L2 charger down to 2.7kwh at 24F.. Should I be worried?

[mkhuffman]

My understanding is that in the USA, single phase power is typically 120/240 volts, while three-phase power is typically 120/208 volts.

At different voltages, the relationship between amps and kW will be a different ratio.

Best to all!

P = IV

Sponsored

 

[COMtnEV]

I know that this issue seems to have been resolved - but it was getting too warm here in MN to really test it when the relevant update was released. Now with manual preconditioning in 2025.18, we have a way to force the battery to warm up and resolve this issue manually if it does happen to occur again.

 

[COMtnEV]

Have had overnight temps in upper teens - low 20s over the past couple weeks, dropping battery temps into the low 40s (per Rivian - my ABRP temps are typically 2-3F warmer). I've done two charge sessions, and it appears that this problem is indeed corrected. I've updated the chart I posted last spring (battery temps are per ABRP) - the two charge sessions are plotted in the thick lines. Although when it happens relative to SoC varied, in both cases after a period of charging at lower SoC where battery temp didn't change very much, the battery the rapidly warmed over a 30-45 minute period to temps above the critical 55F. In both cases the truck maintained maximum charging rate (on my 40A charger) to the end of the charging session (95 and 96% for the two sessions). As an added bonus, the predicted charging times are now much more accurate - they used to be off by more than a factor of two (understimate), even for target SoC of <80%. In both cases during charging ambient temps were 25-55F, so not super cold, but looks like it has indeed been fixed.

 

[MarkNorman]

Here’s hoping! Thanks for the testing @COMtnEV. We also have an easy on-demand battery preconditioning option, so this winter should be much better for Gen 2 folks.

 

[RMSko]

We also have an easy on-demand battery preconditioning option, so this winter should be much better for Gen 2 folks.

Could you point me to where that is?

 

[MarkNorman]

Could you point me to where that is?

Sure, go to the Energy menu and select the Charging tab and then press the “Prepare for Fast Charging” button

 

[VandalSibs]

Sure, go to the Energy menu and select the Charging tab and then press the “Prepare for Fast Charging” button

I wouldn't use this function for AC/Level 2 charging. It's meant for use with DC Fast charging, where temperature range matters a lot more.

 

[MarkNorman]

I wouldn't use this function for AC/Level 2 charging. It's meant for use with DC Fast charging, where temperature range matters a lot more.

Fully aware that is the intended use. Those of us that have been on this thread since last winter understand cold battery temps (below 55) were causing horrible throttling during AC charging in Gen 2 vehicles. Manual preconditioning was not available last winter but would have been appreciated when my R1S was charging at <1Kw on an 48A EVSE.

 

[Time2Roll]

Fully aware that is the intended use. Those of us that have been on this thread since last winter understand cold battery temps (below 55) were causing horrible throttling during AC charging in Gen 2 vehicles. Manual preconditioning was not available last winter but would have been appreciated when my R1S was charging at <1Kw on an 48A EVSE.

Was that 1kW to the battery and more for the battery heater?

 

[MarkNorman]

Was that 1kW to the battery and more for the battery heater?

Early on, there was no indication the battery was getting any heat during L2 charging. Rivian pushed a couple updates and it improved a little. By the time the “real fix” was rolled out, Spring was here and it was warm enough that we couldn’t really test it.

Luckily, the recent testing by @COMtnEV seems to show this is resolved.

 

[RivAW]

I should add I'm using a Tesla home charger and an A2Z adapter

Same setup here. When my A2Z adapter started dying was when the charge rate started great and slowed after a few minutes as you described. Your adapter is the prime suspect assuming you have tried a vehicle reset already.
FYI A2Z has good customer service and a 1 year warranty on their adapters. If you happened to pay for yours with an Amex, then your warranty term is doubled.

Sponsored