So grab a piece of paper and a pencil and create a table. So once you know your total watt hours, the next thing that you need to pick in your system is your battery size. If you still don’t know how to find these numbers, read our article on calculating your power usage for each electronic device for some tips and real-world examples. To use the Wire Size Calculator, just follow these 4 simple steps: Enter Solar Panel output voltage. This is the more expensive option, but allows more flexibility in input wiring. I purchased 10 gauge extension cables but the wire is so thick that it does not fit into the holes on the bottom of the charge controller.  1000W Pure Sine Wave, Additional Parts Also, is there a good way to get power use estiments for devices? SOLAR SIZING Calculator. Look back at your components. 2) Get a MPPT charge controller. What it’s doing is also charging your laptop battery. Optimizing Your RV Battery Investment Most savvy RVers use checklists to prepare for their road trips and camping adventures. Jump To Frequently Asked Questions But smaller inverters are more efficient. The numbers you’re looking at function in this purpose. It’s hard on the batteries. AC components are running off of your inverter. You have saved me alot of effort ? So once you get all of your components listed out, this is all of your electrical things. We also have two phones, and our phones are I think 3 amps but at 5 volt USB so they’re each running about 15 watts and they’re plugged in 3 hours per day.  Renogy 200W Solar Kit (MPPT charge controller) If you’re asking if you can do this without a battery, then the answer is no. so I use it for 10 minutes, thats 0.6 of an hour so 720/0.6 = wH of use? That will just print to PDF right there. Really nice and simple calculator but limited to summer use, what I need to know is what kind of drop off would there be in winter, I need this so I can build a system for use 365 days of the year. Say hey, here’s all my numbers, this is my daily power usage. It’s a really good quick reference for your camper van. What you’re going to want to do is everything that uses electricity, you’re going to write down. So for the charge controller this is a very generous size. we provide a number of ways to help you determine the right system for your RV. We have a chart in our vent fan article (https://www.parkedinparadise.com/best-roof-vent/) which shows the amperage draw for the Maxxfan and Fantastic Fan at each setting. Thinking if I have just 1 and it stops working for some reason, then I have no reserve. Types of solar panel. Which Size: The most popular motorhome solar panel kit we sell is the 120w MPPT kit.This kit is currently a good compromise in power, price and size. Select whether your device is DC powered or will be using an AC inverter. Read our article on inverters for more information. If I have 3 and one stops working, I can re-wire in the field with the 2 remaining? I use a good bit of power because I work from my van. See what is drawing the most power and look at ways to reduce or eliminate it. With that said, it’s usually a lot of work to add more panels on the road so we like doing them all at once. I think that thing was pulling 2.9 [amps]. all I want to do is run a 12″ inch 120v desk fan when I go to sleep in my minivan. Ok, next up is the inverter. In hotter weather that compressor is going to be on a lot more because that internal temperature is going to raise up a lot. If you occasionally are using more power – such as a hair drier for a few minutes once a week – then you won’t be doing too much damage to your batteries. As a general rule, smaller inverters are more efficient.  Renogy 100W Solar Kit (PWM charge controller) Solar takes the sun's energy and converts it into DC (Direct Current) battery power to charge you motorhome’s batteries. Thanks for your work, its the best place for information I have found. So in this case, to discharge 1127 watt hours per day, we need a 470 amp hour battery if we only want to discharge it 20%. For instance, if you need 150W of power, but your system is only 75% efficient, then you would need 200W of panels to get 150W into the batteries. There’s even an app for it! So this component is our general go-to if we were to build a camper van with our own money this is how we would use it. You have two batteries in series (24v) and they are in parallel with a single battery (12v.) So in my application, I have a 12V motor that will use 12 amps (144 watts) for 8-10 hours a day. I reside in my van all year when not at my sister’s down the street. I was using a spare 12v car battery with an inverter but it only lasts 2 hours or less before the battery dies. My question is the AC charger for an electronic device has 0.50A input and 1.67A or 2.0A output, do I use the input or output number for solar sizing? We like to use watt hours because it’s a more accurate estimate of actual power usage, because amps are determined by your voltage. This is the fewest recommended solar power based on the daily power usage and battery size. If you have, let’s say you’re going to be in the desert southwest most of the time and you know you’re going to have tilt mount panels maybe you’ll see 6 hours of sun. You can enter it as one component line. Now in this battery section we have a total for watt hours as well because a lot of the