OK, How Much Electrical Will I Need To Power A Laptop & T.V. For 24/7

[Jim D]

I will get a low power normal size LED T.V. and a normal size laptop computer. Even though I will figure out how much power I will need to power them for 24/7 I would like to hear from other van dwellers and hear what they have to say about their power needs to being able to keep their T.V.'s and computers on for 24 hrs straight. Yeah, I watch T.V. and work on my computer all day and all night. I leave my T.V. on 24/7 and my computer is off when I'm sleeping.

Sure, I'm worried about air conditioning and other electrical needs but for now I want to get to know my T.V. and computer needs which supply my entertainment wants and interests. Alot of people are into gaming and set their electrical up for that and I like that but the gamers can't play for 24/7 and if they can I'd like to know what their power needs are in the way of batteries and solar.

I'm not a gamer at least of now and only want to be able to keep my computer and T.V. on for 24/7. It would be great if I could get experienced people to let me know what's, what to power a T.V. and computer at the same time for 24/7. I need battery capacity and solar output before my van build next year. I'm looking to get 3 100 watt lithium phosphate batteries and 2 200 watt flexible solar screens. Will this be correct?

 

[frater secessus]

It's arithmetic, but only you have the information to do the arithmetic. It's probably simplest to work in Wh (watt-hours). This is oversimplified but will get you started.

Daily power requirement

1. for every 12vdc load: watts x hours/day of use = Wh
2. for every 120vac load: watts x hours/day of use / 0.9 inverter efficiency = Wh <-- replace with your actual inverter efficiency if you know it

For things like fridges that are on 24/7 you can use 8 hrs, assuming the compressor will only be runnning 1/3rd of the time on average. A Kill-A-Watt meter, often loanable from libraries, will be helpful in measuring actual energy use over a 24hr period.

After you add all these up you have your daily power requirement. It is the basis for everything else.


Power storage

Each 100A LiFePO4 battery will hold 1,280Wh if you drain to 0% state of charge (not recommended) or 1,024Wh if drained only to 20% (recommended for longevity). Compare to the daily power requirement above.

Power harvest

Average solar harvest for flatmounted panels is calculable for a given time/place. The formula is

[hours of Full Sun Equivalent] x [combined panel wattage] x [overall system efficiency]

Rough FSE can be looked up in this chart. For the purposes of this discussion we will assume the system efficiency of MPPT systems is 0.83 and PWM systems 0.7.

Your profile says Vegas, let's use that city's data in the chart to find best/worst harvest.

• Dec - 200w of solar will average ~432Wh/day on MPPT (2.6FSE x 200w x 0.83)
• Jun - ~1,257Wh/day

Assessment

How do these daily solar harvest numbers compare to your daily power requirements from the first section? Adjust panel wattage if required, or add another form of charging if there is not enough roofspace for the required panel.

Based on experience watching folks planning their first solar rig, I'd say people typically underestimate their power requirements and overestimate the ability of solar to meet those requirements.

---

Related: a gentle intro to solar

 

[maki2]

Totally depends on the power consumption of your TV and computer. With thousands of those 2 items on the market no one can answer your question with exactitude.

 

[bullfrog]

General rule is put as much solar on the roof as you have space for, buy as much battery as you can afford and you might have enough depending on how often you adjust you location. Otherwise buy a Prius or another hybrid vehicle and install an inverter. The big problem with solar is making sure you have a backup when the sun doesn’t shine or something malfunctions. Almost everyone that needs to be online or using electronics 24/7 has difficulty finding enough roof space on a van for the amount of solar necessary in winter months unless they avoid bad weather areas in my opinion. Most have a small pure sign wave inverter generator as a backup that is seldom used but necessary that runs off propane as you avoid stale fuel problems that occur with unleaded gas. This makes it possible with a smaller system with limited roof space.

 

[Jim D]

It's arithmetic, but only you have the information to do the arithmetic. It's probably simplest to work in Wh (watt-hours). This is oversimplified but will get you started.

