Using a buck converter to make a battery charger

[Peter Brigg]

I have a 24v dc power supply and have been attempting to make a battery charger for a12v lead acid battery using the buck converter pictured here.
I find that the potentiometer for current adjustment has no effect and want to know just how fragile these devices are. It should be easy enough to solder a new one in if that is the case.
I have watched a youtube on these buck converters and it said there is an audible click when the lowest point and highest point of adjustment is reached-I hear nothing.

 

[calab]

Those cheap converters are not worth it. Just buy a charger.
https://endless-sphere.com/forums/viewtopic.php?f=14&t=110991&p=1627719&hilit=buck+converter+charging#p1627719

 

[Chalo]

I think the problem with that idea is that these voltage converters don't limit current, and neither does the typical 12V battery. You might get the voltage regulation you want, but it will run wide open and get hot, possibly burning itself out in the process.

 

[john61ct]

Lead acid no worries about limiting current, they are self-limiting not like LI packs, will not draw more than they can handle just fine.

But of course current limiting is better, if you don't want to provide that large a current rate.

FLA will draw up to 0.5C

AGM maybe 0.8C but only for a short time, and for longevity 0.6C is better than slower.

GEL in between better to limit that actually to say 0.2C

Charging requires 7+ hours assuming a decent rate, going higher does not speed anything up.

You don't have to get to 100% - trailing amps down to 0.005C - every cycle, but for good longevity "most cycles".

And keep your average DoD to 40-50% higher the better.

 

[jonyjoe303]

I use those buck converters as chargers and they always have worked good for me. I once got one that had a capacitor loose (bad soldering).
I never turned them all the way up or down the potentiometer and never noticed any click on them. On mine I always use a volt/amp meter and use that to calibrate the volts/amps going to the battery. Just make sure the battery isn't full or you wont be able to calibrate the amps.
You can also use a multimeter, but once I blew a fuse and no longer use that to adjust the volts/amps.
But they work perfect to charge all batteries, I use them on lead, lifepo4 and li-ion and get very good charge on them. Just make sure the input voltage is higher by several volts (at least 5 volts) in order to get max amps on the output.
Also if the converter is rated 10 amps, its a good idea not to go over 1/2 its rated output on any chinese made converter and use a fan they get hot.

This is the volt/amp meter I use to adjust the volts/amps. This meter is rated 10 amps and you can find for less then 10 dollars.