Gen 2 Mobile Charger Charge Rate Update

Andy Jones reports:

The recent update 2021.12.25.7 has an update which allows the Universal Mobile Charger (UMC) Gen 2 charger to now charge at full rated power.

Previously the 10amp and 15amp tails only actually allowed / limited to 8amp and 12amp speeds respectively. It’s now gone up to 10amps and 15amps respectively.

Great news especially for those who only use the UMC at home. The pictures show before and after the update using the same socket and charger setup. Current was 12A and is now 15A.

Note the power says 3kw in both pics because it’s rounded.

Also note that I didn’t get the higher rate straight after the update. apparently you needed to plug in the UMC for the car to communicate with the UMC to update its firmware. We got it this morning after plugging in overnight.

10 Replies to “Gen 2 Mobile Charger Charge Rate Update”

  1. From further investigation this faster speed only seems to appear for tails with MIC vehicles where the included tails are marked (in small print)
    10 10A 250V and 15 15A 250V.

    For those with older Model 3s where the tails are marked
    10 8A 250V and 15 12A 250V
    No such speed bump.

    1. Mark, I’m puzzled as to how the tail actually controls the amps (10 vs 8 … I get 10 vs 15). Surely, the current is controlled electronically inside the box, not in the tail, where I imagine it is just wires?

      1. There is a MAX31826 1-Wire temperature sensor with a 1Kb password protected EEPROM which is encapsulated in the head of the plug. This is used to ensure the plug does not overheat and also tells the UMC the maximum current rating of the tail – and hence the maximum current to offer to the car.

  2. Couldn’t persuade my new Model 3 to go above 12A then found if I turned off Scheduled Departure and set Scheduled Start it could be changed! Bad news is that next day it was back to limiting setting to 12A again. Annoying. Various other setting revert overnight also, getting to be a pain.

  3. Saw somewhere you have to set the charge limit to 1% above SoC. Is this is a furphy, and why does my MY charge at 12amp on the 15amp tail? Surely this has been fixed by now?

    1. You just need to set it to something above your current SoC, so that it runs a charging session.

      Some tails are specifically marked as 8A and 12A on the tail, and those ones won’t update – you can exchange them at Tesla (although they may want a fee to do so)

  4. Tesla Southport traded in my 2021 lfp and I purchesed a 2023 model y performance. It would only charge 8 amps max on the portable charger they advised me that’s all they do and that is that. I need to purchase a Tesla wall charger. I asked them for my old one back. That was not going to happen. Service said yes old ones work but they overheat. I said but mine have 10 amps written on them. This is misleading. It’s frustrating to pick up a brand new car and have so many issues

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