600W DC-DC boost converter. Youtube review: ★★★★★ - This one is a keeper!

Flashlight Modding and DIY Parts
21

Didn’t read the link yet but:
When charching my laptop I am in need of a constant voltage no? As the internals of my LT (laptop) will do the actual charging of the Lipo battery inside (yes my LT has lipo battery) , the PS is just there to supply the needed power it doesn’t do the actual charging. The internals of my LT will automaticly change the current drawn from PS to follow the right CCCV curve that is needed to charge the lipo. Or to be more precise they will adjust the current flowing into the Lipo. So at the start of the charging process the internals will put say 2A into the lipo thus it will ask 2A from the PS , towards the end of charching the current going into the lipo will go down thus asking less current from the PS.

Same thing as when I plug it into 220V. The PS will always give 19V out noway around it, the current flowing from PS changes depending in what stage of charging the lipo is in.

Now that module I have linked to will keep a constant current while changing the output voltage. So even if the internals of LT only ask 0.5A this module will keep pumping 2A into the LT:

Capisci?

22

You nearly self-answered yourself, dekozn. A couple of remarks, though:

  • Your laptop's innards feature a sophisticated power management circuitry, as you may have guessed. At any time it will pull out all the required power to make it run, including charging the battery if needed. There's not much else you can do besides making sure the power supply feeding it is powerful enough. Failure to do so and it will complain, sort of what happens when you attach one of those puny weak and dangerous chinese fake chargers to a modern phone/phablet: if using the device, it'll very probably make use of more power the supply can provide, draining thus from its internal battery to overcome such a “sparse diet”.
  • And there you went again with “… So even if the internals of LT only ask 0.5A this module will keep pumping 2A into the LT…”; how do you think that could happen? By allowing the PSU to raise the output voltage, something which can't happen because you have set the CV trimpot to that “19V” you speak of. As I said before, for powering up the laptop do not mess with the CC trimpot, set it pedal to the metal or at the very least to a safe value above the absolute maximum amount your computer could ever dream of. Failure to do so and it will complain, sooner or later.

By the way, is that “laptop” some sort of low-power netbook? I'm saying this because if it is a more regular 45+W device, that power module will have trouble feeding such computer.

Cheers ^:)

23

Dear Dekozn ,

Our honorable member , Mr. Barkuti , had a hard time trying to explain some basics of boost converters.., he's done this right and well back up by the law of physics .

The only problem is that , in practice , the boost convertors has limitations that are not explained in the specifications data . So , let's take it easy and specific for your case :

You need 19V output from a 12V input , for a laptop. This is achievable and possible , no problem so far . For this you need a boost converter with only the CV adjustment , BUT , able to deliver the minimum current required by the laptop . For example , my laptop has a PS that delivers 20V at 3.25A ! So , because you "ask" the convertor to raise the voltage from 12 to 19 V at a current of minimum 3 A it means that the input current for converter should be over 6 A , due to the efficiency , that is not 100% ( at this current , around 75-80%) . For a car battery , 6Amps is not much , but the converter should be able to handle this , and the power of about 75 W. For a safe and reliable work , a 100W power will be the minimum requirement.

On the other hand , if the device you are using is a low-power one , the high-power converters are known that are NOT very good at low currents , and their behavior could be unexpected..., as Mr. Barkuti already highlighted ! A laptop is a highly variable load for a PS ,and the boost converters doesn't like it !...

As a experienced rule for the commercial converters , take the specification of Power , divide it by two and then again by 2 and THAT will be the practical power that can be used...safely... ( I didn't divided directly by 4 , on purpose , in order not to scare...)

As for the converters with CV/CC adjustment , just go with CC to the maximum limit , the CV will do the rest of the job.

24

I bought this 250w boost module for the OL scratch build competition but never finished my build :cry: so I’m not sure how reliable it is. I do have plans to use it for something different (when I get around to it).

I also stumbled on this but don’t know how applicable it is to you guys??? Ebay

25

Hi Pinkpanda ,

The 250 W module is a good one , the aluminum base is a great idea , mounted on a decent heat sink will be able to go over 200W BUT with some modifications !

I installed 12 pieces of these in outdoor fixtures ,for 100W leds and for about 1 year they work flawlessly . The PS is a 24V / 8A main , one for each fixture , or 2S 12V automotive batteries , just in case of outage.Everything is for an alarm system with IR sensors and back up , outside of a massive warehouse...

For 100 W are O.K , but if you want 200W ( 2 parallel 100W leds) ,some modifications has to be made .., don't worry , nothing fancy or expensive !

Just replace the inductor with a bigger core ,I used a "T184-52" type ( G613 Feryster ,RTP-33/19.8/11.1-52 ). The numbers after RTP means : exterior diameter / interior diameter / height , and the number 52 represent the material . Be careful , use the SAME " 52" material , otherwise you'll have problems with the heating of the core or even very low efficiency ...( pls, do not ask how I know that...!).

Keep the same number of turns (if I remember good, were 26-27 turns) or you can go up to 30 ,because the core will allow you to do that , and use a bigger diameter of the copper wire, ( I used a 1.4 mm , the original one was a 0.9 mm ) , or you can use 2 wires in parallel , of 0.9 mm .

To unsolder the original torroid and solder the new one , you will need a good iron , over 100W , and do it very fast with a lot of resin flux , in order not to destroy the copper traces . Also you can sustain the weight of the new core with some silicone , because this one is gone be much heavier.

Good thermal paste and strong torque on the screws will give you the perfect path for the heat.

With this modifications , one of the fixture had 2 x 100W LEDS in parallel , input 24 V/8A and output 36V/6A , the temperature of the inductor and the heat sink was around 47 degrees Celsius , after 2 hours ... So , this boost converter was the most simple , easy to modify and reliable one that I worked with .

Good luck !

26

This 600w boost converter says it specs @ 10a max “input”. Does that mean if you hook the input to a car battery it will fry? thx

27

No.

10 amps of input current is about the maximum the module should handle without starting to make creaking noises and smelling funny (LoL!).

Current flows if there's voltage to drop. If you hook up the module's input to a car battery, it'll just power up as it is unloaded (very little input current flow). Now, if you were to connect a 100W gaming laptop to the module output (tuning up the right output voltage, that is) and fire it up with some gaming, the module would have to work hard to keep the load running, as it needs to pull all of the output power plus its working quota (efficiency) from the input (P = V × I).

28

Thank you for the explanation… :+1: