ASK THE EXPERTS: Salvaging Prius Batteries

Toyota Prius battery pack.
Toyota Prius battery pack.
Toyota Prius battery pack.

There are some wrecked Prius hybrids at the local salvage yard, and I can get their battery packs cheap. Can I put two or three of these together to power my pure-electric conversion?

John McElhattan • Fresno, California

Bundling these battery banks is not recommended, for a few reasons. The battery pack in the Prius (or any of the other hybrids) does not have the capacity for much range by itself. Even at low speeds in pure-electric mode, the Prius has only about 2 miles of range before the gas engine starts up to recharge the pack. So you would need a lot of packs to get any decent range.

Also, these batteries are not intended to be discharged very deeply. They were specifically designed to work with a gas engine frequently topping them off. In a pure electric vehicle, you need batteries that can tolerate being deeply discharged before getting recharged.

You would also need the battery management system that is part of the Prius’s computer brain. While these battery packs are perfectly safe in the Prius, if they are installed or managed improperly, they can catch fire, which some tinkerers have already had the misfortune to experience.

Prius batteries work great in the original vehicle’s system. There are other batteries that are better suited to a pure-electric conversion.

Mike Brown & Shari PrangeHome Power Transportation Editors

Comments (3)

Jim and Elaine Stack's picture

I have seen that the LEAF battery pack degrades in the heat. In the Phoenix are we lose 5-10% a year. Other battery systems have cooling and that makes the battery last 20-30 years.
Reconditioning batteries does not work. In a Prius or LEAF finding the bad battery cell and replacing it or a few make the pack work again. Old chemistry LEAD ACID and ALKALINE are not worth even checking.

Robert Pollock_2's picture

This is critical. There is a wave of 3 year leased EVs being returned that all have viable Lith ion batteries in the 20 to 30 kwh range, but there is no way to find them, buy them, or use them. It is a conspiracy on the part of the Utilities. That the Auto Co's want to expand the 'Hybrid' market is another part of the same conspiracy to slow, the acquisition of EVs. As consumers/taxpayers we're about to get the dirty end of the deal(s) again.

Jim and Elaine Stack's picture

The Prius also uses NiMH which is not as good as Lithium. A prius as they said can't even go 1 mile with it's 99 lb pack. I plugin Prius with a 10 Kw Lithium pack that weight 290 lbs can go 40-50 miles so you can see the difference.

It's hard to buy a battery packs with BMS and temperature control for even double what the major automakers are able to do. The LEAF and Focus are amazing and I have had conversions but none even close to what they can do in range. The LEAF also has one of the most efficient heating and cooling systems so you can use them and still go a long range.

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