SOC Creep Above Limit

[Engineer]

I usually plug in over night in my garage (rivian charger) and wake up to 70% charge which is my limit.

My daughter has been in the hospital all week so I haven’t unplugged the rivian since Monday evening. I just checked and my SOC is at 73% which seems like quite a bit over the 70% set point.

Charging graph shows it periodically increasing charge. Is this normal? Will it ever stop or will it eventually get to 100%?

this seems like odd behavior to me.

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[Dark-Fx]

I've definitely observed this happening, but I don't typically leave the vehicle plugged in for more than a couple days in a row. Seems like when it kicks on to condition the battery, it ends up charging longer than necessary to account for the energy lost doing the maintanence.

 

[Engineer]

I've definitely observed this happening, but I don't typically leave the vehicle plugged in for more than a couple days in a row. Seems like when it kicks on to condition the battery, it ends up charging longer than necessary to account for the energy lost doing the maintanence.

I have observed this before but only 1/2 or 1 % over because like you I don’t leave it plugged in for long periods like this normally.

SOC “limit” seems to be more of a suggestion.

now I want to leave it plugged in for another week to see what happens.

 

[Engineer]

Well I got a stopped charging error sometime last night. No apparent reason for it…. I have gotten this before too. Anyone else experience this or do I need to get an appt?

Until this error it’s been plugged in for about 5 days straight without issue. Got up to 73.2 % max charge.

 

[Zoidz]

Is there any possibility there was a brief power line glitch/outage that might have caused the error?

 

[Engineer]

Nothing that registered on my UPS…

 

[not_a_car_guy]

Every time I’ve gone on a trip for more than 3-4 days—I usually leave my truck plugged in—at some point there’s a charging error. When I get back, the LEDs around the charging port are red.

Note: I have a Rivian wall charger.

 

[NY_Rob]

Maybe Rivian is admitting to and compensating for 1-2% vampire loss per day by overcharging?

 

[Magicbus]

I’m away on a 7 week trip and left mine plugged in and set to 50%. It’s been a week and it loses ~1% per day and I see it also charging for 16-18 minutes most days - which is what I would expect. I would try a vehicle reboot because I don’t see any reason the chosen SOC should creep up.

 

[superfly_snook]

Wouldn’t the SOC estimate on your screen be just that and subject to things like ambient temperature? I would guess the SOC as estimated by the software could change. 70% as measured in the middle of night in a cold garage may measure at 70+ the next day in a warmer environment. There may be other factors as well. A 3% change does seem significant but the software could also have some hysteresis around the set point so when plugged in for long periods of time it doesn’t continually charge to stay at a set point but instead charges a few percent over.

 

[MReda]

Mine has been doing this since a recent software update. I think two updates ago specifically, but it's been long enough that I can't remember. It's set to 70%, and if I don't drive, it'll slowly creep up each day pretty much exactly like your graph. It didn't do it in the first ~18 months of ownership, so I'm assuming a bug was introduced.

That's interesting regarding the charging error - the one time I left my truck for a week over the holidays, I got a charging error as well. I wonder if it hits some threshold where it suddenly errors out... Seems like it's approaching 5% at that point, so maybe there is a limit that causes the error.

 

[WorldComposting]

I now work from home so a lot of times I leave mine plugged in all week and I have the same thing over 5 days it will creep up 1-2% above my charge. As far as the charger I have not had any errors but I have a Chargepoint charger so I can get a discount through my power company.

I'm not too worried about it, if I was going to leave for 2 weeks or not drive at all I would probably lower the charge limit to 60% and then it should never even come close to 90 or 100%.

 

[jollyroger]

Wouldn’t the SOC estimate on your screen be just that and subject to things like ambient temperature? I would guess the SOC as estimated by the software could change. 70% as measured in the middle of night in a cold garage may measure at 70+ the next day in a warmer environment. There may be other factors as well. A 3% change does seem significant but the software could also have some hysteresis around the set point so when plugged in for long periods of time it doesn’t continually charge to stay at a set point but instead charges a few percent over.

this is what I was thinking, lower temperatures reduce voltage and I believe that voltage is used to measure capacity as well. However, I’m not a battery engineer so I don’t know if such a variance would be expected.

 

[Engineer]

Wouldn’t the SOC estimate on your screen be just that and subject to things like ambient temperature? I would guess the SOC as estimated by the software could change. 70% as measured in the middle of night in a cold garage may measure at 70+ the next day in a warmer environment. There may be other factors as well. A 3% change does seem significant but the software could also have some hysteresis around the set point so when plugged in for long periods of time it doesn’t continually charge to stay at a set point but instead charges a few percent over.

maybe, but this isn’t that. It is actually charging:

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