Practical advice about a car battery 12VDC to 110VAC inverter typical length of time to last without electricity Featured

The power went out recently and I wished I had an inverter with alligator clips to clamp onto a garage car battery without killing that battery.

Walmart has 150W for about $30 but isn't that too low of an output?

One laptop PC charger output says it's is 19.5VDC at 2.8Amps while another charger says it's 20VDC at 3.8Amps (1.9Amp input at 100-240VAC, 50/60Hz).

Amazon has inverters with dual plugs (why would I need more than one plug when I can use a power strip?) and USB ports, but I don't know two things.

1. What inverter size is needed to adequately charge a typical laptop?
2. How long will it take for a typical car battery to die from doing that?

Forget your car battery idea. Get a UPS:

On Tue, 3 Jan 2023 16:17:26 -0700, John Robertson snipped-for-privacy@flippers.com wrote as underneath :

The uPS idea is rubbish unless you spent a fortune on a UPS with a massive battery - not practical! The car battery would run down quite quickly - inverters take a large current - you could get an inverter capable of n laptops but you would have to run the car engine to charge itsself by measurement, guess at every 30 mins for 15 mins while charging (until V back up to full charge say 13.?V. Otherwise a more versatile option is to have a small petrol generator which has enough power to run essentials, CH. router. a few LED lamps, and use it sensibly, not on all the time etc. in 3 days you might freeze, depending! C+

I'm an old man. Everything with a battery will die. In about five years. Worse, everything with a rechargeable battery needs to be recharged.

I always tell my friends who buy those "jumper" batteries that in five years they'll be calling me to drive over to their house to jump them.

Invariably the thing is dead when you need it five years from now.

The beauty of something that alligator clamps onto a car battery is you always have a car in your garage. And that car always has a battery.

That car battery is always recharged. And it's always replaced about every five years or so.

Even better, for the price of the core charge, the next time you replace that car battery, you can just not bring the old one back.

Now you have a spare car battery (albeit it's a bit worn out). While it may be too worn out to reliably start a car, it's not too work out to run my CPAP machine.

And, I hope, it's not too worn out to run the inverter. If it is too worn out to run the inverter, then I still have the battery in the car in the garage.

Which is why I'm asking whether or not a car battery will charge laptops.

1. What inverter size is needed to adequately charge a typical laptop?
2. How long will it take for a typical car battery to die from doing that?

If that's what you want it's called a 'converter' to change

An 'inverter' changes current between AC and DC which is not ideally what you need (multiplies transformer losses).

RV sales/service outlets have 12vDC to 110vAC inverters if you want to do it that way.

I never knew that a "converter" existed until this very moment!

I agree with you that a converter plus the special plug should work.

One problem with any given converter is you never know how much DC voltage you'll need for any given laptop as it changes from laptop to laptop (I'd rather make a long term investment instead of a short terms purchase).

If I can find a converter which is adjustable to any voltage below around

Here's someplace to start:

They've been around a long time although you might not realize it. The old tube type car radios had a vibrator, a transformer, and a rectifier to get the 6 or 12 volts up to a level required by the tubes.

Mr Bowman's right:

Yup, all the rage back in the 50s, just don't use one too long when the car is parked with the engine off. They drag down a heap of current. Can still recall the background hum of the things, back when I could hear such things. ;-)

I have a charger for my Lenovo laptop that plugs into 12 V cigarette lighter socket, so theoretically less losses than converting to AC and back to DC.

That car charger will certainly be more efficient than plugging the laptop's mains power brick into a 12VDC to 120VAC inverter, but it is still converting the 12VDC to an AC current internally, as a necessary step in the 12V->20V DC->DC boost conversion.

Yes, and such devices are also more convenient, and they are available from most laptop manufacturers or worst-case from a third party.

If you have a moderately-sized laptop pulling 50 watts and you have a car battery able to put out 40Ah or so before dying, then you have a continuous battery load of 4 amps and can run the laptop for about 10 hours.

Car batteries are starting batteries and they are designed for high peak currents rather than the ability to be discharged very far. They usually have very thin plates in order to get more plates with more surface area for the high starting current, so they are prone to issues with the plates warping when discharged a lot. So don't discharge the car battery down too far. 40Ah is not out of the question but don't treat it like a telco battery.

--scott

That looks good.

I've bought single voltage car charger for my last two laptops. The first trip I just used the laptop a little in the car, and i'd park next to a hotel to get wifi.

But over the last 3 trips I lived in the car for a total of 4 months and I'd run the laptop off the car battery every morning to get my email and plan the day's events, and most nights, to read more email etc. It worked fine. I found the charger by searching amazon on car charger brand&model

However, it's not going to work for long unless your car is running. I woudl guesss two hours for only oone laptop, proportionally less for more t han one. I kept the car running almost all the time, partly to listen to the radio and partly because one trip it was February and March and I would be cold without the haater.

AND YOU TALK ABOUT THE CAR BEING IN THE GARAGE, WHERE THE EXHAUST GASES WILL LEAK INTO THE HOUSE AND KILL YOU. After that, the laptop will not work well.

YOu can probably park the car outside, after splicing a much longer wire into the output from the car charger. Probably a thicker wire so y ou don't have too much voltage drop.

I would work things out so you can lock the car while it's running and use a separate set of keys to open it again. Even in the safest quietest n'hood, an unlocked running car is going to look tempting to any boy 12 to 17 y.o.

BTW It is certainly wasteful to convert the car's 12volts to AC and then convert the AC to DC Waste all over the place, which means the battery dies even sooner.

On Jan 07, 2023, micky wrote (in article<news: snipped-for-privacy@4ax.com):

I'm not sure that needed to be shouted and I'm not sure it's even correct given that most garages are /designed/ to have cars running inside of them.

That is, most have huge vents to the outside air, and most garage doors are not airtight and all /building codes/ are different when rooms are above.

I'm not saying carbon monoxide doesn't kill but don't people who kill themselves that way usually /connect/ the tailpipe via hose into the car?

Ron, the humblest guy in town.

Never heard of a garage designed that way. Mine is hurricane proof to

Those cartoonist are clever, and they can draw too. I'm not either, but that's why we have them.

Thanks, I had not looked. Great colection

I've never heard that and all my life I've heard of people dying from cars left running in the garage.

I have never seen a huge vent to the outside, or any vent. In my experience, garages are as air-tight as they can be without spending extra money, because people go into their garage in the winter and at night, and they want to be at least moderately warm.

That's true. They can and most likely do leak around the sides, the top, sometimes the bottom, and even somewhat along each horizontal line separating segments. Despite all that, when we had an attached garage it was far warmer in it than outside. Even though the furnace had no ducts opening into the garage.

Not as far as I know, and certainly not the people who die acceidentally.

There you go.

monoxide nationwide since 2006 after a keyless-ignition vehicle was inadvertently left running in a garage. Dozens of others have been injured, some left with brain damage

This doesn't relate to you but I came across it reading about Rose Parade floats:

In parades during the late 1930s, there was a problem with drivers falling asleep along the route due to concentrations of dangerous carbon monoxide fumes from the float engines.

“The reason they always have an emergency driver on each float is because two or three fellows have been made dizzy by the carbon monoxide in the past and passed out,” said veteran float driver (and professional chauffeur) U.L. Agnameyer in 1939. Pipes carrying exhaust fumes were extended to the rear of the floats that year, reducing the threat to drivers.