This Drop-In Battery Can Add 60 Miles Of Range To Any EV

• A custom-made battery pack can extend the driving range of pretty much every EV.
• Built in Croatia by EV Clinic using brand-new Samsung SDI cells, it can add up to 62 miles of range.
• In older Tesla Model S and Model X EVs, it can also improve the DC fast charging curve.

Batteries degrade over time. There’s no way to stop that from happening. There are plenty of old electric cars out there that are still on their original batteries, and they work just fine, but none of them can deliver the same range on a full charge as when they were new.

The fix is simple, but often very expensive: the battery pack needs to be replaced with a newer one, or sent out to someone who knows what they’re doing, with the hope that they can replace the faulty cells or modules.

Now, though, someone figured out how to keep the old battery and extend the vehicle’s range. Croatia’s EV Clinic built a bespoke battery range extender that can fit in pretty much any EV on the market, adding roughly 62 miles of range without touching the original pack.

It’s just a prototype at the moment, but it looks quite promising. As described in Bjorn Nyland’s video above, the first iteration was made to fit in the deep part of the Tesla Model S’ trunk, which means the car can retain most of its cargo capacity. The battery range extender has 17.1-kilowatt-hours of usable energy, courtesy of several brand-new Samsung SDI prismatic cells arranged in four modules.

The cage also has a dedicated battery management system (BMS), a pyro fuse sourced from the Tesla Model 3, a custom-made cooling plate, and a coolant pump sourced from the Tesla Model S. According to EV Clinic’s representative, the range extender will be wired in parallel with the car’s original battery via Rapid Mate connectors.

Because it’s wired in parallel, it helps reduce the system’s internal resistance, which leads to faster charging. The maximum power input might be the same, but the charging curve will be better, per EV Clinic. There’s also a dedicated diagnostics module and some software that goes along with it, making it easy for owners to keep an eye on the range extender’s status. What’s more, if anything were to go wrong, the add-on battery can disconnect itself from the high-voltage system.

This first prototype was designed for the Tesla Model S with the 85 kWh pack, but future iterations will be available for other EVs, including the 75 kWh Teslas and the aging Volkswagen e-Golf, Nissan Leaf and Smart EVs.

There’s no word on price yet, but it’s bound to be cheaper than replacing an entire battery on an old Tesla Model S or Model X, which usually goes for about $15,000 to $25,000.