HPWC drops to 40 amps after a few minutes....

[HFh]

So, I haven’t posted in a long while.

I’m on my third model s after 5 years (I’m telling you this so you know I’m not a newbie). I have two HWPCs with 100 amps in and properly configured. This past weekend, I noticed that my 2015 P90D charges for a minute or so at 40 amps, goes up to 80 amps. There it happily charges for, I dunno, 5-10 minutes then drops back down to 40 where it appears to stay until fully charged. I tested on both HPWCs and get the same results. I have no idea how long it’s been exhibiting this behavior because normally I have no reason to pay attention.


Any ideas on why this is happening? Bad wiring? Charger? The universe hates me?

Edit: ugh I mean drops to 40...

 

[Saghost]

I don't have a dual charger car, but from what I've read I'm pretty sure that isn't normal behavior.

Sounds like a problem with the slave charger unit of some sort - you have two charger modules, and they are explicitly coded as a master and slave. Dropping back to 40A sounds like it stopped charging on the second charger entirely for some reason (40A is the limit of what a single charger can do.)

Need a ranger or service center to figure it out.

 

[HFh]

I suspect one of the chargers is defective. An interesting question is why the car doesn’t tell me.

 

[Evoforce]

So my suggestion would be to shut the whole circuit down and then power it all back up again. Test... You know how sometimes electronics just need to be reset. It may also be sensing too much resistance in your cable connector at the port that may be overheating. The cable ends are known to wear out by overheating.

 

[HFh]

So my suggestion would be to shut the whole circuit down and then power it all back up again. Test... You know how sometimes electronics just need to be reset. It may also be sensing too much resistance in your cable connector at the port that may be overheating. The cable ends are known to wear out by overheating.

I tried recycling and got the same result. I also realized at that point that my two HPWCs are on completely different paths.

On the heat issue, now that you mention it, I noticed about a month or so ago that my connector was no longer hot when I tried to unplug it in the middle of charging. I remember being mildly surprised but didn’t think much of it. I think it’s been doing 40 amps for a long while.

 

[HFh]

Update: Elon read my logs. Apparently there’s a “coolant restriction” that’s causIng the car to do throttle back. I’ll be taking it in next week.

 

[Rocky_H]

Yes, that 40A number tells you pretty definitely that it's one of the chargers in the car that has stopped working for some reason.