lithium batteries now are listed in watt hours and like I said, it’s a little more accurate. These are the component sizes I’m going to go with. Posted this on wrong Blog entry. We recommend calculating both your summer and winter numbers. The problem with that is then you also need to make sure you have enough panels to run that once is does drop for two days worth of use. Most new caravans, motorhomes and, to some extent, campers, have solar panels mounted on the roof or other flat surface. ABOUT US Using our tool, we factor in: Improved Shade Analysis – Powered by Google Sunroof data, all estimates consider the shading and irradiance levels of every roof plane, with the panel placement optimized for the most productive areas of the roof. Battery Type Read our, Large Systems: Wiring Diagram (AGM Batteries), Large Systems: Wiring Diagram (Lithium Batteries). If I use this to calculate, would I just halve the Ah needed for the battery for a 24v setup? Hey Andy, for winter camping, adjust the list of devices and number of sun hours.  Adjustable tilt mount (optional) So the reason you don’t want to go bigger on your inverter for this is because a bigger power draw is hard on your batteries, it’s going to make them not last as long. This is nice to print off to show people. Now each of these different subjects in this we cover more extensively in a post on our site so if you’re not able to follow along or have some more questions about some details – those you’ll be able to find elsewhere in the electrical guides on our site. Or a refrigerator that cycles during the day.  Renogy 400W Solar Kit (PWM charge controller) This is kind of just a guide for how to use the calculator itself and what some of the different numbers and that kind of thing mean. If you’re in the hot weather all the time you might want to boost that even double it up to 16 hours. The “load” terminals on the CC are in fact pulling energy from the battery, not the solar panels. We offer off-grid packages complete with solar panels, racking, cable, and a power center. Our fridge on average is running about 8 hours a day. So this is just something to keep you aware. Most people are going to be going MPPT unless you’re on a heavy budget or really running the numbers to get the most efficient system possible for your dollar.  Renogy 100W Solar Kit (MPPT charge controller)  Rigid Monocrystalline Always ensure as many cells as possible are in direct sunlight. The solar panel calculator can help you work out what equipment you need to fully charge your next camping, caravaning or off-road adventure. Hey! Recommended Min Solar Watts Copyright © ParkedInParadise.com | Disclosure: We are a participant in the Amazon Services LLC Associates Program. We have our solar panels running to our charge controller, our charge controller running to our battery. example: looking at a microwave that says it uses 720 watts. The calculator takes into account the power consumption you use in your caravan/RV and your travel destinations. Going smaller will be giving up power from your panels. I recharge with a NOCO GENIUS that i hook up and plug in at work, which is an amenity they allow, a grace of God really. If you do a lot of dry camping then you know that battery life is one of the most important things you must plan for, especially if you have a small battery bank. Sometimes if you size down it won’t quite work for a few specific panels and that kind of thing. Solar Power: Solar panels are sold in varying sizes, but a 100 watt panel is a commonly found size – particularly for RVs. Click the to add a new row. Now, this inverter number is only going to pop up if you have AC numbers selected. There is more detail in this in our charge controller article if you want to know. With that said, for smaller 12V systems, it is often advisable to get a PWM controller and more solar panels get more bang for your buck. We have some solar panel wiring diagrams just for reference here. I’m resizing now due to an oversight in my original plans. Watch the video below if you’re not sure how to fill out the calculator. When sizing your RV solar system, If your ideal solar calculations call for 3 solar panels but your roof space only allows for 2 panels. I plan on building a skoolie in the future, and am toying with the idea of running 24v instead of 12v. If you want more information on electricity, head over to our electrical home page. Some general rules to follow are: We based our calculations on a 10% efficiency loss that occurs when using an AC inverter. Now I’m thinking scrap the [free] group 27 deep cycle battery with ~80 amp-hours capacity and just going with 3 (maybe 4) 35 amp-hour AGM in parallel (again a space issue – fitting “short” batteries under the frame). Laptops are another variable component in that they’re only pulling their max watts. Sadly I’ll be ditching my $800 worth of 200 AH AGM batteries for lithium. So they can’t supply all of that charge throughout the day like your batteries are going to be able to discharge.  B2B charger (solar CC included, incompatible with lithium) This is crucial to building a safe and efficient system to meet your energy needs. Hope that helps! Hence the large batts. I’m using 2- 100 Ah AGM battery’s that I’ve wired together in paralell w/ 2, 8 gauge cables. You show the loads directly tied to the battery.  