Multiply your daily power usage (in watt-hours) by the number of days you want to run without charging. If you use 5,000 watts per day and want 3 days of runtime, you need a 15 kilowatt-hour battery bank. The video recommends being generous with this number since weather is unpredictable.
At a glance
Length
17 min
Channel
The Solar Lab
Video from
Mar 2025
Rating
⭐⭐ Great video · 2/2
Best for
RV and van dwellers sizing battery and solar systems for the first time
What this video answers
How do I know if my battery bank is big enough?
What's the difference between peak sun hours and regular sunlight?
Can I use a smaller inverter if I don't run everything at once?
Do I have to use solar panels, or can I charge from the grid or a generator?
Should I buy more solar panels than my math suggests?
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Overview: Choosing Solar Equipment Without the Overwhelm
The Solar Lab's beginner guide walks you through the five core decisions you need to make before buying any solar equipment—whether you're powering an RV, a tiny cabin, a shed, or a full home. Instead of diving straight into product catalogs, the video teaches you to work backwards from your actual power needs, then match components that will actually work together. The approach strips away sales jargon and focuses on the math and logic that makes a system reliable.
This guide suits anyone who's curious about solar but feels lost by the options. You don't need technical experience; the video includes a quick electricity refresher covering volts, amps, and watts using everyday analogies. Whether you're planning an off-grid cabin build, shopping for backup power during outages, or designing a mobile setup for van life, the five-step framework applies.
Key Moments
Key Moments in This Solar Equipment Guide
A garden-hose analogy explaining volts, amps, and watts so you understand power measurement before sizing anything
Step-by-step walkthrough of calculating daily power usage using Josh's off-grid cabin as a working example, including how to handle appliances like fridges that don't draw constant power
Method for determining how many days of battery "runway" you need based on your use case (3 days for Josh's Airbnb, different for weather gaps or blackouts)
Calculating peak sun hours for your location and sizing a solar array so it can recharge your battery bank in one good day
How to pick an inverter by adding up the wattage of everything you might run simultaneously, not just average daily use
The difference between off-grid, hybrid, and grid-tied inverter types and when each one makes sense
What to Know Before You Start Shopping
You need four pieces of information before buying anything: daily power usage (in watt-hours), days of runway required, peak sun hours for your location, and simultaneous power draw (the highest wattage demand at one moment).
Round up your numbers. The video recommends padding your calculations for worst-case scenarios—winter days for a cabin, the harshest season you'll actually experience—so you don't end up undersized.
Check your electricity bill. If you're sizing a home system, your utility bill already shows daily or monthly usage; you don't need to add up every appliance.
All-in-one inverters are the standard now. The video recommends choosing an inverter that combines the charge controller, breakers, and switching logic in one unit rather than buying separate components.
An off-grid inverter can still use AC input. You can feed power from a generator or house panel into an off-grid inverter; it doesn't mean zero grid interaction.
The video includes a free power calculator tool and full written guide linked in the description if the math feels daunting on your first read.
Frequently Asked Questions About Sizing Solar Systems
How do I know if my battery bank is big enough?
Multiply your daily power usage (in watt-hours) by the number of days you want to run without charging. If you use 5,000 watts per day and want 3 days of runtime, you need a 15 kilowatt-hour battery bank. The video recommends being generous with this number since weather is unpredictable.
What's the difference between peak sun hours and regular sunlight?
Peak sun hours are the hours when the sun is high enough in the sky to deliver full power output to your panels. Morning and evening sun won't charge at full capacity. Most U.S. locations average 3–5 peak sun hours daily; you can search this for your zip code online.
Can I use a smaller inverter if I don't run everything at once?
No. You must size your inverter for the highest wattage you could draw simultaneously, not your average usage. If a vacuum plus lights plus a microwave could hit 2,000 watts in the worst case, your inverter must handle 2,000 watts, even if that rarely happens.
Do I have to use solar panels, or can I charge from the grid or a generator?
Solar is optional. You can charge a battery system entirely from grid power (good for peak shaving or backup) or from a generator. The video shows how off-grid inverters accept AC input, so you can feed power in from other sources even if you're not grid-connected.
Should I buy more solar panels than my math suggests?
