Amazon DC-DC Converter Review
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- čas přidán 4. 08. 2024
- The testing of a DC-DC converter from Amazon.
Load Tester
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DC to DC Converter
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Fluke Meter
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Scope
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1157 Light bulbs to make load
amzn.to/3bWYlK9 - Věda a technologie
I'm going to give the 30A it's for intermittent trolling motor use, converting a 48v e-bike battery down to 12v. Hopefully it doesn't burn out... especially since the trolling motor only pulls 16A at it's highest load. Thanks for the characterization of this little unit, I'm going to assume the precautions extend to the 30A version as well.
I think it's the rating on the caps. I noticed subsequent ones have lower voltage ratings. Cheap caps have this behavior.
This was pretty awesome. Thanks buddy
Your welcome
Let me understand your smoke test.
1. The output of the buck converter is 12.3 volts.
2. You hooked the output of the buck converter directly to a 12.5 volt low impedance lead acid battery.
3. The input to the buck converter is from a solar panel directly.
4. There was not a blocking diode between the solar panel and buck converter?
5. Solar panels leak reverse current at night even if they have built in blocking diodes.
6. You reverse biased the buck converter at night which means you probably reverse biased semiconductors somewhere in the buck converter. You definitely reverse biased the electrolytic capacitors at a minimum.
You may have forward biased the bulk diode of a mosfet.
7. The power rating on the pump Is 15 amps, since it is am inductive load, the turn on current is likely to be much higher.
I agree the converter is not suitable for your intended use. There is a number of possible failure points to consider here.
Nice test gear, your testing of the device was well thoughtout and executed up to the point of hooking it up in for the unintended smoke test.
Always put a fuse between batteries and electronics.
I might have made the same mistake, but since your smoke test, I learned not to do that.
Good luck.
I'll agree with all your statements except 5. The reverse current is so small it has minimal effects, at least it should.
The fet is outside of its operating range so it's blocking the current. I'm guessing this is in the miroamp to nano amp range. If the converter can't handle that, then it's got larger problems and yes I could have installed a fuse, but being the pump didn't draw over 15a, the DC to DC was safe to use. But good practice though.
@@stem_saving1644 power diodes have a higher leakage current than signal diodes.
It is impossible to do a sneak circuit analysis without a complete circuit and parts list and spice simulation. Which is not going to happen.
After thinking more on the issue and given the caps was the first failure point. I really suspect the failure point is the reverse bias of the electrolytic capacitors. It does not take much current to grow a tendril between the capacitors plates. And it took 4(?) days for the failure to occur.
I get frustrated by the black box approach by suppliers. Derating parts and quality in the commerical applications does not seem to have been standardized.
A linear regulator may be a better solution, except for the loss of input range and efficiency loss. I consider a buck converter to be a switching power supply. I have not found a off the shelf linear regulator in black box form yet.
Thank you for your efforts, I have learned from it.
I had similar comments as you Peter and would note that the sticker on the device says 24V input and it was being run up 37V. I would say that they likely sent him an incorrect model as the one he is testing is for 24V power and he tested up to 27V on the bench. Appreciate testing that was done :)
@@patrickcallahan2210 I had to rewatch this video, the label does indeed say 24 volts input. There are many models of this device with different specifications that all look the same. The models that have a range usually have the range on the label. You have a good point.
My experience is that capacitors fail due to having an over or reverse voltage or over temperature.
The heat sink in the sun and cooling fins facing down might fry the caps.
If those are output filter caps, the motor, an inductive load, might have over voltage or reverse biased the caps. Which a suber circuit on the dc to dc converter would have prevented. I would guess that there is a suber circuit built in.
I vote -over heated (sun)because it worked for a couple days baking the caps over time.
This was tested on a day that made it to 85. Could it be the heat? Possible but not probable. Being that it only tops the battery off, it's not in full power output. So, the delta above ambient shouldn't be that high.
The voltage range and output current were within range as well. Since its tied to a battery, most of the current will be sourced from the battery during the 1 second the load is on.
The over volt, current, heat protection should have triggered to shut it down, if that were the issue.
Per the manf. "Converter provides over/under voltage input, overload, overhead, and short circuit full protection"
Thanks for the vid. These take work. I appreciate it.
Your welcome, please consider subscribing.
@@stem_saving1644 Cool, done!
I use these on solar panels to run car amplifiers in my home, and one outside to run a different amplifire.
Dose it get hot enough to melt plastic?
Exelent review, that output drop on the short circuit test reminds me of a crowbar circuit.
Thanks!
It would have been nice to know what the caps in the converter were rated at. If they were less than 40v, then the 24v on the back should have been adhered to, irrespective of what the advertised claim was.
Unless you dig out the potting, you'll never see the ratings. If the specs say upto 40v, then it should operate to those requirements. Users shouldn't have to second guess capabilities listed on the datasheet. If that's the case why buy it? That's my opinion.
What happens if you add a 12 volt battery to the 12v output of the converter? Could a 12v battery be used as a capacitor of sorts or the 12v output?
That's exactly what's in the video.
