VESC Boost Charging guide

A-DamW

100 W
Joined
Dec 19, 2019
Messages
190
Location
Idaho county Idaho
Hello everyone,

I have been perusing ES since mid-2008 or so, and have almost always been able to find a supporting example of something I wanted to implement/do/replicate.

Recently I have come up short finding working examples(other than Benjamin Vedders Github, and PowerVelocity's NextGen(customized VESC code) controller) of VESC boost charging.

Some examples:
Boost charging through windings · Issue #141 · vedderb/vesc_tool
PV NextGen FOC 100-180v 36kw max - $699

Topic goals:
Demonstrate boost charging main traction battery pack via VESC controller, using PSU through connected motor winding's.
Using generic VESC software...
Using generic VESC controller hardware...

I will be experimenting with the various VESC's and battery's I have, and posting the results to this topic.

P.S. please chime in with any info to further the cause!
 
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Well oh my heck! It works!!

After messing around a couple hours on Fri-9th, no dice, I woke Sat-10th sick enough to spend all day sleeping in bed.

Feeling a bit better this morning, and having some time to think about it, I realized my thumb throttle and VESC were probably not configured correctly to command a braking current.

So I hooked up a PPM/PWM rc servo tester, configured the "Setup Input" wizard on the VESC for "PPM", with rc PPM knob calibrated in the center(So I could command a braking current), and control type "Current No Reverse With Brake"

Set "Motor Cfg" "Motor Type" to "DC"

Disconnected phase A from motor, inserted Milwaukee 18v battery, 5amp fuse, Powemeter, in series between phase A and motor lead.

Commanded a braking current, saw the powermeter jump to ~150W so I quickly dialed back to 30-40W.

Little tired now, probably all for today.

IMG_20221211_085837970.jpg

IMG_20221211_085826035.jpg
 
Great job on your results, A-DamW!

In the GitHub thread, Benjamin Vedder mentioned that "polarity does not matter" when connecting the power supply to the VESC and the motor.

Quick question about the wiring scheme you used:

Did you connect the positive or negative lead of the power supply to the VESC and the motor?

And congratulations on starting this thread!
Despite the (relatively) lower efficiency than DC charging, boost charging on VESCs could be useful quite broadly.
 
I tried both polarities, they both appear to work just fine.

The output from a bldc motor in regen is just 3 phase AC.

In theory(I am going to try this when I get a minute) you should be able to hook up virtually ANY AC/DC power source that is lower voltage than the main traction battery pack.

So, solar panels, AC wall wort, DC wall wort, 12v car, etc.

And yes, relatively lower charging efficiency vs. direct DC pack charging.

I don't think boost charging will replace my regular charging setup, more like, I am somewhere with no outlets around, so I hit someone up for a couple hundred watthr from their car battery, or my portable charger bites the dust on the road, so I borrow someones laptop charger.
 
A-DamW said:
I tried both polarities, they both appear to work just fine.

That is amazing. 👍

A-DamW said:
The output from a bldc motor in regen is just 3 phase AC.

In theory(I am going to try this when I get a minute) you should be able to hook up virtually ANY AC/DC power source that is lower voltage than the main traction battery pack.

So, solar panels, AC wall wort, DC wall wort, 12v car, etc.

There is something ingenious in using a car battery to top-up an e-bike in case of emergency.
(I'm aware that this may be considered heresy on a forum dedicated to electric vehicles.)
Car batteries can output pretty huge currents—and would probably not miss a couple Wh...

You mentionned solar panels and small (foldable or rollable) solar panels come to mind.
One use-case example: slowly charge the battery of a stationary EV, while using it as a power bank using DC-DC (or DC-AC) converters.
Another example could be on the move: for a quick/partial top-up, during a rest stop in an off-road setting, if quick-charging is not particularly necessary, and/or when finding a place with outlets is too far off track or simply not possible.

A-DamW said:
I don't think boost charging will replace my regular charging setup, more like, I am somewhere with no outlets around, so I hit someone up for a couple hundred watthr from their car battery, or my portable charger bites the dust on the road, so I borrow someones laptop charger.