The video recommends sizing panels to recharge your entire battery bank in one full day of good sun. This gives you a safety margin when clouds roll in or seasons change. A small buffer (like choosing 4,000 watts instead of 3,750) costs little extra and buys reliability.
The number of hours per day when the sun is high enough to deliver full power output to solar panels, typically 3–5 hours depending on location and season.
Watt-hours
A measure of energy use over time; a 100-watt device running for 10 hours uses 1,000 watt-hours (or 1 kilowatt-hour).
Inverter
A device that converts DC power from a battery into AC power that standard home appliances can use.
Battery bank
Multiple batteries connected together to store enough energy to power your system for a set number of days without charging.
Off-grid inverter
An inverter designed to work independently of utility power, managing a battery system and optionally accepting input from solar panels or generators.
Hybrid inverter
An inverter that can interact with grid power, solar input, and batteries simultaneously, automatically switching between power sources for efficiency.
This video cuts through the noise that often surrounds solar equipment decisions. It doesn't try to sell you gear or push you toward one brand; it teaches you how to do the math so you can walk into a decision confident and avoid buying something that won't meet your real needs. The garden-hose analogy for electricity deserves credit too—it actually sticks, and it makes the rest of the framework click into place.
What stands out most is how practical it is. Josh's tiny cabin example gives you something concrete to follow along with, and the five-step process applies whether you're powering an RV, emergency backup for a house, or a remote shed. The video respects your time and intelligence, and I'd confidently recommend it to anyone considering a solar build.
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0:00 - Intro
1:05 - 60 Second Electricity Lesson
2:45 - Step 1: Battery Bank Size
5:44 - Step 2: Powering Your System
7:46 - Step 3: Selecting Your Inverter
8:46 - Step 4: System Type
11:44 - Step 5: Start Shopping + Save Money
16:02 - Summary
Thinking about going solar but not sure where to start? In this quick beginner’s guide, we break down the basics—volts, amps, watts—so you can confidently size your battery, solar panel array, and inverter. Learn how to choose the right system type for your needs and avoid common mistakes that cost you money. Whether you're powering a small setup or a full home, this video will help you make the right choice and save big on solar!
We maintain an affiliate relationship with some of the products reviewed, which means we get a small percentage of a sale if you click our links, at no cost to our viewers.
Video transcript for “How to Pick The RIGHT Solar Equipment (For Beginners)” Accessibility
A full written transcript of this video, provided for accessibility. Select any timestamp to jump the video to that moment.
as solar power has become a lot more powerful and easier for the average person to access its use cases have become a lot more widespread we're seeing bigger systems for whole home use or off-grid living medium-size systems for emergency backup or Peak shaving and smaller systems which
would be good for like an RV a garage a shed or some kind of project use but this means that there are more products than ever to choose from and with so many options if you're new to this it's almost a guarantee that this is going to seem overwhelming how do you choose the components
that are best for you what are watts and amps and how many do you need and how do you make sure your system fits together and works properly honestly it's a lot easier than some other people might be making it seem so hopefully today we're going to be able to help you guys make some decisions so
welcome back to the lab where our opinions cannot be bought before you go ahead and actually select or purchase a kit there's five key things that you need to ask yourself to make sure that you actually end up getting the right products for your needs before we jump into what those five
things are we're going to hit you guys with one of our classic 60-second electricity lessons to make sure everyone is on the same page and you fully understand everything that we're going to be talking about in today's video electricity is actually very easy to understand and the
only thing that we really need to know today for this video is what if you picture a garden hose like a faucet on the outside of your wall that you open and close when you open it allows a certain amount of pressure to flow out and through the opening that's volts volts is something
you don't really have to worry about because it's pretty standardized a house has 120 or 240 volts so volts not super important amps is like the hose coming off the more more amps the thicker the hose is so if you have a 15 amp hose it'll be this big and it's going to allow the 120 volts to
go through at 15 amps a 20 amp hose is going to be a little bit bigger and allow that to flow through much more efficiently the water flying out the end is watt if you were to put that into a bucket the bigger your hose and the more your faucets opened the more water is going to end up
in that bucket within an hour and that's watts and watts is a timely measurement if you have a 100 watt light bulb that means it's going to take 100 watts per hour if you only use it for half an hour it's only going to take 50 WTS that hour and the reason you need to know this
is because everybody's equipment and things that they're trying to power is a little bit different so you can't just Google like how much power does my light tape most fixures will tell you the volts and the amps if you multiply volts and amps you get Watts so if you're going to power 100
