Review of the Korad KEL103 programmable load.

[electr_peter]

I want to add that the device can be used as current limiting device. In Constant Current Mode, the voltage drop across it without Current limiting acting is almost 0v.

DC loads can be used in more advanced situations, you described one of them. DC load in conjunction with PSU can test DC chargers (charger sees positive or negative current depending on voltage). Be mindful of allowable parameters in full setup.

[Kaziq]

Hi,
just a silly question - what is adjustment resolution in CR mode?  I can't find it reviewed in any video. It is very useful in testing limit of SMPS.

Hi. It's been some long time, but I saw your question only now.
I have KEL102, and the adjustment resolution in CR depends on the range:

• 0 - 9.9999 R the resolution is 0.0001 R
• 10 - 99.999R it is 0.001 R
• 1000 - 9999.9R it is 0.1 R

Maximum is 7500 R. Minimum is 0.05 R.

0.0001 R is crazy resolution. I tried to confirm it really works, using Keysight 34461A and Li-Ion battery (the most stable voltage supply I have right now), but the lowest I saw the difference was 0.01 R. Everything below 1 mA was noise. Perhaps with better setup it could be measured.

[killingtime]

Digging up and old thread here, but it's the correct place for this question.

Anybody know what the ripple / noise is on the KEL103 while under load?

An important parameter for testing PSU's. It's quite large on some of the cheaper loads like the KP184.

Thanks.

[Hydron]

This is with 100mA CC load (from a linear 5V supply). The ripple is from magnetic coupling from the (shielded) transformer to the shunt and/or the amplifier circuitry.
Ripple gets worse when either fan starts up (at 2A+, or when the temperature of the main heatsink rises too high).

Edit: has anyone else had issues with getting DHCP to stay on, or to connect with TestController? I think there might be a new revision and I'm not having any luck with those things, which ontop of the transformer/fan noise is a bit annoying.

[Gediminas]

I want to add that the device can be used as current limiting device. In Constant Current Mode, the voltage drop across it without Current limiting acting is almost 0v. I've had the need to test a device using it's Power supply and I've had the need to Current limit it. The response to sudden load changes is quite fast. Can do something that isn't designer for. Quite Happy with it. Excluding the user interface😅

That is good idea!
I have one more good use case, it can do short circuit (shift + short), in this mode load can be used as 30 Amp ammeter.

[AVGresponding]

Also here some clarification about the unit/manual:
The manual is garbage. For example...in battery test mode you have to specify (even if you dont need it) a max discharge time limit and consumed AH limit. The manual states that this is in seconds (discharge time) but this is wrong. You can set the max time to 9999, but this is minutes and not seconds.  The same with AH, its 9999 AH.
The manual is also wrong/confusing with different other things.

Yep, it quite confused me cause it counts somewhat like seconds right to the dot but these are actual hundredth of a minute.


I like the unit with the simple and very clear segment display.
A bit annoying is the fan on the heatsink at the front area that turns on 100% when going above 2 A load. Is that some kind of shunt / measuring construction?
Also sometimes the main fan is not switched off although load is turned off and the heatsink is cooled down. Don't understand the magic behind this yet. ^^

Thanks for the tip. Just got one of these in Tenma clothes, and though it's good value for what it is, the manuals, either Tenma or Korad are beyond obtuse, and no explanation is given as to what the different parts of the display refer to, leaving a great deal to pure guesswork.