Well put.
When travelling, for example, if a portable charger malfunctions, it can be difficult to find a replacement charger with the same output.
A 12V or even 48V charger may be available locally.
But other, less common voltage batteries may be a hassle to charge to get on the road again.
Boost charging can be a lifesaver in such situations.

Laptop chargers, that you mentionned, range in the 80-100W, if I'm not mistaken.
This sort of power is not too bad for an emergency charge, if/when needed.

(Some high-end model of USB-C power bricks can supply upwards of 200W, even 300W with latest generations.
Those could be a great backup option to carry around as a redundant/backup charging solution, naturally while also serving their main purpose of charging phones, tablets, GPS units etc. during "normal" use.)

Lastly:
Some telecom rectifiers can provide high power density and high reliability in dry environments.
I'm thinking Eltek and Huawei ones, for example.
2kW for <1kg makes for quite a lightweight, powerful charger to carry around. 😊
 
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So if I understand this right your basically tricking the vesc into doing a regen charge of the main battery using one phase of the motor windings? This could be extremely useful! Thanks for sharing this!


Was just looking for controllers for my surron and having on board charging would be a hoot
 
To follow your example, a sort of stationary regen using an external power supply.

What changes is the source of the energy:
• In regenerative braking, the motor acts a generator, to convert the electricity generated by the motor, from the kinetic energy of the vehicle;
• In boost charging, the electricity that powers the motor comes from an external (power) supply, the outputs of an AC-DC converter or any other DC source.

Basically:
1) The inverter converts the DC voltage from the power supply unit into a high-frequency AC voltage (using PWM);
2) The AC voltage is passed through an inductive coil, boosting its voltage (through electromagnetic induction);
3) The boosted AC voltage is rectified by the inverter into a higher DC voltage;
4) This higher DC voltage is used to charge the battery.

So we go from lower voltage DC to high-frequency AC, to higher voltage DC. ⚡
 
eee291 said:
I'm kinda confused, where is the dc source wired in exactly?


Disconnect VESC phase "A" OR "C" from motor,
(phase B has no way to measure current, at least on 4.xx HW)
connect(to the leads you just disconnnected) dc source, one lead to the motor, other lead to the VESC, polarity does not matter.

So, said another way, you are disconnecting one of the phase leads from the motor, and inserting(connecting) a dc supply between them.


Requisite ASCII schematic:

MOTOR|-------------------------------PhaseC-----------------------------|VESC
MOTOR|-------------------------------PhaseB-----------------------------|VESC
MOTOR|---------------------|--cut---PhaseA--cut---|-------------------|VESC
---------------------------------|!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!|
---------------------------------|-------DC Supply-------|
 
I was thinking that this ist how it connects but i wasn't sure, thanks for the clarification.

I'll have to try this on my 3shul controller.
 
Souvlucky said:
Lastly:
Some telecom rectifiers can provide high power density and high reliability in dry environments.
I'm thinking Eltek and Huawei ones, for example.
2kW for <1kg makes for quite a lightweight, powerful charger to carry around. 😊

I use Eltek Flatpack s to my backbag charger. It is 1.8kw and under 900g, so very small. I have Nucular 12F controller and that support charging through motor. Battery i have 20S

IMG_20210705_112139.jpg

Also i can use another 14S battery at my backbag so i can charge my bike 20S battery anywhere, even middle of forest. It is good if i want more range. I can change charge power through controller settings. So i can adjust it like anything between 100w - 2.5kw etc.

There is one picture when i charge using backbag battery

IMG_20220212_115853.jpg

I charge always through motor / controller. Even when i am home. Because i can change charge power easily and use different charge profiles etc. So it is more adjustable than normal charger.

There is couple picture in charge screen (charge start automatically when insert charge cable

FB_IMG_1626294940297.jpg


IMG_20220330_154946__01.jpg
 
Nixunen said:
I use Eltek Flatpack s to my backbag charger. It is 1.8kw and under 900g, so very small. I have Nucular 12F controller and (...)

It's nice to see you enjoying your hardware, Nixunen!

This thread is about VESC boost-charging, let's stay on-topic✌️
 
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