Help with sine wave inverter charging

[Joeadeoye]

I made a pure sine wave inverter using a low frequency transformer and full bridge mosfet configuration and it's working fine. Now I want to include a charging function in the same inverter.

The transformer used is 7v-220v and 4 IRF3205 mosfets were used to form the full bridge.

Talking about the charging, if 220v AC mains is applied to the transformer, the secondary side will give 7v AC which is too small to charge a 12v battery.

I have seen some commercial inverters do this, but I don't know how the voltage was boosted from 7v to 13.8v needed to charge the battery.

I have seen some threads discussing the same issue I am having but none of the answers in the thread worked for me.

H-Bridge Battery Charging Concept

Dear All, Can anyone help me to know H-bridge charging.Can we charge a battery using H-bridge?? Thnaks in Advance

www.edaboard.com

Charging Principle in Sine wave Inverters

Which charging technology is used ,in sine wave inverters or home UPS, by leading companies? Thanks

www.edaboard.com

The above links discuss the same issue I am trying to resolve. Please I need help

 

[BradtheRad]

I used a mower which had electric start built-in (Lawn Boy brand). The battery was 6V and the charger read something like 5V with my old-fashioned VOM. The system worked for years.

For a long time I puzzled that the charger could make do at charging on that low voltage. Eventually I realized it had no smoothing capacitor. It produced peaks which were higher than the battery voltage therefore the charger's peaks were sufficient to do the job.

With 7VDC input you can do likewise by a voltage multiplier or boost converter. One is based on capacitors, the other is based on an inductor. You can build either type to double 7V and produce sufficient voltage to charge a 12V battery.