Rivian Battery Poll - VOTE HERE

What battery will you be going with and why ?

  • 105kWh (230+mile range)

  • 135kWH (300+mile range)

  • 180kWh (400+mile range)


Results are only viewable after voting.

cskatx

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Practicality takes me to want the maximum range. Although most of my driving will be local, I live in Texas - a big state, where visiting nearby family is 320 miles round trip. ALso assume range in 100+ degree weather is discounted from spec, and I’d like a solid safety buffer.


Im on the fence between the 135 & 180kWh packs. Knowing that the majority of EV’s on the road today have a 300 mile range and are navigating that just fine. Is is necessary or worth it to go up to the 400mile range ?

Would love your thoughts and input here. I get the bigger is better argument, but what other then that is swaying your decision?
 

MountainBikeDude

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First EV and going for the 180 kWh pack for similar reasons to what many already stated. I drive very frequently, especially between Vancouver and Seattle. I want to be able to do that trip, stop quickly in Vancouver, grab the lady and the gear and have enough range to get me up to Whistler's trails, or backcountry camping without too much range anxiety. Since I'm going to be coming from a 2010 Xterra, I think I'll be pleasantly surprised
 

jjwolf120

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Their are several things to consider in the decision.
1. If you are going to tow, you probably want the 180kwh battery, unless all of your towing is short distance.
2. You need to consider how long you actually drive between stops. If you have a tiny bladder or have a passenger that does, you will be stopping fairly regularly and might not need that large a range assuming availability of chargers.
3. Charging speeds. On very long drives, your actual range after the first stop will be smaller because it isn't worth the time to charge to 100%. If you charge to 80% and drain to 15% your range will be 65% of your 100% range. So assuming a 400 mile original range, after your first stop you have a 260 mile range. If you had a 330 mile range, you drop to 214.5 mile range. If 230, you drop to 149.5.
4. How fast you drive on the highway. The faster you go, the lower your range.
5 What the actual range of the vehicles turns out to be. I'm pretty sure they will hit the minimums promised, but they might come out a little lower or a little higher.
 

ajdelange

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1. If you are going to tow, you probably want the 180kwh battery, unless all of your towing is short distance.
It isn't an option if you plan to tow. 300 mile range can easily drop to 150 or less when towing.

2. You need to consider how long you actually drive between stops. If you have a tiny bladder or have a passenger that does, you will be stopping fairly regularly and might not need that large a range assuming availability of chargers.
While this is definitely true the extra range is always a comfort. If a detour or unexpected bad weather (head winds and rain eat a fair amount of range) pops up you are ready for it. One poster here likened the extra range to extra runway length. Not often used but when you need it....

3. Charging speeds. On very long drives, your actual range after the first stop will be smaller because it isn't worth the time to charge to 100%.
This is because with Tesla the charge rate is tapered substantially to protect the battery. That should tell you something. If you want maximum battery life you should stay out of the top 20% (and bottom 20%) SoC regions. Obviously a manufacturer like Rivian attains a competitive advantage if he does not taper his charge rate at higher SoC and so a battery that will withstand less taper is much sought after. We don't know what Rivian's taper rates will be at this point bur some taper is probable. Thus the reason for not charging fully is, ultimately, protection of the battery.

Tesla sometimes limits charging to 80% just to get people out of the stalls faster. This is because there are now enough Teslas on the road to overwhelm the existing SC network at some times in some locations. It won't be that way with your Rivian, at least initially, but the day will come. Remember that those same CCS stations will be shared with vehicles from VW, Audi, Jaguar....

We often charge beyond what we need to get to the next stop just to have some extra margin on board. This is especially the case if a change in weather seems possible, if the next leg is into unfamiliar territory or just because we don't want to make another stop.

In any case an added percent of SoC, be it a intitial high rate or eventual low, gets you 3 miles in a 300 mile car and 4 in a 400 mile car. Thus you pick up more miles per per percent charge with the larger battery car (but, of course, it takes more charger energy to get that percent).


5 What the actual range of the vehicles turns out to be. I'm pretty sure they will hit the minimums promised, but they might come out a little lower or a little higher.
What the actual range of the vehicle turns out to be depends on how, where, and when you drive it. Rivian will hit slightly above the EPA promise. The Tesla M3 was advertised and sold with its EPA rating of just under 400 mi. They discovered they had made an error in testing, retested and found the EPA rating to be just over 400 miles. This is, of course, a huge deal from the marketing perspective but the car didn't change a bit.
 

davrow_R1T

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This will be my third EV. First had 100 mile range. Second had 75 mile range (strictly a commuter car). I made both work without much trouble.

