Using Portable Charger at Home as Main Charging Method

[GreenHeron]

I just got my 2025 R1S DM Max pack in December, a great Christmas present. About once a month, we take a trip somewhere and use L2 chargers along the route. But most days, my driving consists of commuting and running errands. So when I get home, I charge the R1S with the portable charger on a schedule to 80%. Regarding battery life, I am wondering if I should let the battery run down more regularly and/or charge to 100% occasionally. Thanks for any advice on this subject.

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[mpshizzle]

The Rivian recommended daily charge limit is 70% - I find that with my Max pack that provides WAY more than enough range day to day - and I do a lot of driving. An occasional dip to low SOC and charge to 100% helps the BMS, but it's not really needed all that often. If you want to get really into the weeds on battery care, this video gives a good overview.

TL;DR - don't stress to much about it. The batteries and their management systems are fairly robust.


All that said are you charging with just a regular 120 v outlet? IF so, your portable EVSE will nearly max out that circuit, and most home outlets and wiring are not meant to be maxed out for hours at a time on a daily (or nearly daily basis). Especially if it's an older home. If it's not up to the task the wiring can heat up in the walls and cause a fire hazard. I HIGHLY recommend getting an actual EVSE installed (or at least a unit that plugs into a Nema 14-50 240v circuit). Both for convenience AND for safety

 

[GreenHeron]

The Rivian recommended daily charge limit is 70% - I find that with my Max pack that provides WAY more than enough range day to day - and I do a lot of driving. An occasional dip to low SOC and charge to 100% helps the BMS, but it's not really needed all that often. If you want to get really into the weeds on battery care, this video gives a good overview.

TL;DR - don't stress to much about it. The batteries and their management systems are fairly robust.


All that said are you charging with just a regular 120 v outlet? IF so, your portable EVSE will nearly max out that circuit, and most home outlets and wiring are not meant to be maxed out for hours at a time on a daily (or nearly daily basis). Especially if it's an older home. If it's not up to the task the wiring can heat up in the walls and cause a fire hazard. I HIGHLY recommend getting an actual EVSE installed (or at least a unit that plugs into a Nema 14-50 240v circuit). Both for convenience AND for safety

Yes, I am using a 120-volt outlet. I do about 30 miles per day. My house was built in 1983, don't know if that is considered old or not. So you are advising that I really should not even use the portable charger with the 240-volt adapter and the Nema 14-50 240-volt outlet? So for safety reasons, I should get a unit that plugs into the Nema 14-50 240-volt outlet. Do you have a recommendation? Thanks for the advice.

 

[mpshizzle]

Yes, I am using a 120-volt outlet. I do about 30 miles per day. My house was built in 1983, don't know if that is considered old or not. So you are advising that I really should not even use the portable charger with the 240-volt adapter and the Nema 14-50 240-volt outlet? So for safety reasons, I should get a unit that plugs into the Nema 14-50 240-volt outlet. Do you have a recommendation? Thanks for the advice.

I should preface that I am not a licensed electrician. That said, I've done my fair share of research on the topic, up to building my own charging unit. Going off of industry advice from folks who ARE licensed - the best option is a hard wired unit. That allows for higher amperage charging and the lack of a socket makes the connections more secured.

A nema 14-50 plug from a reputable manufacturer is also a good option, and they are generally built to withstand the consistent loads better (so long as you aren't plugging/unplugging the charger all the time).

***EDIT*** From a safety perspective, there's certainly nothing wrong with the portable EVSE that comes with the vehicle. Personally, I prefer to just keep mine IN the vehicle for emergencies (also keeps wear and tear off the unit). But if you have that plugged into a good 14-50 outlet, and you just leave it plugged into the wall I don't feel like that's a big issue

 

[mpshizzle]

If you're in need of more detail this video can tell you a bit more (it's a bit long).. He briefly addresses 120v charging specifically around the 19 minute mark:

 

[Joe Hoffman]

I do all my home charging using the portable charger. It’s plugged into a Nema 14-50 dedicated outlet.
If it seems too hot or you’re just concerned, then turn down the amperage. Sounds like you have plenty of time to do the charging at lower rates if you plug it in every night.

 

[docwhiz]

I just got my 2025 R1S DM Max pack in December, a great Christmas present. About once a month, we take a trip somewhere and use L2 chargers along the route. But most days, my driving consists of commuting and running errands. So when I get home, I charge the R1S with the portable charger on a schedule to 80%. Regarding battery life, I am wondering if I should let the battery run down more regularly and/or charge to 100% occasionally. Thanks for any advice on this subject.

