New from RuiDeng: the adjustable RD6018 converter — announcement and discussion

So, the updated RD6018 adjustable converter has gone on sale in Chinese stores, as usual first of all on Taobao. It’s a more powerful version of the RD6012, which in turn followed the RD6006. I’ve already arranged to get a 6018 for review, but before that I’d like to take a look at what to expect from the new model, what has changed and what hasn’t, and discuss it with readers.

About a year ago, a model in the RD60xx series was announced. It was the lowest-power 6006 version, rated for 60 V and 6 A. It went on sale toward the end of the year, and there was also talk of more powerful models: the 6012, 6018 and 6024. The more powerful 6012 model appeared in late spring 2020, by which time people had already stopped expecting it. But the manufacturer didn’t stop there and came up with the 6018, rated at 60 V, 18 A and, accordingly, 1080 W.



Nothing has changed in terms of connecting to the outside world: the device can still be linked to a computer or a phone. There’s no information about whether local and remote control can be used simultaneously, but I think it’s still the same as before: the panel is locked during remote control. Some people think that’s a bad thing. I won’t argue; personally, I think it’s perfectly reasonable, though having the option to choose wouldn’t hurt.



The dimensions are almost unchanged; only the module is thicker, at 69 mm versus 65 mm for the RD6012.


The front panel has also been left as it was. Though I should probably mention that in practice I use the knob more often than direct value entry—probably just force of habit.


And if the dimensions haven’t changed, I think we can expect an updated model in the 100MHz case.


There’s an image of the front panel in operation, demonstrating its accuracy. But what it tells me is that the current meter’s resolution is still the same as on the 6012: 0.01 A. The same goes for the voltmeter, though that was obvious from the start, since the module’s output voltage hasn’t changed.


In my review of the 6012, I suggested that the 6018 would use the same board with different components. As it turns out, that’s not what happened at all. The components are indeed different, as expected, but the board has been substantially redesigned, while keeping the same dimensions as the 6012 (the 6006 had a smaller power board).
As far as I can tell, the following parts have been changed:
1. The input inductor is larger, with a thicker wire.
2. The capacitors have a higher capacitance and are correspondingly larger.
3. The converter’s power inductor has also been enlarged, although the ones in the 6006 and 6012 were almost identical.
4. The battery disconnect relay: the 6006 had a 10 A relay, the 6012 a 16 A one, and this model has a 30 A relay.
5. The fuses are now rated at 25 A on both the input and output. I should point out, though, that they’re low-voltage fuses again.
6. Current-sense shunts: the 6006 and 6012 had two, while the 6018 has three.

What hasn’t changed:
1. The heatsink and fan.
2. The secondary converters.
3. The same TL594 as the main PWM controller.


For comparison, here’s an advertising photo of the three models: the 6006, 6012 and 6018.


Unfortunately, the wire connections haven’t changed either. Yes, it’s now rated for up to 18 A, which is great, but how will the power terminals handle that? I don’t know Chinese, but judging by the photo, I’d guess the manufacturer is showing which plugs are best to use..
Also, at these currents, a four-wire connection is really called for, but it’s still missing. What a shame...


It also looks like the charging algorithm hasn’t changed. The GIF shows that, as with the 2012, charging stops when the current drops to 100 mA. I’ve suggested more than once that they make the cutoff threshold adjustable, because if you’re charging a battery with a passive balancer, charging may never stop.


There’s also the challenge of powering this module. In the pictures, the manufacturer suggests installing it in the same case as the 6012. Let’s set aside the fact that the case is rather deep—but how are you supposed to fit an 1100–1200 W power supply in there? In this case, they suggest powering the converter from an 800 W power supply, which gives you up to 720 W at the output...
As they said in a well-known cartoon, “That’s not nearly enough.”

Possible solutions:
1. Try squeezing in three LRS-350-24 units connected in series. But together they’re 90 mm thick, so it’ll be a very tight fit, and you’ll also have to figure out how to cool them.
2. Building your own powerful unregulated power supply is a pretty good option in principle, but it takes some hands-on work. I covered this approach in my review of the ZXY6005 board.
3. Use an 800 W power supply, but limit the converter's output power. That way, you can get either 60 V at 12 A or up to 40 V at 18 A. I did this when building a unit based on the ZXY6020.


Another option is to look for compact, high-power supplies. This is a very difficult route, if only because such power supplies are rare—and you need around 70–75 V. I’ve seen power supplies for power amplifiers on AliExpress. They’re rated for 1000–1500 W and have two 70 V rails (I think you can order them with other voltages too), but it’s unclear how they’ll handle a sustained load. These power supplies often aren’t designed for continuous operation under those conditions, and the price isn’t encouraging either.


Or you could build your own enclosure to fit any power supply. I even found examples of enclosures like this—maybe someone will recognize their own :)


It’s too early to draw any final conclusions, of course, but it’s already clear that some work has been done: the board has been redesigned and the power components replaced. Some problems remain, though—for example, they haven’t added four-wire connections or charge control. And the high power has brought new “complications”: how to power the whole thing, or rather, what to power it from and where to fit everything.
In any case, I hope I’ll get this model to test soon. Then it’ll be clearer what it’s really like, and I may also give some thought to the question of “proper power supply.”

I think we can discuss it now: what do you think of this model?