For me, where I go and how I drive, I want 310 mile range. "300+" will be 'good enough'. So 135kw R1T for me. :like:

If I could just get one! Wait, wait, wait... sigh.
 

ajdelange

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You do understand that, per the discussions in previous posts, a 300 EPA mile vehicle has practical working range of 180 - 240 miles?


[Edit]Footnote: With the new battery technologies coming along the top and bottom 20% SoC may not be so sacrosanct as they are with the current tech. IOW we may be comfortable using the whole middle 80% of the range in which case 300 EPA vehicles are practically speaking 240 mi. Of course we haven't seen this new tech even from Tesla who is promising to announce something in September let alone Rivian.
 
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DucRider

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This is because with Tesla the charge rate is tapered substantially to protect the battery. That should tell you something. If you want maximum battery life you should stay out of the top 20% (and bottom 20%) SoC regions. Obviously a manufacturer like Rivian attains a competitive advantage if he does not taper his charge rate at higher SoC and so a battery that will withstand less taper is much sought after. We don't know what Rivian's taper rates will be at this point bur some taper is probable. Thus the reason for not charging fully is, ultimately, protection of the battery.
This is sort of correct. All charge rates are tapered to protect the battery as the charging changes from constant current to constant voltage. This will happen at different SOC%'s depending on a lot of factors (temperature, battery chemistry, etc). Charging at higher C rates also dictates an earlier taper. Tesla allows the Model 3 LR to charge at over 3C and high C rates are much harder on the battery and cannot be sustained for as long. As a contrast, at the stated 300 kW max charge rate, the Rivian 135kWh version would be a touch over 2C and the 180 kWh version about 1.7 C.
Tesla is also a bit unique in that they make more of the battery capacity available and allow the owner to elect whether or not to charge to 100% (or very close). They recommend not charging to over 90% on a regular basis. Most (if not all) other manufacturers "fence off" portions of the battery at both low and high SOC%'s and actually recommending fully charging every time yo plug in (although it is effictivel less than a tru 100%).
Some manufacturers provide actual vs usable info (BMW, i.e.) for others it must be gleaned from battery specs and charging characteristics. As an example, the Tesla M3 LR allows ~78 out of 80.5 kWh as usable or 97%. The 120 Ah i3 allows 39 out of 44 or 89%. We don't know where Rivian will fall as to usable vs actual battery percentage, but my guess would be on the conservative (lower %) side. Tesla has actually done over the air "updates" to older Model S vehicles where the BMS lowers the usable percentage when battery degradation is detected resulting in an instant overnight range loss for some owners (there are a few lawsuits over this).
What the actual range of the vehicle turns out to be depends on how, where, and when you drive it. Rivian will hit slightly above the EPA promise. The Tesla M3 was advertised and sold with its EPA rating of just under 400 mi. They discovered they had made an error in testing, retested and found the EPA rating to be just over 400 miles. This is, of course, a huge deal from the marketing perspective but the car didn't change a bit.
I think you meant the new Model S Long Range Plus as no Model 3 has promised nor delivered anywhere close to 400 miles.
Rivian has indicated that they will be well over the estimates they originally projected, but a quick poke around their site yields nothing but "Up to 400+ miles". IIRC, someone at one of the events was told the 135 kWh R1T that was announced at 300 miles was on target for over 325.
 

ajdelange

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I shall not waste any time or space speculating on what the details of Tesla's charging algorithms may or may not be. There are physical reasons for backing off at the upper end and they do. We can expect Rivian to do so too but their charging scheme and profiles are likely to be different because they have different battery chemistry and a different approach to battery management.

I think you meant the new Model S Long Range Plus as no Model 3 has promised nor delivered anywhere close to 400 miles.
I think I did and I'll readily admit here to some kind of wierd dyslexia (or disgraphia actually I guess) with regard to the letter S and the numeral 3 - but only when it comes to Tesla model numbers. This certainly not the first time I've done this!
 
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I want the 180 kwhr battery because we plan to tow a 31 feet travel traler. That will give only 200 miles with such a travel trailer at 60 mile/hr...
 

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Don't forget Rivian has mentioned offering a "Portable Jerrycan" battery pack. I have no idea how much range vs size/weight is going to be available. I would think portable battery would have to offer 25 miles of range to be remotely usable. I just did some quick math....
While this sounds good, it is not likely feasible with lithium battery technology. You could certainly not run your battery down and then plug in a fully charged pack in parallel. Lithium batteries must have all the cells balanced, with nearly identical voltage. This is all part of the complex battery charging and conditioning algorithms. So the extra packs would have to be installed and charged before any trip. If these are rarely used there is also the issue of long term storage, where these batteries need to be stored at 50% capacity to avoid damage or degradation. I fly RC planes that use lithium batteries and the chargers for those have a special "storage mode" that puts the batteries into the proper storage range with all the cells balanced. You would need a special charger to do that.
 

