Owon electronic loads - OEL8511 200-500W, OEL1515 150-300W

[thm_w]

Was mentioned in another thread by rs38 that there is no topic for these.

https://www.owon.com.hk/list_dc_electronics_load

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Model Total Power Rang Current Slope Resolution
OEL8511    200W 0-150V/20A 0.01A/ms 1mV/1mA $270
OEL8511B   200W 0-300V/20A 0.01A/ms 1mV/1mA
OEL8511C   200W 0-600V/20A 0.01A/ms 1mV/1mA
OEL8512    400W 0-150V/40A 0.01A/ms 1mV/1mA $375
OEL8512B   400W 0-300V/40A 0.01A/ms 1mV/1mA
OEL8512C   400W 0-600V/40A 0.01A/ms 1mV/1mA $475
OEL8513    500W 0-150V/40A 0.01A/ms 1mV/1mA $550https://www.owon.com.hk/products_oel85_series_dc_electronics_load

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Model Total Power Rang Setting Resolution Readback Resolution
OEL1515 150W 150V / 15A 1mV / 1mA 1mV / 0.1mA $175
OEL1520 300W 150V / 20A 1mV / 1mA 1mV / 0.1mA
OEL1530 300W 150V / 30A 1mV / 1mA 1mV / 0.1mA $206
OEL3015 150W 300V / 15A 1mV / 1mA 1mV / 0.1mA
OEL3020 300W 300V / 20A 1mV / 1mA 1mV / 0.1mA
OEL3030 300W 300V / 30A 1mV / 1mA 1mV / 0.1mA $230https://www.owon.com.hk/products_oel15



+ Supports dynamic current testing up to 5kHz
+ USB, RS232, RS485. No ethernet..

[kite31]

I have one of these, just arrived from banggood. I have done no more than unpack it and read instructions, so no review to offer even if I were actually knowledgeable about anything. It is my first electronic load.

Mine is the 8512. I was attracted by having both connection types on the front panel, coverage of basic functions, high power capability even though that is likely needed only in the short term, compact form factor especially in height and depth, and what appears to be excellent cooling with twin fans pushing through the two heatsink tunnels to relatively open exit grilles. In other equipment I occasionally have to cut off the grilles for better and quieter flow.

I hope to check it out a little more this weekend.

[DaneLaw]

I hope to check it out a little more this weekend..

Look forward to hearing some feedback.
Seems they placed the remote sense on the back, would personally have preferred it on the front.
Great to see 40A/400W (4kV / 400A stacked x10) and 4mm front-banana sockets.

[kite31]

I was able to take a few photos but am having a problem displaying them. Is that owing to the fact this is only my second post or just that I do not normally encounter SMF? On posting, images are not present. Chasing SMF help was no help. Hints please? and after experiment, they are below.

The interior looks neat to my inexpert eye. There are two load transistors either side of each of the heat sink tunnels, and a rather stylish copper shunt. Fans are 60cm. You can see (if photos present) that there are ample air slots in the side of the top cover. That cover is held on by no fewer than 16 machine screws, 7 each side and two on top.

Control is straightfoward as should usually be the case for simple tasks. Values can be entered with the keypad or the control knob, and varied on the fly with the knob.

i loaded it up to 130W (13V x 10A) on a nominally 13.8V 40A supply. If the fans came on they were drowned out by the fan in the switching supply (MP3089), though I detected some air movement out the back. I will try running that up near 400W at some point, "just to see".

[kite31]

Scrolling sideways may be needed to see the above pics on smaller screens. I will reduce size next time.

I ran up 400W from the MP3089 which declined from 13.8V to 12.1V while pushing out 33A. At that point I am fresh out of W but I am not sure the PSU would make it to 40A without a steeper decline in voltage.

Fans came on and accelerated as the load rose over 100W. They seem pretty quiet most of the time.

Tomorrow I will check its voltage sensing on more normal loads, by comparison with a Brymen. So far the Owon seems likely to cover my needs.

[nctnico]

I must say that I find the number of transistors rather low. 8 transistors to dissipate 500W means 62.5W per transistor. That is way above what would count as a good, reliable design. If you do the math on thermal resistance and add in some margins (like elevated ambient temperature and built up of dust), you get to around 35W per transistor max for a reliable DC load. For example, the 300W Korad DC load I have uses 8 transistors. The 500W version uses 14 transistors. These hit the mark at 35W per transistor.

[kite31]

400W not 500W, so 50W each vs 37.5W, while a quick glance at the KL103 suggests its cooling may not be up to that of the Owon which has more open ingress on both sides and those twin heatsink tunnels, so each serving only 4 transistors split 2 per side. We shall see.

Edit: Correction to W / transistor for Korad

[nctnico]

I have a Korad KEL2010 which is not a small unit. But even the Korad KEL103 units use more transistors to lower the thermal stress.

