Model 3 poll - have you changed battery

[Jason71]

So, if you do get a battery warning, what kind of battery does a 2019 M3 need? Should I get one now to keep in the garage just in case or wait until a warning actually appears?

if I had a 4 year old M3 I think I would change it as a precaution. Unless you are planning to sell the car soon you will have to replace it at some point. Might as well be on your terms not the cars.
There is nothing special about the battery. Just go on any motor factors website and put in the reg like you would with any car

Car Batteries | Car Battery Replacements

Give your car the power it needs with a new car battery, and we can help you get it fitted. All our batteries are available with free UK delivery or click and collect.

www.eurocarparts.com

 

[GlynG]

The ones sold specifically for Tesla vehicles have a built in BMS to control charging. Don’t see the point though, they are at least 4x the price of a regular one, unlikely to last 4x as long and have issues in freezing conditions.

The LI 12v replacement battery is expensive and agree 4 times the cost of a standard battery, but, The Tesla lead Acid battery is 3 times the price of a normal 12v Lead Acid battery, so if anyone is intending to keep their car and they need to replace the lead Acid it makes sense to install the LI battery.

Ohmmu LI battery seems to be the most sought but some owners have had the warning on screen the battery needs replacing, but, Its an error that's resulted from firmware updates to the car from Tesla and perhaps something to do with Ohmmu's battery management but they are working on a fix to it, in the meantime the error message can be got rid of by powering down the car, disconnecting the 12V earth lead, and unplugging the HV socket underneath the rear seat, then just reconnect it back up and it seems to be a lasting fix.

 

[MrT3]

The Tesla lead Acid battery is 3 times the price of a normal 12v Lead Acid battery

I've not priced one from Tesla, but certainly comments from people in the US on these forums suggest they don't charge too much. You can also get an equivalent from £70.

 

[M00cow]

I've not priced one from Tesla, but certainly comments from people in the US on these forums suggest they don't charge too much. You can also get an equivalent from £70.

Yeah it's not at all, it's easy to check such a thing in like 60 seconds - just been through on Eurocarparts - Bosch is like £90 for my M3P...
The wifes Mini Countryman is £299 for the same make!

 

[nufan]

Do the cars gracefully give you a warning when the battery is on its way out, and time to replace?

 

[ACarneiro]

Do the cars gracefully give you a warning when the battery is on its way out, and time to replace?

Anecdotal evidence in this forum suggests that, in the good old Tesla way, it's inconsistent.
Some people have been locked out of their cars or stopped mid-drive with sudden total 12V failures and some get a warning weeks in advance.
My sister was in the latter camp: she got an error message on her 2019 M3 and the car would not sleep for about 2 weeks until Tesla got a replacement battery available.

 

[MrT3]

Do the cars gracefully give you a warning when the battery is on its way out, and time to replace?

If the battery slowly loses capacity over time due to age/cycling then yes you get an advanced warning and some time to arrange for a replacement. This is the most common scenario and is equivalent to you noticing your ICE engine not turning over a quickly as it once did when you start it.

If you have a sudden failure, e.g. one of the cells shorting out, then no you won't get any advanced warning.

 

[kuruma]

if I had a 4 year old M3 I think I would change it as a precaution. Unless you are planning to sell the car soon you will have to replace it at some point. Might as well be on your terms not the cars.
There is nothing special about the battery. Just go on any motor factors website and put in the reg like you would with any car

Car Batteries | Car Battery Replacements

Give your car the power it needs with a new car battery, and we can help you get it fitted. All our batteries are available with free UK delivery or click and collect.

www.eurocarparts.com

cheers... there seem to be quite a range of prices

Bosch and Varta both have 4 year guarantees while Lion and Exide are only 3 year. Bosch the best value then?

 

[Jason71]

cheers... there seem to be quite a range of prices

View attachment 1009846

Bosch and Varta both have 4 year guarantees while Lion and Exide are only 3 year. Bosch the best value then?

Isn't there always. I guess you get what you pay for. Most Bosch stuff is reasonable quality so probably as good a choice as any.

 

[kuruma]

so, I got that BOSCH battery. Followed a guide on YouTube to install it. All was good.

