Author Topic: Cheezeball DC Load: DL24P: Pump, or Dump ???  (Read 767 times)

0 Members and 1 Guest are viewing this topic.

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Cheezeball DC Load: DL24P: Pump, or Dump ???
« on: September 20, 2020, 01:59:08 pm »
Anyone have the DC Load shown in the pic?  If so, please post your thoughts.

$42USD delivered, 180W, 200V, 20A, full-disco LCD display, low-voltage cutoff,  bluetooth connection to bug-ridden app.  What else could one want?  Seems great to me.

https://bit.ly/2ZVbN8x

 

Offline No.15

  • Contributor
  • Posts: 32
  • Country: us
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #1 on: September 20, 2020, 02:02:25 pm »
I had a similar one and it let the magic smoke out on the third use
 

Offline Grandchuck

  • Regular Contributor
  • *
  • Posts: 215
  • Country: us
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #2 on: September 21, 2020, 09:20:41 pm »
I have one and can report mixed feelings about it.  The software is useless.  The current is noticeably jittery at low values in CC mode.  However, it is sometimes handy to have around.  The photo shows the external temperature sensor being used to monitor the heatsink of the switching FET of the power supply.
 
The following users thanked this post: frogblender

Offline interflexo

  • Contributor
  • Posts: 14
  • Country: pt
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #3 on: September 27, 2020, 06:12:02 pm »
I had plans to use it (proof of concept only) at half the max power in a computer USB controlled project.

The USB/Bluetooth reported voltage, capacity and temperatures lack the screen resolution.

The remote setup is achieved by emulating the user interface button clicks. You can't use the buttons long press modes to access or change some parameters. You can't inquire any of the programmed settings or where is the cursor blinking. It's like trying to configure the unit by hand but using a blindfold. Who in his right mind would release a product like this?

The unit has an internal and an external NTC.

There is a new unit available with added remote voltage sense.
https://de.aliexpress.com/item/1005001458325206.html?spm=a2g0o.productlist.0.0.3822ccf1zniWmj&algo_pvid=219f12ff-32b4-4855-bf41-41d5690f1ee2&algo_expid=219f12ff-32b4-4855-bf41-41d5690f1ee2-7&btsid=0bb0623116012052587916854ed059&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_
« Last Edit: September 27, 2020, 06:18:21 pm by interflexo »
 
The following users thanked this post: frogblender

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #4 on: October 08, 2020, 08:03:49 pm »

There is a new unit available with added remote voltage sense.
https://de.aliexpress.com/item/1005001458325206.html?spm=a2g0o.productlist.0.0.3822ccf1zniWmj&algo_pvid=219f12ff-32b4-4855-bf41-41d5690f1ee2&algo_expid=219f12ff-32b4-4855-bf41-41d5690f1ee2-7&btsid=0bb0623116012052587916854ed059&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

Do you have any experience with this newer revision?   The fact that these guys are coming out with newer revisions is a good sign.  Any idea about reflashing latest firmware?
 

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #5 on: October 08, 2020, 08:11:20 pm »
I had a similar one and it let the magic smoke out on the third use
Apparently there's a design flaw where voltage spikes above 20v get onto the fet's gate, blowing it up.   You can probably fix permanently with a new fet and a 15v zener.  https://syonyk.blogspot.com/2018/06/the-atorch-purple-fan-mosfet-destroyer.html
 

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #6 on: October 08, 2020, 08:21:06 pm »
I have one and can report mixed feelings about it.  The software is useless.  The current is noticeably jittery at low values in CC mode.  However, it is sometimes handy to have around.  The photo shows the external temperature sensor being used to monitor the heatsink of the switching FET of the power supply.

Couple of quick questions, if you could:
1) Once it hits the low-voltage-cutoff and turns off.... does it stay off (at least until user intervention)?   Earlier versions apparently hit the cutoff, turn off, but then turn back on as soon as the voltage drifts back up above the cutoff (which every battery known to mankind will do)

2)  Is there any output on this thing that can be used to switch a relay ?   I want a battery tester that'll discharge a battery down to my specified cutoff, then switch in a charger or my choosing.  I know this is alot to ask....


