Battery Charger

grimjordax

New Member
This is my latest project I just completed. It is a multi-channel lead acid battery charger. It can be used for VRLA, gell cell and wet cell types. It is designed to charge battery jars with a nominal voltage between 4 and 12 volts. It will also work well with any battery type requiring a constant voltage float charge. It has built in limiting circuitry to keep each channel at or below 1.25 amps. The individual channels may be paralleled for higher current. Once the set voltage is adjusted and the channel is turned on, the charger will try to drive to the set voltage while automatically current limiting. As the set voltage is reached the current diminishes to a fractional amount that is required to "float" the battery at that setpoint. The system has automatic fault detection for over/undervoltage and battery disconnect as well as open cell detection and will automatically turn off the affected channel.
The charger is built around a modular approach whereby the charger cicuitry is on small charger PCBs that connect to a main 24V supply and are driven via a PWM signal from a microcontroller. They also provide a voltage feedback to the microcontroller via ADC input. A 4x20 matrix serial lcd screen and 4 membrane type buttons are used for HMI. The microcontroller used is a Picaxe 20M2 mounted on a Kiwi Patch board. The power supply is by Mean Well and there is a cooling fan mounted left side to keep everything running cool.

nutsandbots.blogspot.com
 

DakLak

New Member
I like the modular approach you've with the high current PCBs so should one fry the others will be unaffected.

Given that there is lots of unused real estate, it's a pity the maufacturer didn't man-up some of those load bearing tracks.

Are you using a single PicAXE for all the charger ports?
 

grimjordax

New Member
Yes a single picaxe 20M2 is used for all 4 charger boards. As for the trace widths, they are considerably larger only on the load bearing portions of the charger PCBs. Thats the way i designed them, as they are custom PCBs I had manufactured for this project.
 

the old fart

Senior Member
Hi Grimjordax

I know this project is nearly 2 years old.

I'm looking for a charger for SLA 6 volt batteries.

Do you have a better hardware drawing please?

Thanks

TOF
 
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