Daily power requirement

1. for every 12vdc load: watts x hours/day of use = Wh
2. for every 120vac load: watts x hours/day of use / 0.9 inverter efficiency = Wh <-- replace with your actual inverter efficiency if you know it

For things like fridges that are on 24/7 you can use 8 hrs, assuming the compressor will only be runnning 1/3rd of the time on average. A Kill-A-Watt meter, often loanable from libraries, will be helpful in measuring actual energy use over a 24hr period.

After you add all these up you have your daily power requirement. It is the basis for everything else.


Power storage

Each 100A LiFePO4 battery will hold 1,280Wh if you drain to 0% state of charge (not recommended) or 1,024Wh if drained only to 20% (recommended for longevity). Compare to the daily power requirement above.

Power harvest

Average solar harvest for flatmounted panels is calculable for a given time/place. The formula is

[hours of Full Sun Equivalent] x [combined panel wattage] x [overall system efficiency]

Rough FSE can be looked up in this chart. For the purposes of this discussion we will assume the system efficiency of MPPT systems is 0.83 and PWM systems 0.7.

Your profile says Vegas, let's use that city's data in the chart to find best/worst harvest.

• Dec - 200w of solar will average ~432Wh/day on MPPT (2.6FSE x 200w x 0.83)
• Jun - ~1,257Wh/day

Assessment

How do these daily solar harvest numbers compare to your daily power requirements from the first section? Adjust panel wattage if required, or add another form of charging if there is not enough roofspace for the required panel.

Based on experience watching folks planning their first solar rig, I'd say people typically underestimate their power requirements and overestimate the ability of solar to meet those requirements.

---

Related: a gentle intro to solar

OK, for the T.V. I'm going for one that is powered by 12 volts D.C.. I looked at one online and it was rated at 28 watts which translated over a 24 hour period to be 672 WH's.

I have a Microsoft Surface Pro 7 and the charger states 65 watts so I'm just going to go off of that for now. I don't really like the tablet with it's keyboard so I'm most likely going to use my desktop keyboard. Anyway, 65 watts X 24 hours is 1560 WH's.

Since I do plan on getting a refer so I may as well do that right now since I have some help . I looked at a Vevor 48 qt. refer/freezer and it was rated at 80 watts. So 80 watts X 24 hrs equals 1920 WH's divided by 3 is 640 WH's.

So now I'm up to 2872 WH's.

If I get 3 lithium batteries that would be 3072 WH's. Even though Battleborn lithium's are the best I can get decent lithium's for about $350. If I added a fourth lithium it would kick me up to 4096 WH's.

I'm planning on 2, 200 watt flex solar panels and they should replace some of the power I use during the day and night. I'm surely not going to stay in Vegas during the summer. So if I get 2, 200 watt flex panels in Dec. I should be getting about 1000 WH's a day. I'm wondering now how much of the 4 batteries can be charged?

Right now I'm planning on installing a very quiet propane generator to take up the slack on cloudy days. I most likely will have to shut all the electrical off when I sleep or at least the computer.

All the power used that I stated are only generalities. I watched a You Tube Video where a guy built a battery bank of "16 Battleborns" to power his house on about 4 to 6 solar panels. I could not understand why this guy just didn't go get a "Tesla Powerwall Battery" to store his energy in? The guy must have spent at least $30,000 or more on RV equipment to power his house.

 

[Jim D]

General rule is put as much solar on the roof as you have space for, buy as much battery as you can afford and you might have enough depending on how often you adjust you location. Otherwise buy a Prius or another hybrid vehicle and install an inverter. The big problem with solar is making sure you have a backup when the sun doesn’t shine or something malfunctions. Almost everyone that needs to be online or using electronics 24/7 has difficulty finding enough roof space on a van for the amount of solar necessary in winter months unless they avoid bad weather areas in my opinion. Most have a small pure sign wave inverter generator as a backup that is seldom used but necessary that runs off propane as you avoid stale fuel problems that occur with unleaded gas. This makes it possible with a smaller system with limited roof space.

