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Preconditioning doesn't pull power from the wall?

Ape Latex

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Definitely not what I saw this morning. It never engaged the charger. I charge to 85% and by the time I got out of my sub, it said 84%. Maybe if I had let it keep going for another 15 minutes it might have kicked on the charger, but it really should be proactive and attempt to zero out consumption at least.
It seems like the truck lets the battery drop 1% or so before starting to charge again.
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Both Bolt EV and MachE which I owned previously would pull from the wall for preconditioning, Rivian does not behave that way, it uses battery if charging has stopped. It will restart charging if it drops below a certain amount (No idea on how much). If battery has a dedicated charging circuit, that might be a design limitation, otherwise, there shouldn't be any difference between turning on AC to DC converter to match the needed demand of heating/cooling circuits, they would just work less efficiently if you're on 110v.

I'm guessing software isn't there yet, and its probably SWOT'ed into "high effort, low value" quadrant, so this is how its going to work for foreseeable future, unless enough/right people complain.
 
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Fully cycling an battery has an effect.... This would have zero measurable effect.
Any cycling on a battery has an effect. Wear is cumulative.
 
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It seems like the truck lets the battery drop 1% or so before starting to charge again.
I think you might be right, I saw some consumption added to the total this morning after running the heat for quite a while, but was getting ready for work and never saw it actually pulling a draw. The EVSE I've been using doesn't graph out consumption so I'm moving the Rivian over to my Juicebox to be able to get a graph of it tomorrow.
 

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Any cycling on a battery has an effect. Wear is cumulative.
Certainly, but it is really insignificant... An EV battery is good for >>5000 cycles....

Let's assume you use 2% of your total cycles for preconditioning (probably much less); let's further assume your battery is a 200K mile battery...With preconditioning you will drop to a 196K mile battery.... Driving habits will have bigger effect...Again, I think you are worried about something insignificant to the life of your EV
 
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Certainly, but it is really insignificant... An EV battery is good for >>5000 cycles....

Let's assume you use 2% of your total cycles for preconditioning (probably much less); let's further assume your battery is a 200K mile battery...With preconditioning you will drop to a 196K mile battery.... Driving habits will have bigger effect...Again, I think you are worried about something insignificant to the life of your EV
It's going to be way more than 2%. It's probably going to be closer to 5%. The Rivian doesn't have a heat pump so it's going to be pretty inefficient to precondition it. I'll have better numbers after a few days of tracking it.

Of course I live in an area that gets really cold in the winter, so I can see how someone from Florida might not have the same grasp of the amount of energy required.
 

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It's going to be way more than 2%. It's probably going to be closer to 5%. The Rivian doesn't have a heat pump so it's going to be pretty inefficient to precondition it. I'll have better numbers after a few days of tracking it.

Of course I live in an area that gets really cold in the winter, so I can see how someone from Florida might not have the same grasp of the amount of energy required.
Fair enough.... Do you really think over 5% of your total battery cycles are going to be based on preheating your cabin? I guess if you drive a lot of short trips and preheat every time.... It maybe 5% of winter cycles, but then you have all the summer cycles with no preheating.... If you have 5% in the summer, the spring, summer and fall are going to offset that largely...

Even at 5% you have gone from a 200K mile battery to a 190K mile battery and they do not fail hard, the slowly degrade so that is the milage that you would project to still have ~90% capacity.... I believe even at 5% it is insignificant but YMMV
 

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I think it can’t match the charging rate to the battery draw. If I have the truck set to charge at 8kW, and the heater is using 1kW, the truck can’t reduce the charge rate down to 1kW to backfill the heater draw. So the heater draws down the battery a little until the charging kicks in at 8kW. The 8kW charging cycles on and off to keep the battery at approximately the desired SoC, but not exactly.
Considering we can set charge rates on the truck itself (and the AC charger is onboard) it should do this automatically. The vehicle is in control of how much power to take in a charge, an EVSE is basically a relay in a box with some primitive communication that says "don't take more power than this."
 
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I stuck my Rivian on the Juicebox and it charged overnight. This morning was in the 50s, but I still preconditioned. By the time I went out to the garage, my juicebox was throwing an error code that the contactor was stuck closed. The Rivian didn't seem to take another charge(port light was solid green) and the graph for the charge session doesn't indicate another attempt to charge. I'll have to open up the juicebox and see what the heck happened.
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