[DaneLaw]

Is it primarily the basic modes it has, not any of these combo/hybrid modes, where it simultaneously enforces two load parameters?  (xx+xx) which can be useful

[CV+CC] Load tries to maintain a voltage (CV) but will limit current if it exceeds a setpoint.
[CC+CV] → Load maintains a current (CC) but stops pulling more current if the voltage drops below a limit.
[CV+CR / CC+CR / etc]. Hybrid control loops that adapt dynamically between voltage, current, and resistance constraints.

Can be handy for..

* Power Supply Testing: Ensure power suplies operate within limits... You can stress them until a voltage sag limit or current ceiling.
* Simulating Real-World loads: Devices like motors or LEDs etc don’t behave like pure resistors; hybrid mode can, in certain scenarios, better mimic those behaviors.
* Battery Testing: Various discharge tests where you want to keep a fixed load but stop discharging when the voltage reaches a certain cutoff.
* Safety interlock, so you don’t accidentally overload DUT..fx pulling current while preventing over-voltage, mimicking protection limits.

Hybrid-combo modes are quite rare in budget electronic programmable loads (except East Tester) but are useful for applying two load parameters simultaneously, enabling more realistic and controlled testing.

The OEL8512 series highlights a minimum operating voltage of 1.1v/40A (0.8v/20A on 8511)... Is it a voltage system-limit, or solely with its full 40A.

[kite31]

@nctnico, are you able to give the heatsink dimensions for the KEL2010, length and cross section please? The KEL103 is also 300W but rated for lower amps and volts individually. A search told me the KEL103 uses a 40mm fan though that seemed improbably small to me.

[kite31]

@DaneLaw, I did not see those modes explicitly in the manual. It has constant resistance and constant power modes, with OCP, OVP, OPP settings available. Here is the manual:
https://files.owon.com.cn/probook/OEL85_Series_DC_Electronic_Load_User_Manual.pdf

[Songhua]

It looks like a very entry-level DC electronic load.

Do we have some public calibration documents for Owon OEL85 series?

Nowadays only user-calibratable instruments are my type.

[kite31]

After some testing in comparison with the Brymen's measurements, it appears to satisfy its claims of < 1 mA/mV error. I really like the fact that the fans are mostly very quiet, and progressive when needed. This is very useful in a home. It will pull the advertised levels of amps and watts (volts not fully tested*), and having banana jacks on the front as well as lug attachment is as useful a minor feature as I had hoped. OCP/OVP/OPP levels are set to 10% above its nominal ratings though I did not test that feature.  Using it is easy.

It is also far more compact than something like the Rigol D3021 which I also considered albeit a bit above what I preferred to pay. Compactness is a big advantage for a home. Owon does not claim to compete in that space or higher, their tag line being "Quality, Cheap, Durable" which pretty much sets out their stall. As is described here with Korad, you would need to write to them to find the calibration menu and procedure. It is not in the manual.

Regarding the discussion on power dissipation, the KEL102 also dissipates up to 50W/transistor but the real difference is in the cooling. The Owon has unobstructed, input slots with two heatsink tunnels slightly smaller in cross-section than the KEL103 but of similar length and each with its own 60 mm fan where the Korads make do with one 60 mm. With half the transistors per tunnel the Owon is better cooled. I do not suggest the Korads are over-loaded. A look at the specs of the IRFP260NPbF shows up to 300W dissipation (each) with junction-to-case and case-to-heatsink thermal flows which should easily allow all of these units to function at their ratings given the active cooling.

The new Owon 85xx series looks a suitable option in its place in the existing market. There is no Australian seller as yet. Mine arrived with a Euro plug I had to replace, that and US (more expensive for some reason) being the only options.

* Corrected a casual error. 150V not tested.

[Hydron]

The issue is not the rated dissipation of the transistor, it is the fact that linear operation requires very aggressive derating - you'll never get anywhere near the max even with a perfect constant 25C heatsink in linear operation.

I'd also be interested in any calibration info, as well as checking for ripple etc (fans and transformers can cause havoc at low currents due to induced current in the shunt circuitry). Finally the dynamic current specs (e.g. rise/fall slope) are worth checking - many of the cheaper options just lie like crazy about these in datasheets.

[kite31]

@Hydron, I understand about derating, I checked the charts on the spec sheet. I was trying to say that it starts from a decent ceiling, those transistors being in the Korads. It is the heatsinking and cooling I emphasised in the OEL8512.

You could write to Owon for the calibration procedure, as was done with Korad. I do not need it today given the apparent conformance sufficient for my needs. The other factors, slope, overshoot, ripple are on my list to check at some stage. I have a scope (Rigol), and am waiting for a Siglent 3303X-E PS. I am not into reviewing as such but will get around to those elements of the Owon from curiosity and describe them here if some more comprehensive review has not turned up on the web in the meantime.

