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Charging time 2016 60AH

Posted: Tue May 14, 2019 11:45 am
by Kim1965
I have recently bought a 2016 i3 Rex and wondered how long it should take to charge using a 32 amp type 2 connector. I charged mine last night with the range at 10 miles and it took 4 hours to get to fully charged. Is this right or should it be closer to 3 hours?

Re: Charging time 2016 60AH

Posted: Tue May 14, 2019 1:42 pm
by MKH
Is your car set for 'reduced' or 'maximum' charging?

Note that the the car will only accept up to 30 amps, even if the charger can push more.

Re: Charging time 2016 60AH

Posted: Tue May 14, 2019 2:17 pm
by Kim1965
Thanks Mark, it is set to maximum

Re: Charging time 2016 60AH

Posted: Tue May 14, 2019 2:24 pm
by CharonPDX
Four hours sounds about right. It doesn't pull maximum amperage right at the "ends" of the battery. So about 0-5% it won't pull the full 30A, and 95-100% it won't pull the full 30A. Yeah, BMW claims 32 hours, but I have a 10kW EVSE, and when I drained my battery to 1%, it took a smidge over 4 hours to go to 100%.

Note also that ambient air temperature makes a difference! If it's cool out (below 65°F,) or really hot (above 100°F) it will charge slower. (Those two temperatures are vague guesses based on personal experience, I don't know what the car's actual thresholds are.)

Re: Charging time 2016 60AH

Posted: Wed May 15, 2019 3:58 am
by MKH
What Charon posted. Actual will be nearer 4 hours. Early in the charge cycle some of the time/energy will be used to either warm or cool the batteries to optimum charging temperature, late in the charge cycle some of the time/energy will be used in cell-balencing, which helps maintain the battery pack's 'health' and max charge it will take.

Re: Charging time 2016 60AH

Posted: Wed May 15, 2019 11:24 am
by alohart
MKH wrote:
Wed May 15, 2019 3:58 am
Early in the charge cycle some of the time/energy will be used to either warm or cool the batteries to optimum charging temperature, late in the charge cycle some of the time/energy will be used in cell-balencing, which helps maintain the battery pack's 'health' and max charge it will take.
Cell balancing is a passive process that discharges those cells with the highest charge levels so that their charge levels more closely match the charge levels of other cells. It does not occur while charging is active, so it doesn't consume any charging power. Cell balancing occurs while the battery pack isn't being charged or discharged. It occurs more rapidly at higher charge levels.

Re: Charging time 2016 60AH

Posted: Thu May 16, 2019 9:28 am
by CanisLupus
What would be interesting to know is 'For any given EVSE , which power level (kW) is it communicating to the vehicle as it's MAXIMUM Allowable ? ' . 30 Amps is close to our i3's maximum but if the EVSE doesn't allow our maximum then which power level will our i3 step down to ? The ChargePoint stations usually indicate about 5.8XX KW when I charge from them . Is 5.8XX one of the charge levels that our i3 will utilize ? With this thought in mind I might try the different settings in the charge level menu and see which power values show on a ChargePoint Station .

Re: Charging time 2016 60AH

Posted: Thu May 16, 2019 10:54 am
by tjburbach
CanisLupus wrote:
Thu May 16, 2019 9:28 am
What would be interesting to know is 'For any given EVSE , which power level (kW) is it communicating to the vehicle as it's MAXIMUM Allowable ? ' . 30 Amps is close to our i3's maximum but if the EVSE doesn't allow our maximum then which power level will our i3 step down to ? The ChargePoint stations usually indicate about 5.8XX KW when I charge from them . Is 5.8XX one of the charge levels that our i3 will utilize ? With this thought in mind I might try the different settings in the charge level menu and see which power values show on a ChargePoint Station .
The level 2 EVSE really just tells the i3 how many amps it is allowed to pull from this station. That's it, all the decisions on how much power to push into the battery is made internally by the charging controllers on the i3 (EME). I suppose with one of the smart EVSE stations you could change the advertised amp limit to force the i3 to consume less power.

Look at the description of what the control pilot signal is sending to the car.
https://en.wikipedia.org/wiki/SAE_J1772#Signaling

Re: Charging time 2016 60AH

Posted: Thu May 16, 2019 11:53 am
by alohart
CanisLupus wrote:
Thu May 16, 2019 9:28 am
The ChargePoint stations usually indicate about 5.8XX KW when I charge from them . Is 5.8XX one of the charge levels that our i3 will utilize ? With this thought in mind I might try the different settings in the charge level menu and see which power values show on a ChargePoint Station .
There aren't distinct power levels that an i3's charger supports. The charging power is the lesser of what an EVSE (AC) or charger (DC) can deliver and the maximum that an i3 can accept (~7.2 kW AC or 50 kW DC).

Many (most) U.S. public charging stations are powered by 2 phases of commercial 3-phase power (208 V) rather than both phases of split-phase residential power (240 V). 208 V @ 30 A is 6.2 kW which is close to what you've experienced with ChargePoint stations.

Re: Charging time 2016 60AH

Posted: Tue May 21, 2019 7:18 pm
by jadnashuanh
Actually, the i3 can pull enough current to use 7400W. So, it depends on the voltage level involved how many amps that is...it's not amps limited, it's power. My 30A EVSE can see 248vac input, which equates to just over 7400W. If you were on commercial 208vac, the same 30A EVSE would only provide 6240W. So, to determine how long it will take to recharge, you need to know more than just the amps available. The car won't try to pull more amps than the EVSE signals it has, but with an EVSE, the amount of actual power transferred is the product of the amps and the voltage...not all results will be the same. My summertime voltage input tends to be closer to 240vac and won't max out my car's abilities. Some places may only see closer to 220vac if they are at a far end of a transmission line or there's a brownout situation.