Constant Current/Voltage Battery Charger

[PeterDove]

Hi All,

I built a lead acid battery charger and then made an instructable from it. Thanks to all those that have helped along the way to help me get a better grip on electronics - better than sitting up all night reading books!

My next project is starting soon.. so apologies in advance...

Any comments appreciated.

**broken link removed**

Peter Dove

 

[fever]

nice one.
my scooter uses 12v (2.5Ah) lead-acid battery **broken link removed**
so is there any ckt which can indicate the charging process.imean while charging RED led and when charging is over Green led....

 

[fever]

i wonder what is this battery type.imean gel type,or flooded,or wet type.
(all i know is while servicing it is filled with distilled water).
so guys if any one has idea of its charger pls help

 

[PeterDove]

nice one.
my scooter uses 12v (2.5Ah) lead-acid battery **broken link removed**
so is there any ckt which can indicate the charging process.imean while charging RED led and when charging is over Green led....

The circuit I described actually reduces the current as the battery voltage approaches the value selected - so in effect it is a taper charger which works very nicely. When the battery voltage is at the voltage being provided there is only a few mA going through. Use a multi-meter to check the current going through the R3 resistor as the battery is battery is being charged.

Peter

 

[PeterDove]

How to charge

Hi,

I had a look on the site and there arent any guides for charging. Generally one should take a charge time of 12-16hrs for lead acid.

So for a 12V battery set the voltage of the charge to 14V, and then you take the capacity / 12hrs ( or 16 to be safe ). Yours is 2.5Ah / 12 = which is about 210mA. You would then set the charger to be 14V at 210mA and charge for about 12-14hrs.

Hope this helps.

Peter

 

[fever]

thanks for ur ino.
ru planning for any process indicator for this ckt.imean any led which indicate the finishing of the charging.
and for charging my battery what modifications do i need in ur circuit.

 

[PeterDove]

thanks for ur ino.
ru planning for any process indicator for this ckt.imean any led which indicate the finishing of the charging.
and for charging my battery what modifications do i need in ur circuit.

I am in the process of making a pretty complex circuit which will be a smart charger.

Peter

 

[fever]

nice.
i'll be waiting for ur update

 

[Ayne]

I think it is a good idea that put a brain(Microcontroller) in the circuit. It will check the charging process, as the charging will complete it will automaticaly disconnect the battery from power supply using relay and also run an indicator (Bell or Led) for indication.

 

[Sceadwian]

Both Atmel (AVR's) and PIC's have IC's specifically designed to be used as smart chargers. Developing an overly complex analog circuit to do it is wasted effort. Between using ADC's and PWM outputs as analog sources the micro controller can completly control the charging process.

 

[PeterDove]

Both Atmel (AVR's) and PIC's have IC's specifically designed to be used as smart chargers. Developing an overly complex analog circuit to do it is wasted effort. Between using ADC's and PWM outputs as analog sources the micro controller can completly control the charging process.

Hey buddy - complex to me is using a pic takes more learning than banging lots of componenets together. But it is actually what I am using, PIC, digital potentiometers and a few A/D components - just awaiting for the Microchip samples to arrive. I love Microchip

 

[fever]

nice.
if possible try to make it for different battery types.
imean one mode for lead-acid,another mode for Ni-Mh etc....