DIY Solar Battery Charger, with a DC to DC Buck Converter.

#diy
#power
In this video, we performed an experiment to see is we can use a constant current DC to DC buck converter as a solar battery charger or charge controller. The goal of the experiment was to see if a DC-DC buck converter as a cheap device, can be used as an alternative to the more expessive MPPT charge controllers in the market today.

To see the first experiment, please watch the video below.
Solar MPPT Charge Controller vs DC-DC Boost Converter, which is Better for Solar Charging?

Mentioned video (DIY Digital Battery Capacity Tester)

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[vztech]

Hello!  I've been using that same buck converter to charge my 12v, 100ah LifePO4 battery with a 240w solar panel for more than a year now without a problem.😁

[crazyham]

Thanks Mate.
I have used a 20 to 30V input to 13.8V, 7 Amp output Buck Converter successfully to maintain a 2nd battery in my car for my amateur radios.
It also generates less ripple (RF noise) than a solar regulator which is good for my purposes.
Thanks for the video Mate 👌

[mghuertas]

Hi friend thanks for sharing i will be doing a similar setup for charging a dewalt battery using 12v car lighter with a step up 😮

[SA-yclf]

Didn't you see the input current? It is only 1.05 amp, buck converter boosted it to 2.35 amp.( 6:52 ) Perfectly working, And you showed in a comment that the converter is working at 89% efficiency. So why you're saying it doesn't work?
While your panel is making only 34.8 watt from sun at that time, how can you expect more than 31 watt from the converter? The problem is your solar panel. Maybe it is because of shedding. But you're blaming the converter.... Lol.

[Eric-czer]

This project i feel like it is working as well as it still can tune the voltage to the voltage level and charging the battery with 2.3A. However, there is a harmonic noise u mentioned about in video is actually related to the buck converter is damaging rn. It is using higher than its specification, im suspecting on the current/power, may need to check on its datasheet.

I did work on this kind of project before as I am using the MPPT Solar Panel Controller converter which works well for me, i think mine this model have current supportation up to 5A which is enough for my project.

*I would recommended kick start by observing the specifications pf the solar panel (short circuit current & open circuit voltage), DC-DC buck converter (max charge current, Iin, Vin, Vout) and battery (max voltage & Power)*

I would suggest you do a vid using this model, try it out with charging the battery on sunny day and night, to see the changes of the voltage output. I met a problem on the input side where the voltage is pump up over time when sunny day turn cloudy (From my solar panel - from 24V drops to 3V) will have a pump up voltage over time on Vout of buck converter. I scare it would hurt my other component so i changed it.

But yeah Hope your project works well!!😊

[Martinsebas]

Try with out using the input power Meter.

[gussiong]

I use dc to dc buck converter for charging my battery and i put welding diode for anti Backflow 😂

[jec_ecart]

What you're experienceing is buck converter "collapse" basically the source Cound not generate the power which buck converter demanded.
These cannot replace an mppt long term, but in emergency they'll charge your battery. Especially if battery & solar voltage is not very far apart.

[firstnamelastname]

This is quite common, what happens is when your input does not have enough amps to feed the buck converters output, the buck converter will draw the input down to just over the output voltage, so in your case your solar panel is pulled down to ~14V and at that voltage it will only deliver 0.5A. Im using a step down converter as a temporary charge controller, but i run 57V charging and my pannels 2x36V in series still perform somewhat good at 61V that the buck converter will pull it down to, to supply the output 57V.

[MrBurtonf]

The converter is probably working. The problem is likely demanding more power from the converter than is available from the solar panels.

[LostSoulsMed.]

Have you tried adding a PWM SCC to the output of the converter to solve the problem of converter collapse, since the pwm regulates the voltage to charge the battery. And also it would be an interesting topic if adding dc buck converter to convert higher voltage pv panel closer down to the charging voltage and converting that excess vomtage to usable current to charge the battery, since the pwm only steps down the pv voltage to the battery charging voltage without converting that excess voltage to usable current. Please make a video about this, if a PWM can solve the converter collapse issue. A lot of us wants to try alternative ways to charge batteries from solar without using an expensive MPPT, and once they get damage, its hard to find a good technician to trouble shoot their complicated components. Please make a video about this🥺thanks

[mrtechie]

Maybe the solar panel voltage is dropping under load. It looked like one of the panels was shaded.

[jec_ecart]

Other thing that's important is that they're non isolated devices.. Means you MUST use diodes for back feeding & reverse polarity protection.
Maybe you can repeat the experiment with proper diodes. Get at least 50A rated ones. Lower are trash.

[mentalfusin]

I really enjoy your videos and how you take the time to explain everything!
👏👏😎

[ruthp]

I use the same module with 30w 18v panel. Efficiency is quite low. It can charge only 0.5A or 8w. However, if I connect this module directly to my 12v fan, it can give 12v 1A or 12w. I don't know why. I seem if I increase output voltage to 14.6 current will drop.

[Jayromemagtipon]

Buck converter. And mppt is the same voltage. Compared to Pwm. Buck converter have current limit. And the power current is depend on the highly sunset condition to get the set limit current.
Mppt. Have automatic current limit if in low sunset it can boost Current. And limit the current. Thats what i think. I use a mini 5a buck converter to charge my battery. It works. But the current is continously increase. And very fast decrease . It has a unstable current but stable voltage my exp. Using buck converter as charger it can charge but low efficiency

[MegaCyrik]

Looks like it pulled down the panel too much. I read that this can collapse a panel voltage permanently so be carefull. I have 5 of those bucks and i use them on a small buffer on my mppt that charges the buffer at 30v and empty it into my 12v bank continuesly.

[martipetdebullar]

What I want to do is to use it to reduce my 24volt panels to 12volt system and I believe it will work. I have 12volt interter and 24volt panel and just want to use it to reduce to 12 volt

[VDOless]

This may seem like another stupid question but I love the knowledge I gain from my own stupidity: power input = power output + losses. Even under ideal conditions power output can never be higher than power input - especially with a BUCK converter. How could we expect it go higher than input with step down topology? I'm sure there's a law of conservation of something or the other that you're trying to override against the physics of the universe😮. Respect the attempt though and I'm slightly anxious to see you "Shock the World" if you do succeed. I'm still trying to figure out the detail I've missed here. In any case, doesn't it seem that we're overanalyzing the problem at the wrong point in the circuit? I'd say work on the input supply to amp up the power required in order for the buck mechanism to step it down to your required output charging VA.

Guys please feel free to correct any part in the above since as I was typing this, not a single page of a textbook was turned 😄

[petervoss]

I want to supply a12 V motor direct from a 550 W 48 V panel.What would be the best system to do it ?