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2 Battery Replacements w/in 15k -- Trouble Ahead?

Hi there, I’m contemplating buying a used 2014 Lexus IS350 (33k miles) from a non-Lexus dealership. I managed to pull down the complete Lexus service records, and I’m wondering how much of a red flag the following is:

The car needed a jump start at 3720 miles. Then at the 10k check-up, they replaced the battery:


And then at 15k they replaced the battery AGAIN:


However, things seem to have been fine in the 23 months / 17k miles since that second replacement (or at least there is no Lexus service record of further problems), and a July '17 35k check-up reported the battery as “OK.”

So what I’m wondering is: Did this guy just have bad luck with two bad batteries in a row, or is there some lurking problem with the alternator or rest of the electrical system that is killing these batteries, and I’m buying a lemon?

If not obvious from the repair notes and/or laws of probability, is that something my local mechanic can unpack for me?

Thanks for any thoughts!

My crystal ball broke last week, so I can only guess at possibilities. :wink:

Could be bad luck, and got 2 bad batteries.

Could be a problem with the car.

Could be the driver is a dink and keeps leaving lights on, or decided to sit in the car with the engine off and all the accessories/radio/nav screen on for a long time.

About the best you can do is to mention these things to the mechanic (not from the dealership) you have do the pre-purchase inspection so that he makes sure to test the charging system and check for any parasitic drains on the battery.

But there’s really no way of knowing from that paper why the two batteries went bad.


There’s another possibility. The original owner may have been using it three times a day just to drive to the corner store. I have a neighbor who does that. That kind of use can constantly drain the battery a bit at a time, as the engine doesn’t run long enough to charge it again after each start.

But as Shadow stated, there’s really no way to tell from here. You could have the battery and charging system tested independently prior to purchase. That might help build your confidence if nothing else.

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Agree with the other posters. There is no way to know for sure. There other used cars out there and if this one makes you nervous… back away from this one and head to the next one.

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Agree. The other thing is if the dealer replaced both batteries, it might have been from the same old stock on the shelf. If no parasitic drains are found and the charging system is good, next time get a battery from someone else.

That points out two very important things to check. And both are easy to check. If both checks are ok, then the battery problem is probably due to other causes, as mentioned above.

Hey thanks for the thoughts guys! I’ll find a mechanic to double-check this. And do I have the magic words right? A test for a “parasitic drain on the battery” and checking the status of the “charging system”? I assumed the latter is basically the alternator but more inclusive.

Unfortunately, the dealership is 40 miles from my trusted local guy, so I’m going to have to call a few mechanics in the vicinity of the dealership to confirm they can check out the car.

Thanks again.

Also, interesting enough, the carfax calls it a “commercial” vehicle, but given its make, model, mileage, condition, and service records, it seems obviously not an uber or rental. Seems like it was someone self-employed and driving around or had a company car – realtor, sales rep, etc. Not sure it bears much on the battery Q but it’s one more puzzle piece.

Most likely just registered to the business for tax reasons. Which brings me to another pet peeve with the tax laws. Why a business can deduct the expense of a vehicle in the production of income but an individual can’t deduct car expenses in the production of income-except in very very rare circumstances. If individuals could deduct the same expenses that small business can, even more than the 40% would be paying no tax.

A standard battery and charging system test is a good idea. Batteries can be damaged by undercharging, overcharging, being completely drained b/c the lights were left on, subjected to severe jolts like the car hitting a big pothole at speed, and just bad luck. You can keep your battery in better health by giving it an over-night low current or trickle charge once in a while, if that option is available to you.

A battery wouldn’t be a deal killer for me. If you like the car and the price is right you might try negotiating the price down a bit to cover a future battery replacement. Say knock a 150 bucks off the asking price and it might make you feel a bit better about things.

And yes, it’s possible for batteries to fail prematurely.

I have seen IS and GS models with intermittent battery discharge, it typically occurs once a year, so infrequent that there is no interest in researching the problem.

A service bulletin was finally issued last year describing an intermittent battery discharge. The repair involves replacing the Network Gateway Computer. This repair is covered for 4 years/50,000 miles but will be difficult to verify. Your neighborhood mechanic won’t find a problem with the charging system or battery.


Wow, that’s some deep deep knowledge – thanks!

I found the bulletin:

It was issued after the 2d battery replacement in the car I’m eyeing, and there’s been no battery problems I can see since, which might explain (if this is indeed the problem) why Lexus didn’t do the full repair in any of the services.

I wonder if I can buy the car and take it into Lexus the next day and ask for this to be done (since the factory warranty expires in about 9 months), or if I have to have a battery failure first.

Very interesting.

I had a similar problem with a Jetta. Found the first battery dead at the 6 month point (dealer replaced), and another at about 1.5 years and yet another at the 2 year point. (more or less, not sure of the times)

Found (guessed) a problem with the dome light, occasionally it would not turn off. If I happened to not use the car for a few days and that occurred, dead battery. There was electronics that held the light on for 20-30 seconds after the door was closed, and that electronics is where the problem was.

Guessed at the solution, turned dome light off, no more problems.

That is a complicated test procedure and certainly the dealer can perform this. But not free.

edit: I’d advise getting this done before you buy the car.

Why not pass on this vehicle and look for something else?

Or carfax could be wrong. They often are.

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