You will be fine with L1 charging. (120v) You can easily replace the 30 miles of range you use each day.
No need to go to the expense of rewiring.

This is actually true for most EV drivers. They don't drive more than 30 or 40 miles a day and 120v L1 charging is just fine.

 

[malditofman]

I just got my 2025 R1S DM Max pack in December, a great Christmas present. About once a month, we take a trip somewhere and use L2 chargers along the route. But most days, my driving consists of commuting and running errands. So when I get home, I charge the R1S with the portable charger on a schedule to 80%. Regarding battery life, I am wondering if I should let the battery run down more regularly and/or charge to 100% occasionally. Thanks for any advice on this subject.

Don't overthink battery stuff or watch super nerdy and long winded YouTube videos on the subject. An EV or ebike battery should be charged to 100% periodically to rebalance the BMS. I do it every couple of weeks. Otherwise I charge the ebike and EV to 80% daily. Neither battery is LFP chemistry, which could be charged to 100% all the time without issue. Studies have shown that battery degradation is not a huge issue. The first two years it's minimal and after that range loss is about 1.8% annually. Just enjoy your beautiful Rivian. Drive well.

 

[Riviot]

I just got my 2025 R1S DM Max pack in December, a great Christmas present.

Which Saint are you making sacrifices to, and what are you sacrificing?! Apparently Saint Nick doesn't care about mine.

I should preface that I am not a licensed electrician. That said, I've done my fair share of research on the topic, up to building my own charging unit. Going off of industry advice from folks who ARE licensed - the best option is a hard wired unit. That allows for higher amperage charging and the lack of a socket makes the connections more secured.

Despite my hat saying [SURNAME] ELECTRIC, I'm not licensed either, but I concur with the above.

 

[slillie]

With a Level 1 charger you are going to be plugged in 24/7 whenever you aren’t driving your car just to add 30 miles to the battery. That’s a real pain.

Buy a level 2 charger and pay the bucks for an electrician to install a a 14-50 receptacle in your garage.

I would not hardwire your L2 charger, The plug and the receptacle are more robust than the wiring itself. Your electric stove and dryer are both plugged in and are not hardwired. When I switched from Tesla to Rivian I needed to add a short RV extension cord to reach my new receptacle. It was Easy peasy.

 

[docwhiz]

With a Level 1 charger you are going to be plugged in 24/7 whenever you aren’t driving your car just to add 30 miles to the battery. That’s a real pain.

Buy a level 2 charger and pay the bucks for an electrician to install a a 14-50 receptacle in your garage.

I would not hardwire your L2 charger, The plug and the receptacle are more robust than the wiring itself. Your electric stove and dryer are both plugged in and are not hardwired. When I switched from Tesla to Rivian I needed to add a short RV extension cord to reach my new receptacle. It was Easy peasy.

30 miles in a Rivian takes 15 kWh
L1 charging (120v, 12 amps = 1.4 kW) or 10 hours for 15 kWh
Not quite 24/7
Just plug in overnight (you do eat and sleep at home, don't you?).

Math.

 

[SwampNut]

What you are doing is perfectly safe and you should ignore the manufactured fear about it. If it meets your needs, use it. I went for many years charging just with a portable EVSE on a 240v 30a outlet and that was fine for me. My motorcycle charges on a 120v circuit mostly, I rarely need a full charge fast at home.

 

[SwampNut]

Math.

You forgot the other part of the sentence...math is hard for some people.

 

[Donald Stanfield]

I should preface that I am not a licensed electrician. That said, I've done my fair share of research on the topic, up to building my own charging unit. Going off of industry advice from folks who ARE licensed - the best option is a hard wired unit. That allows for higher amperage charging and the lack of a socket makes the connections more secured.

A nema 14-50 plug from a reputable manufacturer is also a good option, and they are generally built to withstand the consistent loads better (so long as you aren't plugging/unplugging the charger all the time).

***EDIT*** From a safety perspective, there's certainly nothing wrong with the portable EVSE that comes with the vehicle. Personally, I prefer to just keep mine IN the vehicle for emergencies (also keeps wear and tear off the unit). But if you have that plugged into a good 14-50 outlet, and you just leave it plugged into the wall I don't feel like that's a big issue

Agree. I have a dedicated charger for my Rivian but my wife uses the charger that came with her BMW in a 14-50 outlet.

 

[slillie]

30 miles in a Rivian takes 15 kWh
L1 charging (120v, 12 amps = 1.4 kW) or 10 hours for 15 kWh
Not quite 24/7
Just plug in overnight (you do eat and sleep at home, don't you?).

Math.

No worries. Whatever works for you.

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