wat light bulb and you get a 1,000 watt battery Bank you can power that light bulb for 10 hours and in that example if your inverter is only 50 wats which all inverters are way bigger than the inverters grow as the batteries grow you probably won't R into this problem but if that inverter was
only 50 WS it wouldn't be able to power the light bulb it needs to be at least a 100 wat invert so now that we're all speaking the same language the first step is to determine what you're going to be powering and for how long the goal here is to get a battery Bank size this is actually really simple
to do but a lot of people assume their power needs and then they end up getting a system that's way underpowered for what they actually need we're going to use Josh's tiny cabin as our example there's a little bit of light math required here there's no way around it but let's get into it
so Josh airbnb's his tiny cabin inside that cabin he needs to power simple things like lights which are about 20 watts his mini fridge was about 50 WS a UV bulb which is about 100 WTS and some kitchen appliances he has a TV in there light stuff the goal here is to find out how much power you're
going to be using every day and so to do this we're just going to be taking the wattage from each device multiplying it by the amount of hour you plan to use it each day and that'll get us our average daily usage we tend to recommend using the largest numbers possible for this math so if he's
going to be Airbnb in this cabin throughout the winter obviously in the middle of winter they're going to be using way more lights way more power for heat stuff like that I would go with those numbers make sure that you have enough in the middle of winter his guests use roughly 10 hours
of Lights the UV bulb for the water treatment is on 24 hours there's no way around it the fridge is also on 24 hours although fridges don't run their rated output all the time they run about 15 to 20% of their rated output per hour we have an entire video showing how fridges actually work they use
a lot less power than a lot of people tend to say they do anyways we're going to go with the high-end number here and say that it uses 20% of its rated power every hour roughly 3 hours on the TV and do this kind of practice with everything inside of the cabin add it all up and try to get
a number of how much power roughly gets used every 24-hour period if you're having any trouble with this we'll leave a link to a calculator in the description down below but we're regardless when you're doing this we recommend rounding up on any numbers that you can and giving yourself a
little bit of extra leeway just in case if you're trying to do these numbers for your entire house I would just say go get your electricity bill most electricity bills show you your daily weekly and monthly usage so it's all laid out for you right there in our example we determined that Josh uses
roughly 5,000 watts per day at the tiny cabin and so that's the daily usage in our case 5,000 Watts the next part is to determine runway for this example Josh has his limit at Airbnb uh set to about 3 days so no one can actually stay at the cabin longer than 3 days so he knows he only needs
that 5,000 watts per day for a maximum of a 3-day period so in his case he takes the 5,000 Watts he needs per day multiplies it by three which lands him at about a 15 kilow hour battery bank for you guys it may be you want to use the amount of time that you experience a blackout during a
natural disaster like a hurricane or maybe you live somewhere that's really sunny and you're just trying to plan for like the 3 to 4 days in a week where you might not have sun and you just want to get through that longest Gap whatever it is the amount of time that you're going to
go without power is your multiplier you take your daily power and multiply it by the amount of days that you don't think you're going to have Sun generating you new power make sure you write down these numbers we are going to need them again in 1 minute step two is going to be how do you plan
on getting power into your system the two main options here are solar or not solar which would be the Grid or a generator we're going to start with solar if you plan on going solar you need to figure out your array size and there is three main steps to this first thing you need to do is is
determine your daily Peak Sun hours Peak Sun hours are when the sun is nice and high in the sky and actually hitting your panels at the right angle in the morning and at night the sun's obviously much lower you're not generating full power out of your panels most places in the US have an average
of 3 to 5 Peaks on hours per day you can find this number really quickly with a quick Google search The Next Step here is to determine your wattage so you're going to take your battery Bank size that you already determined in our example it was 15 kwatt hours and you're going to divide
that by your Peak Sun hours so in our case it's going to be 15 Kow divided by 4 we actually get five Peaks on hours where we live but we're trying to be safe and make sure that we have a powerful system so we're going to use 4 hours and that actually gets us like 3.75 we're going to round
up and call it 4,000 watts this means that our 4 kilow solar array would be able to power all of our batteries within one day of good Sunshine we always recommend you try to get it full within one day just because you can never predict the weather Josh's example if he just got one good day of sun