ajdelange

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While this sounds good, it is not likely feasible with lithium battery technology.
It is entirely feasible electrically speaking. As a practical illustration of this I offer the example of a banks of interconnected PowerWalls. Each Powerwall has its own BMS (which handles balancing and many other things as well). Effectively, adding a supplemental lithium battery pack to a Rivian (or other BEV) would be the same as adding another Powerwall to an existing Powerwall systems. In the powerwall system there is a bus. The energy sources (utility, solar cells), storage units (Powerwalls) and loads are all connected to this bus. It would be the same with a motor vehicle system. The individual batteries would be connected to the bus as would be the loads (the motor inverters) and the sources (the motor rectifiers, Level 2 charger and DC charge port).

You could certainly not run your battery down and then plug in a fully charged pack in parallel.
You would definitely be able to run down your main battery at which time Jerry could take over but, of course, you wouldn't want to do it that way. The storage units would manage their contributions to the loads and share the sources using the same principles at play in the PowerWall architecture.

Lithium batteries must have all the cells balanced, with nearly identical voltage. This is all part of the complex battery charging and conditioning algorithms.
Those are contained in the vehicle's and Jerry can's individual BMS.

So the extra packs would have to be installed and charged before any trip.
Why? My first reaction to this statement was that there wouldn't be much point in installing the Jerry can were it not charged but then I realized that one could very well install it empty and drive it to a fast charger station to charge it.

If these are rarely used there is also the issue of long term storage, where these batteries need to be stored at 50% capacity to avoid damage or degradation.
We have no idea what the optimum storage SoC might be for such a battery but whatever it is it will be the same as the truck's as most likely the Jerry can will be built from the same cells used in the truck. I have already added, on Rivian's behalf, a lot of nifty features for their Jerry can so I will add one more: a J1772 connector to allow them to be maintenance charged with a Level 2 charger.

You would need a special charger to do that.
No. Just a standard Level 2.

Please understand that I am not telling you what Rivian will do or should do. I am just pointing out what the current technology would allow them to do.

Where I see the limitation of an electric Jerry can is much more mundane: the weight. Assuming specific energy of 250 Wh/kg a "can" holding 100 kWh (about 200 to perhaps 250 miles for an R1T) would weigh 400 kg (880 lbs). One does not casually toss that kind of weight around. This is fork lift magnitude. Of course I expect that these things, if they are ever actually offered (Rivian has a patent) they may be modular and there may be smaller packs available.

I save the elephant in the room til last: Cooling. A critically important feature of battery management is keeping the cells withing a proper operating temperature range, This would require that a Jerry can interface not only to the vehicle's electrical system but to its cooling system. I don't recall the patent application but I am sure this is included.

Of course the simplest integration is that implied by simple up scaling of the Jerry can I illustrated in No. 24. With that concept you run till you are low on battery, stop and recharge from the Jerry can via the J1772 port. Not nearly as elegant as the solutions I've proposed above.
 
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azbill

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I save the elephant in the room til last: Cooling. A critically important feature of battery management is keeping the cells withing a proper operating temperature range, This would require that a Jerry can interface not only to the vehicle's electrical system but to its cooling system. I don't recall the patent application but I am sure this is included.
This is one of the major concerns I would have with a Jerry Can approach. If the can is small compared to the normal battery, and you run the normal battery all the way down before using it, then that small battery powering that big truck will heat up much more than the normal batteries do. That is why I think it would be better just to have the option to plug int he extra battery and use it along with the normal battery. All the cells would run cooler that way. Secondly, a small battery by itself would require a significant performance reduction when using it.
 

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Serious question, since I'm not a battery or electrical guy. Would it be feasible to have the jerrycan DC charge the main battery instead, or would there be too much loss?
 

ajdelange

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This is one of the major concerns I would have with a Jerry Can approach. If the can is small compared to the normal battery, and you run the normal battery all the way down before using it, then that small battery powering that big truck will heat up much more ...
There are several reasons for not wanting to discharge or charge at high multiples of C (the battery's capacity). If the power gauge on my X is to be believed it can be discharged at 3.5 C but that would be for seconds. So indeed it make much more sense to put a Jerry Can battery on the bus when it is installed in the vehicle and I cannot imagine Rivian doing it any other way. Note that if you were to install a 100 kWh Jerry can in a truck with a 100 kWh main battery a discharge rate of 50 kW which was 0.5C in the stock truck now becomes 0.25C. This is good for the main battery.

Now consider the case where you are trucking along with a small Jerry can and one of the pyro fuses goes in the main battery pack. The main computer in the truck is, of course, aware of this and, in continuing to run on a small installed Jerry can would either advise you to slow down or force you to. So I would not be too concerned about that aspect of it either.
 
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