One of my hobby units comprise of 6V 4aH SLA Battery. The problem is that the charging section of the unit does not contain a automatic full charge cutoff (it is bad for the battery for not having one). I have to depend on my electronic instincts to estimate the fully charged state. So, I decide to assemble one myself. A simple one.
I came across this circuit
![6V SLA Battery Chargin with Cutoff.jpg 6V SLA Battery Chargin with Cutoff.jpg](https://www.electro-tech-online.com/data/attachments/32/32596-93cdbfe33b0faf9e59ff80826e9259a9.jpg)
The charger power supply section is built around 3-terminal adjustable regulator IC LM317 (IC1). In the charger power supply section, input AC mains is stepped down by transformer X1 to deliver 9V, 500
mA to the bridge rectifier, which comprises diodes D1 through D4. Filter capacitor C1 eliminates ripples. Un-regulated DC voltage is fed to input pin 3 of IC1 and provides charging current through diode D5 and limiting resistor R16. By adjusting preset VR1, the output voltage can be adjusted to deliver the required charging current. When the battery gets charged to 6.8V, zener diode ZD1 conducts and charging current from regulator IC1 finds a path through transistor T1 to ground and it stops charging of the battery.
Should I go with it. Or do I have better options ?
Half of the components needed are with me and the rest are easily available. Please scrutinize and point out any flaws.
If it is Good enough to proceed then, “the output voltage can be adjusted to deliver the required charging current.” What should be the optimal output voltage ? Do I adjust it after connecting the battery ?
Thanks
Zmint
I came across this circuit
![6V SLA Battery Chargin with Cutoff.jpg 6V SLA Battery Chargin with Cutoff.jpg](https://www.electro-tech-online.com/data/attachments/32/32596-93cdbfe33b0faf9e59ff80826e9259a9.jpg)
The charger power supply section is built around 3-terminal adjustable regulator IC LM317 (IC1). In the charger power supply section, input AC mains is stepped down by transformer X1 to deliver 9V, 500
mA to the bridge rectifier, which comprises diodes D1 through D4. Filter capacitor C1 eliminates ripples. Un-regulated DC voltage is fed to input pin 3 of IC1 and provides charging current through diode D5 and limiting resistor R16. By adjusting preset VR1, the output voltage can be adjusted to deliver the required charging current. When the battery gets charged to 6.8V, zener diode ZD1 conducts and charging current from regulator IC1 finds a path through transistor T1 to ground and it stops charging of the battery.
Should I go with it. Or do I have better options ?
Half of the components needed are with me and the rest are easily available. Please scrutinize and point out any flaws.
If it is Good enough to proceed then, “the output voltage can be adjusted to deliver the required charging current.” What should be the optimal output voltage ? Do I adjust it after connecting the battery ?
Thanks
Zmint