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Inverter question

MaxStravinsky

MaxStravinsky

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I just read where one of the other members bought a Cobra 800W Inverter for his car to turn it into a back up generator. My car has a usb port as well as the cigarette lighter. I had been thinking that I could buy a usb to usb cord to power up my laptop for movie viewing during a power outage, but such a cord seems not to exist. So I'm thinking an inverter would be the way to go.

What power would I need, and what is a good brand? Anything else I need to be aware of?

thanks!
 
Not to mention that USB port in most cars is awful, so even if it was possible, your battery on your laptop would still drain. Most of the car USB ports are not high output.

If you're just trying to run a laptop a small 100W job would cover most machines no problem. You could also run an auto-air adapter that goes off a cig plug, basically its just a DC booster that brings it from 12 to 19VDC. That might actually be the easiest way, unless you need to run a long cord from where the car is to where the laptop is.

-Mike
 
I live off grid. My house uses a Xantex Prowatt 600 to run the hot water heater and some other stuff: http://amzn.to/2dWKIdz

Its true sine wave output, has low battery alarm, and a meter on the front to show if your battery is getting low. Been in service for 3 years now without any issues.

You will need to run it directly to the battery for full power. In a pinch you can just use the cig plug provided you don't use more than 72 watts +/-.
 
Don't go too cheap on the inverter size. I would go a little bigger than the 100W the good Doctor suggested. I bought a cheap 80W (160W surge) from Harbor freight and it sort-of ran my laptop's charger brick but wouldn't run my wife's, so that money was wasted. So I got a 200W (400W surge) for $20 and it does the job nicely.

Remember you can only get 10A (120W) out of the cig lighter before the fuse blows. I just make sure I don't plug anything big into my 200W inverter unless I'm using the battery clips.
 
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Car engine is a very inefficient way to make electricity

Most cars are a poor substitute for a generator. As mentioned, you are very limited in what you can pull from the "lighter" power port, and even if you hardwire an inverter to the battery, you're going to quickly overtax the alternator if you pull more than 1000-1500W.

Alternators are not cheap, though once you burn out the original you might be able to replace it with a truck model with higher output. Trucks in general tend to have higher-output alternators; the hybrid models of Chevrolet Silverado or a GMC Sierra are designed to supply AC power.

If you're just trying to run a laptop a small 100W job would cover most machines no problem. You could also run an auto-air adapter that goes off a cig plug, basically its just a DC booster that brings it from 12 to 19VDC. That might actually be the easiest way, unless you need to run a long cord from where the car is to where the laptop is.
Click to expand...
I have an auto-air adapter that runs off pretty much any 12VDC source, has both an airplane plug and cigarette lighter connector. There's a button on the power brick to switch between "Power only" and "Charging", though that functionality might be specific to HP laptops -- the "power only" mode is intended to reduce max wattage to avoid blowing a fuse on low-output sources (e.g. many airplane power ports).
 
A more battery-efficient device (tablet) plus a spare battery pack sounds infinitely easier.
 
If you were going to use the vehicle as a backup power source the inverter should be wired to the battery if there is any chance you will need more than 5 or so amps. you need to be careful, in a power outage situation if you kill the car battery you will most likely not have a way to charge the battery.
To be honest on of those little 2 cycle generators harbor freight sells would probably be a better solution. They are always on sale for $88 and supply up to 700 watts continuous and 900 peak. This should be more than enough to keep a laptop or other small electronic device happy. It supposedly will run 8 hours on a gallon of gas
 
I have the Cobra 1575 Inverter and have had it for 6 years. I also bought a dozen of them for the work vans and Never in 6 years running shop vacs, saws, spot lights ETC..have I ever changed an Alternator. These Inverters are run all day 5 -6 day's a week all day. I wouldn't run my rear defrost, heat, radio, lights ETC in my truck while doing so but who would do that?..That Cobra Inverter has been 100% and helps the guy's out tons. One of the guy's used his to heat his Home (gas forced hot water) back in the ice storm of 2008.
 
Honda EU2000I Inverter Generator would be a better investment.
I have hooked up a few of these to small gen-tran panels for emergency heat, refrigerator and lighting.
They are lightweight, fuel efficient and quite.

You will have to be selective with loads. But they provide clean power for computers, tv's or other electronic devices.

They cost about a $1000.00 with a 3 year residential or commercial use warranty.

Simple transfer switches for say just a heating system run around $80.00 and are very easy to wire.

A preppers dream!

Cheap lesser quality generators have dirty power and blow stuff up that is why this generator is so nice.

Honda quality, a great warranty and you can put it in your car and help out other family members due to it's weight and low fuel requirements!

$1100.00 and you will never worry about a winter storm if you have a smaller home with a gas or oil heating system.

Great for a small job or camping as well..
 
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Something to be aware of is most people that don't go for a whole house solution are generally looking to power the fridge, furnace and maybe some lights or light electronics. Be sure you have ample current to run everything. You will very quickly burn up a refrigerator or pumps on the furnace if the voltage does not stay in spec.
 
Chet0729 said:
Something to be aware of is most people that don't go for a whole house solution are generally looking to power the fridge, furnace and maybe some lights or light electronics. Be sure you have ample current to run everything. You will very quickly burn up a refrigerator or pumps on the furnace if the voltage does not stay in spec.
Click to expand...
That and remember that motors have a starting current surge several times larger than what they draw running. A 1A motor can easily take 3A for a moment while it gets up to speed.

Actually I just did some looking and the rule of thumb for motors 1hp to 10hp is the starting current is 3X the run current. It's worse for smaller motors.
Here's a link to a .pdf table of starting currents. Look at the Single Phase, 115V column. A 1hp motor requires 16A (almost 2kW) to start.
 
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MaxStravinsky said:
Most of this is going right over my head - all I want to do is be able to watch movies on my laptop when the power is out.[grin]
Click to expand...
Buy a deep cycle car battery and a DC adapter specific to your laptop, and you're golden, as long as you've already got the movies downloaded before the power goes out ;)

Chet0729 said:
Something to be aware of is most people that don't go for a whole house solution are generally looking to power the fridge, furnace and maybe some lights or light electronics. Be sure you have ample current to run everything. You will very quickly burn up a refrigerator or pumps on the furnace if the voltage does not stay in spec.
Click to expand...
With some whole house solutions you can add a "load shedding" module (around $200 plus installation and relays), this actively monitors generator current and frequency and can selectively drop certain circuits. It's specifically designed to quickly "shed" low-priority loads, for example when AC motor is starting up, and then restore them afterwards.

cockpitbob said:
That and remember that motors have a starting current surge several times larger than what they draw running. A 1A motor can easily take 3A for a moment while it gets up to speed. Actually I just did some looking and the rule of thumb for motors 1hp to 10hp is the starting current is 3X the run current. It's worse for smaller motors.
Click to expand...
Many generators, even cheap chinese imports, now report their average and peak capacity. For example, my little 12K claims motor starting capacity of 16.8kVA at 240V.
 
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MaxStravinsky said:
Most of this is going right over my head - all I want to do is be able to watch movies on my laptop when the power is out.[grin]
Click to expand...
Buy a 150 watt inverter for the lighter port and you should be good to go. Just don't run the car battery down. (You should also buy a jump start battery anyway.)

Or do what Kevin suggested with the marine battery and inverter.... Both are at Wal-Mart. Oh... And a charger for that battery... Top it off once a month or so like I do.
 
Prepper said:
Buy a 150 watt inverter for the lighter port and you should be good to go. Just don't run the car battery down. (You should also buy a jump start battery anyway.)

Or do what Kevin suggested with the marine battery and inverter.... Both are at Wal-Mart. Oh... And a charger for that battery... Top it off once a month or so like I do.
Click to expand...
You can buy the cheap generator for less and not have to worry about charging the battery.
 
MaxStravinsky said:
Most of this is going right over my head - all I want to do is be able to watch movies on my laptop when the power is out.[grin]
Click to expand...

Yeah but you posted in the survival forum so you're going to get off-gridders talking about home-brew wood gassifiers.

What laptop do you have?
 
Chet0729 said:
You can buy the cheap generator for less and not have to worry about charging the battery.
Click to expand...

Perhaps, but then you got to deal with gas storage and rotation, changing the oil every 25 hours of use in the generator, generator only lasting a few hundred hours, etc. I personally wouldn't run a generator to only watch movies... if I'm running a generator, I'm also powering the fridge and pellet stove, and a lamp as well as some USB chargers.

By the way, to the OP, it is important to keep in mind that a car battery is not a near-umlimited source of power. A laptop will have a fairly significant battery drain. Say your battery has 109 Ah, then you really shouldn't use it beyond 50% of its capacity. So, that's 55 Ah. A typical efficient laptop is going to use around 30 watts (but it can vary a lot... my old work Lenovo used 90!) So,

V * A = W
or
A = W / V
A = 30 / 12 = 2.5 amps

Thus, for a 55 Ah in half the battery, that is 22 hours of run time. Which is something, but it isn't a week-long ice storm blackout.
 
Prepper said:
Perhaps, but then you got to deal with gas storage and rotation, changing the oil every 25 hours of use in the generator, generator only lasting a few hundred hours, etc. I personally wouldn't run a generator to only watch movies... if I'm running a generator, I'm also powering the fridge and pellet stove, and a lamp as well as some USB chargers.

By the way, to the OP, it is important to keep in mind that a car battery is not a near-umlimited source of power. A laptop will have a fairly significant battery drain. Say your battery has 109 Ah, then you really shouldn't use it beyond 50% of its capacity. So, that's 55 Ah. A typical efficient laptop is going to use around 30 watts (but it can vary a lot... my old work Lenovo used 90!) So,

V * A = W
or
A = W / V
A = 30 / 12 = 2.5 amps

Thus, for a 55 Ah in half the battery, that is 22 hours of run time. Which is something, but it isn't a week-long ice storm blackout.
Click to expand...

2 cycle engines don't require oil changes but I hear what you are saying. Not sure how long one of those $88 ones will last but I know one of my friends in construction uses his every day and it is 5 or 6 years old. It is a Generac 10kw. He does new construction and usually is working before power is available.
 
Or, do this:

3peAhrAl.jpg


I bought the marine battery at Walmart, but the Cobra 400W inverter and the Schumacher charger were from Amazon. Walmart didn't have too good choices for those.

- - - Updated - - -

Chet0729 said:
2 cycle engines don't require oil changes but I hear what you are saying. Not sure how long one of those $88 ones will last but I know one of my friends in construction uses his every day and it is 5 or 6 years old. It is a Generac 10kw. He does new construction and usually is working before power is available.
Click to expand...

Oh, 2 cycle generator. Mine's 4 cycle. Actually it would be more convenient for long outages to just dump the right amount of oil in the fuel, rather than have to bother with changing it during a lengthy outage.
 
Prepper said:
Or, do this:

3peAhrAl.jpg


I bought the marine battery at Walmart, but the Cobra 400W inverter and the Schumacher charger were from Amazon. Walmart didn't have too good choices for those.

- - - Updated - - -


Oh, 2 cycle generator. Mine's 4 cycle. Actually it would be more convenient for long outages to just dump the right amount of oil in the fuel, rather than have to bother with changing it during a lengthy outage.
Click to expand...
Yup, those $88 dollar HF ones are 2 cycle

A friend bought one, I am waiting to get a report.
 
Chet0729 said:
Yup, those $88 dollar HF ones are 2 cycle

A friend bought one, I am waiting to get a report.
Click to expand...

Cool! I'll be eager to hear how well it works out. I'm always nervous about getting anything with "Harbor Freight" in its name, but if it works sufficiently, then it works. And, $88 is less than one marine battery. Although that seems to be the sale price, currently is $120. Blackouts don't happen very often, so if it got me through several of them then went belly up, I'd consider that reasonable. Some people spend that much on fuel per day for their whole house generator.
 
Our ham radio club has an old one and it works. It's not quiet like a Honda, and I don't think I would get one to use daily with a motor home, but for occasional backup it seemed fine. One nice little feature I hadn't seen before is the gas cap has an oil measuring cup built in so a: you don't forget the oil and b: you don't lose the measuring cup.
 
Prepper said:
Cool! I'll be eager to hear how well it works out. I'm always nervous about getting anything with "Harbor Freight" in its name, but if it works sufficiently, then it works. And, $88 is less than one marine battery. Although that seems to be the sale price, currently is $120. Blackouts don't happen very often, so if it got me through several of them then went belly up, I'd consider that reasonable. Some people spend that much on fuel per day for their whole house generator.
Click to expand...
I may pick one up to leave at my daughters house just for a few lights or the boiler.
 
I have one of the older blue H.F. 800 watt geni.
It got me through a 3 day power outage during the Halloween storm years ago,only uses 1 gallon of gas for 3 1/2 hrs run time.
Actually kept my Fridge going and a light. I have a wood stove for heat.
Check out the youtube video on different model numbers for the Storm Cat. There is a difference.

If you get the flyer sometimes they have them for $88

https://www.youtube.com/watch?v=MyIKv2ZpFxA
 
BobR51 said:
I have one of the older blue H.F. 800 watt geni.
It got me through a 3 day power outage during the Halloween storm years ago,only uses 1 gallon of gas for 3 1/2 hrs run time.
Actually kept my Fridge going and a light. I have a wood stove for heat.
Check out the youtube video on different model numbers for the Storm Cat. There is a difference.

If you get the flyer sometimes they have them for $88

https://www.youtube.com/watch?v=MyIKv2ZpFxA
Click to expand...

1 gallon in 3.5 hours? I guess they don't have a feature to lower the power if the needs drop? My Honda eu2000i goes 10 hours on a gallon.

By the way, that video freaked me out... the guy talking sounds exactly like me. For a moment, I thought I made that video then forgot about it all.
 

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