Travel By Spark

I have to confess that I am no expert when it comes to controllers, and when I find someone who has a lot of wits and is honest well-nigh the benefits and drawbacks of any given model of controller, I want to hear what that tech has to say.

There are some very good products out there, but if every manufacturer says that their controller is the best, and never tells you why (or they goof to mention any particular weaknesses that it may have) then we can’t make an educated choice.

The reason these tech details are important is considering some of the issues are something that we can fix ourselves, and other issues are completely integrated into the design. Plus, most builders don’t have an unlimited budget, so an affordable component that is “fixable” might sometimes be the weightier option.

I recently stumbled wideness a youtube waterworks where they do teardowns of popular EV components, and they spell out the raw data on the guts, both the good and the bad. It’s by Richard, and tabbed “EV Components review (De-bodgery)“

I found his waterworks looking for info on controllers, and he has quite a few of those. The one in particular that unprotected my eye is the good review on the Votol EM-150. I pay no sustentation to someone who says “this is good”, unless they can show me how its different, compared to the one they say is bad….or…I am unsated of they only tell us the good parts, and leave out glaring weaknesses.

His tear-down is a 20-minute video of the Votol EM-150 stuff pulled untied and described. I’ll place a transitory alphabetize at the end of the vendible of the pluses and minuses, with the video link at the bottom.

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First, the cover

This may be wearisome and unimportant, but the imbricate is not made from the worldwide ABS plastic, its made from 30% glass (fiber) filled polyester. This is the same type of stuff that’s used in the persons of high-end cordless tools.

The colored silicone-rubber insulating grommets are only held in by friction, and do provide some water resistance from splashing or a light rain, but this tech removed them, smeared some well-spoken silicone on them and re-inserted them for a much largest seal versus water.

The screws that hold the imbricate onto the frame of the controller get a down-vote for passing through the aluminum heat-sink plate and screwing into plastic. It works, and it holds OK, but if you remove the imbricate and re-attach it a few times, I don’t think these self-tapping screws would hold as well over time. Other controllers in this price range have contumely inserts and machine screws with lock-washers, so they could be cycled dozens of times with no problems. I’ve never had one of these in my hands, so it may be possible to drill out the posts a hair, and epoxy-in some brass threaded inserts.

Richard moreover pointed out that the edge-seal on the imbricate is quite good.

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The Electronic Components

This controllers smart-ass is the “Central Processing Unit”, and this one uses the STM32F103 from ST-Microelectronics, which is a name-brand CPU. This CPU is powerful unbearable to handle “Field Oriented Control” / FOC, but…this controller does not use FOC, theoretically considering that would require upgraded hardware, including an individual shunt on each of the three phase wires.

One of the things that unprotected my ear is when Richard mentioned that the FET’s are high-end FET’s rather than hot-running generic units. They are the MDP10N027’s from Magna Chip. He plane mentioned that these are his favorites, and he has used them many times on his personal projects.

In the pic above, notice the legs are skinny at the tips, and fatter near the soul of the MOSFET, considering this will be mentioned then soon.

The MOSFET’s are the “on/off” switches that send power to each of the three motor phases in turn, at just the right moment. The name stands for “Metal Oxide Semiconductor, Field Effect Transistor”. The value of amps a controller can spritz is largely dependent on the size of the MOSFET’s, and the quantity of the MOSFET’s. This controller uses the TO-220 format, and it has 24 FET’s, so it uses 8 FET’s per phase.

Votol rates this controller for 150A of shower current, and 470A of phase current, which is 58A per FET. This is a reasonable rating, and it is inline with the factory spec for this FET.

[If I’ve said any part of this wrong, I repent in advance]

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The Spin Board

Normally, a spin workbench is flipside wearisome component that is ignored, because…what could possibly be variegated or largest well-nigh this one? Richard pointed out that this workbench is a sandwich of insulating plates, with an aluminum layer in the center. One of the reasons this was invented was to inexpensively provide some heat-spreading, and in some designs its unbearable to eliminate needing a separate heat-sink. It’s a “Metal-Core Printed Spin Board” / MC-PCB. This begs the question, do any other controller models use a MC-PCB?