75Ah (x1) Battery (AGM option) If you’re in the desert southwest and an angled system you’ll have 6-7 hours of available sun. Than you might be looking at PWM controllers for anything under about 400 watts. Alternatively, you may choose to purchase a pre-configured solar panel kit. It is a battery charger that works anytime the sun is out. A cheaper option is to go with a battery isolator. Solar.com has substantially upgraded its solar savings calculator to provide more accurate cost and savings estimates with solar. 100Ah (x1) Battery (Lithium option). If you want to know more, post your specific setup plan to an electrical forum or send us an e-mail to see if you want to make any adjustments. Solar Load Calculator For Off-Grid and RV Solar Power Systems Last updated on April 1, 2020 By Lacho Pop, Master of Science in Engineering The most crucial step for achieving a cost-efficient sizing of your off-grid and RV solar power systems is the correct determination of the electricity usage.  Battery isolator It doesn’t take much just to run the laptop. We have a fridge, and I know this fridge draws 3.9 amps. Simply select the type of car or motorhome you have, and select your towing unit if you’ll be using one.  600W Pure Sine Wave This really helped me calculate what setup would be needed. Thank you for any help. AGM and FLA batteries should only be discharged up to 50%. If you do that, you’ll start reducing their lifespan significantly. If you have an angled system, so you can tilt mount your panels towards the sun, you can boost that up to 5 hours. In this case we have a list set up and you can add and delete component lines. Going into a solar controller rated at 12v. Direct current. Solar, Alternator and shore power. This is relative to how much total capacity the battery has, so larger batteries can discharge more quickly (hence a larger inverter). *Fuses and wire gage size are going to vary depend on how long your are running the wires. I’m running four 100 watt panels… 2 series of 2 (alternating in my rooftop real estate – a 5ft x 7ft trailer) combined in parallel into the charge controller. The battery stores the current as amperage, similar to a gas tank storing gasoline.  10A MPPT (most efficient), Batteries But if it’s just charging the battery and I’m surfing the internet – 120 [watts]. We don’t save any of your information. Because each day is like its own reset in terms of the electricity that you’re going to use. Lensun 100W 12V Flexible RV Solar Panel Kit with 10 Amp Controller, and 2pcs 5M MC4 cables $ 299.00 thank you! So I don’t need anything more than a 200 watt inverter. I have the same solar charge controller shown in your diagram, but I can’t find the specs for it. Seems to me that this would not only run the A.C units but would also charge the batteries inside the trailers. There are many differences between these batteries.  Renogy 200W Solar Kit (PWM charge controller) Battery life is affected by how quickly you are using power. Jump To Solar Wiring Diagrams. The third co… Thanks so much for the thorough diagrams! On-grid solar system involves solar panels and inverter. There’s no reason to do that.  Renogy 300W Solar Kit (PWM charge controller) So if you’ve done all your calculations and you’ve written down your things. Check out the FAQ for info on charging while driving and upgrading panels. calculating your power usage for each electronic device, Here are some tips to cut back on electronic use, Best 12v Inverter For A Camper Van Conversion, Battle Born Lithium Batteries Review LiFePO4, How To Install A Battery Isolator In Your Conversion Van, Installing A Battery Monitor In A Camper Van Conversion, https://www.parkedinparadise.com/cassette-toilet/, https://www.parkedinparadise.com/portable-propane-water-heater/, https://www.parkedinparadise.com/best-roof-vent/, http://www.smartgauge.co.uk/batt_con.html, https://unboundsolar.com/solar-information/sun-hours-us-map, Optimizing Your Camper Van Electric System, How To Calculate Wh For Each Electronic Device, over two years living in a DIY camper van, Select whether it is an AC or DC powered (AC uses an inverter), Choose which battery type you want to use, Enter your estimated sun hours (direct sunlight you expect on the panels), Aim to use as many 12v DC powered electrics as possible, Cook efficiently – fuels like propane and butane will make your system smaller than cooking with electricity. Excellent page guys, nice work. There is further reading on all parts of the system, extras to install tips and advice on all things electric! You shouldn’t go below this necessarily. Usually 12, 24, or 48 volts. So this is in our solar and electricity guide. Silicon solar cells are currently available in three main types, which are known as monocrystalline, polycrystalline and thin-film amorphous. Oops…. They are also quite a bit more expensive, but they last longer. Thanks for your input!! Please be sure to take this into account when calculating and using our 12v solar panel calculator. “12V” solar panels typically output between 18-22V, which fluctuates based on external factors (sun, temperature, angle, etc).  B2B charger (solar CC included, compatible with lithium), Solar Panel Kits First, Thanks for sharing your knowledge. Winter sun hours will be less than summer ones. 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