I was under the impression that freerolling on an EUC was not in the realm of human capabilities 
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At first, I was also thinking of using a halogen light bulb to dissipate the heat more easily than resistors that need a lot of airflow. However, I was afraid that the bulb filament breaks because of the strong vibrations of the board, and I really don’t want this part to fail. I also considered embedding a hairdryer under the board, but the resistor is fragile again, and it is usually designed for higher voltages.
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With just a mosfet and a resistor, I would expect a very high battery voltage ripple, because a very large current rises and stops almost instantly. This can cause a lot of issues. This is why in my setup, I used a wound resistor to create enough inductance to prevent the current to rise too fast.
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I’ve got one of those rheo brakes too but I’ve never used it bc it’s 10s and I’ve never had issues with 10s voltage
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I think you’re on to something.
How about a DC motor + mechanical load that is controlled via PPM filtered for only negative values. That way, whenever you hit the brakes you’re also putting a load on the battery. A switch on the motor would be what enables and disables this “super braking mode”
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Thank you so much for joining this thread!
So you wanted a certain level of inductance because you were using PWM to control the average amount of current being shunted through the resistors (via the half-bridge)? If you didn’t have that inductance then all those pulses would create a lot of ripple and/or EMI?
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Yes that’s exactly that! It makes the current smoother.
The only annoying thing with the added inductance is that you need a freewheeling diode, but in this case it would be enormous to sustain so much current (~50 A max for my board). This is why I am using a half-bridge (two mosfets) and not just a single mosfet + diode.
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Ahhh…makes sense! I was wondering why the half-bridge instead of using a single switch. Thank you.
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This seems like the best option, overbuilding a pack so you have desired capacity + braking headroom.
One more cell per P group takes up more room but also serves as a great energy buffer.
IMO, this solution is nice but is not for everyone, because the battery cells are heavier than the dissipator. Also, if a typical 80 kg rider + 10kg board is descending a 15% slope at 30 km/h, and brake all the time to keep the same speed, he needs a braking power close around 1100 W (neglecting the friction). For a 12S 4P setup, this means already 5.5 A / cell, which is more than 1C, so it is not recommended for a long time.
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Lol
Yup, I had commented on it earlier. That doesn’t mean I remembered the regen dissipator being there or that the thread came up in my search…LOL
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Sounds off to me? Size of your pack doesn’t matter if we’re talking fully charged battery anyway? Unless you charge almost full at 4.15v instead of 4.2v/cell, then yes you’re right you have some room
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By overbuilding I meant having a whole p group of energy thats practically “empty”. ( i know all cells in a p group are at the same voltage)
If you are satisfied with the range of a 12s4p for instance, you can build a 12s5p and charge it to 4.xx volt and have the same range with braking headroom.
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Think you could maybe post a schematic of your version? 
Thank you for your feedback btw!
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Sure, here is the schematic of the brake dissipator circuit of my board:
dissipator_en is the control PWM from the microcontroller.
The actual dissipator (combined resistor + inductor) is plugged on the connector P20.
The top block is the dissipator current measurement probe, to check that the system works. The bottom block is where the switching takes place.
To decrease the load on the mosfets and improve the reliability, the switching is made with two parallel branches, each with its own fuse, to avoid short-circuiting the battery in case a mosfet fails. This way, the main battery fuse does not blow and regenerative braking remains possible, instead of shutting down the board and fully losing braking. The switching is not full redundant though, because the failure of a single low-side mosfet will take down both branches.
The pre-drivers and mosfets are the same as the ones of the H-bridges for the motors, to minimize the number of different parts.
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Impressive work, just came from your build topic too, I’m blown the @Mainflow way 
So you’re effectively managing overcurrent, is this voltage scalable too via the mcu? Means one circuit could fit different battery configurations right?
I heard my call?
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Yes, the dissipator voltage is continuously controlled by the microcontroller to avoid excessive battery regen current. You just have to set the parameter that defines the maximum acceptable current to the battery, and the extra current will go to the dissipator. The board should then be able to work with many battery configurations.
Some more info on how this voltage is computed: here.
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I just got an Aeboard with 58.8v
Battery on a 60v esc. As you can imagine braking over 70 percent charged is very sketchy.
I have an old inboard m1 that has a dump load bar set inside the bottom of the deck.
If an esc had a 12v brake output could you activate a 10-20a resistive load with a large solenoid? Then it would be more consistent as it works each time you brake.
They seem to have admitted it was a bad choice of parts but refuse to replace it. Instead renaming it “k2 upgraded” with 12s battery not 14s lol.
Id love to try one of these rheostat devices if theres any for 14s or make something up myself.
As per the original question/scenario maybe you could make a 400w dump load that you switch on at the top and switch off at the bottom. You can get 100w leds now for a few quid but they need cpu type heat sinks.
Could make a snap on snap off unit or just a 400w front light bar from hell lol.
I live on top of a three mile hill and just set off at around 90 percent on a meepo. This was fine till the esc components wore over 1500 miles and one day cut out down the steepest hill ive ever seen in my county. (I replaced the battery with a bms bypassed one and still cuts out so i dont think it was worn cells)
I have two of these 100w cob leds. At 56v in series they will draw almost nothing but 60v and over start pulling hard. Maybe i can set these up under my esc heatsink hmm
￡1.51 | High Power LED COB Chip 10W 20W 30W 50W 100W Light Warm Natural Pure White For DIY 10 20 30 50 100 W Watt Outdoor LED Foodlight
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