Thanks Bullfrog. I wasn't planning on running many AC appliances in the van off of my DC battery bank. I think I can live alright with just DC appliances. I can get a DC car cord for my Surface Pro. If I have to get any AC items I can run them off my generator. I plan on spending the cash on an extremely quiet generator that can run in my van with the exhaust piped to the outside. This will be better financially in the long run.

I can't say this generator is the one I will purchase but it is an example of a super quiet generator I'm looking to get. The generator linked below is gasoline and propane and is very quiet because it's inside a quiet housing with a low tone muffler.

https://www.electricgeneratorsdirect.com/Westinghouse-IGEN4500DFC-Portable-Generator/p117164.html

 

[bullfrog]

Good thinking as inverters are somewhat inefficient and use power even with nothing hooked up but on. Be aware there are no quiet generators just less noisier ones. Many van owners mount them on a cargo tray that slides in a hitch mount. You want to get one light weight enough you can carry or cart it so when possible you can run it with a 100’ extension cord away from the van. By positioning a few sound barriers it is almost impossible to even hear mine 100’ away during the day and just slightly at night. I know this is pretty impossible in urban settings so you can use sound and vibration materials in the rear doors and cargo carrier just make sure it is ventilated and has good air flow even if you have to run a fan in a large foam box. If you are able to limit your use at night or on cloudy days that will really help. Having a small power pack you can carry into a library or restroom to recharge might benefit as well. If you charge it in the vehicle don’t use the ciggy plug but have a designated circuit with fuse and better Anderson plug or something like it to charge. It is not unusual to hit three days straight with bad weather/cloudy skies so be prepared. If you regularly drive 4 hours a day a DC to DC charger might be considered as well to bulk charge but will possibly have some negative maintenance/mechanical results in the very long run. These are only my opinions and as they say “results may vary” and experimenting will be necessary. There are already lots of threads on generators you need to read here as well. The generator above is plenty big even enough to heat and cool with. I have a Harbor Freight Predator 3500 on gasoline and it runs a 25’ travel trailer just fine but does require a bit of maintenance. On my smaller camper I run a 2500 dual fuel Champion on propane for a 5,000 BTU air conditioner and ceramic heater which only requires a little maintenance. Both trailers have solar as well.

 

[frater secessus]

So now I'm up to 2872 WH's.

Good on ya for doing the legwork.

If I get 3 lithium batteries that would be 3072 WH's. Even though Battleborn lithium's are the best I can get decent lithium's for about $350. If I added a fourth lithium it would kick me up to 4096 WH's.

Understood. I do suspect charging will be the bottleneck rather than capacity.

Most of us running LFP use more modest batts. BB is nice, but IMO no longer has the Golden Boy status it did in the beginning.

I'm planning on 2, 200 watt flex solar panels and they should replace some of the power I use during the day and night. I'm surely not going to stay in Vegas during the summer. So if I get 2, 200 watt flex panels in Dec. I should be getting about 1000 WH's a day.

I see 864Wh, but the difference is almost moot because

* 864Wh made and 2,872Wh consumed results in a deficit of 2,008Wh/day
* 1000Wh made and 2,872Wh consumed results in a deficit of 1,872Wh/day

In both cases desired power consumption dwarfs solar harvest. With the loads, capacity and solar charging we are discussing in this thread I'll WAG the 4batt bank would go from fully charged to depleted by the third day on the road. And that's with solar doing it's best to keep the thing afloat.

It really is possible to live offgrid on solar forever, but it takes sufficient paneI.

Example: I've been offgrid on solar the last 1,548 days but I'm running ~twice the solar and ~half the loads. I make and use ~1.71kWh/day, running most loads off the panel during the day daytime. I use 515Wh overnight on average, about 40% of the 100Ah LFP bank. It's charged again by ~11am the next morning. I suspect it would take ~1,350w of panel (!!) to power the loads described In vegas in Dec.