 

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #7 on: October 08, 2020, 08:23:24 pm »
I have one and can report mixed feelings about it.  The software is useless.  The current is noticeably jittery at low values in CC mode.  However, it is sometimes handy to have around.  The photo shows the external temperature sensor being used to monitor the heatsink of the switching FET of the power supply.
Hey, wait... were you making a wisecrack here?  "It is useless, unless you only need a cheap thermometer, in which case it's handy to have around!"
 

Offline Grandchuck

  • Regular Contributor
  • *
  • Posts: 215
  • Country: us
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #8 on: October 09, 2020, 12:40:17 pm »
I have one and can report mixed feelings about it.  The software is useless.  The current is noticeably jittery at low values in CC mode.  However, it is sometimes handy to have around.  The photo shows the external temperature sensor being used to monitor the heatsink of the switching FET of the power supply.

Couple of quick questions, if you could:
1) Once it hits the low-voltage-cutoff and turns off.... does it stay off (at least until user intervention)?   Earlier versions apparently hit the cutoff, turn off, but then turn back on as soon as the voltage drifts back up above the cutoff (which every battery known to mankind will do)

2)  Is there any output on this thing that can be used to switch a relay ?   I want a battery tester that'll discharge a battery down to my specified cutoff, then switch in a charger or my choosing.  I know this is alot to ask....

1)  It stays off.
2)  No output for that.
 
The following users thanked this post: frogblender

Offline duckduck

  • Regular Contributor
  • *
  • Posts: 109
  • Country: us
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #9 on: October 09, 2020, 06:30:17 pm »
Anyone have the DC Load shown in the pic?

I had the 150W version (ATORCH DL24). I did not test its accuracy, but it seemed to function OK. Build quality seemed decent enough. I didn't ever use the PC software or Bluetooth. It was very handy for seeing which USB chargers are decent and which are crap. I did some unnecessary surgery and destroyed it. You might consider making a case for it. It's pretty easy to damage the bare PCB if you are not careful. I paid US$26 plus a couple of bucks for shipping. I don't know that I'd pay US$42, but then I just bought it to play with.
 
The following users thanked this post: frogblender

Offline frogblender

  • Regular Contributor
  • *
  • Posts: 56
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #10 on: October 29, 2020, 08:11:32 pm »
SO I bought the version that doesn't come with a heatsink - you must add your own.   1000W, don't ya know.   https://www.aliexpress.com/item/1005001345772275.html

1)  The included 12v PSU is garbage.   It cuts out intermittently, and you will waste an hour or 4.  Roundbin it immediately.

2)  The FET will promptly explode.  The problem outlined by Syonyk (https://syonyk.blogspot.com/2018/06/the-atorch-purple-fan-mosfet-destroyer.html) still exists.  I think the problem is an opamp stage driving the fet:  it is bode unstable, and the oscillations exceed the ±20v Vgs spec.     My fet failed short circuit - which will cause big problems if connected straight to a Lipo battery (it's funny that the brand name is "ATORCH" - this should be taken literally).

Replaced FET with FDH44N50.   The specs to look for in this application:  1) lowest possible °C/Watt on Junction-to-case,  and, 2)  175°C max junction temp (most big fets are 150). 

I put a 16v Zener from gate to source to clamp the oscillations.  There's probably an easier/better fix by changing something in the opamps' (there are multiple) feedback loop to improve stability, but I was too lazy.

3)  Heatsink:  my heatsink box yielded a nice copper sink with blower (not fan), 12v @ .8A, harvested from some old compaq P4.   I drilled/tapped a 6-32 thread in the copper, and a screw holds it nice and hard against the fet.

4) Do not use the included white plastic standoffs - they interfere with your heatsink.  Use rubber feet.

