

[@idunasorchard]

It seems like the cold weather voltage spike is more common and more of a concern in most situations than a cold weather amperage spike because of a low sunlight angle with the exception of extremely high altitude cold situations that can come at times when the sun is very high in the sky. For people near sea level it seems like a cold induced amperage spike exceeding a charge controller’s capacity is very unlikely.

[@Casmige]

Absolutely no consideration of an allowance for the earth being flat......just sayin’...

[@james.8985]

@@Casmige No mate; that's why the panels are FLAT 😆

[@mikefranks4528]

Well, I guess crow is on the menu tonight. Subbed. 😀 Will be using your calculator and maybe the forums on my first build. Thanks for all that you do, EXPLORIST Life! 29NOV21-Update: Oh and I just saw your full tutorial on a full electrical set up and will definitely be buying your kits!

[@robparla5513]

Wow the calculator is super helpful in combination with the video. Thank you!!

[@deanhenthorn1890]

The first 30 seconds tells me all you need to know.

[@dsmith6404]

😂

[@jameswilliams4653]

hello, I have a trucker camper 19ft long.. what size system should it take???

[@EXPLORISTlife]

Do a youtube search for "EXPLORIST.life How Much" and watch that video to get started with sizing your system.

[@6248cjl]

Uuuummm...yeah...🤔😬 this old brain can’t handle all those numbers. I’m the one that just says “this is what I want to power, now hook me up”.

[@EXPLORISTlife]

Yeah, that's definitely why I've got all of the free wiring diagrams at www.explorist.life/solarwiringdiagrams and why I opened up the consulting service. 😁

[@shareethornberry8385]

Or watch 30 seconds, repeat, take notes, watch again, correct notes, and go on to next 30 seconds like the rest of us oldsters. And read his website stuff, print out a printer friendly copy, highlight, underline, and color code until it looks pretty. By that time you will get most of it. And he did say contact him for additional comments and questions.

[@6248cjl]

Sharee Thornberry 😂❤️

[@Psalmist.SamuelAdams]

Just completed first consultation last week I learned so much create safety in the system I have and allow more efficiency I would recommend consultation to anyone seeking to do their own solar system It is Well above worth the money I promise the best absolutely the best thank you so much

[@Psalmist.SamuelAdams]

Looking forward to the next consultation after I receive needed products from explorerist can't go wrong here

[@mohamedsheikh2502]

you are a great guy and a good teacher thanks, god bless

[@MBergyman]

You created an excellent little tool, thanks for sharing.

[@EXPLORISTlife]

Thank you very much! Glad it was helpful!

[@ambikesandboards]

Wow u draw such straight lines and square corners :)

[@tweedeldee8122]

The calculator is awesome!

[@EXPLORISTlife]

Thanks! 🙂🙌

[@garystewart5997]

excellent video however how can the amperage increase if the solar panels are in series? the diagram for the amperage shows the panels in series.

[@mikecraig5629]

Hi Nate, Thanks for the video. Could you please post up the formulae on your calculator website. I just get some results and wanted to check them against the formulae.

[@EXPLORISTlife]

Next time I get in there and edit that page, I'll consider it. Thanks for watching!

[@tl3234]

If my solar panels have 9.5A (ISC) should I put a 9A fuse between them and the controller to prevent them from damage?

[@laxbouas]

Yo the calculator is top tier! very good job

[@EXPLORISTlife]

Glad it was helpful. Cheers!

[@timmerylee977]

Can you link panels that are not the bulk rectangles. I have seen shingled roofing?🤷🏼‍♀️

[@richardnorth6988]

Not gona lie, my brain hurt for a bit there but came away knowing more. Great tutorial and will defiantly watch that again 👍

[@user-zo6xg8bx4l]

I have two panels of different wattages (140 and 100). Your calculator (which is a good start) assumes one has the same make and model panels. Is it possible to make a calculator which would accommodate differing panels? Thanks.

[@venturingthemiles]

How would you apply this for series parallel? Do you need to do the calculation for both strings and add them together? I've watched all the videos and I can't find anything on sizing mppt for mixed panels in series parallel! Thank you 😊

[@EXPLORISTlife]

The calculator accounts for series/parallel: explorist.life/solar-charge-controller-calculator/ If you're going to be purchasing from us, you can always reach out to shop.explorist.life/support for some more personalized guidance.

