43 kWh battery for the Renault Zoe

Renault Zoe 43 kWh battery


Made by Imecar.


The 43 kWh battery for the Renault Zoe was built by Imecar Elektronik Turkey in cooperation with Renault Turkey.


The 18650 format cells used appear to be the popular green cells made by Panasonic, the NCR18650B (3.400 mAh). We’re talking of more than 3.400 cells used in the battery pack. If we consider that the battery pack has 43.000 Wh capacity and each cell has 12,41 Wh (3,65 V x 3,4 Ah), it takes 3.465 cells.

Each cell is around 45 g, this means that the 3.465 cells weigh 155,925 kg. Then add the connectors, cables, BMS (Battery Management System) and a case and it should surpass 200 kg for the whole battery pack. But what’s 200 kg when you get a 43 kWh battery in return?


Renault Zoe 43 kWh battery range


Renault Zoe 43 kWh battery range


Imecar probably went with the NCR18650B cells because they are now very cheap and easy to buy. But Sanyo/Panasonic, LG Chem and Samsung SDI already produce great 3.500 mAh cells in the same 18650 cylindrical format. Instead of 43 kWh we would get 44,2 kWh. Not much difference in capacity but the 3.400 mAh cells when compared to the newer 3.500 mAh cells are a bit dated, regarding the lifespan, internal resistance and safety.


The imecar project has merits, yet I think projects like these need more volume production to be sustainable. Buying cells in big quantities and making the battery pack in a mass production line is the way to go.

In this aspect Kreisel Electric is way ahead with its big battery factory opening in March 2017. It will have the mass production advantage to offer good prices. In the 2017 summer I expect to see Kreisel Electric selling batteries with 40-50 kWh capacity for popular first generation electric cars as the Nissan Leaf, Renault Zoe, BMW i3 or the Volkswagen e-Golf.


Volkswagen e-Golf with a 55,7 kWh Kreisel battery and 106 kW fast charging capability. Good for 435 km NEDC range


Not only Tesla Motors is proving that if automakers wanted they could build great electric cars that consumers would see as viable alternatives to gas cars. Also companies like Kreisel or Imecar show what’s possible with current battery technology.


Note to automakers: cost isn’t a valid excuse to keep making  batteries with low energy density for electric cars. Because higher energy density not only increases the capacity, it also drops the kWh cost, since the same mass (raw materials) store more energy.



More info:







Pedro Lima

More than natural resources, are wasted human resources that bothers me the most. That’s why I’m a strong advocate of a society based on cooperation, not competition, that helps every individual to reach his full potential so that he can contribute back to society. “From each according to his ability, to each according to his needs”.

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11 Responses

  1. sapcmc says:

    It is a nice project but at retail prices just in batteries we would be talking of about 8500€ plus BMS, labour and so on.

    But a great idea that shows it is possible in future to upgrade to bigger sized packs.

    I could definitely consider upgrading my ZOE to 60 kWh in 5 years if that would cost me by then 5000€.

    • Pedro Lima says:

      Not sure if in 5 years (2021) you will want to do it, because by then electrics cars will be cheaper than gas cars. You’ll probably prefer to buy a new car with features like autonomous driving, AEB, 150 kW fast charging, more efficient powertrain (4WD like Tesla), etc…

      But go at least 200.000 km in the R240 then think about the upgrade. Anything less is a waste of a battery 🙂

      • sapcmc says:

        That is wishful thinking! Evolution will move fast but as fast as that I am afraid. In China there are also new battery factories being built that will be about 1/2 of capacity of Teslas Gigafactory. We will need at least 10 more giga factories to be able to supply enough batteries for prices to be below cost of a gas car.

    • Sia says:

      Keep your old battery, and add another 24 kWh to it. So buy an 24 kWh pack from these people (should cost about $5,000 in 3 years) and put it in the trunk. It will probably need its own charger. This way the amount of retrofitting is minimal and you can do that yourself. And you have not thrown away your old back which is probably down to 18 kWh. The packaging can also be minimal.

      You lose some trunk space, but your range is now up to 240 km (150 mi), and you are back in business. You may want to use the Leaf’s charger, which then will allow you to fast charge the auxiliary pack.

  2. James says:

    Hi Pedro,
    Your knowledge of cells is unsurpassed.
    Where can I see more information on the 3,500mAh 18650 cells from “Sanyo/Panasonic, LG Chem and Samsung SDI”
    I can’t find them anywhere (or are they not for sale in small numbers)

    There is always tradeoff between the capacity of a cell and its maximum power output.

    Tesla use the best energy density cells and therefore really push the limits of power drawn from each cell, this means they have to properly cool everything and it could impact on cell life. Tesla appear to have a really good understanding of cell cooling and cell-life (because they have researched everything) and therefore cell life is well understood and is a total non-issue for them. Tesla are engineering driven.

    Nissan/Renault etc use super-safe, low energy density, high power cells and they only draw moderate power from them, they hope this means they can get away with minimal cooling systems and also will greatly extend cell life with minimal testing. They play it safe and minimise R&D costs. They are car assemblers who do a bit of R&D here and there.

    • tosho says:

      When you have a large battery pack you have to draw/push much less power from each cell to achieve a good input or output of the pack compared to a smaller one. There is no “secret” or “really good understanding” to Tesla’s battery packs. Both supercharging without degradation and the high output are a direct consequence of the large cell count in the pack

    • Pedro Lima says:

      Hello James.

      tosho is right, when you have a larger battery the charge/discharge C rates will be lower for the same power input/output in kW.

      If your car is in the highway and using 30 kW from a 30 kWh battery, that’s 1 C rate discharge. In the other hand if your battery is 60 kWh the discharge rate is only at 0,5 C.

      The less C rate the better. Means less heat, more lifespan and more efficiency (you can get more energy from a battery if the discharge rate is slower).

      Regarding the 18650 cells with 3.500 mAh capacity check the link bellow:


      They are easy to find in Chinese online stores like Gearbest or Aliexpress:



      • James says:

        I don’t think I articulated my point very well.
        Totally agree about C-rating of cells
        But there is tradeoff between maximum continuous C-rating of a cell and its energy capacity

        A Tesla 85D has 96S 74P battery pack, each cell has a capacity of near to 3400mAh and a recommended C-rating of 3C https://en.wikipedia.org/wiki/Tesla_Model_S#Specifications

        A Nissan leaf has a 96S 2P battery pack, each cell has a capacity of 33Ah and a recommended C-rating of 7C

        They both have similar pack voltages under load of ~360V

        An 85D draws max 311kW from the pack, which is 863A at the pack and 11.6A per cell, this is a 3.4C discharge.

        A Leaf draws max 80kW from the pack, which is 222A at the pack and 111A per cell, this is also a 3.4C discharge

        However the tesla cells are exceeding their recommended continuous discharge rate of 3C and the leaf cells are nowhere near their recommend continuous discharge rate of 7C.

        This is why a Tesla battery needs liquid cooling and lots of testing and good engineering
        and a Leaf pack can be very simple, cheap to develop and cheap to manufacture

    • Val says:


      look at NKON.nl

      • James says:

        Wow really good website (in europe as well)
        Have you bought from there before, did everything go ok?
        They have NCR18650B (3.4Ah) for 3.50 euros each

    • Sia says:

      That is why a Leaf is as cheap as $25,000 while a Tesla Model 3 will be at $35,000 (this will be the 42 kWh model and not the 60 kWh model which starts at $45,000). The average Joe doesn’t have that $10,000 to pay for a Tesla. And the Leaf is much more reliable than the Teslas will ever be.

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