ASI BAC 800 72V (20S) FOC 50A 3250W Peak BBSHD Controller + Display + Cover


UK EU Orders: ASI BAC 800 36V – 90V FOC 50A 3250W Peak BBSHD Hot Rod Controller Full Kit

Out of stock



 ASI BAC 800 72v (20S)C 50A 3250W Peak BBSHD Hot Rod Controller Full Kit

Full kit including replacement controller cover, 750C display, Full PAS

“Plug N Play”

Outside of UK and problems ordering? Please email [email protected] or use the “contact us” page for a same day reply

Ultimately designed for high speed performance and throttle use.

Top speed  45 MPH !!!!

This is recommended as a throttle only and single speed (easy to adapt your free hub to single gears) application due to high RPM and low gearing. Your bike will accelerate like a rocket and still hit around 45 MPH, depending on how you gear your bike. You can accelerate faster or have a higher top speed. We find 45 MPH is enough. Bigger explanation further down.

Because of the weakness of the Nylon gear, the use of low gears is necessary and we recommend front 42T and rear no smaller that 28T on 29er or 27.5″ wheels and 26T on 26″ wheels.

We have tested this set up thoughoughly with a 250 lb rider without issues.

No need for gear changes as the massive increased RPM range and large rear gear allows blistering acceleration and high top speed. Because of high voltage, low amps are used to obtain more watts. For  example 72v x 50A = 3600 watts compared to 52v x 50A = 2600 watts. and we all know that high amps create motor killing heat.

A 72V  system uses less power and generates less heat but makes you go much faster.

The down side? = more money for the more advance controller (advanced field weakening) and the higher cell count battery. PAS is less suitable and  the motor spins much faster. Because of the higher RPM a really good chain line is really important: drastically reduces wear and stops chains from snapping.

You no longer need other gears! your weedy legs are obsolete!!

We ship the controller with three power levels.

level 1 is around 1000w and hits speeds of around 30 mph with modest acceleration (similar to a standard BBSHD) and a range of around 30 miles

level 2 is around 1900w and hits speeds of around 40 mph with good  acceleration and a range of around 20 miles 9 we tend use this setting all the time,as our main settings).

level 3 is full power  and hits speeds in excess of 40 mph with blistering acceleration  and a range of around 12-15 miles (we use this button like a Turbo, its too much for day in day out riding).

Order for USA (In stock no UK shipping) please go to:


Did you ever wish your BBSHD went substantially faster, pulled harder and you didn’t have to be told you can’t buy the controller you want – shush it’s a secret?

Well thanks to a very clever friend of ours, we are the UK and EU distributor for this exceptional device.

This controller has everything: field weakening (allowing higher rpm), set maximum amps, set maximum watts, maintain these figures while volts drop, Bluetooth, totally plug n play and potted to 100% waterproof.

Advanced processing and state of the art allows it to compute much faster and much more accurately than the standard Bafang unit (or any modded Bafang controller). Imagine your first media phone in comparison to the latest Iphone/Android device? – Things have moved on and these Canadian devices have not been designed with penny pinching mass market sales like the original.  All of this makes your 52 V motor pull much harder and release around 15% more speed than a 50A Bafang controller and whopping 100% more power than the standard, while still using your standard display! (NB, please see our note about displays). We might add the power is designed to come in without the mechanical snapping lurch of an inferior set up.


These controller have been set up so that it can handle anything from 50 A up to 3250 W (easily within their design).vThis might mean a little explaining:

We have tested the BBSHD to destruction and on more than one occasion right up to 4500 Watts and learned a few things, real facts and not the odd exception.

Amps create heat, heat weakens the nylon gear and too many watts snap the pinion. So how do we get around this? Simple, know the limits but don’t get too close. Sure these are now nearer the limit, but ridden correctly (let the motor spin and don’t labour in the wrong gear), a reliable ride can still be had. At the lower volts where big amps are needed, we have capped the limit to 50A but as you increase your volts, we capped the watts to 3250 W. A ludicrous controller at 50A has 2500Watts – so does ours, but now add 10 -15% improvement through field weakening!

But here it gets even better, Change your battery and go up to 20s 72 V (any voltage form 10S to 20S, 36V -90 V) and the controller takes it (not a Bafang originated 60 V cap). Your watts have now jumped to a dangerous 4200 watts on a “hot” (fully charged battery at 84 V), so we reduce this limit to a safer 3800 W, but still so much powwweeeeer!


When more funds for a bigger battery are available and you decide to go over 59 V with the same unit, just add our 750C display and suddenly 45- 50 MPH is on the horizon and full PAS function!!!

PAS 9 levels (in watts):
1=60, 2=120, 3=210, 4=330, 5=480, 6=660, 7=870, 8=1110, 9=1500 (throttle full power)

We uploaded a video of the full working prototype. Note the cover of the motor and display are for this video only. An existing Bafang wiring loom will be used.

Take a peak!


DISPLAYS, a painful note.

Unfortunately not all displays are equal. Bafang released a myriad of display, and different firm wares. We are a small company and haven’t managed to test all of them; but what we have found is that all the original displays still  show everything (time, speed watts etc), but will not allow PAS. You can still ride your bike with the standard display on throttle only.

But, if you include the 750c display that we list, full PAS is restored.

How you budget your expectations and wallet is up to you. You can buy the kit without the display and see if perhaps your display gives PAS (we cant help here as there are too many combinations) and if not buy separately; or you can buy the kit with our display included and everything works.

With exception, we think the Standard 750C display will still give PAS on 52 V (up to 60 V) set ups – BUT NOT work over 60 V (ours are physically altered).

At present we are taking advance UK orders for deliveries to you within three weeks from 12 January 2019.

The kit includes:

ASI BAC 800 36V – 90V FOC 50A

Wiring loom to connect direct to existing BBSHD loom with Anderson Power connectors

750c display (full function including PAS)

Motor side cover

Free UK and EU delivery

Gearing (video tutorial to follow or call for explanation):

We recommend leaving the CYC motor alone and as standard. But change the rear wheel and your cassette.

Remove the old 9 -10=11 speed cassette and use the Shimano XT CS-M771-10 Sprocket as shown in the photo. Use spacers to give you a perfect chain line for the gear of your choice. For 27.5 and 29er set ups we recompensed a 28T rear gear. For 26″ wheels a 26″ T gear and for fat bikes as big as you can get!

If you want to be very smart, you can use a 2.35 mm spacer from your old cassette to space out a 17T as a “Get you home” cog for pedaling or PAS assist in power level 1. But you might have to manually put the chain onto the cog. Use your old derailleur as a tensioner and give your self enough chain (we recommend KMC x10e chains) to move up and own the three speeds you have. You will want to adjust your max/min screws so the chain does not slip off the outer sprockets (You may need to change these for longer screws)


Photos of rear gears and spacers are not included


for USA orders please go to: