Internal charger expected life

Internal charger expected life

At 57,000 miles the internal charger failed. The car can still charge at a supercharger since supercharging bypasses the internal charger. Of course I didn't buy a extended warranty. Question: WHAT IS THE EXPECTED LIFE OF A INTERNAL CHARGER?

Tâm | August 26, 2015

I haven't seen any published study on this subject.

tes-s | August 26, 2015

I have seen reports of a couple failing.

Perhaps best to supercharge as much as possible to extend the life of the onboard chargers?

Turbo25 | August 26, 2015

More importantly, can you let us know what the out of warranty cost of replacement is? | August 26, 2015


I'm not sure even Tesla knows. I suspect it's designed for the life of the car (maybe 200,000-400,000 miles), but a few will fail before this. Not many reports on the forum of charger failures so it appears to be a good design.

Factors that might shorten the life slightly includes how often it is used, temperatures it encounters (it is cooled by the liquid cooling system), power running through it and vibration/shocks.

ST70 | August 26, 2015

22.7 years

GHammer | August 26, 2015

All electronic components have a similar life cycle curve with a relatively high failure rate early in life and then a long time with very low failure rate followed by a steadily rising failure rate as the components age. Some components like electrolytic capacitors have a much higher aging factor than others like semiconductors. Resistors operated within their spec range have virtually no failure. In a complex high power device like the charger it is difficult to tell what the limiting factor would be, probably the high frequency switching transistors or the AC to DC rectifiers. Charging at less than maximum would probably reduce the heating on those components and extend the life. Assembly issues like not mating the high current devices to their heat sinks could also lead to early failure.

Rocky_H | August 26, 2015

@hammer, Well described. I work for a semiconductor company, and we call it the "bathtub curve", and those early ones, "infant failures". There will be some percent of the product that does just fail very early in their lives, which can be hard for consumers to understand, but most will last for a very long time.

bish | August 26, 2015


Mine failed at 62,000 miles. I did not have the extended warranty. Out of pocket cost for installation of a re-manufactured unit was $2400. It would have been $2800 for a brand new unit.

P.Dolby | August 26, 2015

If they turned the unit over to you after replacement I would be interested in finding out what the cost of repairs would be.
So much so that I will look for a failed unit. I would be keen to see if it could be repaired as I am familiar with what usually goes bad with them.

ca-blessed | August 26, 2015

$2400 replacement?! - well, damn.
maybe that warranty is warranted then :-/

mscott | August 26, 2015

I wonder if this is another argument for having dual chargers? Fault tolerance! ;-)

More seriously, if the charge load is spread out evenly between dual chargers, then the life of both chargers might be extended due to the reduced workload. It would be nice to know if you had dual chargers and one failed, could you still charge at up to 40A with the good one?

Since installing a second charger is $2K, I would think replacing a failed one would be in that neighborhood (possibly plus some labor to remove the old one).

Seira321 | August 26, 2015

Master failed at 57,8xx miles. Model S 85. Had done a software upgrade during the day so asked service advisor if the charger failure could be due to a software upgrade and response was no.
Asked if charging at 40 amps would cause master charger to fail quicker than if charging at a lower rate. Was given an answer that yes, supercharging too frequently would decrease battery life quicker Asked again if charging at the maximum amp would affect the master charger. Response was dual chargers can handle 80 amps and single chargers at 40 amps, so charging at those rate won't affect the charger.
Now that I think about it, I should have asked if he meant no effects on the battery or the charger since the first time I asked he answered supercharging and battery pack.
Had also asked about how much cost would have been if there had been no warranty. Was told $2500.

It would be nice if someone can compile a spreadsheet regarding master charger failure with age of car, miles driven, if master charger failed shortly after software upgrade, and anything else, like how often was car supercharged prior to failure.

SCCRENDO | August 26, 2015

Master charger failed at around 12500 miles as I returned from my first service. Coincidence???? Anyway replaced under warrant. Now 70000 miles no further problems.

SCCRENDO | August 26, 2015

Warranty. Oh what the heck. Brian's no longer around.

tes-s | August 27, 2015

Dual chargers do not provide fault tolerance. Someone posted they had one charger fail and could not charge.

KeepAusWired | August 28, 2015

I can confirm that dual chargers do not provide fault tolerance. When my master charger failed with about 1,500 miles on the car, my charging capability was limited to 16 amps (with frequent error messages and charging interruptions) even though I had a fully functional secondary charger. The ranger who replaced it, however, told me that if the secondary failed, you would still be able to charge at 40 amps on the primary. My understanding is that the secondary charger is not engaged at all unless you are charging above 40 amps. | August 28, 2015

I vote for @hammer's explanation, although back in the Stone Age rectifiers used diodes, not switching transistors. Same difference.

Greenee | August 28, 2015

Yes, I had a master charger fail at 7,000 miles. It was replaced. I was told by Service that the secondary charger only engages when you charge above 40 amps. When the master charger failed the secondary charger did NOT come to the rescue.

murphyS90D | August 28, 2015

Switching transistors are used to multiply the rectified 240 volts AC (maybe 340 volts DC max) up to the over 480 volts DC needed to charge the battery.

Dcp9142 | August 28, 2015

Mine failed at 46k miles.

Michael1675 | August 28, 2015

My master charger failed just over 50,000 miles.

ca-blessed | August 29, 2015

this is a lot of ~50-60,000m failures.
if it's that common of a failure, shouldn't it be fixed or recalled?

prp | August 29, 2015

@ca-blessed, 10 failures, which is more than the number described in this thread, is less than 0.01% of the tesla fleet. Statistically thats very small, but no-doubt frustrating for those inflicted with the failure.

kawdennis | August 29, 2015

Mine went out at 19,000 miles

Kimscar | August 29, 2015

The charger was probably designed to go many hundreds of thousands of miles. Part of the design of course it to work out a MTBF (Mean Time Between Failures) We don't have access to that info so we are all guessing.
There will be those that fail early and some that go on for life of car. At same time some design flaws can be uncovered that shorten the life and are addressed in a revision.
I had one replaced around 5000 pro actively. Not seeing a problem but the engineer said there was a problem.

rick | August 29, 2015


Since the 2nd charger is 2K installed after purchase, it surprises me that your replacement for charger 1 is that high. I'm curious as to why. Difference unit? more difficult installation? Arbitrary R&R pricing?

bish | August 29, 2015


I asked the same question and the only answer i got was that it was a different component than the dual charger.

But the fact that they offered me a choice between a re-manufactured one or a brand new one tells you that enough are failing that somebody is rebuilding them.

But i have faith that Tesla will learn from these failures and build a more robust unit. Also, the replacement unit came with a 12 month/12,000 mile warranty.

rxlawdude | August 29, 2015

So much for the "if Tesla fixes a problem under warranty they will cover the component forever" tripe I've seen.