SLA and Load Control

[kalaman]

Hi all,
I will make circuit with pic microcontroller which is control the SLA battery's work. It will cut the voltage when the battery's voltage 10V.

When the circuit cut the load from battery i guess the battery's voltage will increase. Approximately one minute later the circuit will see i.e 12.5V standby voltage in the battery and will make the load work. Namely the circuit will go into a loop from 10V to 11V. What would you say for this type instance.

(My charger will wait for morning to start to charge.)

Maybe i couldn't say what i think because my english is bad.

 

[Hero999]

What do you want help with?

If you want us to do it all for you then please look elsewhere.

 

[kalaman]

hi hero999
Was the question bad or nonsense ?

I want any help or any clue not all circuit schematic or pic's codes.

 

[ericgibbs]

hi hero999
Was the question bad or nonsense ?

I want any help or any clue not all circuit schematic or pic's codes.

hi kalaman,
You require a Vbattery detector circuit that will have a upper and lower voltage threshold level.

As you say the battery will discharge down to about 10.8V. [this is the lowest discharge voltage that is recommended].

If you used a PICs ADC, you could detect when the battery/load voltage is in the order of 10.8V and disconnect the battery from the load.
It would remain in this disconnect mode until you pressed a push button 'Reset', which would also be detected by the PIC and the load would be reconnected.

It would be also possible to detect a fully charged battery state to do the same reconnect action. If the battery voltage dropped quickly the PIC program could detect this condition and disconnect the load and await a manual 'reset'

By using a PIC it would be possible to build/program a 'smart' battery status monitor.

Does this give you any ideas?

Eric

 

[Hero999]

Have you investigated comparators or do you really want a PIC?

I would use a comparator with lots hysteresis and a suitable voltage reference (if you want you can buy comparators with that built-in). No programming required, just select the appropriate resistor values and connect it together.

 

[ericgibbs]

Have you investigated comparators or do you really want a PIC?

I would use a comparator with lots hysteresis and a suitable voltage reference (if you want you can buy comparators with that built-in). No programming required, just select the appropriate resistor values and connect it together.

hi,
As hero suggests, I would use discrete logic ic's, a good starting point would
be the MAX8211 battery voltage monitor ic.

If you want to use a PIC as a learning exercise, choose a PIC with an inbuilt ADC.

Eric

 

[kalaman]

hi kalaman,
You require a Vbattery detector circuit that will have a upper and lower voltage threshold level.

As you say the battery will discharge down to about 10.8V. [this is the lowest discharge voltage that is recommended].

If you used a PICs ADC, you could detect when the battery/load voltage is in the order of 10.8V and disconnect the battery from the load.
It would remain in this disconnect mode until you pressed a push button 'Reset', which would also be detected by the PIC and the load would be reconnected.

It would be also possible to detect a fully charged battery state to do the same reconnect action. If the battery voltage dropped quickly the PIC program could detect this condition and disconnect the load and await a manual 'reset'

By using a PIC it would be possible to build/program a 'smart' battery status monitor.

Does this give you any ideas?

Eric

thank you. you have understood me. I was thinking only one low level (10.8V). but you made entered my head. I think i it will be okay two low treshold level one is for example 10.8V and 11.2V. Then I can get rid of memory effect.

Am I right ? Or suggestion.

Thanks . Best regards.

 

[kalaman]

i forgot one think. I will use PIC MCU. there will be some qustions about charging.

thanks again