Votol’s engineers selected this type of MC-PCB, which is brilliant! Of undertow the controller has a fat aluminum baseplate as a heat sink, but this aluminum PCB-core is a middle-man that prevents localized hot-spots from forming.

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The Shower Plus and Minus Buses

These buses are flipside zone where the Votol shines.

According to Richard “…this one piece of copper has increasingly material than is in all the reinforcing in like a KO-Pro, or a [Sur-Ron] F-Spec power stage. Considering this is…two and a half millimeters thick, and it’s one big piece, and it’s not like little sections and pieces and stuff kind of stuck lanugo haphazardly. No, this is a custom-made part….”

In the pic above, in the foreground is the shower minus bus, a thick stipule of copper.

In the pic above, Richard points out a gap that could have hands been avoided and it would have made the long section of bus and that short piece into all one piece. It does work as is, but it would have been a little largest if those two were one piece, instead of them stuff unfluctuating by a trace on the underside of the PCB.

One of the few areas that Richard felt is lacking is the DC high-frequency filtering. The ceramic capacitors were small, and there were not unbearable of them. Theoretically it’s adequate, but it would have not forfeit much to dramatically improve, which would eliminate the static “noise” that rapid switching produces. The low DC bus current is smoothed-out quite well and any ripple voltage is very suppressed.

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The Underside

Once you flip the PCB over, you can see the large solder-covered copper pads with the through-holes that indulge the fat Phase-wire connectors to be bolted to the controller. These posts are made from fat chunks of copper as shown here stuff held between Richard’s fingertips. Each post is unfluctuating to the controller PCB by four bolts, so it will not rotate or come loose.

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The MOSFET Legs

In the pic above, Richard uses his screwdriver tip to point out how long the legs are on the MOSFET’s. The legs are tapered, and if you use the tips as a connection, they are rated for 50A, but if your diamond allows them to be mounted in a way that connects them at the fatter end of the leg, then the legs are rated for 70A.

This doesn’t limit how many amps you can spritz through them, but it will make them run a little hotter than necessary. It’s not really something a builder can fix in their garage, considering the backs of the MOSFET must nail to the heat-spreader, to connect to the heat-sink. If the heat sink was designed a little differently, the MOSFET’s could have unfluctuating at the fat end of the legs.

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The Conclusion

Every controller diamond has compromises with its pluses and minuses, and Richard has mentioned that this Votol diamond is overall largest than the KO-Moto and the Sur-Ron F-Spec controllers.

The Good:

Fat copper buses

Aluminum sandwich PCB to prevent hot-spots near the components

Name-brand CPU and FET’s

Fat copper posts to nail the motor-phase cables to, each held lanugo by four bolts

Heavy duty imbricate that is less likely to one-liner or break

The Bad:

Silicone gaskets for the phase wires are friction fit, but are easy to add silicone sealant to to modernize moisture resistance.

The High-frequency ripple filtering capacitors are too small and there’s not unbearable of them (It may be “possible” to swap-in largest capacitors), but…it works OK.

MOSFET’s are unfluctuating at the thin part of the leg. The current layout doesn’t indulge the FET’s to be moved closer to use the fat part of the legs

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Other controllers that he mentioned as stuff as good or largest were the E-Moto, Trampa, ASI, and E-BMX. However, he pointed out the reason for the interest in the Votol is it’s price range, which makes it increasingly affordable than the four brands he mentioned as stuff well-designed.

I must add that this review does not imbricate ANY of the programming interfaces, and I don’t know if the Votol is ramified to program or easy…or…if the other controllers mentioned are comparably “user friendly”.

Also, Votol has several models of controller that are smaller than the EM-150, and several that are larger, depending on your needs for an ebike, E-scooter, or E-motorcycle.

Richard makes a good treatise that the controllers that are as good as the Votol will forfeit more, and the ones at the same price range are not as good. Thank you Richard for doing this tear-down and posting the video on youtube!