Electronics > Projects, Designs, and Technical Stuff
XL6009 Boost-Converter overheating trying to charge a 2S LiPo
tooki:
I tried one of those little boost boards shown in the second video. Couldn’t get a power amp to work right, kept cutting out during peaks. After running the numbers, I calculated that with the component values they used, the maximum current it could output when boosting 5V to 12V was just 150mA — the 1A or whatever they claim basically refers to the maximum input current.
Now, in theory that should work for you, but with the variability in Chinese modules...
What I don’t understand is why you’d attempt charging using a boost converter module instead of a charging module, which will do the job properly and not burn down your house. Lithium ion charging is something you do NOT want to mess up.
Forsaken:
--- Quote from: tooki on July 31, 2020, 03:41:48 pm ---I tried one of those little boost boards shown in the second video. Couldn’t get a power amp to work right, kept cutting out during peaks. After running the numbers, I calculated that with the component values they used, the maximum current it could output when boosting 5V to 12V was just 150mA — the 1A or whatever they claim basically refers to the maximum input current.
Now, in theory that should work for you, but with the variability in Chinese modules...
--- End quote ---
The quoted (and more) videos do use the exact board I do and seem to work fine with 10-15W output. The Datasheet claims 3A max input current, which I indeed did not trust. That is why I did search for actual test results. I did not find any evidence of such a module overheating/failing below 10W.
Beside that the massive mismatch in input/output current and extremely quick overheating do seem odd to me for a "simple overload".
--- Quote from: tooki on July 31, 2020, 03:41:48 pm ---What I don’t understand is why you’d attempt charging using a boost converter module instead of a charging module, (...)
--- End quote ---
I want to be able to charge the battery from variable input sources. I did not find any module except 5V/USB-Chargers and ones like the one I did order.
Edit: Also I'd like to exclude the boosting circuit from the actual project to keep things as compact as possible.
--- Quote from: tooki on July 31, 2020, 03:41:48 pm ---(...) which will do the job properly and not burn down your house. Lithium ion charging is something you do NOT want to mess up.
--- End quote ---
By my understanding the BMS module is there for exactly that reason? (To secure the charging process and prevent "burning my house down")
Beside that I did not expect using a boost converter would be an issue, it is basically a switched-mode power supply, right? So what is the difference between that and a 8.4V power brick?
Just to clearify to prevent my reply from coming across wrong: I am not denying your claim or searching for excuses or whatever. I simply did search for a solution that matches my requirements to the best of my abilities.
Siwastaja:
You need a CC-CV supply to charge a battery. A CV supply is not sufficient. High quality CV supply shuts down, or provides very limited current in hickup mode; an improper one might burn.
Forsaken:
--- Quote from: Siwastaja on July 31, 2020, 04:35:39 pm ---You need a CC-CV supply to charge a battery. A CV supply is not sufficient. High quality CV supply shuts down, or provides very limited current in hickup mode; a improper one might burn.
--- End quote ---
So something like this would be fitting? https://www.amazon.com/Adjustable-Converter-5V-30V-0-5V-30V-Supply/dp/B073B3MJCF
What should I look out for to make sure not to take unnecessary risks?
Siwastaja:
Yes, it's of a correct type, but the quality of those cheap modules vary. The very least what you can do is to derate the current, i.e., don't turn it to full current but maybe 50-60% of it.
Having a BMS is an extra layer of safety in case the CC-CV supply - which can be called "charger" - burns out and outputs excess voltage.
Make sure the BMS is what you expect it to be, though. It needs to be able to actually disconnect the batteries in case of battery overvoltage.
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