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Discussion Starter · #1 ·
I am aware of the ABC mantra (always be charging), but I am also aware that battery packs are rated for only so many charging cycles (admittedly this is a pretty large number these days). So ... if I know I'm going to have only 3 or four days in a row of only 30-40 non-highway miles, does it really make sense to charge ("top off") every night that week or does it make sense to wait until the night after my last planned errands for the week and charge it then?

Thanks,
pat----
 

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"charge cycles" isn't how many times you plug in, but rather the multiples of battery capacity charged.

For example, assume L2 charging, the following are effective the same from a battery-wear perspective:

1) Drive 40 miles a day, charge nightly.
2) Drive 40 miles a day, charge once every 5 days.

Things change a bit with DCFC, since charging at really high current levels will cause increased wear on the pack...

But for normal use with a L2 EVSE, I would plug in every night.
 

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A lot of it depends on how often the battery control module samples the voltage on the cells. My wife has a 10 mile commute to her office and we were charging our M3 up every night. Over a couple years we had phantom range loss because the BCM didn't know about the low-end of the battery voltage. For the past couple months, we've run the car down to 20% and charged it back up to 80% and seen about 15 more miles of range at the top end.

Apparently the MS BCM does a better job sampling the batteries but the M3 will do it only once in a while and, I suspect, muxes through them to save complexity.

I'm not sure which tactic Rivian has taken or if they provide any guidance.
 

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I am aware of the ABC mantra (always be charging), but I am also aware that battery packs are rated for only so many charging cycles (admittedly this is a pretty large number these days). So ... if I know I'm going to have only 3 or four days in a row of only 30-40 non-highway miles, does it really make sense to charge ("top off") every night that week or does it make sense to wait until the night after my last planned errands for the week and charge it then?

Thanks,
pat----
I wouldn’t purposely wait, but it doesn’t hurt your car to go in between charges. If we’re over 50% and doing normal commute stuff, we’ve left it unplugged. Admittedly more so when we had a mix of IcE vehicles. When we’re all electric, it’s second nature to just plug it in everynight.

For longevity if you don’t need it, turn your max charge rate down to 50 or 60%.
 

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Keep in mind that the Rivian's default recommendation for the R1T for everyday driving purposes, is to charge to 70%. Th U/I for charging and setting max charge thresholds is really nice (and easy to use) in the vehicle, on the display. Range will show based on driving mode, so if you are looking for MAX range, remember to set to CONSERVE and lower height setting
 

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Curious about the 70% recommendation…Tesla, Porsche, etc. suggest in the 80-85% range, and that’s even probably a conservative estimate.
Take it with a grain of salt. I know Tesla takes some capacity as reserve already. It’s entirely possible that 70% = 80% on another car. There’s also a difference in thermal managment and bums systems. Etc.
 

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The worst thing you can do to a battery pack is noodle it down to (below) zero %, because some cells will be damaged due to heterogeneity of cells in the pack.

Fretting about 70%, 80%, or 90% is not worth it.

I personally don't charge my I-Pace to 100% all the time, preferring to charge it to 80-95%, but that's comparatively less important.
 

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With my Tesla, I plug it in whenever I get to 60% battery remaining. Anything above that, I don't plug it in. While I can't say with 100% certainty, they seen to use more power when plugged in than if its sitting unplugged. I hear the car clicking and doing something all the time when plugged in. Rarely hear it when not. Assuming its doing some sort of battery check or checking in with Tesla or whatever. Point being, it's lost power that you pay for. Naturally, a very minimal cost. But, between that and giving consideration that charging cycles "may" have some impact, I figure it certainly doesn't hurt anything to not plug it in if you know you have more than enough range to cover the next day's driving needs and a buffer for something unexpected that might pop up. For me, that number is 60% of the Tesla battery. Will be higher with the Rivian since it gets less range.

Plus, how many times will that charge door work before it breaks? Every time used is one time closer to the end of its life cycle. Figure, can't hurt to not over use it and plug it in every single time you drive 10 miles.
 
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