I'm wondering now how much of the 4 batteries can be charged?

We already know this: 864Wh of their 4,096Wh effective capacity.

I'm planning on installing a very quiet propane generator to take up the slack on cloudy day

With a ~2,000Wh charging deficit you'd have to run it every day. The upside is that once you've invested in it a generator will run all kinds of stuff, even a small A/C unit. Whenever you want and for however long you want.

I don't think you will be discouraged by any of this, but just in case: don't be discouraged! To adapt van Moltke, "no plan survives first contact with the math." It's a rite of passage. We all went through it.

 

[Jim D]

Good thinking as inverters are somewhat inefficient and use power even with nothing hooked up but on. Be aware there are no quiet generators just less noisier ones. Many van owners mount them on a cargo tray that slides in a hitch mount. You want to get one light weight enough you can carry or cart it so when possible you can run it with a 100’ extension cord away from the van. By positioning a few sound barriers it is almost impossible to even hear mine 100’ away during the day and just slightly at night. I know this is pretty impossible in urban settings so you can use sound and vibration materials in the rear doors and cargo carrier just make sure it is ventilated and has good air flow even if you have to run a fan in a large foam box. If you are able to limit your use at night or on cloudy days that will really help. Having a small power pack you can carry into a library or restroom to recharge might benefit as well. If you charge it in the vehicle don’t use the ciggy plug but have a designated circuit with fuse and better Anderson plug or something like it to charge. It is not unusual to hit three days straight with bad weather/cloudy skies so be prepared. If you regularly drive 4 hours a day a DC to DC charger might be considered as well to bulk charge but will possibly have some negative maintenance/mechanical results in the very long run. These are only my opinions and as they say “results may vary” and experimenting will be necessary. There are already lots of threads on generators you need to read here as well. The generator above is plenty big even enough to heat and cool with. I have a Harbor Freight Predator 3500 on gasoline and it runs a 25’ travel trailer just fine but does require a bit of maintenance. On my smaller camper I run a 2500 dual fuel Champion on propane for a 5,000 BTU air conditioner and ceramic heater which only requires a little maintenance. Both trailers have solar as well.

I saw a You Tube video where a guy mounted his Harbor Freight generator on a receiver hitch and I don't want to do that. I may stealth in a town now and again and even though the video showed this guy parking his class A RV in town along with other RV's with generator mounted on the hitch I don't even want to do that.

I will never purchase anything from Harbor Freight again especially a generator. I'd rather spend the money on a quality generator made to be super quiet from an upstanding company like Westinghouse, Cummins, Firman and Honda. I purchased from Harbor Freight in the past and it's ALL junk. The Westinghouse generator I linked to is encased in a shell to keep the generator super quiet. The generator is without a doubt going inside the van and will run on Propane (LG). I have to learn about "Decibel Noise (Db)" levels which are usually given online when your looking at generators.

https://www.electricgeneratorsdirect.com/Firman-Generators-WH03041-Portable-Generator/p111950.html

I will run a dedicated electrical line from my battery bank to electrical ports I install in my van living chamber. I may use my vans cigarette lighter to charge my computer when I'm up front but that's it.

As for DC to DC charging, my van has two starter batteries. I have an old 6.2 liter diesel and if I can avoid running a charge cable back to my 3 or 4 battery bank from my 2 starter batteries I will. I really don't want to tax my alternator. I don't want to have to drive daily to charge my batteries. I will if I can stay on BLM land for 2 weeks at a time in Nevada to save my diesel fuel. Hopefully by the time I have to live in my van gas prices will come down to under $3 a gallon again.

I'm going to read many of the threads here on generators from this forums members. You and others are shaping my plan already to satisfy my electrical needs and what I'm going to do with myself . I have to stay in Nevada even though there's nothing here for me in Las Vegas anymore. I read and study everything I can here on this forum and listen to everyone's experiences and take them to heart.

