How long will electric car batteries last? [closed]

My UPS's batteries have to be replaced every 3 - 4 years even though I use Deep Cycle batteries. I am wondering how long electric car batteries will last before having to be replaced, and at what cost, and are new buyers aware of this possibly expensive future maintenance problem?

closed as off-topic by duskwuff, RoyC, PlasmaHH, Scott Seidman, Dmitry GrigoryevMar 12 '18 at 7:52

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• This might be an interesting article for you, especially the graph: teslarati.com/… – plocks Mar 11 '18 at 18:56

Because they are such a large investment, electric car batteries, the ones used for traction, are typically managed so they target an 8 year life.

This is done by providing more nominal Ah of storage than would be needed to achieve the Ah specification in 'normal' consumer use (laptop, phone, drone). In the early years, the battery pack is operated avoiding full charge and full discharge, which prolongs its life substantially. Later on, as the battery degrades, the charge management system allows a larger state of charge swing, to deliver the same specified Ah, until at end of life it's using the full voltage swing allowed.

• So, for example, a Nissan Leaf would include software for its charging systems to simply avoid getting close to a full charge when new; and the car's operating system would avoid allowing the car to go into deep discharge (unless an emergency?); and together these would gradually change that allowance band over time? I see the sense, just hadn't considered the idea until now. – jonk Mar 11 '18 at 7:01
• @jonk This general idea is taken to its extremes for satellites, where the peak charge voltage is 3.92v, and replacing the pack is rather more difficult. – Neil_UK Mar 11 '18 at 10:03
• Oh, they can just use an RTG. Lasts decades. :) Used on voyager 1&2, etc. I keep asking for one for my home and they just don't want to listen for some reason. ;) – jonk Mar 11 '18 at 10:12

http://www.hybridcars.com/hybrid-car-battery/ will describe all the different types and sources.

Anecdotal

Mitsubishi spec 10yrs on theirs and it holds good charge in Winterpeg weather. My friend who bought the 1st one in Canada, expects his to last much longer than 10y

"Mitsubishi's Vice President of Sales and Marketing, Tomoki Yanagawa says that the battery pack is expected to last a minimum of 10-years without any appreciable decline in capacity or function."

But the warranty I believe is only 8yrs. http://www.myimiev.com/

• I think that's a good estimate, my 2004 Prius's (NiMh) battery lasted 13 years (and only had 2 bad cells) - when I bought it everyone said I'd be replacing it after 5 – Taniwha Mar 11 '18 at 8:01

I have included a few relevant links here for Li-ion battery life:

Basically they can now quickly determine how long any type of battery will last by measuring currents and voltages very accurately during short tests (rather than testing over the entire life of the battery). Importantly, an active thermal management system (during both charge and discharge) is essential to ensure optimal battery life.

Why do Li-ion Batteries die? And how to improve the situation? (31-10-2013) https://www.youtube.com/watch?v=pxP0Cu00sZs

Similiarly this Panansonic Paper on Li-ion batteries: https://www.motor-talk.de/forum/aktion/Attachment.html?attachmentId=736740

• Good answer but probably not very relevant as the OP appears to be using lead acid batteries. – RoyC Mar 11 '18 at 10:26
• Probably still relevant as the question was about EV practice, which is basically, don't use lead acid. – Brian Drummond Mar 11 '18 at 12:30

Purely anecdotal: I bought my hybrid in 2003. I had no trouble at that time finding out how long the battery would last and how much it would cost to replace it, and factored that into my decision. To the best of my recollection, I found the information in Consumer Reports. It would be even easier to find it now, I'm sure.

The battery actually lasted over 10 years, and was about $6k to replace. This was 2 years more and$2k less than I had budgeted for, so I felt like I came out ahead.

My UPS's batteries ...

Are you talking about lithium batteries used for electric cars or about lead batteries used in gasoline or diesel cars?

I doubt that car batteries would work in this environment.

I work in automobile electronics industry and had a project dealing with car batteries. I was told that car batteries are designed to ...

• ... be discharged for a few seconds, then be re-loaded again and that the charge of the battery is kept constant for a long while.

If you discharge the batteries for a longer time or you don't keep the charge constant using special circuits the battery will be defect after a very short amount of time.

• ... work in an environment with engine vibrations which cause the liquid inside the battery to be mixed.

If the battery is not operating in a vibrating environment the liquid inside the battery will stop moving and the different components of the liquid will separate from each other - which will also cause the battery to be defect.

• 'be discharged for a few seconds, then be re-loaded again...' I believe he is talking about the batteries that power electric motors, not the battery that starts a combustion engine. The rest of your points may be valid still. – damanptyltd Mar 11 '18 at 21:31
• @damanptyltd This is a good question. I understood it in another way because I know a lot of people who want to use starter batteries for gasoline cars for a lot of purposes... I edited my answer. – Martin Rosenau Mar 12 '18 at 6:23
• I doubt the last statement is true, otherwise we would see an UPS with vibro function by now. – Dmitry Grigoryev Mar 12 '18 at 7:56
• @DmitryGrigoryev I have never seen UPS with regular car batteries. – Martin Rosenau Mar 12 '18 at 20:25