he could charge up enough for 3 Days of Runway the faster you can fill those batteries the more luck you're going to have just not running out of power and the last part is figuring out your array size so now that you know you need a 4,000 WT solar array panels come in all kinds of shapes and sizes
you got to figure out what works best for your house maybe you only have room for 100 WT panels or you have room for 400 WT panels whatever it is pick the panels that will work for you if we were going to choose 400 watt panels we would just divide the 4,00 ,000 watt by 400 that gets us
10 panels and we know that with 10 400 WT solar panels we will easily hit our 4,000 watt solar array if you're not planning on using solar and you're planning on using the Grid or a generator you don't even have to worry about this step just hang in there and we will get to this later on
step three is determining how much are you going to be powering at one time and what kind of power do you need 120 or 240 volts the goal here is to determine what inverter works for your system and to do this it's really easy in the First Step you added up all the appliances that you know
that you're going to use in this step you're going to add the wattage for everything that you plan to power all at one time don't cheese out on yourself here you don't want to be running around from room to room turning off a light so that you can turn on the vacuum make sure that you account for
everything that could be on all at once in Josh's example we went to his cabin flicked on everything it surged at around 2,000 watts and then it ran at around 1,200 W steady so uh he needed about a 2,000 WT total output and since all of his appliances only run off 120 volts he only needed
an inverter that can do 120 volts and so now he has the three main important pieces of information the first one he needs an inverter that can run 2,000 Watts continuous it needs to be able to run 1220 volts 240 would obviously be be a bonus so he could upgrade in the future and it needs to
have at least a 4,000 wat solar input and so now there's only one key decision left for him to make step four is determining what type of system suits your needs this is this is a very simple step but it's mandatory and no matter what you pick in 2025 we recommend going with an all-in-one inverter
this just means that your inverter includes all the separate parts like the breakers the solar charge controller the less accessories that you need to mount outside of your inverter the more that they're all housed within your inverter the better most of them also allow you to program it
for time of use settings so you can tell it when to charge when to discharge based on input power states of battery solar conditions things like that in Josh's case the cabin is completely off- grid there is no grid power available so he needs an off-grid inverter this eg4 3000 would actually
be a perfect solution to Josh's needs it has a 3,000 W output so a little bit of buffer for what he uses it does 120 volts it has a 5,000 W solar input so a little bit of buffer for what he needed and it's a really cheap affordable and well reviewed off-grid inverter something important to
know is most if not all offgrid inverters by this point have an AC in that doesn't mean that they tie into the grid but what it does mean is that you could for example when we do testing we take an extension cord we plug it into the wall in our house we snip the other end off and run it into
the inverter it puts AC power in we can use that power to charge our batteries and whatever so if you're not planning on interacting with the grid necessarily you can still put AC power directly from a generator or a house into an off- grid inverter it doesn't mean it has no capability
to do that the other option if you're not looking to go off- grid would be something like a hybrid system where it can actually interact with the grid uh it can read your battery percentages it can read your solar input it can read the input coming in from the grid and it can kind
of determine okay we're going to charge your batteries with grid power because there's no sun available or we're going to charge batteries with solar and also power some devices with solar because we have so much excess solar available right now it's smart enough to be able to make
those decisions you can also get inverters that have the ability to sell power back to the grid if this is something that's still confusing to you we actually have a full video breaking down all the different types of inverters that we will link in the description below on a final note as we
mentioned earlier maybe you don't want to install solar at all in that case you need to look at the AC input on your inverter maybe you're doing this to Peak shave an example of that would be you have an inverter with batteries and everything set up you have no solar panels during the night when the
power is off peak and it's at its cheapest you use the inverter to charge those batteries and then during the daytime when the power is on Peak and it's expensive you actually power all of your devices in your house with the batteries to shave off that on Peak portion of your bill saves you a
little bit of money and in that case you might not want solar panels at all if you don't you just need to look at the AC input and make sure that during those nighttime hours or whatever the situation is that you're trying to to do that you have enough AC input to fully charge your
battery Bank during said time and so the final step is to start shopping now you might realize really quickly that the system you need or want is outside of your budget but know that it's okay to actually start small and expand later however if you're going to try to cheap out there is a
