Obioban
Posts: 100
Joined: Wed May 22, 2019 6:16 am

What is the charge rate of reduced speed 120V charging?

Tue Apr 06, 2021 12:20 pm

Currently constructing a house, and will be living in an apartment in the interim. There's only one plug I can use (120V), and it pops the breaker if I don't use the reduced rate option.

What is the KW/h rate, when you're in reduced rate on 120V?

Thanks!

User avatar
MKH
Gold Member
Posts: 840
Joined: Fri Nov 02, 2018 5:48 am
Location: Dallas

Re: What is the charge rate of reduced speed 120V charging?

Wed Apr 07, 2021 4:48 am

From another site have seen this:

"For the i3 level one charging, 12, 9, and 6 amps at maximum, reduced and low settings."


You can convert amps to watts by multiplying amps x 120 volts. Therefore, a 6-amp charge cycle draws about 720 watts. If you do that for five hours, you would use 3.6 kwh (720 x 5 = 3,600 divided by 1,000 = 3.6 kwh.

(Divide watt hours by 1,000 to get kilowatt-hours).
Mark H.
2015 i3 Rex, Capparis White, Tera World, Technology & Driving Assistant, Parking Assistant, Harman Kardon Audio System, 19 inch 427 wheels, EVoInnovate EVSE

eNate
Posts: 664
Joined: Mon Sep 09, 2019 5:33 pm

Re: What is the charge rate of reduced speed 120V charging?

Wed Apr 07, 2021 12:54 pm

It depends on your EVSE's base rate.

15A reduces to 11 and 8.

12A reduces to 9 and 6.

10A reduces to 8 and 6.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

Obioban
Posts: 100
Joined: Wed May 22, 2019 6:16 am

Re: What is the charge rate of reduced speed 120V charging?

Thu Apr 08, 2021 3:40 am

My only 120v charger is the stock, US spec occasional use charger that came with the car.

eNate
Posts: 664
Joined: Mon Sep 09, 2019 5:33 pm

Re: What is the charge rate of reduced speed 120V charging?

Thu Apr 08, 2021 6:22 am

In the US, some stock OUCs are 12A and some are 10A, they varied over the years. You'll have to check your label on the back.
2 0 1 7   B M W   i 3   9 4 A h   B E V  O a k l a n d
 Wokeby Trunk Extension | Duosida 16A L1 EVSE
 SeaSucker Monkey Bar Roof Rack

jadnashuanh
Posts: 5196
Joined: Thu May 22, 2014 2:07 pm
Location: Nashua, NH USA

Re: What is the charge rate of reduced speed 120V charging?

Mon Apr 12, 2021 4:55 pm

The first couple of years, they supplied 12A EVSEs in the US, then they dropped it to 10A units. The US electrical code says a device like an EVSE must derate the supply to NGT 80%, so the 12A would be okay on the nominal 15A circuits in the US. The hassle is, there could be lights, a garage door opener, and who knows what plugged into that circuit, so that's why they dropped their standard issue unit to 10A, so there'd be less likelihood of tripping breakers when people didn't have a dedicated one for their EVSE to plug into.

Since power = volts * amps, whatever amps you can supply off of that 120vac circuit, would be half what it could be if you had 240vac available. And, the AC-DC conversion done in the vehicle is less efficient, so it's actually less than half, and because the charging takes longer, that may mean the vehicle will have to supply cooling for longer to keep everything working correctly as the batteries warm as they're being charged.
Jim DeBruycker
2014 i3 BEV, 2021 X5 45e
(The i3 will be sold soon, <17K-miles, interested?)

Return to “News and Main BMW i3 Forum Discussions”