For a week.

Today, we've got notifications to change our 12V battery.

What?!

Mobile service will charge us £108 to come and have a look. Car tells me it won't sleep while idle. Reboot doesn't make any difference.

Only thing I can think to do at this stage is to reinstall the battery. Anyone else have any ideas?

 

[kuruma]

the error message can be got rid of by powering down the car, disconnecting the 12V earth lead, and unplugging the HV socket underneath the rear seat, then just reconnect it back up and it seems to be a lasting fix.

Just seen that @GlynG wrote this which I might try later on when the wife gets back with the car... although I'm not too sure what the "12V earth lead" is. I've got positive, negative and the hose.

 

[GlynG]

Just seen that @GlynG wrote this which I might try later on when the wife gets back with the car... although I'm not too sure what the "12V earth lead" is. I've got positive, negative and the hose.

The negative cable is the earth lead, all modern cars use the negative as the earth, Positive feeds all equipment and the car body completes the circuit, the negative lead on the battery is directly connected to the body shell.

Just as an aside - maybe of interest. Up to the early 60s all cars were positive earth, It was discovered this was the reason cars used to rust and rot very quickly, some cars much worse than others - Vauxhall for instance, The change to negative earth systems instantly rectified the issues - though it also destroyed the industry standard for undersealing cars - and believe it or not main dealers even in the early 70s still had a chap employed solely to underseal brand new sales - it was an option they pushed hard with because it took years to convince the public it wasn't necessary anymore.

 

[kuruma]

oh... interesting. Ask me anything you like about DIY, photography, computers and guitars but for some reason cars have always remained a mystery to me

 

[JIBYC]

Mine failed quite spectacularly at just over 4 years last year.

Replaced in Norwich during a walk-up appointment for about £92.

The advisor did point out that the cars are very specific about which battery type, and they have to specify the battery variant in service mode.

 

[Js1977]

Replaced in Norwich during a walk-up appointment for about £92.

Ill stick my neck out and say that is not a bad price at all!

 

[KennethS]

Ill stick my neck out and say that is not a bad price at all!

+1

Our Model 3 will be 5 years old in August and when our 12v battery goes I will happily pay that for a replacement from Tesla.

 

[kuruma]

The advisor did point out that the cars are very specific about which battery type, and they have to specify the battery variant in service mode.

I'm not sure about tha (unless you're switching between LI and acid. The service manual only says this:

If replacing a Clarios (Varta) 12V battery with an AtlasBX 12V battery, or vice-versa, update the vehicle configuration.

That makes it sound like you only have two 12V battery options. I simply followed @Jason71 's advice to follow his link, stick in my reg and pick one of the four recommended for my car.

I'm a bit puzzled as to how it took a week for the car to decide it had an issue with the 12V rather than it deciding instantly. I just might have a duff battery. Eurocarparts were helpful on the phone (not). They won't test the battery for me in the car, but are happy for me to take it out of the car and bring it back so they can test it out of the car. Plonkers...

As soon as Mrs K gets home, I'll get the multimeter out...

 

[kuruma]

Battery tested ok at 12.55V. I followed the method @GlynG outlined and the warning has gone away. There was an initial worry when the screen stayed black for a minute or two after reconnecting the battery but it did eventually show the Tesla logo and come back.

 

[WannabeOwner]

the screen stayed black for a minute or two after reconnecting the battery but it did eventually show the Tesla logo and come back

That sounds like the amount of time it would take for a full reboot (what used to require both-buttons press and also foot-on-brake), so although probably a heart stopping moment! I think it likely just the normal "boot from scratch" time.

 

[JIBYC]

To answer some of the above

Yes, £92 is a very reasonable price, almost at cost. They said they do about 2 Fremont cars a week.

Re the battery type, as I understand it, Tesla added some diagnostics to try and give some advance warning before the 12v fails. I'd guess that these are tuned to the battery type, hence they have a short list of supported types.

My 12v didn't fail slowly, according to the tech it just went pop. As a result the car would have kept the high voltage battery engaged permanently resulting in a 15% loss per day. Not great as I was on holiday.