Issue with lvl 2 charging?

[abirozy]

Good morning everyone.

Ok, first let me say my technical knowledge of charging sucks. I have had a Tesla for 6 years, just plug in and unplug when done. I work for the city and get free lvl 2 charging. I usually plug in when i get to work and am full by the time I unplug.

The Rivian gets significantly more range than my S (318 vs 249) and the other day, I notice my Rivian was plugged in for almost 10 hours and had still not topped off. Usually with my Tesla, I would stay at a pretty steady 16MPH - 22 MPH range being added. I tried to trouble shoot and would ocassionally log on to the app to see my charge rate. To be able to compare equally, I leftmy Rivian on miles / hr like my tesla is.

I very rarely got above 12 MPH of range added and was usually below 10. Sometimes I was even at 4 or 5. At the time, I was using an adapter on one of the Tesla destination chargers, so I thought maybe the adapter was effecting the charge rate. So I changed to a regular lvl 2 with the standard plug and got the same result. To test out if something had changed with the chargers, I drove my tesla the next day to work and got the usual 20 mph range added that I normally get.

1). Is this normal? Is it a setting on my Rivian? Or should I be worried?

I understand that there is a vastly different charging curve (sorry, not that technically minded to talk about it with any authority) but I would figure on a lvl 2, or any other lower level charging it would stay pretty consistant since the draw is not that much.

Thanks again for any insight / help

Adam

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[Dark-Fx]

A significant amount of public charging is 30/32A. The stations that are on 3 phase power tend to be 208V, which means you might be limited to ~6 kW of power. The Rivian's battery is ~125 kWh. It would take over 20 hours to fill the battery of the Rivian on one of those chargers.

 

[IRun]

Rivian is definitely slower due to larger pack size.
At work I use a 6.6kw charger and get a steady 11.8
At home I plug in the mobile charger to my 14-50 and get about 15.5 miles per hour. Same plug gets me 30 miles per hour on my model 3.

There is a setting on the Rivian charging settings that allows you to limit the amps, much like on Tesla, are you sure that is set to the max? If not you may have an issue but way to many variables to diagnose on the internet.

 

[guernsej]

How many kWh is the charger?

 

[cohall]

What was your kWh rate? Pretty sure that's the only figure that matters. Miles added per hour cannot be looked at across vehicles, due to difference in efficiencies.

 

[abirozy]

I will have to see if it is posted... I can look at the KWH or amps in the display, but I think they change. The work chargers are supposedly in a "bank" that will allocate based on how many vehicles plugged in and a number of other factors.

Sorry I could not answer off top of my head. I will try to get the information. I think it may be the efficiency thing though. That makes sense to me.

 

[ajdelange]

The essential thing to be aware of is that your Rivian requires more energy to go one mile (~ 500 Wh/mi) than your Tesla (~ 240 Wh/mi) therefor when connected to the same capacity charger (X W) the Tesla will take charge equivalent to X/240 miles per hour but the Rivian will only take on X/500 (about half as many).

Because your Rivian uses more Wh to go a mile and because it will go more miles than your Tesla it has a bigger battery so if you note charge progress by % be aware that 1% of the capacity of your Rivian battery takes more Wh to fill than are required to fill 1% of your Tesla battery. Thus for a fixed charger power it takes longer to add a % to the Rivian.

So yes, all perfectly normal.

 

[zefram47]

And this is why miles per hour as a charging rate is a horrible metric. Sure, it indicates how many miles you recover in some unit of time, but you have to remember that a Tesla gets around 4 mi/kWh and the Rivian is closer to 2 mi/kWh. So at the end of the day if your Tesla was doing around 20 mph, then of course the Rivian would be around 10 mph on the same charger. Most public chargers are 6.6 kW or 6.6 kWh in one hour, which translates to close to 24 mi in the Tesla and 12 mi in the Rivian.

 

[nc10]

I will have to see if it is posted... I can look at the KWH or amps in the display, but I think they change. The work chargers are supposedly in a "bank" that will allocate based on how many vehicles plugged in and a number of other factors.

What state of charge are you trying to maintain? 70%?

 

[Akay07]

Good morning everyone.

Ok, first let me say my technical knowledge of charging sucks. I have had a Tesla for 6 years, just plug in and unplug when done. I work for the city and get free lvl 2 charging. I usually plug in when i get to work and am full by the time I unplug.

