Best Wattage of Solar Panel for a DIY Camper Electrical System (and why there isn't a 'best' one)

For car camping and hunting I cable lock a 220 watt Off Grid TREK solar "blanket" to the two crossbars on the roof of my compact SUV. Then I plug the blanket into my BLUETTI AC200 MAX. During late summer and early fall it powers a small cooler all day and charges the 2 batteries of my e-mountain bike at themed of the day. It worked very well this year for 5 days of hunting in north central Nevada. IT's also a comforting system to have for extended power outages.

I like how you do these informative videos, very clear🎯😎☕
I really need to get off my behind and get a system set up, for my watchmans trailer,( it's a crude, 8x12 box, from a fire/rescue ambulance. Kinda short, inside and plan on raising the roof later on.
I need enough power to operate a small chest freezer, DVD player, flatscreen tv and a few lights,,,and AC unit, 5k btu, mounted at back wall.( necessary during summer🔥)
Main thing holding me back is not being able to save enough money, the expense of running a small invertor/generator ( gasoline), is not getting any cheaper.
Crazy part about it is, if I didn't need to run the generator, for freezer and AC, I could more easily save money, for the solar power set up. I just need to figure out how to make things come about🎯😎☕

Nate. Please use examples for better clarification. I am not quite sure what you mean about the Voltage. I am still in learning mode. Thank you for your knowledge.

For a solar system in a vehicle is it necessary to ground the negative terminal of the battery to the chassis? Also if my solar system is isolated from the vehicles electrical system won’t grounding the solar system to the chassis cause problems?

So I have ordered the Renogy DCC 50 amp MPPt/DC to DC charger. It only excepts a maximum of 25 V which is less than the 20 V over the battery charging voltage. Will this be a problem? I will be using three 200 W panels in parallel to keep the total voltage under the 25 V

I'm not sure I understand this video correctly. You're saying 3-100w panels are basically the same as 1-300w panel. I was looking at panels and I found a 100w - 24.3v panel that measures 873.62 sq inches (41.8 x 20.9) for $95. I then found a 485 w - 43.3v panel that measures 3645.6 square inches (91.4 x 40) for $224. So for a little more space and almost half the price, I could have 1 panel instead of 4? Am I missing something?

I'm building a 780W solar array, just connected to x2 12v 120ah batteries do I need to ground the panels.

Hi Nate! Thank you for such in-depth explanation on Solar. Are flexible monocrystalline solar panels (300W/12Vx4) off ebay capable of powering a water pump of 550W/24V.

Hi just watched your video. Thanks. I am looking to install panels soon. You say battery size+ 20v. In my case 12 + 20=32. I have a renogy 50amp dc to dc combined mppt in the spec it says 25v(660 watts) max input. Can you explain your thinking please.Could I use a perc panel with this spec( Voltage ratings (STC) : Vmp = 41.3V; Voc = 49.3V Thanks

I had been planning to arrange my 2 200w panels in series, but with a slight tilt relative to each other (why is irrelevant, please don't ask)... but now I've realised that perhaps the panel with the non-optimal tilt will give less amps, and this will limit the amps coming from the more optimally tilted panel. Is this correct? If yes, I would change my plan to ensure that they are both having the same orientation.

These array calculations are confusing if for some reason you have only 3 panels and do not want to place all of them either series or parallel for example difficult shadowing issue.
What would be calculation for 3 similar 12v/5A panels where two of them would be in series and one parallel between those two?

So if I have 100 ah battery with 60 +60+50w solar panel how should I put them in series or parallel?? Here in Denmark is not so much sun

Very well explained. Every video from you is great.

You missed one important factor. Higher voltage between the panels and the charge controller is preferred because the wire size can be greatly reduced making it cheaper and easy for routing and high voltage give less efficiency loss.

Have you ever been involved with Solar on a motor yacht? We have a 50 foot one and all the lighting is 12 volt. I am installing a new refrigerator and freezer, both will run on 12/24 as well as 120 volt. If it wasn't for the 3 - 120 volt air conditioner units I think I could figure it out. The AC's draw about 25 to 30 Amp to start then about 15 to 20 for run. We live in Florida where it hot all the time and have a lot of sun. I figured one time that all the 120 except the AC would be around 1800 watts. There is a 12 v battery charger that charger 3 batteries that could be charged via a solar charger I think. That would remove that 120 volt load maybe.
Looking for some ideas on this.
I have room for at least 4 - panels 2 x 4.

I need help. I am converting ambulance into a camper, I think I want like 700watts but i don’t even know how much I need. Please help me someone

You need to update your info. Why are there no 450w panels? Now there are over 500W panels. Why would anyone choose 4 - 100W panels???! LOL. What a waste of roof space and it costs more.

Sorry dude! English please

Love your stuff mate , great little videos

10 years ago I thought the same way and built my system. After my experience, upgrading and rewiring I am sure now that you are totally wrong. Mistake in your logic and math is Shadows. RV solar system is not house roof array or array of power station. Very often RV panels has shadows from something - trees, houses, other RV, own antennas and AC. Nature of panels they do not like shadows and drop all power if only about 10% covered by shadow. All other panels in series stop to work as well. Solution is to use smaller panels in parallel. It can be less efficient for MPPT and needs thicker wires but overall performance should be better in real world

So I have 2-200 watt solar pannels wired in parallel and receiving approximately 22 v with 6 amps in full sunlight max, this is the most I’ve ever seen. Does this sound right? Please and thanks.