[@willadam4121]

Thanks for the good info. What if the solar panels are mismatched? Will your calculator work and how? Thanks

[@EXPLORISTlife]

It will still works, but you'll have to tinker with it a bit to get the proper array voltage/amperage heading to the charge controller.

[@mauricio8983]

Holly crap. That was an extremely well done explanation. I understood ! Of course by the time I add the period I will have forgotten everything, but that’s not your fault. Great job.

[@seanmoon1444]

Omg ur a wealth of knowledge thx for all your maths plugged my panel info into calc but it didn’t give a recommendation

[@EXPLORISTlife]

What information did the calculator provide in the ''Detailed Results" Section?

[@seanmoon1444]

Wow 1st off ur amazing with the speedy reply the series parrellel thing threw me for a loop but amps going into charge 18 comming out of solar 86.11 300v per panel 1200 total

[@EXPLORISTlife]

Gotcha. The array voltage is too high. that's why it isn't making a recommendation. Try using a series-parallel configuration to lower the array voltage.

[@Seqhael]

Hey I love this, but I found it was quite confusing when I plugged in your own personal solar array of mismatched panels, as I think the calculator expects all the panels to be the same? I was trying to calculate your array on a 48v battery, 2x200w, 2x55w, except 4x35w panels instead of 2. I suppose like you said, the array voltage will be less than the 48v battery bank voltage

[@EXPLORISTlife]

The calculator is not set up for mismatched solar panel sizes.

[@idahocartel]

Is it to okay over size a the solar mppt controller knowing you might want to add. Down the road panels?

[@jacquedreyer5479]

Great video - you threw me off track with the Max Power Voltage (i.e. 22.65Voc Vs 18.90 volts) Had to go back to look at the solar panel label again to verify. Thanks for the videos - much appreciated!

[@EXPLORISTlife]

Awesome! Glad it helped. Thanks for watching!

[@llnp5469]

question... i see your example you mention 5 panels, but i dont know how or for some reason in a previous video you mentioned all panels must match in pair numbers,, can you please clarify, can we use 3 panels, 5?

[@garretdoi6218]

Can I charge a battery bank of 12 deep cycle marine batteries all in parallel, using 4 each 200watts solar panel in parallel, & produces 32volts each & 8amps each out puts close circuit each?? If so what brand charge controller, & model number type should I purchase; temperature during summer 🏝️85*-95* & winter🏝️ 60*-70* degrees.. thanks you for the info & advice.. 👍🏽🤙🏽😁

[@ShortyzProductionz]

Plug In all the goodies numbers to his program to get you the exact charge controller that should suite your needs

[@GerberDaisy]

Thank you for being an AWESOME teacher. We are in the beginning days of building our Shuttle Bus and your videos are helping us understand solar and what we need to purchase. Sincere Thanks.

[@SawmonandNatalie]

00:03:40 where did you get this formula from to calculate Voltage at a specified temperature?

[@EXPLORISTlife]

That was from a conversation with some of the engineers at Victron. A google search for Solar Panel Temperature Coefficient Calculation should yield good results, though.

[@SawmonandNatalie]

​@@EXPLORISTlife I found an article with all those formulas. Here is a link to it: doi.org/10.1016/j.solener.2008.10.008 Also, I looked at the calculator code you have on your WordPress website and the last item is not calculated according to the formulas or your method in the video without the calculator. The calculator on your site uses the following formula to calculate the "Max Amps Coming out of Solar Charge Controller": (Example for 12V Battery Bank) Total Number of Arrays * P_STC / 14.4 P_STC = Solar Panel Wattage (Max Power) at Standard Test Conditions (the 1st field on your calculator) Whereas your calculation earlier in the video tells us to use: Total Number of Arrays * P_T / 14.4 Where P_T is the P_T = Max Power Per Panel at estimated Low Temperature P_T = P_STC * ( 1 + β * ( T - 25 ) ) here β is the temperature correction coefficient for max power: β = (the value for Temperature Coefficient of P_max on the Solar Panel Specs sheet) / 100

[@SawmonandNatalie]

@@EXPLORISTlife btw, amazing videos. We love your channel. It is an amazing resource.

[@EXPLORISTlife]

I've made a minor change in the calculator since producing this video for the sake of clarity, so they aren't EXACTLY the same anymore... but what exactly are you trying to figure out? What metric are you trying to find?