right and a wrong place to do so the wrong place would be your inverter your inverter needs to be to be big enough and have the proper output and input settings for your needs if you go cheap on your inverter you're going to end up needing to sell it and buy a new one later or you're
going to need to end up buying a second inverter and wiring them together to run parallel doing a bunch of unnecessary work that could be avoided if you just buy the right inverter the first time the right place to save some money would be on your batteries you don't want to cheap out on
your batteries but you don't have to buy all your batteries all at once if you can't afford to do so you can very easily buy half of the batteries that you need right now set up your entire system and then in the future when you can afford it you buy the other half of the batteries most batteries are
expandable within their family so if you go ahead and get a few server batteries now and then you want to go ahead and expand later it's as simple as sliding three more server raack batteries into that cabinet plugging them in and you're pretty much good to go there's no real hassle or setup
or or anything needed additionally another place to save money that would be the right place would be on your solar array exactly the same as your battery bank if you just buy half your solar array now you set it all up solar panels can be wired in tons of different configurations depending on
what your inverter requirements are but you could very easily just buy the second half of your solar array wire it all up plug it in and you're good to go on the contrary if you actually have the budget to do so we always recommend purchasing a little bit of a bigger system than you actually
need power needs tend to Almost 100% increase with time maybe you have kids they are using way more Electronics than you thought they would maybe you buy an EV maybe you just got a bigger fridge little things like that can make a huge difference in how much power you're actually
consuming so if you have the means to do so buy a bigger kit than you think you're going to need if you're still looking for ways to save money you can also do that by installing your system or parts of it or helping with parts of it yourself a lot of it really isn't as complicated as you might
think you could start small by digging the trench from where you're going to have your solar panels to where you're going to Route them into your house to help the installer save some time you can go as big as building your own panels stands and getting them all mounted and just having
someone come in and do the final connections on your inverters or whatever it is that you don't feel comfortable doing and if you watch some YouTube videos on this stuff you'll realize it's actually really really simple we also recommend buying from somewhere like shop solar or signature
solar they package everything into bundles and kits so you're going to be getting stuff that they already know all works together and it's cheaper than buying everything individually it ships all at once and you get everything that you're going to need to make what you just bought
work they also have great support you can easily call them uh We've Miss shop to both of those companies and you can ask them for help they'll help guide you through things it's a lot easier than just trying to go out spam the internet and buy a million components and put them together
yourself and R2 cense is to never ever ever ever lease your system you're getting scammed Finance it do anything other than leasing the system a bonus two cents that we have that might help you guys in the long run is if you're doing research watching videos which is good that's what you
should be doing you should be learning as much as possible about things that you're spending your money on and how they work and and how good they are if you're doing research and watching a ton of videos just be aware of Lifestyle creators there's nothing against LIF style creators uh I
was one for a little under 10 years the point is people that maybe they have a homestead and that's what their channel is about and then they get a solar setup from a company they tend to be a lot more excited and generous towards the company and the brand because they actually just got something
that changes their life like their life is now dramatically different because of this product so even if it's not the best or has problems they might not be fully transparent about all those things because they're Gass a lot of them also get paid to do so and they get paid well so they tend
to say the better side of things a channel like us here at the lab and a lot of other channels that stick to reviews uh we actually spend money to get these products here and it costs us money to store them when you're doing your research just make sure that you're getting your info
more from people who do reviews and test multiple products not from someone who just got one thing one time you tend to only get the good side when you do that so hopefully this helps you guys at to some degree feel a little bit more comfortable moving forward we have tons of discount codes
that we have with multiple companies Linked In the description down below to help you save money when the time comes to actually pull the trigger on a system we have video reviews on tons of products we have howtos and kind of like an educational playlist that goes a little bit more into depth
on all the points that we made today that is all we got for you guys thank you so much for watching hopefully we were able to help some of you we will catch you next time peace out and stay charged [Music]
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