I found a neat-looking buck converter on eBay with a 60V maximum input voltage and a 30V maximum output voltage. The trimmer potentiometer let me take the output voltage up to 40V with predictable results.
By Julian
Youtuber, shed dweller, solar charge controller aficionado
Hello Julian, interesting videos. Can you tell me if there is a specific name for the pen device you use to turn the trimmer screw with?
…A BIT NAUGHTY…..!!!!!!!!! NO….. EVIL!!!!!!!!!!
You might want to do a YouTube video on some of these mods (try the 8V reg first, it's easy for <30v (i.e. 78L08 or L09 with a diode). The mosfets are harder because they must be LL or 6V capable on the gate, and have very low Rds! …not so easy. External gate driver would be MUCH better, but requires a lot more modding. Also at lower currents you can use the 'ol IRF3205's you may still have lying around (yeah they don't fit, but). I expect you will have to replace the almost certainly blown up LT3800 though. …anyway, just a though 🙂
Hey I have that same converter that little skinny one it's junk I tried using 55v in to reduce down and it smoked it.
There is recently some better buck down units that accept up to 70v but you pay a bit more for then. There is a few for 14 bucks but are like 180w. Not bad.
Newest buck I've seen lately is a blue one that's 800w 70v to 58v max looks similar to the 1500w red ones.
Can b this module use for charging a 12v battery from 19v adapter?
What boards do you recommend that allow you to exceed all the warnings and still get away with it?
I do believe that the linear regulator built into the control chip died because of input overvoltage, and it probably powered most (if not all) of the circuitry inside that lil chip
The module should never be operated above 20V output!
From the data sheet, page9:
In LT3800 converter applications with output voltages in the 9V to 20V range, back-feeding VCC and VBOOST from
the converter output is trivial, accomplished by connecting diodes from the output to these supply pins.
Deriving these supplies from output voltages greater than 20V ***will require additional regulation to reduce the feedback voltage***.
Exactly that circuitry to limit Vcc to 20V is missing, Vcc is fed from a simple diode out of Vout.!
Probably the chip will run off specs until 30V, but 20V is the regular limit for Vcc. Period!
The best is to immediately replace the 50K pot with a 20K one.
i would put the output of the boost in the garden, directly into the buck-boost that you want for your PS.
hello sir julian… can you do for me how to explain the dc to dc ZK-4KX buck boost converter. Thank you
RIP … a moment of silence for the departed :'(