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Charging over amp limit: 34/32A
- Thread starter dsgerbc
- Start date
Most likely just normal variance.
Also, I'm sure you know, but your circuit is good to 40 amps.
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When I start charging, my screen shows the amps increasing from 0A to 34A. It stays at 34A for less than 2 seconds before it settles at 32A
Manitoba Keith
Member
BUT, 80% on a constant load is 32 Amps. You can change it but it looks like you have it set to 32 Amps. Go figure.
doghousePVD
My grandfather’s car
Feel the temps of the plug and wires. If they are only a little warm I wouldn’t worry about 2amps.
I worry about software/hardware not respecting limits. 34/32 is nothing, but what's other than software/hardware is stopping the car from trying to pull 48a?
It is not very uncommon for people to see 34 amps. There is a lot of rounding going on and the rounding is always up. Assuming you are drawing a hair over 33 amps times the 335 volts you are right at the 7700 watt rating of the MCU.
I can't imagine the MCU taking 7700 watts... where are you getting that? It can't really take anything like that, IMHO.
AlanSubie4Life
Efficiency Obsessed Member
This is sort of interesting. Interesting that it consistently draws excess.
So it has not always behaved this way? It was correlated with the breaker change, or was it correlated with something else? Or did you only start paying attention to the screen closely when you changed the breaker?
I think the denominator number is just determined by what the UMC (or whatever) communicates it can source. The numerator (actual current) is probably dead reckoned by the AC-DC to match the target. And measured by something else...but perhaps there is no "check" or feedback of that measurement to the AC-DC to back off - the AC-DC dead reckoning is assumed to be close enough to not need correction?
Maybe it's only dialed back if excessive voltage drop is detected. But this sort of small discrepancy due to AC-DC variation is ignored?
No idea really.
How does it behave if you change the max current limit setting - is it always 2A over, or is the current overshoot proportional, or what?
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It's charging normally today. It's not that I check often, but this is something I would have noticed before. A few days prior I was trying to diagnose the noise from the panel and started/restarted the charge a few times. It was completely fine, not going over 32. The only thing somewhat different yesterday was the initial SOC, which got under 40% due to some work driving, which normally doesn't get below 60. I may try get it under 40 again and see if it tries this again.
Ok, you are talking the mobile connector unit(doh)... I've only heard it called the UMC(universal mobile connector).
I was interpreting MCU to be the ECU or whatever Tesla calls it(or rather them.. presumably one for general car control and another for 'advanced' features). My bad.
AlanSubie4Life
Efficiency Obsessed Member
It’s a UMC not the MCU. You had reason to be confused.
TomB985
Member
I wonder if there is something interesting going on with the onboard charging unit. I would imagine you would see warning messages if that were the case, though.
How does the system measure current?
How does the system measure current?
I sure would say it is very uncommon. I've been here a lot of years, and I don't ever remember seeing this thing of the currently running amps being higher than the allowed amps. I would say something like this sounds like a software display glitch, and I would expect that it would clear itself up with a reboot of the center screen.
AlanSubie4Life
Efficiency Obsessed Member
If you see it again, try lowering the current limit just to see how it behaves. And a reset.
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