Question, can i put multiple devices behind a converter/stabilizer aslong as the amps are enough combined all powerdraw?
Yes, in theory. This inverter has caps that are cheap. You might experience same thing I did.
Do you think this product would work on a 12 V system to get my iceco fridge to work it’s showing an error of low-voltage and not running, wouldn’t this regulate the voltage to keep it at 12 V? Thanks
Depends on the input voltage and output current. In my case I think the caps are cheap and can't withstand the 30v+. Might work for lower voltages.
I recently purchased this rugged Boost unit as 12 to 48v DC at 6 amp output max . I intend on using only 34% duty cycle on same max 6 amp, that reduces the use wattage less than 1/2. Should I assume it will stay working? Should I use a higher rating such as 8 or 10 amp which is more costly?
The unit I reviewed is a buck not a boost. You should be fine so long as the instantaneous isn't higher than the max output. I would also add filtering to reduce transients.
I had one almost identical fail and smoke on me recently. The cause wasn't clear, but the output caps were bulging... it's hard to say if this was cause or effect though - the whole thing got hot enough to burn a large hole in the PCB just above the output wire.
On mine the input caps were rated at 50v and the output caps at 35v.
Thanks for the input. Another good data point.
thanks dude
but i wanna ask about something
can i control with output amper or not
if my motore worked with max amper 7A so how can i use it
There is no feedback control if that's what your asking. The motor determines the current the converter will output so long as it's with its rated spec.
Thanks so much for this. Super helpful. My issue is my 12v LEDs flicker when my water pump in my van conversion pumps - same for diesel heater pump. I think I need a regulator for the LEDs because the pumps draw a sharp quick recurring load... Will this product fix the issue? Thinking no as it's limit is 12v? Thanks 😅
There is an off Chance it could work, but what you're describing sounds like an instantaneous power problem.
A capacitor or lager alternator is probably a better solution... but can't say for sure since I don't know all the details.
Measure the relevant voltages. You will probably need an oscilloscope. OR just bypass the wiring with some thick wires and see if it improves.
thank you sir
Hi can I ask you a question? If I connect thise amazon dc to dc step down to my high voltage solar panel to go from 36v to 12v. Will the dc to dc converter only work once my panels reach the max 36v or does the converter start operating as soon as the panel feeds it any power? I hope my question was not confusing.
I wouldn't.... you can expect similar results I had.
@@stem_saving1644 :
He needs a charge controller between the solar panels and DC-DC converter. In this case the DC-DC converter will be the load.
A 36 volts battery is requiered to stabilize the output voltage of the solar to 36 volts, using the36 volts solar controller.
Clearly not. Because he tested it with 12 volts
i got 2 of theses im trying to run a 12v inverter off a 24v bat bank i need more than 20a so i had the idea of paralleling them but ive seen some info that says the load will not be = on each branch unless u use a resistor in each?
now that i seen the end im not soo happy i bought 2 lol
That's correct, the load won't be equal. A resistor will probably get pretty hot, so it's not an ideal solution. I think the cheap caps couldn't handle the current transients, so they vented.
I have two 40 amps wired together giving me 80 amps on solar panels, yes it will work as long as they are the same units. They run a car amp well and keep several batteries charged and my walkies on standby.
Hi. Can you recomend the best 12 volt stabiliser kit or module. With fluctuatif load?
Can't really say. I haven't tested them all to make a good analysis. Much of it is based on the design and if they use inferior components. Always look at the specs first.
@@stem_saving1644 ok. Many thanks for the reply. If you found a great stabiliser would you mind reply to this comment. I have an offgrid solar system and chose dc to be my appliance like TV. Since inverter have a bad efficiency and could shorten the life time of my deep cycle battery.
What do mount his on my bike. I need 12 volts and 5 bolts DC. Can I first run a 48 to 12 volt DC-DC and then into a 12 to 5 volt DC DC converter?
Or get a dc converter that has multiple outputs.
When you were ramping up input voltage, why did you only test it up to about 30 when it is supposed to be rated to 40v. I would have wanted to see if you could go 5% or 10% above that, since if you get a 40v nominal battery it can be pushing 45v or so when fully charged.
Only have 33v supply.
@@stem_saving1644 LOL that makes science.
can you use the same ground wire for input and output ? if i am trying to use this in my car ?
If it's non isolated you should be able to.
@@stem_saving1644 i used 2 of this modules and used same ground no problem in my car
Can you please add a small component fan and see if it will last without overheating?
You didn't watch the end? Nothing left to work with.
Hi, can you tell me what's the standby consumption please thx
That's one thing I didn't do but should have.
Hello, if you apply 44 volts to the input, will it ruin it?
If you watch the end of the video you'll see.
I saw a lot of really expensive options out there and then these cheap ones caught my eye. What I want to ask is how do you judge if the converter is good or not before buying it?.... because from all your tests this cheap one sort of performed okay ...but later screwed up.
Good question. I personally look for line and load regulation, over/under volage, over current protection, over temp proection and efficiency. This converter seemed to fit the bill.
