PICAXE Mini Mppt 12v Battery Charger

S

Solar Mike

New Member
Here is a small Mppt charger designed specifically for 12 or 24 volt batteries, I wanted a minimal system fitting on a 100 x 100mm pcb that will handle a PV panel up to 150-200W and voltages of 70 volts or so. Thought it may be of interest to some members here, components are getting very hard to buy with over year long ordering delay, so this design all bits are readily found quite cheaply on AliExpress - noting quality is an ongoing issue on that and other sales platforms.

I suddenly have a lot of 12V alarm units to build each with a small lead acid battery and powered from a small PV panel, the other charger designs I have are all too big. So have thrown a pcb together and will send the gerbers off to be made, No circuit dia. as I have yet to draw that up, will post here when its completed.

Top PCB 100 x 100:
25588

Bottom:
25589

Once I get the boards back, will have a play, write some software and post back here.

Cheers
Mike
 
S

Solar Mike

New Member
Have also implemented a PWM only version, same 100 x 100mm foot print, using two or four back to back mosfets; this is for those smaller 18v PV panels where MPPT would be an over complication. With suitable extra thick wires soldered to the pcb, and the additional mosfet pair, current could be increased to 30 amps if required. The single mosfet driver chip still works ok here as it now runs at 400Hz PWM rather than the 32Khz of the MPPT version.

25593
25594

Cheers
Mike
 
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