[nctnico]

A look at the specs of the IRFP260NPbF shows up to 300W dissipation (each) with junction-to-case and case-to-heatsink thermal flows which should easily allow all of these units to function at their ratings given the active cooling.

No. The 300W is a purely theoretical limit if the case is kept at 25 degrees celsius. This can never happen in the real world. When a transistor is mounted onto a heatsink, count on having 1.1deg/C of thermal resistance between the transistor and heatsink for real world production results. The cooling aggregate solution is around 0.3 deg/C. With junction to case at 0.5 deg/W, you are at 1.9 deg/C in total. At 40 degrees ambient and 60W of dissipation, the junction will be at 154 degrees C already. At 35W it still is at a toasty 106 degrees. Ideally you want semiconductors to operate below 90 degrees C.

[kite31]

No. The 300W is a purely theoretical limit if the case is kept at 25 degrees celsius. ...

I know. I just said so 

[thm_w]

For hobby use I don't care if the thing runs at Tj ~130C if its cheap, and I'd rarely if ever use it there. Modern CPU's will run at ~95-100C, and this FET is rated to 175C.

For professional use its a concern for sure, but I don't think this is in that class. The Rigol DL3000 series was 20-30W per FET, but they never officially released a 500W variant.

[DaneLaw]

@DaneLaw, I did not see those modes explicitly in the manual. It has constant resistance and constant power modes, with OCP, OVP, OPP settings available. Here is the manual:
https://files.owon.com.cn/probook/OEL85_Series_DC_Electronic_Load_User_Manual.pdf

It doesn't look like it has any hybrid modes, most of the entry models dont... You often need to look at the more expensive models from Keysight, Chroma, Kikusui, ITECH  to find these hybrid/combo modes where it simultaneously enforces two load parameters.
I think the only programmable budget load that got hybrid mode support (xx+xx) is East Tester models, like ET54xx and the rebrands of it.

Have you checked your OEL8512 dynamic mode?.. its rated at 5Khz (0.1ms & 20us risetime)  does it perform that in practise?

[kite31]

No, I have not done some other more basic tests yet. Working on it ... slowly

[KedasProbe]

Anyone know where the T versions are since I don't see any other models on their website?
They mention "T" as suffix in the manual but there doesn't exist any model with T at the end 

from the manual: (present in both series)

Test Function
Battery test,OCP: Optional, only for “T” version

4.13.1 Battery discharge test function (Only available for
T suffix version)

Thanks

[DaneLaw]

Anyone know where the T versions are since I don't see any other models on their website?
They mention "T" as suffix in the manual but there doesn't exist any model with T at the end 

I doubt that there is a T-model.. The OEL85xx-x lineup is listed above.
If it ain't incl. from scratch, it's likely an unlockable feature that you can add for a given amount, that seems to go under the label "OEL-T1"

[KedasProbe]

I asked owon hongkong about the extra functions order number OEL-T1

first they said, what do mean? what is OEL-T1?
I gave them a link to their own website.....

They said ah you need to ask your seller, it cannot be updated after you bought.

I asked eleshop and they answered (after contacting owon) that the OEL3000 series has the OEL-T1 option build in.
So I assume the original name of the OEL3015, OEL3020 and OEL3030 are OEL3015T, OEL3020T and OEL3030T.
Although strange that they called it an option since you can't add it later.

I'm going to wait for more reviews since what else is wrong in the manual/specsheet?  ...

[KedasProbe]

Is there a way to get the (fast sampled) current curve, like when you do a short test?

[Kean]

I recently got an OEL1515 and have another on the way.  I bought it from the AliExpress OWON Instrumentation Store and it came double boxed.  https://www.aliexpress.com/store/1102839982

This one is labelled OEL1515_T on the serial label, and has the battery testing mode which is accessed under MENU->PROGRAM->Battery MODE.
Firmware is V1.1.0 (2025-06-26).

It seems you can only run battery tests in CC mode, which is a pretty common limitation and fine for my needs.
You can enable Voltage, Capacity, and Time stops - up to 150V (on this model), 999.999Ah, and 99999s.  You must enable at least one of these.
Current measurement accuracy seems OK vs a quick current clamp comparison, and is certainly better than the current readout on the SPM6053 PSU.

The fan speed is variable, but it can get pretty loud once you are sinking more than about 10W watts.  It does not run at full speed immediately, so I suspect it is temperature based as there is a lag in speed change vs settings.  It stops the fan immediately when you disable the load, and is slow to ramp up again when re-enabled... so I'm not 100% sure.

I have not yet tried PC control/data logging.  That isn't a priority for me as I'd normally do that on my IT8511+.