[@OYMInternetRadio]

Hi, WEll done on your videos. The one thing I have not heard anyone talk about when size your requirements are the devices that do not take watt hours. So you may have your computer on for a period of a few hours which is fine, but things like kettles to make a cut of tea, they may be 1.8 kilowatts, but they are only on for a short period of time, so who do you factor that in. This also applies to power tools where you might only have them on every now and again like a mitre saw for example.

[@EXPLORISTlife]

1.8 kilowatts = 1,800 Watts. If you run a 1,800W device for an hour, that's 1,800 Watt Hours. Half an hour would be 900 Watt hours. 15 minutes would be 450 Watt hours. Something like a miter saw that only gets a few seconds of use at a time would indeed be difficult to calculate as the use is also pretty inconsistent.

[@OYMInternetRadio]

@@EXPLORISTlife Yes, I agree, the likes of a kettle which only stays on for about 5 minutes would also be difficult to calculate.

[@EXPLORISTlife]

That one is pretty easy too since it's consistently on for 5 minutes at a time. 1800W / 60 minutes = 30Wh per minute. x 5 minutes = 150Wh per use.

[@OYMInternetRadio]

@@EXPLORISTlife Ok, I didn't think about looking at it that way, thank you. :-)

[@samuelstewart2762]

Hi i like the way you broke down the calculations and made it so simple i'm not that good with maths either but you my friend by far out shine a lot you should play the lotto with your skills after all its a math problem

[@rogerberges1374]

good information!!! but why you decided to use 14,4 voltages? any specific reason? where do you the number from?

[@EXPLORISTlife]

That is an average charging voltage for a 12V battery bank and is what Victron uses in all of their calculations and datasheets.

[@Masteradamant]

my controller only shows wattage when using the power... is there any other controllers that detect wattage better? If not I know I need to buy more cheap controllers

[@EXPLORISTlife]

Your controller will only tell you the power it is putting out. So if your batteries are full and you aren't using power; your charge controller will stop outputting power do it doesn't overcharge the batteries.

[@Masteradamant]

@@EXPLORISTlife that makes researching solar slightly complicated since I need to use appliances but that is ok

[@Masteradamant]

@@EXPLORISTlife I’m more like Vosk at least.. I have a separate system to make sure I’m using enough power to test my limits and can controller or adjust the power being used after finding the maximum

[@paulerger3688]

I understand I don’t want to put more volts into my controller from my panels. Will it damage my Renorgy 20 amp controller if I put more than 20 amps to it from the panels? The manual says the controller no more than 260 watts.

[@nickharper6436]

Hi great video. I have 140w single panel but might add more later. Can I use a MPPT that is bigger than I currently require so it’s good to go if I add more solar later?

[@kenname-private5355]

Nat: I am trying to use the calculator to determine the size of charge controller and number of panels needed. I have examined the spec sheet for the REC330NP and the REC365AA panels and cannot identify some of the data needed; #1. the spreadsheet asks for the STC (T=C) but I cannot find anything that looks closed to that, #2. Need Max Power Current (IMP) with same issue, #3 Last question asked is for the number of panels in each series but the large text asks "Panels/Strings in Parallel. I will have only two panels wired in series so am not sure how to answer number #3.

[@daniellamberth7877]

I beredd this. But have one question. Heat do I do of the spec sheet spenat show solen of your variables in your calculator. Like temperaturen coefficient for one.

[@Sblackphoto]

What are the effects of if you have the wrong controller? If you add more solar panels after etc

[@EXPLORISTlife]

Best case scenario, it would work fine. (Ex: oversizing the controller) Worst case scenario, it would damage the controller. (Ex: overvoltage to the charge controller)

[@GarthVader78]

Hi Nate, Im loving the series, I cant find 'episodes' 1-4, 6 and 17. Do you have a list you can point me to?

[@runtr8389]

Nice, you must live at the south pole , ,,, what about in Australia , where we have a summer temps up to +45 deg c in the shade , over + 65 deg in the sun, how much the the volts drop off then , my friend ? please add the to your calculator ,,

[@EXPLORISTlife]

I'll see what I can do, but ultimately sizing the charge controller (What this video is about) needs to be based off of the minimum temperature because an excess voltage would result in damage to the charge controller.

