DCDC DC-DC CCCV cc cv module
Links… so many of them.
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Who can find the lowest price for this highly common module?
US shipped seems like just over $23.
Ali: US $21.52 shipped for one,
https://www.aliexpress.us/item/3256804988272624.html
or if you wanted 3 saving maybe make sense. I would worry about returns being and issued compared to 'zon.
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Haha I think they typed their title wrong. It should say BOOST not BUCK.
Then they could not change the name or something and therefore lowered the price maybe?
Nice find I guess even if confusing. Interested in learning about the OEM(s) for sure…
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https://www.aliexpress.us/item/3256805417617113.html
@surfdado is testing this for 15S->18-20S
When I tried it it worked fine for like 18V to 50V (got real hot tho fan sux) I am interested in what surfdado sees with it.
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That will not be a stable, reliable solution. 
It might survive for a bit, and not quickly burn out from oscillating itself to death or overheating, but IMO it will not be a long lasting converter. But at the price I know many will take the chance as cost is a much higher priority than long term (i.e., expensive) reliability.
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What would you say about this one? Other than, obviously, very subpar cooling that could be addressed. But is it in a similar boat?
Any low cost converter that has seemingly great current and voltage specs is not going to be a reliably designed, stable unit. Just my personal thoughts but a stable, reliable, and not-hot-running converter with a great specs is not something that can be made inexpensively.
Having said that, any one of these units could run in a board without problems for years and years…or burn out the first day. That’s the issue with unstable designs, you never know when they’ll be a problem without lots of testing.
Many riders will have no problems with these cheap units though, but a few people will. Each of us has to decided whether we want to take the chance or not.
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They can be made quite affordably… after you amortize the engineering development cost over millions of units 
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Side note for anyone wondering why anyone would do this: Pinning the DC link voltage has many benefits, thats why EVs will pin it to 460V or 925V through a bidirectional converter.
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So what you’re saying is I should probably have a back up unit in case I want to try taking this and going and riding some serious miles off road without wanting to carry it back the whole way if there’s an issue 
What are you powering with the converter?
Your board won’t move if the converter fails? Or is it something like your lights and you’re riding at night?
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I’ve been using a unit similar to this for a while with no observed adverse effects.
I think these are intended to be used to charge batteries from a solar panel. I’ve been using a cheap 12 volt power supply with mine.
Voltage Boost Converter, DROK DC 8-60V to 10-120V 15A 900W Numerical Control Step Up Voltage Current Adjustable Regulator Constant Module Output 48V 24V 12V Power Supply with LED Display Heat Sink https://a.co/d/fjLmB6j
What are your thoughts on this @Battery_Mooch ?
I’m not able to say anything about this particular unit, or any other unit. Well, other than it would be crazy of us to think that this is a true 900W unit can be run at 15A at a moderate to high input-to-output voltage difference.
I have zero info to go by otherwise and any unit might survive for years or minutes. There are verrry good reasons why quality, name brand units cost so much more.
The details matter guys, just looking at specs means nothing…really…it means nothing. They’re almost always exaggerated and/or apply only to certain in/out voltage combos or current levels. Add on the vibration/shock we subject these things to and the small, often quite warm, space they operate in and there’s no way to predict anything.
For anyone who needs a converter, buy the ones you’re interested in and do some basic checks. How hot do they run? Any weird behavior? Anything seem to be working loose?
Without test equipment you’ll just have to see if the unit burns out before you expect it to. If it does, try a different unit. Not much more we can do than that.
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Thanks for the input. Add soon as I typed out the question I knew you were going to say something to this effect.
https://www.aliexpress.us/item/3256804783360051.html
300W high power DC DC Buck Converter CC CV Variable DC boost power module supports solar MPPT with 7-80V input 1.4-79V output
Anyone know of a good a source for high quality buck converters for 18s voltages? I like the prices of these aliexpress converters, but I am concerned about their reliability.
I thought I found a really high quality buck… well, I did, but it got super hot. Digikey was a great source and I found this cool Murata 75v to 12v dc, but it got INCREDIBLY hot at zero load on the 12v side! no good!
Back to the quest of finding a good 12v buck…
Murata has great DC-DC converter modules, that shouldn’t have happened.
Some modules need a minimum load and/or output capacitors added in order to be stable. Otherwise they can go into oscillation and that can create a lot of heat. Check the datasheet to be sure.
A really “noisy” input can force it into oscillation too and sometimes requires a cap on the input.
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I have a ACDC meanwell power supply, since September 2014.
Many thousands of hours on it.
model RSP-500-15.
Rated for 500 watts output, it will happily exceed 600.
I have increased its ventilation and ask it to output 600 watts for a half hour or more, charging hungry healthy depleted lead acid batteries, regularly.
Its adjustable voltage range is also far wider than its spec sheet states.
I would not hesitate to buy any MeanWell product based on my experience.
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did you find one?