EV Battery Replacement Calculator

It is a rule of thumb, not a market quote: a new battery pack generally adds back substantially less than its own cost when the car is sold, and this calculator models that recovery at about 65%, leaving 35% as Net Cost After Resale Gain. Your local market, the vehicle's model and whether the pack is OEM or a third-party refurbishment can all move that figure, so treat it as an order-of-magnitude assumption rather than a valuation.

Often, yes -- resale recovery is only one of the questions. The Recommendation output weighs the practical one instead, comparing replacement cost against your vehicle's current value and age to judge whether keeping and driving the car makes sense. Cost per Mile Added prices the extra service life you buy: it is the replacement cost divided by the miles you will drive over that extra life -- Annual Miles Driven multiplied by Years of Life Extended. At the defaults that is 12,000 miles a year across 8.3 years, so an $8,000 pack works out to about eight cents a mile -- a purchase cost spread over distance, not an energy or fuel figure. A pack that recovers only 65% of its cost at resale can still be far cheaper per mile than replacing the whole vehicle.

It scales with how much capacity you recover -- the gap between your Current Battery Capacity and the restored 95% a new pack provides -- divided by 3 and capped at 10 years. A battery replaced at 50% capacity gains more Years of Life Extended than one replaced at 85%, because there's a bigger capacity gap to recover. The divisor of 3 is this calculator's own convention rather than a measured figure, and the reading it produces is relative to not replacing at all: a pack still at 85% has years of service left in it, so swapping it now buys you comparatively little extra life, while a pack at 50% is close to the end of its usable life and a replacement resets the clock almost entirely. It is not a claim that the new pack itself lasts longer in one case than the other.

Recommendation compares Battery Replacement Cost to Current Vehicle Value, not to battery degradation directly -- if the replacement cost exceeds 70% of what the vehicle with its degraded battery is currently worth, the calculator recommends against replacement regardless of how low the capacity has dropped, since you'd likely be better off selling or replacing the whole vehicle.

Only at the "Recommended" threshold -- replacement is called "Recommended" rather than merely "Consider" when the cost-to-value ratio is favorable AND the vehicle is under 12 years old, since an older vehicle has less remaining service life to amortize the replacement cost against even when the price looks reasonable.