But most of my testing was steady state. I'm guessing they used cheap caps that had high series resistance and weren't derated properly. So, long story short, the ambient temps combined with high current pulses caused the caps to over heat and vent and the converter self destructed.
Unfortunately, this has to be tested under real world conditions to see that.
@@stem_saving1644 I have an 8 amp requirement ...Would getting a convertor having a current rating ....let's say 20 amps help run the device cooler since I'm barely reaching the max current ?
It might help with self heating. If your load is steady state, 8A, it might work for your application. Worst case you can return it.
@@stem_saving1644 yea I'll give it a shot it's steady state 8amps
@@stem_saving1644 I noticed that the converter was in the sun also but maybe im wrong.
I bought one that was 480 watt 12volt to 24 volt and have had great results. I ran a zerobreeze mk2 "240 watt" off it many times for extended periods. Maybe the boost converters are better built.
@wingman0114 thanks for the post. Interesting results, which brand.
@@stem_saving1644 MGGI
Let me get this straight, you were inputting 37-40v into a 24v input converter then it blew after 3 days?
No, you missed the technical points
Well I bought the same one which has the same voltage input and output as your one does and when I put 24 volts in i get the same 24 volts come back out of it, very disappointed in the product
Does it consume any current?
Yes all dc-dc's consume current in the conversion process.
@@stem_saving1644 Sorry, dumb question! Have you measured the consumption? Reason I ask is that I'm trying to figure out a means to adjust alternator output on my car without needing a switched source, just throw it in series with the alternator sense lead. Internally regulated alternator.
It depends on the load. No load, it draws 0.01a. With a 1ohm load at 12v its 12w on the output. It would draw about 12.63w on the input. It's really depends on what your powering. Resistance wise.
They have these in 40 amps. It is rated input 24v not higher than that. Mine are on solar panels rated 22v 24 hours a day and I have had no problems.
They must have derated them, mine were 30+ volts
On Amazon, within the various brands, there are different rated units to select to purchase
Not sure if they are the same design. Might have changed. With larger currents a larger transformer and filtering circuitry is required. They could also be using better caps. Lots to evaluate. Thanks for the note.
@@stem_saving1644 they shut down when overloaded and when the input voltage from the panels get too low they cut off until the next day.
@@stem_saving1644 they make them with different output voltages 6v 7v 9v 12v 13.5v.
👍
I want to get one of these, so I looked it up and the specs I found say input voltage is up to 35V. And given that it's a cheap Chinese product it's probably not a good idea to run it at it's max rating. So it might have burnt out simply because you over-volted it.
It wasn't ran at its max. So no reason for it to fail. My specs has 40v as a max, they might have lowered it now.
@@stem_saving1644 will this work with dc pulsed input? I want it to use it on my motorcycle but the dc voltage that comes from the regulator it jumps a lot from 8-38 volts.
My input jumped around as well on my panels (not below 12v) and I suspect it caused the caps to fail as I suspect they are the cheaper versions that either can't handle peak currents or voltages.
How long it stays below 12v is the key. Most regulators will brown out unless you have caps to hold up the voltage. Unless you get a buck/ boost converter.
@@chriscs9080 Look up the max input voltage then maybe subtract a few volts for the "made in China" factor. It would be good to know what the actual voltage rating of the input caps is but the device is sealed shut so you would have to break that seal.
Concur with that. Derate it by a factor of a lot. I see the input voltage spec changed since I bought it. Maybe they realized the issue.
It says very clearly when your purchasing the converter, do not connect directly to a solar panel. There's probably a reason for that.
Not on the one I purchased. Read the description closely before I purchased it.
@@stem_saving1644 It appears the solar panel produces voltage spikes that blew your caps.
The panels upper voltage max is below the converters threshold so that can't be it either. There are lots of applications where buck converters are used on panels.
@@stem_saving1644 Well, on the video I saw it was over 30v, which would mean you have 2 panels in series, since solar panels are typically 24vdc, which would be 48vdc, which is over the 40v limit.
@@stem_saving1644 The reason they say not to connect directly to panels is because Solar arrays, like all electronic devices, are prone to surges in voltage that can harm components and increase downtime. Surge protection devices can help keep systems running and profitable.
The wires look awfully thin
This is what happens when you use a buck for mppt WITHOUT A BLOCKING DIODE
How so? What evidence says it doesn't have one built in? Pwm or mppt can both keep a battery charged. Although mppt will do it more efficiently.
@@stem_saving1644 I use these on my 60v 300w panels to charge lithium @ 13.8V (100A battery) , when i burnt my first one, i put in a DIODE and never had a problem since
@@FellaMegaOld these are rated at 40v. Not sure how they worked at 60v for you.
But any good buck would have a good inline series schottky. I can't say what this does or doesn't have since it was potted.
@@stem_saving1644 There cheap, they where $20 in 2015
Uh uh uh.........um ....uh.....hmmm....um
you didn't show input and output current. this test make nonsense
That can all be calculated. If you have voltage and resistance, which I showed in the video. Also have efficiency calculated.