Votol controllers for hot rod builds | Ebikez.co

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I must admit that I’m no expert when it comes to controllers, and when I find someone who has a ton of experience and an honest understanding of the pros and cons of any given controller model, I want to hear what the tech has to say.

There are some really good products, but if every manufacturer says their controller is the best and never tells you why (or they don’t mention any specific weaknesses it might have) then we can’t make a Wise choice.

These technical details are important because some issues are something we can solve ourselves, while others are fully integrated into the design. Plus, most builders don’t have unlimited budgets, so “repairable” affordable components can sometimes be the best option.

I recently stumbled upon a YouTube channel where they take apart popular electric car components and detail the raw numbers inside, both the good and the bad. Here’s Richard’s work, titled “Electric Vehicle Parts Review (De-bodgery)“

I found his channel looking for information on controllers and he has a lot of them. What particularly caught my attention was the good reviews of the Votol EM-150. I don’t pay attention to people who say “it’s good” unless they can show me how it’s different from what they say is bad…or…I’m pissed They only tell us the good parts and ignore the glaring weaknesses.

His teardown video is a 20 minute video showing the Votol EM-150 being disassembled and described. I’ll put a concise index at the end of the article, with pros and cons, and a video link at the bottom.

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1. Cover

This might be boring and unimportant, but the cover is not made from the usual ABS plastic, but from 30% glass (fiber) filled polyester. This is the same type of material used in the bodies of high-end cordless tools.

The colored silicone rubber insulating grommets are only held in place by friction and do provide some water resistance from splashes or light rain but this tech removes it puts some clear silicone on it and puts it back in For better sealing effect. water.

The screws that hold the cover to the controller frame are vetoed for going through the aluminum heatsink and screwing into the plastic. It works and holds up nicely, but if you remove the cover and reinstall it a few times, I don’t think the self-tapping screws will hold up well over time. Other controllers in this price range have brass inserts and machine screws with lockwashers, so they will cycle dozens of times without issue.I’ve never held one of these, so maybe just drill a hair out of the post and epoxy some Brass threaded insert.

Richard also pointed out that the edge banding on the cover is quite good.

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Electronic component

The brain of this controller is the “central processing unit”, which uses STMicroelectronics’ STM32F103, which is a famous brand CPU. The CPU is powerful enough to handle Field Oriented Control/FOC, but…the controller does not use FOC, apparently because that would require a hardware upgrade, including separate shunts on each of the three phase lines.

One thing that caught my eye was that Richard mentioned that the FETs are high-side FETs, not general purpose units that run hot. They are MDP10N027 from Magna Chip. He even mentions these as his favorites and uses them many times in his personal projects.

In the picture above, notice that the legs are thin at the tips and thicker near the body of the MOSFET, as we’ll get to that again shortly.

The MOSFETs are the “on/off” switches that sequentially supply power to each of the three phases of the motor at the appropriate moment. The name stands for “Metal Oxide Semiconductor, Field Effect Transistor”. The amount of current that the controller can flow is largely dependent on the size of the MOSFETs and the number of MOSFETs. The controller is in TO-220 format and has 24 FETs, so 8 FETs are used per phase.

Votol rates the controller for 150A battery current and 470A phase current, or 58A per FET. This is a reasonable rating and meets the factory specifications for this FET.

(Apologies in advance if I am wrong)

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circuit board

Often the board is another boring component that gets overlooked because… what could be different or better about this component? Richard pointed out that the board is a sandwich of insulating boards with an aluminum layer in the middle. One of the reasons this was invented was to provide some cooling cheaply, and in some designs it’s enough to eliminate the need for a separate heatsink. It is a “Metal Core Printed Circuit Board” / MC-PCB. This begs the question, do other controller models use MC-PCB?

Votol’s engineers chose this MC-PCB, great! Sure, the controller has a thick aluminum base plate as a heat sink, but this aluminum PCB core is a middleman that prevents localized hot spots from forming.

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Battery Positive and Negative Buses

These buses are another highlight of Votol.

According to Richard “…This one piece of copper has more material than all the reinforcements in the KO-Pro or (Sur-Ron) F-Spec power stages. Because it’s… two and a half millimeters thick, and it’s a big piece, it’s not like small parts, pieces, and stuff stuck together randomly.No, this is a custom part…”

In the picture above, in the foreground is the battery minus the bus, which is a thick piece of copper.

In the image above, Richard points out an easily avoidable gap that allows the long and short sections of the bus to be combined into one. It does work as-is, but it would be nicer if the two were in one piece, rather than connected by traces on the underside of the PCB.

One of the few areas that Richard felt was lacking was DC high frequency filtering. Ceramic capacitors are small and not in sufficient quantity. Obviously it’s good enough, but it doesn’t cost much to make a drastic improvement, which would eliminate the static “noise” produced by fast switching. Low DC bus currents are well smoothed and any ripple voltage is well suppressed.

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bottom layer

When the PCB is flipped over, you can see the large solder-covered copper pads with through holes that allow the heavy phase connector to be bolted to the controller. The pillars are made of thick blocks of copper and are shown here held between Richard’s fingertips. Each post is attached to the controller PCB with four bolts so it cannot rotate or loosen.

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MOSFET legs

In the image above, Richard uses the tip of a screwdriver to indicate how long the legs on the MOSFET are. The legs are tapered and they are rated for 50A if you use the tip as the connection, but if your design allows them to be mounted in a way that connects them to the thicker end of the leg then the legs are rated for 70A.

This won’t limit the amount of current you can flow through them, but will make them run a bit hotter than necessary. This isn’t something a builder can fix in a garage, since the back of the MOSFET has to be connected to a heatsink in order to connect to it. If the heatsink is designed slightly differently, the MOSFETs may be connected on the butt ends of the legs.

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in conclusion

Each controller design has its pros and cons, Richard mentions that this Votol design is overall better than the KO-Moto and Sur-Ron F-Spec controllers.

OK:

Fat Copper Bus

Aluminum sandwich PCB prevents hot spots near components

Famous brand CPU and FET

Thick copper posts for connecting motor phase cables, each held by four bolts

Heavy-duty cover that won’t crack or break

harm:

The phase wire’s silicone gasket is a friction fit, but it’s easy to add silicone sealant for moisture resistance.

The high frequency ripple filter capacitors are too small and not enough (maybe “can” swap in better ones), but…it works fine.

The MOSFETs are connected in the small parts of the legs.The current layout does not allow moving the FETs closer to use the fat parts of the legs

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Other equally good or better controllers he mentions are E-Moto, Trampa, ASI and E-BMX. However, he pointed out that the reason people are interested in Votol is its price range, which makes it more affordable than the four well-designed brands he mentioned.

I must add that this review doesn’t cover any programming interface, and I don’t know if programming the Votol is complex or easy…or…if the other controllers mentioned are relatively “user friendly”.

Also, Votol has a variety of controller models smaller than the EM-150, as well as some larger controller models, depending on what you need for your e-bike, e-scooter or e-motorcycle.

Richard makes a good argument that a controller as good as the Votol would cost more, while a controller in the same price range would not be as good. Thanks Richard for tearing it down and posting the video on YouTube!