By Marco Loglio
October 2017. My 10 year old Vectrix was in the need of the replacement of the original NIMH battery pack composed by a stack of 80 cell in series 1,4V each.
The range was reduced after 23.000 Km, to only 20 km with one charge . The idea behind the project to replace the battery was to dramatically increase the range of the scooter and in the mean time reduce the weight of the vehicle to make it more easy to handle.
For the new battery pack i decide to use my lithium Vanadium cell grouped into a stack 32S 2P. In this way i could keep the most of the electronic parts ( excluding the charger ) as the voltage of the battery pack a very similar to the original.
Each cell is 300x98x14 mm dimension and weight only 800 gr. The capacity of the cell is 60 Ah and the medium voltage 3,7V. Weight and dimension was ideal to replace the old cell as i could exactly match the dimensions of the original aluminum battery box . The weight was lowered from the original 80 Kg to only 51 kg so obtaining the wanted reduction of the total weight of the scooter of about 30 Kg.
About the capacity of the pack it soared from the original 3,7Kw/h to 14,3 Kw/h , thus increasing the original range from 80 Km with one charge to almost 350 Km.
The first step has been remove the upper part of the seat compartment and get access to the original battery pack. After disconnect all the cable and sensors i got the empty battery box in which display the new 4 packs in which my new battery was composed.
Every pack has two Anderson connectors to complete the series and another cable for the signal to the BMS that was also installed in the vehicle.
I test the charger connected to the BMS and the battery pack, and it was working properly indicating that all the connections was correct. The new charger has a power of 10 A and the time for a complete charging is 10 hours, taking into account that the BMS set the top of the discharge when a 20 % capacity i still remaining in the pack. The battery charger is a detachable one typically off board. The weight is less then 1 Kg and easy to store in the under eat pace. The original charger cable was removed so that we have another gain of weight when the new charger is left out board .
Finally i connected the positive from the battery and the negative from the BMS to the controller making sure that the original signals from the NIMH battery pack a neutralized.
The new battery pack has an expected life of 10 years, retaining after 3000 cycles of more then 90 % of the original capacity.
Now my Vectrix is ready to start a new and much more exciting life allowing longer trips and the end of the range anxiety that a always accompany my before trips on this still good electric scooter.
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