5) One other problem:  there is a TO252 diode on the PCB, with a .7v forward drop.  At the ATORCH's rated 20A... that's 14watts into the PCB, which may already be stinking hot from the fet.  If you run high power at high amperage... I can foresee melted solder on the TO252.


Anyway, it works pretty good now.  Reasonable accuracy (at higher voltages/currents at least;  I didn't test a low current.   You might have problems if you want to characterize an LR44 or somesuch). 

I put 250W through it for a couple of hours, draining a 48V ebike battery, with no issues.

I put 500W through it for maybe 10 seconds, before dialing it back cuz I'm chicken.   I wouldn't trust it more than maybe 300W.

Overall, not bad.  For the money, it is alot of watts.

 

Offline ptluis

  • Contributor
  • Posts: 15
  • Country: pt
Re: Cheezeball DC Load: DL24P: Pump, or Dump ???
« Reply #11 on: November 18, 2020, 01:59:10 pm »
SO I bought the version that doesn't come with a heatsink - you must add your own.   1000W, don't ya know.   https://www.aliexpress.com/item/1005001345772275.html

1)  The included 12v PSU is garbage.   It cuts out intermittently, and you will waste an hour or 4.  Roundbin it immediately.

2)  The FET will promptly explode.  The problem outlined by Syonyk (https://syonyk.blogspot.com/2018/06/the-atorch-purple-fan-mosfet-destroyer.html) still exists.  I think the problem is an opamp stage driving the fet:  it is bode unstable, and the oscillations exceed the ±20v Vgs spec.     My fet failed short circuit - which will cause big problems if connected straight to a Lipo battery (it's funny that the brand name is "ATORCH" - this should be taken literally).

Replaced FET with FDH44N50.   The specs to look for in this application:  1) lowest possible °C/Watt on Junction-to-case,  and, 2)  175°C max junction temp (most big fets are 150). 

I put a 16v Zener from gate to source to clamp the oscillations.  There's probably an easier/better fix by changing something in the opamps' (there are multiple) feedback loop to improve stability, but I was too lazy.

3)  Heatsink:  my heatsink box yielded a nice copper sink with blower (not fan), 12v @ .8A, harvested from some old compaq P4.   I drilled/tapped a 6-32 thread in the copper, and a screw holds it nice and hard against the fet.

4) Do not use the included white plastic standoffs - they interfere with your heatsink.  Use rubber feet.

5) One other problem:  there is a TO252 diode on the PCB, with a .7v forward drop.  At the ATORCH's rated 20A... that's 14watts into the PCB, which may already be stinking hot from the fet.  If you run high power at high amperage... I can foresee melted solder on the TO252.


Anyway, it works pretty good now.  Reasonable accuracy (at higher voltages/currents at least;  I didn't test a low current.   You might have problems if you want to characterize an LR44 or somesuch). 

I put 250W through it for a couple of hours, draining a 48V ebike battery, with no issues.

I put 500W through it for maybe 10 seconds, before dialing it back cuz I'm chicken.   I wouldn't trust it more than maybe 300W.

Overall, not bad.  For the money, it is alot of watts.


I like it, it's cheap, works fair enough but definitely the diode mod is necessary.
I don't like the way they erase the main chips reference, but anyway I've found out what the microprocessor is, second chip from the left, it's an HC32F030E8PA  ARM Cortex-M0+, 48 MHz
 https://www.keil.com/dd2/hdsc/hc32f030e8pa/
The other chip on it's left I couldn't find out. if anybody knows tell us.

I bought the dl24p and the new version dl24p 4 wire. This 4 wire version doesn't have the dc-dc chip MC34063A.
Regarding the dl24p 2 wire version, this one (4 wire) starts faster, but both have the same firmware 5.1.
I only tested those units at low current máx 2 Amps or 30w max, because I didn't have proper heatsink available at the moment and my available time for electronics is short at the moment.


 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf