Using an inverter in reverse............

[Modulation]

............to get 12volt from the mains. Any reason not to?

 

[Bilgediver]

Well it will just go B_A_N_G however there are devices which incorporate the facilities of invertor and charger and do exactly what you want and will charge the batteries when there are mains available and will power mains devices when the mains are not available...However it all costs money.

 

[Billjratt]

YES, it doesn't work that way. Just use a transformer to get 12v. The inverter takes 12v DC and makes oscillations (AC) which it then feeds to a step-up transformer, or it makes high-voltage oscillations and processes the wave shape to look sinewave. sticking mains in the output won't be enjoyed by the bits inside.

 

[Billjratt]

Damn, pipped.

 

[justdrifting]

A 12v adapters called a battery charger!There cheep enough not to try an expensive inverter

 

[shmoo]

you mean like pushing a car along in gear to refill the tank?

 

[exfinnsailor]

How far would you have to push to get a gallon of diesel into the tank /forums/images/graemlins/smile.gif could do with getting fit /forums/images/graemlins/laugh.gif

 

[William_H]

You may be a little confused by the very early inverters where the heart of the device was a transformer. The transformer was driven by transistors switching the 12v in at 50 times per second with a secondary giving the 240V 50htz output. Many of these had a little additional circuitry so that the transformer could be used in reverse and the box would work as a battery charger or inverter as required.

However modern inverters do not use a large 50hertz transformer. The 12v is switched at around 500khertz and the transformer is built tiny to suit this high frequency. This usually produces about 340V DC which is then switched or "assembled" into 240V AC (RMS) so there is no circuitry of any use in a battery charger. The new process is far more efficient and cheap to make. olewill

 

[VicS]

[ QUOTE ]
you mean like pushing a car along in gear to refill the tank

[/ QUOTE ] You'd have to push it backwards!
/forums/images/graemlins/laugh.gif

 

[Anonymous]

Nicely explained

 

[mikefleetwood]

Why would you want to?

A small 12V DC power supply is so much cheaper (and safer).

How much power do you need? Or do you want a battery charger, as others have suggested?

 

[Modulation]

thanks. This is the info I needed - I had assumed that inverters were straightforward transformers.