mosfet prevents battery damage


Posted on Feb 5, 2014

Sealed-lead-acid batteries, which find wide use in power-electronics products, such as UPS (uninterruptible-power supplies), inverters, and emergency lamps, supply power to the load whenever utility power is unavailable. When you restore utility power, a charger supplies the power to the load and charges the batteries (Figure 1). You can add a dio


mosfet prevents battery damage
Click here to download the full size of the above Circuit.

de to protect a load from current resulting from a reverse-connected battery. The diode, however, won`t protect a reverse-connected battery from the charger circuit. If the charger is on, a potentially dangerous current can flow into a reverse-connected battery. The battery voltage, which normally opposes the charging voltage, now aids it, which lets a higher current flow into the battery. If you add an N-channel MOSFET to the circuit, you can protect the battery from this damaging condition (Figure 2). The MOSFET conducts only when the battery is correctly connected, which lets the battery charge or discharge. In this condition, the transistor gets forward-biased, which switches on the MOSFET. If the battery is reverse-connected, the transistor and MOSFET turn off, thus preventing current flow. This simple circuit provides reverse-battery protection in both charger and battery paths, thereby protecting the battery, the charger, and the load. You can use a microcontroller to measure battery current and make a decision on appropriate action, as well.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Bartels AutoEngineer
800W-soft-start-light-dimmer
Output-limiter
mini fm transmitter circuit
Simple Voltmeter
touch free timer switch circuit
5-motor walker circuit
A typical liquid crystal display inverter circuit OZ965
555 Touch-sensitive switch circuit diagram



Top