Cheezeball DC Load: DL24P: Pump, or Dump ???

[fubgumfaw]

Has anyone used their DL24M yet?
Can you really get 600w from it?
Any issues?

I'm not overly fond of the hugeness of the thing. 3 mosfet modules attached on the 3 sides does make it LARGE. You can't attach the mosfet modules one to another. Those sets of shunts are for each mosfet module like I suspected. I'm thinking of using tall stand-offs to make it more vertical and then solder in 4mm bullet connectors and run wires to each module. Basically...anything to make it more compact and less kludgy! How do you put this thing in a case? Best plan I have is to mount it on a piece of plywood.

I took one out of the box, took pics and then got busy with EV stuff. I bought 2 full 600w setups and it's all sitting in the shipping box still. I want to use one to test battery capacity on my Zap scooter. It has 2 LION and 1 LIPO pack in it that I built that total about 120Ah at 82v. Maybe tonight I'll get one of the load testers put together to try out...

So yeah...in a box...LOL

[MaP0]

600 W depends on your voltage. At high voltage and low current may be but definitely not with low voltage and high current.

Limiting factors are mainly the diode at the input and the shunts. Their thermal load of those depends exclusively on the current (U=R*I and P=U*I). The shunts remain cold at 10 amps, become very warm at 15 amps and are extremely hot at 20 amps (you can no longer touch them). I don't know how the Chinese come up with the idea that the central board with 3 extensions can handle 40 amps. From my point of view, 20 amps should not be exceeded. The shunts are all on the main board, the extension bords bring no relief for the shunts. I replaced the diode at the input with a STPS8015CW with heat sink. I can post photos later. I installed additionally a better heat sink at the MOSFET. I just did a test with 30 volts and 4 amps (only the central unit without extension boards). the resulting 120 watts were no problem after my modifications. With 3 extension board you would have under these conditions 480 W.

[fubgumfaw]

I figured as much! Watts aint watts like it should be! As usual being current limited is a problem with all of these things.

[fubgumfaw]

I can't find it now...
Somewhere back in this thread someone mentioned a logging app that works with the DL series load testers. Anyone remember what that was and where to find it?

Just today I found this app, but it doesn't list the DL series devices. For all I know...it might be the same app!
http://www.nongnu.org/dataexplorer/

[HKJ]

I can't find it now...
Somewhere back in this thread someone mentioned a logging app that works with the DL series load testers. Anyone remember what that was and where to find it?

Maybe it is TestController you are thinking about, it supports the DL24 and a few hundred other devices.
EEVBlog thread: https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/
Program: https://lygte-info.dk/project/TestControllerIntro%20UK.html download link at the bottom of the page.

The program requires that Java is installed, this makes it possible for the same program file to work on Windows, Linux and Mac

[fubgumfaw]

That's it! Thanks for posting.

[abaumgaertner]

Just got 4pcs of latest revision: SKU DL24PNEW https://www.aliexpress.com/item/1005001458325206.html

1) Bluetooth Antenna directly on PCB (seperate board for BT on previous revisions)
2) no software volume control for the beeper yet
3) PSU is still not great: tested at 12V / 1A - Voltage rises from 11,68V to 11,85V with PSU temperature. PSU gets quite warm during test.
4) all boards are badly bent around the MOSFET due to excess height of heatsink (2-3mm) - nothing a mill couldn't solve

[MathWizard]

I have a large heatsink from a big old style stereo/amp. Some day I plan to make a load tester. I wanted to be-able to test computer PSU's, but I'd probably need 2x the heatsink for that.

[Bluegizmo83]

Has anyone every tested the USB-C port on these DC load testers to see if they will trigger PD (power delivery) modes? I'd like to be able to test USB-C PD chargers and battery banks that support outputting up to 20V, but they will only output voltages above 5V if the charger and load device negotiate with each other via the PD standard and choose a higher voltage...

[RCinFLA]

Believe you are correct on microprocessor.  Closest STM part is STM32F030R8 but not exact pin for pin compatible.  Only Chinese spec sheet seems to be available so will be a bit of pain to Google translate it.  Hopefully they are using similar I/O options so may use the STM part as a guide.  The 48 pin package is identical to STM part with same alternate pin assignments so I think they are similar uC. 

The 16 pin SOIC with the 3.759 MHz crystal at end is ADC chip but haven't figured out part number.  It has I2C data , crystal to end pins 1 & 16, and is 16 pin SOIC. Thinking maybe a pressure load cell chip simiar to HX711.  It has three inputs for voltage across load, shunt voltage for current, and external temp sensor.  Temp thermistor next to load MOSFET goes to 32F030 ADC PA00.


As to series pass load MOSFET.  Rds_ON is not so important since MOSFET not operating in saturated switch mode.  It is the gate total charge, Qg, that is the trouble maker.  Driving so much gate capacitance with a feeble LM321 with series resistor is slooooow response.  Receipe for instability with the three stages of gate rise/fall capacitance effect.  The feedback cap across LM321 MOSFET gate driver is 0.1 uF.  So response is very slow and if you disconnect a battery load and if op amp cap it fully charged to point of fully turning on power mosfet then reconnect battery it could cause some damaging high currents.

The included power supply has a problem with AC neutral and board grounding.  When I connected a charger on a LPF cell I was testing, the DL24P reading went crazy.  I checked the ground on DL24P and it seems to be about 1.4v above AC neutral-ground.

