Sur Ron 72v ASI BAC8000. (13.7-15.8 Kw) “Race” V2.5 72v 42Ah

Original price was: £3,499.00.Current price is: £2,999.00. (price including VAT)

Sur Ron 72v ASI BAC8000. (13.7-15.8 Kw) “Race” V2.5 72v 42Ah

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Sur Ron 72v ASI BAC8000. (13.7-15.8 Kw) “Race” V2.5 72v 42AhBattery


Controller + Display + RaceV2.5 72v Battery 42Ah + Mounting Brackets 

Higher Volts, Higher Amps Higher RPM+  Higher Speed !

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

5 power levels fully tuneable by you (but not exceeding the max power).

Power sets 470A Phase and 13700W OEM Sur Ron Motor,

560A Phase and 15.800W Sotion & *KO RS Motor

Upgraded Internal Configuration, Upgrade High Power BMS, New Handle and New Graphics. New Stainless Steel Grade 316 casing



Sorry no international shipping


Developed specially for the new FIM Open (unrestricted) class and evolved especially from racing experience and testing with our own team rider. We have spent hours getting the maximum performance, balancing maximum power to heat and motor damage. (we can go a touch higher but the risk of overheating the motor increases massively – cant win a race if the bike over heats!).

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 for racing  this class. 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 metal work and extra added powered coating (you scotch it, it still wont rust!!).

Our latest “non steam up” display (we ditched this display that al the other still use),  allows you the rider to individually tune each of the 5 power levels to your own requirements. we found this especially handy if you want the power set up for a particular track. For example, you might want it set for a MX track near you where mode 3 is perfect for jumps, but still hit the button to flick into 4 for the straight and 5 for going ballistic. On our own 72v full race bike, we use 3 for wet muddy slippery riding, 4 for up hill dryish climbs (wheel spin is always  an issue with crazy high power) and 5 for going nuts  🙂


This controller is now tuned and dedicated for our aftermarket  battery  @ 72v (max 85V). This is  a 72v Kit and no longer wasted to work on a std 60v battery battery (our slightly less powerful ASI BAC4000 will work on all batteries). It carries around twice the mount of energy of a standard battery, so loads  more range!! (speed and acceleration kills range, so when comparing to a standard bike, you need to ride in power mode 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, but now totally tuneable by you (you can not turn the max power up, just set each level how you like it)

The controller comes fully potted and with all leads and looms fitted and waterproofed. The mounts are in place, stainless steel and powder coated in black.

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:

Pure Off-road/MX Race:      10-14 stone rider 58T.           15-17 stone rider 60T.        18+ stone rider plus: 60-64T

Controller Feature Set

  • FOC (Field Oriented Control)
  • improved torque throughout the rev range
  • Higher RPM compared to the stock controller on 52V and especially on 72V
  • 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 and we set at 470PhA. The ASI BAC8000 designed for much bigger motors, will not throttle back and will never be stressed.


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 latest display does allow you to set each of the power level to the way you like, but NOT increase the overall power.

Our kit is not compatible with the Eggrider. We dumped that display over a year ago due to too many reliability issues (constant updates 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 V2.5 72v 42Ah Molicel P42A 21700 cell 3024wH – (58% bigger capacity than a 60V standard battery, but due to a better voltage cut off is near 100% more range if used at the same power)

We upgrades this very popular battery to handle more power. The More nickle sheet (lower resistance and heat). Bigger more powerful hybrid BMS giving 80 Amps more, A new stronger lifting stapes and new stunning graphics

Designed to run the: ASI BAC4000, ASI BAC8000 KO Controllers Nuclear controllers  (any 72v capable controller) up to 400 Amps Peak DC line 220A

If this battery is to be used by a third party controller the controller can not be set above 1600o watts.


We upgrades this very popular battery to handle more power. The More nickle sheet (lower resistance and heat). Bigger more powerful hybrid BMS giving 80 Amps more, A new stronger lifting stapes and new stunning graphics

Designed to run the: ASI BAC4000, ASI BAC8000 KO Controllers Nuclear controllers  (any 72v capable controller) up to 400 Amps Peak DC line 220A

If this battery is to be used by a third party controller the controller can not be set above 1600o watts.

Please make sure yurt controller is set to a power rating that will not damage your motor. The battery is the “fuel tank” and it is the controller that controls  how much “fuel” (Power) it takes and gives to the motor.

Dominator upgrade available:

Designed to run the ASI BAC 4000 or 8000 and Nuclear controllers  (any 72v capable controller) up to 330 Amps and use on the Sur Ron Light Bee.

This will not work with the original X Controller.

These power packs are designed for ultimate power supply and are 58% bigger watts hours (3020) compared to the standard battery (1920Wh although only allows 1000Wh to be used because of very high LVC) and able to give out almost 4 times the power (discharge -amps)

High Power Sur Ron Battery 20S1 P 72v 3020Wh 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 208 cells that retail in the UK for around £6 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.


20s10p Molicell p42A 21700
Light weight 17 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!
* We currently do not have a program for the KO “Factory” motor

Please ALSO note, these are genuine new cells 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. The Cells are genuine branded 21700 cylindrical cells (not cheaper pouch)

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 

* Warranty 12 months of battery and 6 months for the controller, Due to the nature of use of these devices  (off road) warranty is limited to 6 months from date of purchase. Any damage the result of water ingress, alteration may void warranty. This includes shortening of cables and changing connectors. It is the owners responsibility to proof against water ingress and not use in unacceptable very wet conditions or use direct water from hose/washers.

Please note, Lithium batteries are considered hazardous and due care and attention should be taken. Although these cells are in wide use, and professionally manufactured in a purpose built factory; because of the power of the battery, we strongly recommend that precautions are taken. We do not recommend charging inside the family home and charging should be supervised. We take no responsibility for misuse. These batteries are thoroughly tested (full discharge and charge cycles at the manufacturing stage and also pre-delivery). These are not DIY or amateur built devices

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 19 kg
Dimensions 50 × 28 × 35 cm