How to store electricity from generator??

Question

i have a small generator that produces 250 Watt (VA)...now the problem is how to store that electricity for around one day as the current produced is in terms of 250 W ...

should i use a lithium-ni battery or capacitor or ??

if i can store it in a capacitor then what should be the range of the capacitor????

please reply....urgent.

Answer 1

With present-day technology, there is only 4 ways or storing the power. None of which is pleasant.

Your best option is to store it chemically in a battery, You must rectify the generator output (convert it to DC using diodes) and use that to charge the battery. Lead-acid batteries are your best bet today, because of availability and cost.

The battery will deliver DC back to you when you need it. If you need AC, you must convert it back using an inverter. These can be found in automotive stores, or a cannibalized UPS from a computer.

Super capacitors reaching 100F or better are very expensive, and hard to find. They need elaborate voltage and charge balancing electronics for voltages above 5V or so. They would function identically to a battery in this application, so it's definitely not worth the additional expense.

Your other options are to store the energy mechanically by running a compressor, heater or pump. You could pump water into a tall water tower & use a water wheel or turbine to generate power when needed. That's the way hydro-power dams do it. You could compress air into a large pressure tank & power an air turbine to convert the escaping air into electricity. These aren't to practical on small scales :).

Stick with the lead-acid battery.

Answer 2

You want to store a days worth of output from your generator? Your statement is not clear. I'll assume that.

that's 250*24 = 6000 watts or 6 kW. A lot of power.

Not easily done.

capacitors will store it for a second or so.

Large marine 100 amp-hr lead acid batteries ($300 each) will store only 1kW, so you need more than 6 of them to allow for losses, say 8. And you need a battery charge controller and a 250 watt inverter.

Good luck

PS, it will take 30-40 hours or so to charge the batteries, using the full output of the generator.

.

Answer 3

A day's worth of generator time is 24h* 250W = 6000Wh.  From that you estimate the storage you need. The most economical would be lead-acid batteries. A large deep-cycle one is about 60Ah, at 12.5 V or so, or about 750Wh. You'd need at least 8 or 9 of these batteries, probably double that to cover charging loss.

This is well beyond what is reasonable for capacitors. Li batteries would work but they're more expensive.  NiMH or NiCd is a possible compromise if weight is a factor.  

Answer 4

As they say, capacitor and lithium-ion are out for different reasons, but because of the incomplete details in your question, you probably don't need as much battery as they calculate.  I read your question as stating that the generator produces 250 watts, but you don't use that much.  Thus you only need to store the surplus.  If you are using 225 watts, then the batteries to store the excess 25 watts would be one tenth the size given in their figures.  Much less expensive