[ledtester]

Video review:



Some takeaways:

- boards were bowed due to the spring tension of heatsinks
- reviewer had a hard time fastening the modules together
- corner tabs around the board are prone to damage during shipping
- display is dim
- volts, amps agree with those shown by a RD6018 under test

[Dawe]

Guys,
I've got issue with DL24P, 4-wires voltage measurement is inacurate and the error seems to be linear function of load current. As per attached figure which shows several V/A point measured.
Once again, not talking about 2-wires voltage measurement, but real 4-wire (the Brymen on picts is hooked to the power supply terminals at the same point as the voltage measurement wires from DL24P.
Anyone experiencing the same? Any thoughts? Thanks

[RCinFLA]

FYI,  some resistor values, particularly for temp sensor may not be correct.  The temp sensor thermistors are 10k

You can use Adobe reader layer to turn on/off layout layers.

[Pukker]

Hello,
Who knows the coéfficent for the external NTC of 10k?
Is it 3950 or something else.

Thanks.

[razvanu]

Need a little help:
1. Fan stays allways on, dont't know why, after power adapter get fried maybe the two tranzistor from picture attached



2. Primary mosfeet is 0 ohm on all three pins, gues is shorted ? From where can I to buy only this IRF... ?

edit: solved both issues. 10x for schematic pdf

edit2: put a heatsink oh the reverse diode protection

[Creep]

Just got this thing and so far seems to be a decent piece of kit for the money.

However, I've ran into a bit of an issue, maybe someone here can shed some light:
The load seems to be doing some funky stuff when faced with an unstable input voltage (in this case, current limiting due to overload). Basically, I wanted to find out how a certain power supply behaves in an overload condition, and based on my observations with the DL24, it looked like the power supply has hiccup mode protection (i.e. output of the power supply being disabled in an overload condition and reenabled after a while to try again). However, when hooking up a purely resistive load to the supply, it becomes evident that it is actually using output current limiting.
The testing was done using the Constant Resistance mode and I can clearly see the voltage dropping down to nearly 0 as soon as I drop the resistance to exactly the point where the power supply would start dropping the output voltage so as to limit the output current.

Does the DL24 have a significant overshoot when changing the load applied or is there something more mysterious going on here? Some sort of a positive feedback loop forming between the DL24 control circuit and  the power supply control circuit maybe?

[HKJ]

Does the DL24 have a significant overshoot when changing the load applied or is there something more mysterious going on here? Some sort of a positive feedback loop forming between the DL24 control circuit and  the power supply control circuit maybe?

Most likely all modes except CC is done in software, this means they will have a slow reaction time and may easily overshot or undershot.

[razvanu]

Did some seriously DAMAGE today 20V @9Amp and made some fire

[fisafisa]

Hi
Any idea on the model of the lcd?
I have damaged mine and I was looking for a replacement.
I have tried with an ILI9341 SPI but with no success so far.
I have analysed the siagnals to the curent Lcd and I mostly agree with the schematic.
The only exception is last pin which in fact serves as control to the LCD back lighting not as a MISO.
It seems a PWm to control light intensity.

F

[Pukker]

Did some seriously DAMAGE today 20V @9Amp and made some fire

Serious damage indeed.
But always keep in mind:
Made in China? Yes, then always divide max. specifications by 2, or better, by 3.

[razvanu]

Did some resolder of the PCB after one picture on this thread, but I will never go over 5 Amps or 105W

[thm_w]

Received the DL24MP-H



Spec same as DL24: 200V, 20A, 150W. But, has four times the transistors.

Some reviewers received IRFP260N (blacktopped), I received 38N30 (300V, 38A, Vgs 30V) that appear to be recovered parts. Decent FETs if they are real.

Fan is loud, turns on when you turn on the output.
At 60W heatsink is ~42C
At 80W heatsink is ~60C

There are also some 0.25R 6W resistors on the side of the heatsink that get hot as well.
This is just using their included NTC probe, I'm sure the FETS are much hotter than the heatsink temp. So maybe 100W max that I'd want to run this at?


Notes:
- If you have the current resolution set to 1mA (actually shows as 100uA), the maximum  CC is 2A. If you go above that it will shut the output off. The other option is 10mA resolution which allows the full output current.
- Fan temp sensor appears to be the NTC beside the heatsink, add some thermal compound to couple this better to the heatsink. Its still a terrible representation of the temperature though, shows about 20C lower than actual.
- Press and hold + and - to clear reading

[Roelio]

Hello all after much reading I’m very careful with my DL24.
I saw a picture of a guy who put some power resistors between it. Can someone tell my why this would help? And won’t this mess up your readings?

[thm_w]

Hello all after much reading I’m very careful with my DL24.
I saw a picture of a guy who put some power resistors between it. Can someone tell my why this would help? And won’t this mess up your readings?

https://imgur.com/a/YRA0rrm

You can look at where the leads are going. I sense, the top lead, connects to the bottom of the resistor then to the real load. Since its a series circuit, current will be the same everywhere and the reading on DL24 will be accurate.
Vsense is the brown lead, bypassing the resistors and going to the input (battery connector). So voltage reading will ignore the drop across the resistors and be accurate.
It can help as it will distribute some of the power into those large metal resistors, so the DL24 does not have to dissipate as much.

Only thing I'm not sure of is if there is a limitation on DL24 inputs for voltage difference in sense and current input terminals.


There is also the cheaper ($20) relay controlled load if you only want to use fixed external resistors, with no adjustment:
https://www.aliexpress.com/item/4000938929839.html

[Anomalia]

I have used the device (dl24p) at low power and voltage without any problems. I then thought about measuring the battery capacity of an electric bike.
The battery was 36v (+ 40v full)

Quite a buzz and a bang. Even the cat ran so hard in place that it didn't get moving right away Discharge was less than 90w and contact for cooling good.

Would you help a little bit of what parts I would order here to make it work at even 2/3 of the promised power? The voltage range I need is wide.
Probably a zener, what about a mosfet? Would it be FDH44N50. I read somewhere that the standard IRFP260N (certainly original) has also been used and the device has worked well since then.