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BMW i3 Range Extender

BMW i3 range extender and regenerative force improvement – EVchip

EVBOX for BMW i3 and i3 REX is a range extender controlling load applied to engine via throttle control. No problems with warranty - undetectable by dealer. It is easy to install, as it uses factory plugs.

Alternative torque progression with LeafBox (proposal, tested on car)
Alternative torque progression with LeafBox (proposal, tested on car)

Alternative accelerator pedal interpretation for efficiency

Until now all BMWs i3 and i3 REX have simple “accelerator pedal (acc) position → power” transition. Position of accelerator pedal is converted to power demand immediately. This we can see at energy usage panel in the car, but I have verified that also with chassis dyno.

This method suffers from two negative effects:

  1. Acceleration of the car is not stable at all. The car first accelerates better, then, falls down with acceleration – as acceleration is simply dependent on torque, and because car has almost constant power for any rpm and any desired acc pedal position – it is logical that torque MUST go down (see graph – thin lines in the big graph – torque of car (=acceleration) for various acc pedal positions (verified with dyno).
  2. Some parts of our acceleration are not crossing optimal motor efficiency (red and orange areas). In some areas it is impossible, but of course everything can be optimized.
Accelerator pedal to power demand map from 2012 ECU (normal mode, not for ECO).
Accelerator pedal to power demand map from 2012 ECU (normal mode, not for ECO).


I have prepared an alternative power demand curve (presented as bold line in the small graph vs. thin line with same color – factory) that promotes two things: more constant acceleration and more efficiency.

Constant acceleration is, in my humble opinion, something perfect for our BMW i3 and i3 REX.

Remaining more in the optimal efficiency area – this is more or less a “side effect”, as we have “constant torque” strategy instead of “constant power” strategy. I cannot directly say whether this will extend the range or not (or maybe a bit) because I haven’t tried this on my test route.

For acc pedal levels over 70% torque demand curve becomes more and more „constant power” type. For 100% pedal it is just factory 100% power line, not altered.

Below 30% of acc pedal I have used less flat torque curves (not shown on the graph) because of the need for a jump start at lights or cross-roads.

EVBOX for BMW i3 and i3 REX feature of N-mode on demand. While driving in D-mode you can almost remove leg from acc pedal. EVBOX for BMW i3 and i3 REX will set motor power to exactly zero (0 kWh) so you will be rolling without energy conversions. This increases efficiency with longer distance trips and is good for overall range (autonomy). Power gauge is visible on right side.

EVBOX for BMW i3 and i3 REX can be ordered worldwide. We accept PayPal as a method of payment. Delivery via courier. Warranty: 2 years, Money Back Guarantee: 14 days

Price: € 236 net.

EU citizens need to provide valid VAT number for tax exemption. Non EU citizens pay net price.

Shipping included (in EU).

Shipping outside EU: +35 Eur.

Deliveries for USA/Canada will be provided from our new distribution center in Lake in the Hills, IL.

Free standard shipping or DHL Express service (extra fee).

EVBOX for BMW i3 and i3 REX – FAQ

  1. Do you ship to USA?
    Yes, we ship to USA.
  2. What modelyears and versions of BMW i3 and i3 REX is EVBOX compatible?
  3. Can it be detected by the dealer/car manufacturer?
    No. There is no risk for warranty as it is undetectable.
  4. Is that difficult to install EVBOX for BMW i3 and i3 REX?
    No. You can do that within few minutes, without any car modification. Box uses factory plugs.
  5. Is there any risk for battery?
    No. Battery works with same maximum current as designed by factory. In fact, smoother power control and low speed reduced energy drain in ECO mode helps battery to be more durable (and thus - increases range). Using Leaf Box is good for battery life.
  6. Is the range increased?
    Yes. You will observe up to 10% better range in ECO mode. This is caused by more sophisticated and precise electric power applying, and gliding (N-mode on demand) functionality + slightly increased regen in D-mode. Battery is not drained to lower level, than factory designed.
  7. Is that legal to use EVBOX?
    As there are no car permanent modifications, modifications of power, emissions, safety – there are no reasons for such solutions to be illegal (like for car alarms or other additional equipment).
  8. Can I return EVBOX for BMW i3 and i3 REX?
    In additional to your Statutory Warranty (2 years) we offer a 14 Day Money Back Guarantee. If for any reason you are unsatisfied with EVchip for e-Golf/e-Up, please contact us within 14 days of taking delivery, and organise to return the product and receive a refund. Product must be undamaged.
  9. I have another question concerning EVBOX for BMW i3 and i3 REX.
    Contact us via support chat.
  10. Do they have certification?
    Yes, CE approval, E20 10R-03 2680


Notice: Evtun is not responsible for unauthorized changes.