 

[Jim D]

Good on ya for doing the legwork.



Understood. I do suspect charging will be the bottleneck rather than capacity.

Most of us running LFP use more modest batts. BB is nice, but IMO no longer has the Golden Boy status it did in the beginning.




I see 864Wh, but the difference is almost moot because

* 864Wh made and 2,872Wh consumed results in a deficit of 2,008Wh/day
* 1000Wh made and 2,872Wh consumed results in a deficit of 1,872Wh/day

In both cases desired power consumption dwarfs solar harvest. With the loads, capacity and solar charging we are discussing in this thread I'll WAG the 4batt bank would go from fully charged to depleted by the third day on the road. And that's with solar doing it's best to keep the thing afloat.

It really is possible to live offgrid on solar forever, but it takes sufficient paneI.

Example: I've been offgrid on solar the last 1,548 days but I'm running ~twice the solar and ~half the loads. I make and use ~1.71kWh/day, running most loads off the panel during the day daytime. I use 515Wh overnight on average, about 40% of the 100Ah LFP bank. It's charged again by ~11am the next morning. I suspect it would take ~1,350w of panel (!!) to power the loads described In vegas in Dec.




We already know this: 864Wh of their 4,096Wh effective capacity.



With a ~2,000Wh charging deficit you'd have to run it every day. The upside is that once you've invested in it a generator will run all kinds of stuff, even a small A/C unit. Whenever you want and for however long you want.

I don't think you will be discouraged by any of this, but just in case: don't be discouraged! To adapt van Moltke, "no plan survives first contact with the math." It's a rite of passage. We all went through it.

I'm doing my best to hammer out a plan for my electrical needs. If I can get an ultra quiet propane generator that can operate in the garage I'm going to build in my van I will. I have to find out how much propane I will need per day and budget for it on cloudy days and in summer. I'm used to sleeping with the T.V. on so a little rumbling in the van garage won't bother me to much. I have to learn about "Decibel Noise" now so I can judge the noise level of these so called quiet generators. I've been looking at this "Firman" Whisper Quiet Propane generator and am interested if it's quiet enough.

https://www.electricgeneratorsdirect.com/Firman-Generators-WH03041-Portable-Generator/p111950.html

I don't want the pull cord model of this generator. I will want the electric start model and if they don't have the electric start with a remote I would go back to the Westinghouse model that does which is not a bad idea.

 

[bullfrog]

There are smart phone apps to measure sound decibels. I would highly recommend borrowing or renting a generator and trying what you are preposing before spending a lot of time and money. Open the doors and windows and insure you have plenty of ventilation and probably not a bad idea to wear ear protection. In my opinion a lot of the noise created by a generator is not just from the generator but from surfaces around it vibrating.

 

[Jim D]

I do have an old Sears Craftsman generator from the 1980's that has only been run a couple of times. Wasted money. It's very noisy though. I'm not putting it in my van to test the noise level because it is noisy. My van right now is a rattle trap so I will have to deal with that. It was used as a work van for 10 years and before that my brother slipped off an icy road in it. Before I do anything the whole drive train needs to be rebuilt before I go out into the boonies with it. I'd rather spend the cash now rather than break down in a camp ground or on the road. I'm thinking about going to an RV place to see if they will turn on one of their super quiet generators for me so I can know what kind of noise level I'm getting into. May even purchase a generator from them if I like it.

 

[Jim D]

This picture is what I was looking for. I looked at one generator and it stated the dB noise was only 25 decibels. Put that generator in my van garage and I'm good with that. The van garage will lower the sound level even more.

 

[rruff]

I'm doing my best to hammer out a plan for my electrical needs.

Your laptop power will be way less than 65W... probably less than 10W typically. If you have it already, get a little watt meter doohickey and measure it. Do the same with your refrigerator and TV.