The Rivian gets significantly more range than my S (318 vs 249) and the other day, I notice my Rivian was plugged in for almost 10 hours and had still not topped off. Usually with my Tesla, I would stay at a pretty steady 16MPH - 22 MPH range being added. I tried to trouble shoot and would ocassionally log on to the app to see my charge rate. To be able to compare equally, I leftmy Rivian on miles / hr like my tesla is.

I very rarely got above 12 MPH of range added and was usually below 10. Sometimes I was even at 4 or 5. At the time, I was using an adapter on one of the Tesla destination chargers, so I thought maybe the adapter was effecting the charge rate. So I changed to a regular lvl 2 with the standard plug and got the same result. To test out if something had changed with the chargers, I drove my tesla the next day to work and got the usual 20 mph range added that I normally get.

1). Is this normal? Is it a setting on my Rivian? Or should I be worried?

I understand that there is a vastly different charging curve (sorry, not that technically minded to talk about it with any authority) but I would figure on a lvl 2, or any other lower level charging it would stay pretty consistant since the draw is not that much.

Thanks again for any insight / help

Adam

Like others have said the difference in miles added is due to battery size. My mustang "added" more miles per hour vs my truck because I'm getting basically the same range on a smaller battery pack.

What I saw at work charging on a 6.6kwh charger, is that the rate would change. The rate would drop to 3 (no shared amount between charging stations) for like an hr or so and then go back up to almost 6 kwh. It did this on hot and on mild days. Not sure why it does that every day. My mustang did not.

 

[ajdelange]

Like others have said the difference in miles added is due to battery size.

I hope nobody said that. The difference in miles added is due to the different consumptions (watt hours required to go one mile). Now if it takes more Wh/mi in one car than another and the two have comparable ranges then it stands to reason that the higher consumption car will have a bigger battery and will, thus, take longer to pick up a given percentage charge from a charger operating at a fixed rate. So they are related.

 

[MoreTrout]

Think of it this way. You have an ICE F-150 that gets 15 mpg and and some other small SUV of your choice that gets 30 mpg, and both of them have the same size gas tank. Call it 10 gallons. If you spent 5 minutes on both filling both gas tanks at the same pump, would you expect both to get the same range because they were filled by the same gas pump for the same amount of time? Of course not. The truck would go 150 miles and the SUV 300 miles. Yet your time spent filling them would be equal. Using your EV charging thought process, the truck got 150 miles/5min and the SUV got 300 miles/5 minutes. Pump and hose that the gas flowed through worked exactly as advertised.

No different for a large brick shaped EV truck vs an aerodynamically optimized EV sedan. Make the assumption that the charger is working normally and the vehicles are under normal conditions. You will deliver the exact same amount of energy in the same time to both vehicles. But that equal amount of energy will only get you 1/2 the distance in the EV truck vs sedan, just like the ICE truck only gets half the distance of the ICE SUV on 1 gallon.

 

[mindstormsguy]

Everyone who is telling you it’s the battery size is wrong. The batteries are not impacting or limiting your charge speed. It’s the difference in driving efficiency that is doing it, like some others have explained. If a vehicle is more efficient at driving , it’s also going to get more miles/minute of charging.

 

[ajdelange]

Everyone who is telling you it’s the battery size is wrong. The batteries are not impacting or limiting your charge speed.

That is true if you reckon charge speed in effective miles range added per kWh charged or in terms of kWh charged per hr but it is not true if you reckon charge speed in terms of % SoC added per hour. It's explained in No. 11.

It’s the difference in driving efficiency that is doing it, like some others have explained. If a vehicle is more efficient at driving , it’s also going to get more miles/minute of charging.

Speed figured in estimated miles added per hour charging depends on consumption (Wh/mi), not efficiency (watts/per watt i.e. dimensionless number beteen 0 and 1). All these vehicles are very efficient in that 85-90% of the energy put in goes to the road be that energy 250 Wh/mi or 500).

[EDIT]I recognize that Rivian trucks have a display that shows the reciprocal of consumption and that that display is labeled "Efficiency". Rivian's decision to do this does not help peoples' understanding.

 

[abirozy]

What state of charge are you trying to maintain? 70%?

honestly my goal during the week is simply to maintain the same soc (if i am using the term correctly). so I drive 80 miles a day and I would like to be able to work the week using only the lvl 2 chargers at work.

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