When a battery is empty of water does it work when refill it up back

Awesome video. Many thanks. Mike

Hi Your spreadsheets for calculating amp hours shows items that are at 110volts. Frig, TV, etc. All of my stuff is 220 volt (European). How does that effect the calculations the spreadsheets are doing? The SS are great but I feel I must be missing an important fact and have no idea how to adjust. Thank Tim

Hi great videos by the way , would u be able to explain this ? Which is best more volts or more amps going into the mppt charge controller ? Reason I ask I am thinking about getting a votronic 3 way system. but it has a max voltage input of 36 volts , so if I do go this way I would wanna wire up my pannels to increase the amps like u have explained in previous videos , but in reality which is bets more volts or more amps many thanks for your time John

Hi I need you help I have new trailer I’m Want to install 300 Watts solar panel but is my first time I’m no sure wat parts you recommend?

How do you set your VOC 20V higher that the charge controller if it has a Max input VOC of 25VOC? Have a Renogy Dual input DC/DC 30A charger and want to add solar but assumed I’d have to run all the panels in parallel to keep the VOC bellow 25

What are the things that i real need to set up my solar home system

when calculating wire size i notice my panels have 2 voltage specs and2 amp. specs, the two that multiply up to the wattage of my panels are the rated voltage Vpm and rated current Ipm not the open circuit voltage or the short circuit current. So are these the specs i use in your wire size calculator ?

Hi can 600 watts 24v solar panel work on pwm 60amp charge controller to charge two 200ah 12v gel battery bank?

I have a 24v battery bank and 24v solar panels. So should I wire my solar panels in a series parallel circuit. To achieve 48v to achieve the 20v higher than my battery bank?

So i want to put at least 3000plus watts of solar on my fifth wheel RV and am going to be pulling a 16 foot trailer behind my RV. I would like to put another 1000-1200 watts on the pull behind trail bumping up my solar wattage so when i dry camp (boondocks) i can plug it into my fifth wheel trailer solar system giving my tons of power to run two ac units a lot as well as tvs, microwave, and all other items in my fifth wheel. Can this be done and also adding plug in system from trailer to fifth wheel. Thank you for your great videos that has helped me so much to under stand solar systems and installation processes!!!

how close in volts & amps do panels need to be effectively wired in series. ie: 1 panel at 190 watt, 19.2 volts 9.8 amps and the second panel at 110w 17.2 volts and 6.4 amps. Is it correct as 190 + 110w = 300 watt array, 19.2 + 17.2= 36.4 v but degraded by the 6.4 amps of the lesser panel. resulting 36.4v x 6.4 amps= only 232.96 watts of the 300 watt array, thus 77.6% efficiency

Do solar panels mounted an inch or so off the roof shade the van's roof so cool things off, or due to the heat of the panels, do they heat up the van. I'm about to add solar panels to my 2020 sprinter. Along with all the Victron equipment you recommend in your videos! I have a question, If I mount my solar panels about an inch off the roof of my Sprinter, will the panels cause the roof to be hotter or cooler. In other words, even though the panels will shade the roof, will the heat from the panels cause the roof to be hotter, and therefore the inside of the van hotter as well. Thank you for your super great videos. If I don't see you doing it or recommending it, I don't do it with my Sprinter.

Something to consider, is the analogy of why we don't have one big tooth; cause if one tooth goes bad, or gets hurt. Then the whole system is bad. If we have multiple, the others can continue to work. But obviously it's personal preference

First video to figure this out, thanks for this great series. My silly son is freaking out and thinks that I'm going to die. I'm out to prove him wrong ♥

can those big 375W panels handle the road vibration?

Hi Nate, again I want to thank you for all the help that all your Videos you provided., I installed 840 Watts with my 4 -100 amp BBs and they work great. My class A is Almost all Electric, Samsung Fridge, Induction cooktop, Microwave, Tv, Hot Water is by Propane or Electric and force Heat is with Propane. I use approx. 30% of Bat. thru night ( Fridge and Misc) The morning I throw everything at the Array, Mr Coffee, Toaster, and Induction... check it out... I can make it through the day without running the Gen. as long as I have about 7 hours of sun.. It's working great and I am Loving it ! So again Thank you!

How about 6x 190 watt plus 100 amp controller

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Yeah!!! The basix. That's the stuff!

My favorite person for learning how to improve my RV.

Hi, great videos!
You have helped me a lot during my van build. Could you kindly help me with a question… I’m connecting two solar panels to my solar controller tomorrow and I was wondering if I can just solder them instead of using mc4 connectors?
I brought two mc4 branch connectors as four wires need to connect in two from the controller. The connection is just terrible and I was very tidy on crimping them. This connection is inside van so doesn’t need to be a water tight seal but I do need a strong connection! I pain on soldering two positives to the positive and two negatives to the negative. And make sure the put plenty to heat shrink so they do not connect in the wall space.

Your thoughts on this would be very grateful

Many thanks Justin

Thank you for providing so much information! How should I go about determining my solar needs if I also plan to have alternator charging capabilities?

Hello I have a question if I run two separate strings of 480w each to two separate charge controllers to one battey bank do I have only 480w total or 960w total thanks

Can you hook 2 different sized MPPT chargers into the same charging system? and if so can 1 be only 20 amps (for my portable solar panels) and then my other main one is 100 amps - my main question is does a solar charge controller have to handle the ENTIRE system or only be rated for its own array of panels?

What if it's a 48v system

what happens when the wattage on solar arrays are more than the max charging watts on the battery bank? for ex. 4,500w in panels with a max battery charging input of 2,400w. and is it better to have more wattage in case of rain, shade storms etc?