And are you really running your laptop and TV 24/7 ?! Even if you never sleep surely they wouldn't both be cranking at the same time? Maybe you are being extra conservative or something, but it's much better to be realistic. You can absolutely power a laptop, TV, and refrigerator with normal use, using a reasonable solar and battery system that fits on a camper.

 

[bullfrog]

25 DB is extremely quiet, almost too quiet to really believe. The Westinghouse generator you listed was I believe 56 DB which is probably low for most generators that are around 3,500 watts. I also have an older 1,000 watt generator which is as loud or louder than my 3,500 watt generator! There is a lot of difference between manufacturers as well as size and age. There have been a lot of improvements but none of them are quiet in my opinion. My motorhome has a large generator that itself is quiet when the motorhome is running but noisy when parked as it vibrates and rattles everything like cups and plates in the cabinets. Most motorhomes have several walls built into special sound proof compartments which are as far as possible from common living and sleeping areas and direct the sound away from the interior as well. Most older motorhome’s generators make plenty of noise outside just look at some of the comments on noisy neighbors threads. Stealth with a generator running probably would only work at a truck stop in my opinion.

 

[Jim D]

Your laptop power will be way less than 65W... probably less than 10W typically. If you have it already, get a little watt meter doohickey and measure it. Do the same with your refrigerator and TV.

And are you really running your laptop and TV 24/7 ?! Even if you never sleep surely they wouldn't both be cranking at the same time? Maybe you are being extra conservative or something, but it's much better to be realistic. You can absolutely power a laptop, TV, and refrigerator with normal use, using a reasonable solar and battery system that fits on a camper.

I'm sitting in front of my computer right now with the T.V. on. I'm in a house right now but will have to do the van life in a few years. I always have the T.V. on. The computer I can shut off at night.

I read somewhere that my tablet was only running on 5 watts but when I tried to check it today I ran into, "Look On The Charger" and the charger stated 65 watts. I just used the 65 watt number because I always keep it plugged in. If I took it off the charger most likely it would only be 5 watts. The battery doesn't last long when I watch You Tube videos.

Right now I'm just in the planning stage and everyone's input is very valuable to me.
T.V. is on all day and night, the computer is on most of the day and I watch both of them at the same time. Typing right now listening to the T.V. .

 

[Jim D]

25 DB is extremely quiet, almost too quiet to really believe. The Westinghouse generator you listed was I believe 56 DB which is probably low for most generators that are around 3,500 watts. I also have an older 1,000 watt generator which is as loud or louder than my 3,500 watt generator! There is a lot of difference between manufacturers as well as size and age. There have been a lot of improvements but none of them are quiet in my opinion. My motorhome has a large generator that itself is quiet when the motorhome is running but noisy when parked as it vibrates and rattles everything like cups and plates in the cabinets. Most motorhomes have several walls built into special sound proof compartments which are as far as possible from common living and sleeping areas and direct the sound away from the interior as well. Most older motorhome’s generators make plenty of noise outside just look at some of the comments on noisy neighbors threads. Stealth with a generator running probably would only work at a truck stop.

Yeah, the Firman is 58 dB also. I did see one that was 25 dB's but can't remember which one it was in my journey through generators. I looked at the generators before I knew what sound levels in dB's was so now I look again. I can always sound proof my van garage to lower the dB's.

 

[Jim D]

I looked at the generators again and all the propane are between 52 and 61 dB's. I guess I'll still take the Westinghouse at 52 dB's. I will just double sound proof my van garage since I haven't built it yet .

 

[Jim D]

Here's the Westinghouse 4500 I was looking at.

 

[maki2]

You do not NEED to run a TV all night. You could use talk radio or podcast or even audio books or playlists for distraction if you can’t sleep without noise. There are devices that can play them which are are powered with USB that are not big power consumers.

Forcing your “living on the electrical grid” old habits and patterns into a nomadic life is never going to be cost effective or easy. Try changing away from that TV habit instead of trying to force square pegs into round holes. Human brains are actually pretty good at adapting.