[@dougwinter7888]

How can I charge both my Lithium Ion house batteries AND my under the hood Lead Avid Battery with the same solar Panel. My RV sits most of the time, and when I use it, I have a much lower power draw than what your builds show (I still use propane to power the fridge, heater, hot water heater, and stove top.) So I have quite bit of excess Solar. Thanks.

[@EXPLORISTlife]

The 'proper' way to do it would be to use two separate arrays. Build a big and proper solar array for the house battery bank and then get a little 20W or so panel and dedicated charge controller for the starter battery. The starter battery doesn't need much to keep it topped off.

[@dsmith6404]

What if I have 4 panels now but plan to add more down-the-line Is there such a thing as buying too big of a controller?

[@EXPLORISTlife]

This may take a more in-depth look at your personal setup. If you have purchased/are purchasing from our store (shop.explorist.life) reach out for some more personalized help: shop.explorist.life/support If you've purchased/are purchasing elsewhere, reach out to your dealer for support. We'd love to have you as a shop.explorist.life customer so we can provide a bit more help in the future. 🙂

[@noahriding5780]

If you max out your charge controller's capacity... can you still add more solar panels by just putting them through a 2nd charge controller and then having that charge controller connected to a different battery within the same battery bank (But different entry point)? Or is this increasing risk? Thanks.

[@bpexodus]

Quick question. I'm a newbie, so go easy on me! I have 4 100W 12V solar panels that I want to hook up to my oukitel 2000w power station. There will be 2 arrays of 100W panels in series going to the power station in parallel. Should I use 2 charge controllers, cut off switches, fuses, then connect it to the power station, or should I connect the panels directly to the power station?

[@EXPLORISTlife]

I'm not familiar enough with that unit enough to know off the top of my head. Usually those portable units have decent instructions to show you how to connect solar panels. Perhaps reach out to their customer support if not, though?

[@bpexodus]

@@EXPLORISTlife The question isn't specifically about the Oukitel power station in particular. I was asking in general, can I (and should I) hook the solar panels directly to a power station, or should I use charge controllers, cut off switches, and fuses before I hook the panels to a power station?

[@EXPLORISTlife]

Ah, I see. You generally don't need anything between the solar panels and the power station.

[@bpexodus]

@@EXPLORISTlife ok great. That's all that I needed to hear! Thanks!

[@dagwood1327]

I really enjoy your content. I bought a high res wiring diagram. But I couldn’t download it. It was order 64247. My web browser said a problem repeatedly occurred. I have very slow internet so I even went to town with a faster internet. Same problem. Thanks.

[@EXPLORISTlife]

Darn! Sorry about the glitch. For problems with an order or download; send me an email to the address listed on my 'contact-us' page: www.explorist.life/contact-us/

[@user-vs7bb9cj2b]

Hi. Like your video very much however it got me a little confused. If wired in series volts add up eg 5 x 100w equals 500w. Amps stay as per panel. If I am correct in my thinking why did you multiply by 5 when calculating the amps ? Apologies in advance if I am incorrect

[@EXPLORISTlife]

The multiplication happens after the charge controller. Maybe this would help: kzbin.info/www/bejne/gJzFpGtqqKd7qck

[@grantkay7230]

Hi Nate liked your video on unequal solar panel systems. I wonder if you can help me. I have three panels on my van. 100 w + 20w + 180w they are wired in parallel and I'm getting up to 16amps would I be better wiring them in series. I am in Scotland and so winter is not so sunny but summer is very sunny. Regards Grant

[@indaba1960]

OK slightly confused (mainly because I am probably wrong) but I get that when you have a series of panels in series you multiply the voltages together (taking the temperature effect into account) but I thought that for a series array the current remained the same whereas you seem to suggest (and this is probably my misunderstanding) that to get the total current IN to the controller you multiply the currents by the number of panels (taking into account the difference between the panel voltages and the battery charging voltage) - is this correct or can anyone point out where I have made a mistake? Thanks

[@EXPLORISTlife]

If panels are wired in series, the current in doesn't change regardless of how many panels we have. Once that higher voltage gets regulated down to 'battery charging voltage' on the downstream side of the charge controller, that's when the amperage really ramps up.

[@indaba1960]

@@EXPLORISTlife awesome thanks, I now have a handle on it 😊😊

[@sailingcloudslifestylemari8611]

I have 4 panels 300 watts and I bought 2 mppt 100/50 and I have 400 amp in battery bank. Is this victron mppt are the right size ?

[@augustofaria1776]

​ @EXPLORIST life - DIY Campers I started my home solar journey, so far think only made 1 mistake. based on Victron's and your solar mppt calculator. I had already bought one, a Victron 100/50 for a 24v battery system. The calculators called for 150/35, when I change the temp setting by 5 degrees it calls for 100/35. Can i use the 100/50 by changing the settings of the MPPT? Thank you in advance.

[@adnanabdel-ghani2018]

You are so good young man,I have been going through all of your videos,I looking for one about inverters ,because I looking for a kind of inverter where I can get a neutral line and live line,thank you

[@InvisibleCitizen]

Can over size my charge charge controller so I don’t have to replace it if or when I expand it on my camper-can?

[@EXPLORISTlife]

Generally, yes.

[@LivingFree365]

I think I broke your calculator. It says I have 27.27 Amps going into the Charge controller and 137.84 Amps coming out of the charge controller. I don't have any Negative numbers on my labels. When I'm done punching in all the numbers, doesn't have a recommended Vitron Controller for me to buy?

[@CG-xr5bz]

Can this work with dc to dc charger to van battery also. Which video?

[@edwardzvonik7157]

I'm not getting any voltage from my panels. I have 3, 195 watt panel routing to one smart controller 100/30 and 2, 195 watt panel routing to another 100/30 smart controller. Any idea where to start troubleshooting.

[@EXPLORISTlife]

This may take some more in-depth troubleshooting. If you have purchased/are purchasing from our store (shop.explorist.life) reach out for some more personalized help: shop.explorist.life/support If you've purchased/are purchasing elsewhere, reach out to your dealer for support. We'd love to have you as a shop.explorist.life customer so we can provide a bit more help in the future. 🙂

[@TimothyMurray-z5p]

Why did you use 14.4 volts to divide the watts (around 5 minutes into the video)? Is this because it is a 12v system? What number would you use for a 24v system? Thanks, Tim

[@EXPLORISTlife]

That's the approximate charging voltage for most batteries. For 24V, double it.

[@farmermike9262]

I'm running a 200w solar array on a tacoma . Can I just use a dual input dc/dc charger or is it recommended to use a separate solar controller?

[@EXPLORISTlife]

I recommend separate solar charge controllers and DC DC Chargers. www.explorist.life/solarwiringdiagrams

[@jakeblackburn1979]

Hi Nate I’m trying to calculate my charge controller but my panel spec for Temperature Coefficient of panel (Voc) is listed in mV/K How do I convert this to %/°C I’m coming up empty on google searches. Any help is greatly appreciated! Thanks Jake

[@chasing_tail_rv]

I have the same problem. My panel specs say Temp. Coefficient of Power -0.43%/K and Temp. Coefficient of Voltage -0.12V/K Not sure how to convert that or is it the same.

[@leilastevenson]

Does the amount of heat matter to the amount of volts produced? I live in Southern California and we range near or above 100° for 5-7 months/yr

[@mB-mp6io]

I have off gridd inverter rated at 2400 w but the its mppt charger is rated at 1000w. is that means that the max power from solar panels passed to inverter is 1000w?

[@EXPLORISTlife]

A properly sized charge controller connected to 1000W of solar would push 1000w to the battery bank. An inverter rated for 2400w can pull 2400w from the battery bank. If this is happening at the same time, the net positive or net minus would be either going into or coming from the battery bank.

[@sreehyd23]

Thanks for all your input, They are quite helpful ..

[@EXPLORISTlife]

No problem. Happy to help!

[@petewarby7158]

What a legend 100% what I was looking for AND a brilliant free calculator :) thank you bud

[@EXPLORISTlife]

Hey Pete Warby, No problem! Glad it helped! :)

[@calebmateiciuc4637]

Hi! Can you explain the difference in simple terms ( or if you have a video on it ) of the difference between more Volts vs more Amps. I have seen a video that said that by adjusting the voltage we can save money on charge controllers, but how does that affect the operation of electrical components??

[@EXPLORISTlife]

Sure! Here is a playlist that will teach you all about that. Your question really isn't one that has an answer 'in simple terms': kzbin.info/www/bejne/gJzFpGtqqKd7qck Alternatively, if you want the 'in simple terms', 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/

[@leepittman4923]

Hi I have a Question I have a 48 volt club car I want to put solar on it can you tell me what kind of solar panel i will I need and I want to use a boost controller