M3 RWD charging at 40amp after PCS replacement?

[DeLo81]

Hello, I’m a new owner looking for some help with a very specific question. Hoping someone here has the answer.

I recently bought a 2020 M3 SR+ RWD. I had a Wall Connector installed on a 50a breaker so it’s configured to charge at 40a but the RWD M3s only charge at 32a. Still following? Please stay with me. When I first charged it would only charge at 16a and I assumed correctly that the PCS was failing and Service replaced the PCS. Now it can and will charge at 40a but should only charge at 32a. Is it ok to charge at 40a or should I leave it set at 32a. Is it possible Service installed the larger PCS, the one used for AWD? Thanks for your help!

 

[jjrandorin]

Thats interesting and the first I have heard of this specific issue. As you state, Model 3 RWD is supposed to max out at 32amp charging.

My understanding is that the devices that control L2 charging in the car are 16amp devices, and RWD vehicles have 2 of those (thus up to 32 amp charging) and AWD / Performance (and early LR RWD) have 3 (thus up to 48amp charging). This would basically mean they added one of those devices to your vehicle by mistake, when it was in for service (or because they didnt have parts, or some other reason).

If the car can physically charge at the higher rate, it should be fine to leave it there. If you go back to tesla, they may tell you to leave it alone, or they may want to exchange parts and reduce it back down to "what its supposed to be".\

If I was going to keep the car, I would just leave it alone and enjoy the faster L2 charging on a SR+/RWD vehicle, but I am not an insider or anything, just a regular owner.

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(moderator note)

I changed your thread title because the original title was "model 3 wall connector help" but this doesnt appear to have anything to do with the wall connector at all. The issue is your questions around the car charging at 40amp after PCS replacement by SC.

 

[Soul Surfer]

Can you tell us if the car is inside or out? Would the charging rate be affected by the lowered temps? Mine is underground so despite freezing cold Toronto, it had no affect, although I did get a once after a very cold day.

 

[Msjulie]

My 3 can charge 40A but unless I am in a hurry I charge at least just to be a little kinder on the battery. It's charging overnight so no big hurry

Maybe it's fake new but mine is at 38 cause once upon a time I read that was reasonable, maybe 32 is better if you're not in a rush. Experts with facts please chime in

 

[Sklith]

AC charging at a lower rate won't do much to help the battery out since even at 48A that's only 0.13C on a AWD Model 3. Anything less than 0.5C (2 hour charge time) shouldn't harm the battery. Lowering the amps can extend the life of the onboard charger, though.

 

[terranx]

Should be fine to charge a model 3 rwd at 40A. Might as well enjoy the bonus.

 

[dmurphy]

Won’t hurt anything but sure does sound like they put a long range PCS in there. Maybe that’s all they had on the shelf?

Either way, I’d say just enjoy the faster charging. If you can find someone with a wall connector setup for 48A, that’d kinda confirm it.

 

[DeLo81]

Thats interesting and the first I have heard of this specific issue. As you state, Model 3 RWD is supposed to max out at 32amp charging.

My understanding is that the devices that control L2 charging in the car are 16amp devices, and RWD vehicles have 2 of those (thus up to 32 amp charging) and RWD / Performance have 3 (thus up to 48amp charging). This would basically mean they added one of those devices to your vehicle by mistake, when it was in for service (or because they didnt have parts, or some other reason).

If the car can physically charge at the higher rate, it should be fine to leave it there. If you go back to tesla, they may tell you to leave it alone, or they may want to exchange parts and reduce it back down to "what its supposed to be".\

If I was going to keep the car, I would just leave it alone and enjoy the faster L2 charging on a SR+/RWD vehicle, but I am not an insider or anything, just a regular owner.

=====================================
(moderator note)

I changed your thread title because the original title was "model 3 wall connector help" but this doesnt appear to have anything to do with the wall connector at all. The issue is your questions around the car charging at 40amp after PCS replacement by SC.

Thanks for the info and more accurate title!

 

[sightman]

Considering the car can regen well over 50kW during a drive, you are all good. Very interesting though.

 

[DeLo81]

Thanks everyone. Now I kinda wish I had a 60a breaker put in so I could charge at 48a.

 

[Rocket_man]

My 2022 M3 RWD has the LFP battery chemistry, and the on-board charger that limits me to 32 amps. But you have the SR+ model... doesn't it have the NMC battery? Which I thought could charge at a higher rate?

 

[stopcrazypp]

My 2022 M3 RWD has the LFP battery chemistry, and the on-board charger that limits me to 32 amps. But you have the SR+ model... doesn't it have the NMC battery? Which I thought could charge at a higher rate?

It's not the battery that is the issue, it's because the onboard charger in the SR+ (or RWD) only has two of the 16A charger modules, so you get only 16A*2 = 32A max. The more expensive LR and Performance models instead have 3 of the 16A charger modules, so they can support 16A*3 = 48A max.
Onboard Charger

I believe this is how the board in the LR one looks:

This one is probably the SR+ one:

2017-2022 Tesla 3 M3 Power Conversion System PCS OnBoard Charger 1093219-10-G | eBay

The EPC shows two part numbers:

9	ASY,PCS,48A-CD,1PH,MDL3	1135558-04-A	Tesla Only	1	1
9	ASY,PCS,32A,1PH,CD,MDL3	1135558-03-D	Tesla Only	1	1

Parts Catalog

OP got lucky because they very likely installed the "wrong" one (maybe they ran out of the 32A one or it could be a mistake).

 

[flashflooder]

Thats interesting and the first I have heard of this specific issue. As you state, Model 3 RWD is supposed to max out at 32amp charging.

My understanding is that the devices that control L2 charging in the car are 16amp devices, and RWD vehicles have 2 of those (thus up to 32 amp charging) and AWD / Performance (and early LR RWD) have 3 (thus up to 48amp charging). This would basically mean they added one of those devices to your vehicle by mistake, when it was in for service (or because they didnt have parts, or some other reason).

If the car can physically charge at the higher rate, it should be fine to leave it there. If you go back to tesla, they may tell you to leave it alone, or they may want to exchange parts and reduce it back down to "what its supposed to be".\

If I was going to keep the car, I would just leave it alone and enjoy the faster L2 charging on a SR+/RWD vehicle, but I am not an insider or anything, just a regular owner.

=====================================
(moderator note)

I changed your thread title because the original title was "model 3 wall connector help" but this doesnt appear to have anything to do with the wall connector at all. The issue is your questions around the car charging at 40amp after PCS replacement by SC.

The RWD (at least my 2018 build) has 3 legs in the PCS. Capable of charging at 40A from a 14-50 or 48A from a wall connector.
I am here because 1 of mine just went bad, a few hundred miles out of warranty. I can only charge at 32A at home now.

 

[cvergara]

Hello!

Recent PCS victim here as well. Picked up my 23 RWD and it now also charges at 48A. The work order shows they replaced the PCS with a 48A PCS . Must be what they do now when the PCS dies during warranty.

 

[Big Earl]

Hello!

Recent PCS victim here as well. Picked up my 23 RWD and it now also charges at 48A. The work order shows they replaced the PCS with a 48A PCS . Must be what they do now when the PCS dies during warranty.

A 50% improvement in AC charging is a nice surprise.

 

[rpiotro]

Thanks everyone. Now I kinda wish I had a 60a breaker put in so I could charge at 48a.

Careful. You can't just put a larger capacity breaker in unless the wiring supports it. If you burn your house down insurance won't cover it.

 

[terranx]

The insurance thing is a myth. But they may drop you after the payout