The ATORCH "Purple Fan" MOSFET Destroyer and "150W" Load Bank

At this point, having read the title, you can probably guess my overall opinion on this little work of art…

This is a companion discussion topic for the original entry at

(Comments from Blogger)

2018-07-02 by Unknown

The 24C32B is a 2-wire serial EEPROM, 32Kb. The data sheet should be readily available, and they’re quite easy to work with, even without an eeprom programmer.

2018-07-03 by Russell Graves

You’re right - I’ll update the post. Not sure how I missed that, but I was able to find a datasheet for that unit by searching "24C32B EEPROM datasheet."


2018-07-03 by Unknown

I’ll bet the control voltage for the thing is a DAC made from a PWM and crappy RC filter, amplified, then fed to the fairly capacitive FET gate, and for some frequencies the whole mess is not stable.

2020-02-07 by d_t_a

Thanks for the review.

I’m wondering if you happen to review this new model, how accurate (voltage/current) and if it’s “safe” (hopefully not a MOSFET destroyer)…

DL24/P load tester
DL24/P Color 2.4" APP DC USB tester electronic load 18650 battery capacity monitor discharge charge power meter supply checker|Voltage Meters| - AliExpress

2020-02-09 by Russell Graves

No idea. I haven’t really cared to get another iteration of this hardware.

2020-03-17 by Unknown

Really well made blog!
If I were to put some Zeners (15V) across the leads, where should they be? Gate-Source or Gate-Drain? Both directions or how?

I have the DS1054Z scope and have yet to do some tests with the load as well. My friend burned the mosfet in his slightly different version (heat piped sink) likely due to inconsiderate overcurrent.
Regards from Emil N

2020-12-03 by Unknown

Put the Zener across the Gate and Source

2020-12-22 by TechTronic9000

I have the DL24p,I’ve used it a lot of times. It’s the one with single wires that has a voltage drop and thus not very accurate measurement. I just managed to short the mosfet going 2 times over the rated power. It uses a IRFP260N.

2020-12-23 by Pukker

I have also blown my mosfet in the DL24. Replaced with an new ORIGINAL one and now it is working well. The mosfet on the unit has same markings but in a different way as the original and so I think it was an clone. Tested also copy’s which I ordered from Aliexpress (sold as original) and they have an RDSon ten times higher then the really orignal ones.

2020-12-28 by Chris

what would be a better Mosfet Model?

Noticed a question about DL24/P load above. I purchased DL24/P from AliExpress Hidance store two months ago. Needed cheap programmable load for my RC hobby LiPo battery pack discharging, had obsoleted CPU fan in shelf and also due to curiosity. Still didn’t assembled it due to lack of free time. I hope that it will not blow into my face on powering on. By the way thanks for a warning about possible load shorting. Will try to test the load before attaching real batteries to it. Have no wish to torch my house.

Funny that visual interface is very similar to one which various cheap Chinese USB testers have. Most likely they all share the same firmware with modifications for particular appliance. And very likely are made from refurbished electronic components. 200V support for load you described is clearly bogus. I wouldn’t risk even with voltages above 30V. The reason behind these loads IMHO is raised popularity of RC hobbies with a need for small battery pack discharging. And abundance of people who want to test their USB chargers and cables. Which both doesn’t involve voltages above 30V.

Looks like that boost converter ebay link is toast;

Not sure whether it’s worth it to keep them updated, but…

Yeah… ugh. I knew they were changing referrer formats. I’ll have to see if I can figure out how to bulk convert them.

I recently picked one of these up expecting the worst. The documentation on these units is bad and doesn’t even tell you how to auto-calibrate the device or turn on the auto off function. The auto-off/auto-standby feature isn’t on by default and is what seems to keep this device from blowing itself up regularly.

First, make sure no load is connected to the device and the coarse and fine nobs are turned down all the way. Then, you press the change display button quickly SEVEN times. The device will beep, and the voltage and amperages will be calibrated back to zero. I seem to only have had to do this once and it made my voltage results in testing some LifePro4 cells much more accurate (within 0.05 volts and amps accuracy against my bosh meter connected directly to the battery terminals).

Next, there is an option to setup auto-standby or timer functions by hitting the button quickly FIVE times on the first or second screen only(One in chinese, one in english). The auto-standby option seems to keep the unit from re-applying load once the voltage limit has dropped below the specified low voltage limit, which has been very nice in load testing some 5v, 12v, and 3.2v cells. The screen displays “OFF” in the lower right when this feature is turned off (which for some reason it is by default.) It will display “AO” when in automatic mode, or the set test time when doing a straight timed test when you are testing a direct power source that doesn’t need the low voltage shutoff. I would highly recommended having the auto-standby feature on when testing any batteries to prevent any excess damage/wear on them.

I also recommended upgrading the horrible cooler if you are gonna push this thing. The temp diode on the board is in the wrong place. At 47C on the temp display my MOSFET was hitting 105c as the tiny cooler was heat soaked with a heavy load. I upgraded the cooler to a tower type cooler master and it does a much better job handling those temps. I have no idea where it gets it loads temperature from, but it is far away from the MOSFET/heatsink.

Still, don’t buy if you don’t already own. I bought the device as a curiosity and expected the worst. The fact the device has no inline fuse protection is such a let down.

@khaosmaou - thanks for the extra information! Hopefully that proves useful.

I honestly haven’t used mine in years. I’ve got better options for whatever it is I want to do these days.