ASI BAC4000 for Sur Ron with: Loom, Display, Mounts, Fully Assembled

Original price was: £1,175.00.Current price is: £899.00. (price including VAT)

ASI BAC4000 for Sur Ron Programmed with: Loom, Display, Mounts, Fully Assembled

Categories: , Tag:


Our latest and improved fully motor protected upgrade!!!

ASI BAC4000 for Sur Ron

ASI BAC4000 Controller + Display (fully tuneable by you)+ Mounting Brackets with Wings” 

Further, Faster an More Power!!

Please state which preset  map you would like ((OEM Sur Ron, Sotion or KO RS)):

60v Bypass 7.5Kw.

60v  Aftermarket 11.5Kw.

72v Aftermarket 13.5 Kw

Indidivaul tuning can be undertaken by you with a third party app (details supplied on request)


This is truly plug n play
All taxes and import duties paid and free UK shipping

Mounting including side “wings”


We listened to our customers and improved and changed things as this product evolved. We originally started this project in June 2020. That’s months of learning and evolving, just on this one device. We truly believe this is the very best Sur Ron controller upgrade on the market. We KNOW that other sellers have copied our program (they say to be copied is the greatest compliment), but now that we have pushed the boat even further. Our latest program has now been revised to include MORE power! Improved thermal roll back for motor protection, no problems with up hill starts or roll backwards stalls, no cutting out, extra water proofing, higher grade materials used.

This controller is set for a BMS Bypassed battery. We do not sell controllers on their own except for this “bypass” setting. All our controllers are set and matched to our battery options. We will not unlock this controller. If this is an issue, please consider your purchase.

You tell us which program you want and we do the set up:

The controller now features  a full working display showing: speed, power, battery charge, date and trip. Set with 5 power levels as default that can be flicked at the touch of a button on the fly (just your thumb, no gloves off or stopping).  Can be used like a gearbox to slip up and down the power levels (5 levels set as our default) to suit your terrain and riding style.

The controller comes fully potted and with all leads and looms fitted and waterproofed. The mounts are in place, made of plastic to include our protective “wings”.


Power levels:

5 Power levels on the fly at simple handlebar push of a button.

Please note that running on full power for your type of battery, may reduce the lifespan of your battery.

Unleash more performance and range with correct gearing.  Higher gears (smaller rear sprocket) does not mean higher top speed. Over labouring the motor with the wrong gearing costs top speed, acceleration and range.

A fast efficient spinning electric motor goes better – simple!.

Our recommendations for a fully equipped 72v system (OEM and KO RS Motors):

For road use:                           10-14 stone rider 52T.           15-17 stone rider 54T.        18+ stone rider plus: 56T

For Off Road/Off Road:       10-14 stone rider 54T.            15-17 stone rider 56T.         18+ stone rider plus: 58T

Pure Off-road/MX Race:      10-14 stone rider 56T.           15-17 stone rider 58T.        18+ stone rider plus: 60T

For Sotion Motor we Recomned 48T or 52T

Controller Feature Set

  • FOC (Field Oriented Control)
  • Improved torque throughout the rev range
  • Higher RPM compared to the stock controller
  • Silky smooth throttle control and responsiveness, like a fine adjustable knob on a light switch
  • Improved efficiency due to FOC algorithm, premium internal components within the controller (like the mosfets) which increases efficiency while reducing heat losses
  • Loom
  • Mounting Kit
  • Install Instructions
  • Display
  • Both the ASI BAC4000 and ASI BAC8000 use almost the same programming. The ASI  BAC4000 under exceptional hot day and extreme hard use may throttle back and restricted to 430 Phase Amps. the ASI BAC8000 is capable of 850Abut restricted by us to 470A. The ASI BAC8000 designed for much bigger motors, will not throttle back and will never be stressed (although it will thermal roll back if it senses the motor getting too hot).


Others copy, so we improve and change. The old APT display (as used by everyone else) had a tendency to steam up on a hot day if  the bike had been washed with a hose or exposed very heavy rain, So guess what? we went to another display manufacturer and had another display developed just for us. We are the only Sur Ron kit that now uses our dedicated display. Its got our program and logo on it, so lets see how long before we are copied again (PS, its really good to use)!

Our kit is not compatible with the Eggrider. We dumped that display over a year ago due to too many reliability issues (constant updated needed)

For a real show of power, take a look at this customer set up here on YouTube (we do not endorse road riding and this set up should be used on off road in accordance with legislation:

For a real show of power, take a look at this customer set up here on YouTube (we do not endorse road riding and this set up should be used on off road in accordance with legislation:


Please note that Electron Cycles Limited no longer has any association with ERT

We reserve the right to slightly modify or change this product without notice.


Buyer releases Electron Cycles or any person trading on or behalf of the business known as Electron Cycles from any liabilities, therein known as Electron Cycles (expressed or implied, arising by law or otherwise) that may occur from the use of products sold by Electron Cycles and purchased by Buyer. These products are being sold for “Off Road/Competition Use” only and may be used only on two wheel vehicles (bicycles, electric bicycles, two wheel electric powered vehicles) used solely for “Off Road/Competition” (off-road being defined as a private land with land owners permission and not public highway or byway). The Buyer also recognises that Lithium batteries are classed as hazardous and should not be: stored, used, charged in place, facility any area that is not fire proof or safe to do so. That batteries should not be taken into the family home, office, workplace or school place. No other applications are intended or implied. The Buyer of product sold or provided by Electron Cycles acknowledges and agrees that Seller disclaims any warranty and expressly disclaims any liability for personal injury or damages or any damages to vehicle, expensed occurred, personal property or third persons. Electron Cycles will uphold the warranty of the manufacture of the product sold for a period of six months from date of purchase from manufacturer defect. In the event a manufacturer’s warranty exists, it is agreed and stated that Under no circumstances shall the seller or manufacture be liable for any labour charged or travel time incurred in diagnosis for defects, removal, or reinstallation of this product, or any contingent expenses.

Additional information

Weight 2.9 kg
Dimensions 35 × 20 × 20 cm