Sur Ron 72v ASI 13.5kW Enduro V2.5 Kit, ASI BAC4000 + Race V2.5 72v 42Ah.

Original price was: £3,318.00.Current price is: £2,849.00. (price including VAT)

Sur Ron ASI 13.5kW EnduroV2 Kit, ASI BAC4000 + RaceV2.5 72v 42Ah.

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Sur Ron ASI “EnduroV2.5″ 72v 13500W Kit ASI BAC4000

RaceV2.5 Battery 72V 42Ah

Tunable Display, Mounting Brackets 

Higher Volts, Higher Amps Higher RPM+  Higher Speed !

This is truly plug n play and expect RELIABLE burst speeds of around  70+ MPH
All taxes and import duties paid and free UK shipping

Mounting including side “wings”

Power sets 431A Phase and 13500W

Tuned for our 72v aftermarket battery.

NO PROGRAMMING NEEDED (but free remote tuning session inc)!!


Sorry Only Ship To UK – EU Mainland – Sorry No International Air shipping

International customers, please email for details, 20% VAT removed

We dispatch within three working days.

Free UK Shipping

We listened to our customers and improved and change 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 battery and 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. Stainless steel battery with extra added powder coating (you scratch it, it still wont rust!!).

The acceleration is phenomenal! Remember when your buying this kit, it was only us and one other business (ERT) that created this product for the Sur Ron. Others have copied, but NO ONE can compete against the quality of these kits.

ASI BAC4000 13500W 431A Phase

So what’s different to the ASI BAC8000? the simple answer is size. The BAC4000 is about 40% smaller so it heats up a bit quicker. So on a very hot day, will throttle back a touch if ridden very hard. The BAC8000 doesn’t get hot at these power levels so is a little more constant. The BAC4000 is set at 13500w and 431A phase.

This controller is now tuned and dedicated for our aftermarket  battery  @ 72v (max 85V). This is  a 72v Kit  It carries around twice the amount of energy of a standard battery, so loads  more range!! (speed and acceleration kills range, so when comparing to a STD bike, you need to ride like for like)

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 suite 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. From super echo to absolutely blistering . We don’t just make this gear, we ride too. Personally in heavy mud and soft slippery conditions (where you don’t want to spin out all the time and actually stay on the bike for the full ride), or blasting around the streets (road legal bikes obviously) and is  a good compromise between power and range, mode 3 is enough.

Hit mode 4 for that extra grunt needed for deep sand or on the street, getting a  “wiggle On” (mode 4 will also prolong the time before thermal roll back kicks in under very hard use).

Mode 5: “When you absolutely, positively got to kill every motherf***er in the room, accept no substitutes” (quote from Pulp Fiction). Mode 5 should be used and thought of like an after burner from a video game. At full power sustained open throttle, thermal roll back will come in, if used for too long and start to slow the bike down. It should be used when you want extreme bursts, like on a MX track. You don’t need the full open throttle all the time, but when you want it, its there. Like to fire out of a corner or hit that BIG jump – mode 5. Its not designed for full open constant use (that’s mode 4), but you can leave it in this mode, just not full on, all the time – get it?

Please note that running on full power for your type of battery, non stop with a wide open throttle is not a good idea and effectively red lining the motor like on a petrol bike. We strongly recommend that you upgrade to our heavy duty bash guard to increase air flow over the motor, make your frame stiffer and take heavier knocks. Increased air flow over the motor (cooling) will increase reliability and stop thermal roll back kicking in so quick (where power is reduced temporally to help the motor cool). However if you do ride very very hard and get close to overheating the motor, Our new improved thermal roll back will gently cut the power until the motor cools enough to accept full power again. This only tends to happen if your riding full open throttle down a very long straight (road).

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:

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

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 431 Phase Amps. the ASI BAC8000 is capable of 850A but 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, se 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 programming and logo on it, so lets see how long before we are copied again (PS, its really good to use)! The display has a choice of 5 power levels, each one can  be tuned to your riding style.

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:

Battery RaceV2.5 72v 42Ah Molicel P42A 21700 cell 3024Wh massive increase over the standard a 60V battery, but due to a better voltage cut off is near 110% more range if used at the same power)

Designed to run the ASI BAC 4000 or 8000, EBMX, KO and  Nuclear controllers  (any 72v capable controller) up to 400 Amps and use on the Sur Ron Light Bee.

This will not work with the original X Controller.

High Power Sur Ron Battery 20S110P 72v 3024Wh 42Ah Molicell p42A high power 4200 mAh  per cell).  ANT Bluetooth BMS (works on IOS and Android) designed to fit inside the Sur Ron battery compartment utilizing the existing battery tray. The Cells are genuine branded cells specifically designed for high output discharge and sustained high drain. Other inferior cells used in cheaper packs simply can’t deliver like these. If you think the cost is high, these batteries have 200 cells that retail in the UK for around £8 each! not including: BMS, fabrication and shipping taxes.

The whole battery is fitted in  hand made stainless steel case designed to handle those inevitable and hopefully not painful “Offs” with hard off road rides and giving masses more protection.


20s11p Molicell p42A 21700
RaceV2 72v 42Ah = 15.6kW 180A DC
Capacity 42Ah or 3024Wh
Stainless Steel 316 powder coated casing.
Light weight 18 KG
Full function BMS monitoring: cell balance, heat and discharge. Individual series condition with balanced charging
Double sandwich configuration using special custom made cell  holders (not glued).
0.2mm pure welded Nickle laser cut sheet.
The BMS gives a whole range of safety features including short circuit  detection and shut down, overheating and damaged series connection
An integrated handle for lowering the battery in and out.
Charging port via an XT60 connector.
The main battery to controller connectors we use are the same type as used by Sur Ron to keep everything compatible. This allows you to swap your standard battery back should you wish.
Battery is in a super tough hand built stainless steel case designed to keep your battery safe in an accident and waterproof  except immersion or direct jet washing at the cable exits.. Designed to fit straight into the bike and maximize the whole battery compartment (the hatch bolts need swapping  out with longer bolts that we supply – 2 minutes and simple). No movement- no rattles!

Please ALSO note, The Cells are genuine branded 21700 cylindrical cells (not cheaper pouch) and made up into complete battery specially designed by us, built at the factory and final assembly and quality control here in the UK . All warranty work is carried out here with us in the UK.

We simply can’t buy a single battery, Thanks to commercial fees, shipping and taxes the mark-up is minimal!

Charging: First time charging is important. Always connect the charger to the battery with the charger powered up from the mains. This will stop a “Connection Spark”. The battery needs a “Balance Charge” on first charge. Please charge for 12 hours first time.

Please note, charger is not supplied but can be found here:

Self Fitting:

We will include a 13 page illustrated set of instructions. However we do strongly advise for one of our fitters to install. We do make the assumption that if your fitting this kit yourself, you know what you are doing. All kit leaves here tested and working. Think of it like this. You buy a motor from Honda, Suzuki etc and fit yourself. You would not expect Honda to talk you through the fitting. We will not give support outside of Monday – Friday normal business hours.

This is a plug and play system, but we now believe there are at least three slightly different version of the Sur Ron Lightbee motor. This can cause some minor issues. Because of this we now include 1 hour free remote support during our working hours (9 – 5.30 Mon-Friday). We strongly advise that you factor in our working hours when fitting. We will not give support outside these hours. To give remote support you will need either an media phone/note pad and good internet connection.

We do not warranty damage caused from your fitting. Every kit is bench tested before leaving our premises.

We give UK support!!!!

* UK Warranty 

Our warranty is limited to 12 months for battery and 6 months for the controllers from time of purchase an dis for manufacturing defects. Due to the use and the nature of this device (Off-Road) and the potential excess  exposure to: water, rain, mud and the possibility to sustained high powered use/abuse, we do not warranty controllers that show signs of damage, excess heat or water penetration. All devices are fully bench tested working with a full working motor before leaving our premises. Any damage caused by your installation is not covered by our warranty. alteration may void warranty. This includes shortening of cables and changing connectors. We highly recommend the use of one of recognized fitters where installation is fully covered.

Warranties are not transferable.

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

Bike not included



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 18 kg
Dimensions 50 × 28 × 35 cm