A battery still needs a recharging source.

And one on my sump pump. Look up battery backup

...batteries.

Just stack a couple of 12 volts on a trickle charge and hook up an inverter when needed, and poof, a battery powered generator.

just sayin'

NeoGreen, I think you might have a level of mechanical and engineering ability above mine.

But great idea. Gas-powered generators can be dangerous and expensive. And sometimes all we need in emergencies is something to power a few small items, like a cooler for medication and a phone. Your generator idea would do that without danger.

To use a generator as an inverter you lose a lot of energy. Using a battery as some have suggested would power DC devices, but you would need a large and expensive inverter to run AC appliances.

https://en.m.wikipedia.org/wiki/Power_inverter

I asked a stupid question

The Tesla solar roofing includes a major battery pack (thin batteries that pretty much become a wall on a wall).

The roof power doesn't really go directly to the house but to the batteries and whether the sun is up or not, the house is really running off the battery pack.

Those roofs are REALLY expensive and about 50% of the cost is the battery wall.

So, one could rig a Tesla battery wall in an apartment, but that would be a lot of money to spend on what could be a temporary residence. If one moves, the de-installation, and re-installation would cost a fortune.

I'm not only thinking about refrigerated items and the ability to cook; but more importantly, people who have medical equipment which they need to survive, and can't always make it to a hospital or shelter. For them it would be a life-saver

... could probably be done a LOT cheaper than a whole house or apartment.

I did a quick google search and found several examples of laboratory/hospital fridges with integral battery back ups.

Didn't see any consumer versions, though. That might actually be a pretty good marketing advantage.

And, to run nothing but the compressor wouldn't take hundreds of dollars added to the retail price.

You might be onto something there, luna.

Last edited Tue Sep 11, 2018, 09:20 AM - Edit history (1)

medical equipment

we had a massive UPS on the roof.

But even at that, it was never intended to power the equipment for more than a few minutes -- enough time to do an orderly shutdown of the equipment.

The OP seems to be a little confused by the terms already.

A generator generates electricity (typically, by spinning a coil of wire in a magnetic field).

A battery stores electricity (typically, as a reversible chemical reaction).

Using a battery to spin a generator simply wastes some of the stored electricity to generate a lesser amount of electricity.

As others have commented above, just use a battery for powering the devices. Use an 'inverter' as needed to convert the DC from the battery to AC for those devices which require AC.

Get several deep cycle batteries.

Have them on a charger so they have a full charge when the power drops.

Have an inveter to rub essential 110v equipment and also a connection with several car style 12v outlets to let you charge phones, tablets etc with your batteries.

To recharge you can either use solar if you have exposure or you can take the batteries to your car, hook them to it with jumper cables and run the car to charge. Then take your batteries back inside.

Be careful about hydrogen outgassing from flooded lead acid batteries. If you use this type of battery, you need ventilation and NO sparks.

Battery operated power sources like you describe are available. On the smaller end of the scale you have things like Uninterruptible Power Supplies (UPS), like you might buy for your computer. On a larger scale you could invest in very large banks of batteries, like those that people that live off of the grid might use.

The main problem you run into if you're looking for a temporary power source for emergencies is that batteries store far less energy, by weight or volume, than liquid fuels. For example, uing Wikipedia's numbers ( [link:https://en.m.wikipedia.org/wiki/Energy_density|Energy Density), gasoline stores about 270 times as much energy as the lead-acid battery you'd find in a UPS.

Now, that's a gross oversimplification - some batteries will do considerably better than lead-acid, the efficiences of the different systems in producing AC power will vary considerably, etc. All those factors pale in comparison with the difference in the energy densities.

Another big factor would be the cost of a sufficient number of batteries as compared with a few gallons of gas. The cost might justfiable if you're designing an off-the-grid house, but not so much for something you might use in an emergency.

But their purpose is to smooth the power spikes