Chargepoint Questions

[protonic]

Hello. I just bought a 2017 i3 (only 13k miles!) and have just installed my Chargepoint Home Flex. I used to make fun of these cars but now I'm driving one (I still make fun of the Prius). I installed this charger at my business and selected "home" during the Chargepoint app setup. For this reason, when I go through the settings for utility pricing I only see residential electricity plans. I called Chargepoint tech support but the lady I spoke with was clueless and did not offer any help (other than telling me to go through the settings and try again). Is there a way to correct this? I tried every link in settings and don't see an option for this.

I installed a 50 amp breaker along with 6 Guage wire. I see the i3 is only capable of 32 amp charging. Is it possible that the i3 may get some sort of firmware upgrade to charging speeds? Not that big of a deal for work since I am there usually all day.

Also, since I am only charging at 32 amps, that is all I'm being charged for by my power company correct? I'm a little confused on how this works since all my other equipment at work needs to have the correct size breakers and wire conductors.

Lastly, what speed are you guys showing for the last 20% charging. I'm showing 11 miles per hour. Is this correct?

Thanks!

 

[Pahaska]

You are only charged for the power you use. The size of the breaker has no bearing. on how many amps you are drawing. It just keeps you from exceeding the capacity of the wiring.

 

[Anonymous]

Isn't there the option to enter in your electricity provider and rate info manually, from your bill?

 

[JohnWasser]

Is it possible that the i3 may get some sort of firmware upgrade to charging speeds?

Highly unlikely. There would be little reason to put a charger capable of higher currents in the car without already using it.

Also, since I am only charging at 32 amps, that is all I'm being charged for by my power company correct?

Correct.

I'm a little confused on how this works since all my other equipment at work needs to have the correct size breakers and wire conductors.

The breaker and wiring rating sets the maximum you can draw. In the USA, a device can draw no more than 80%, which is why a 32A device need a 40A (minimum) circuit. You can always draw less than 80%.

Lastly, what speed are you guys showing for the last 20% charging. I'm showing 11 miles per hour. Is this correct?

"Miles of charge per hour" depends on your driving style. Kilowatts is a more useful measure. I charged on a Fast DC charger yesterday and it was going at 45kW until I reached about 95% charge. Look at the Chargepoint app to see the charge rate.

 

[protonic]

Thank you for the replies everyone. Very helpful. My i3 is on the charger now and it's only 3.82kw. Maybe I didn't run my battery down enough. I'm at about 3/4 full battery.

I'll check out the app again. I thought you could only select from the drop down list of companies and plan prices. I'll just reinstall the app if I can't manually enter info.


Thanks!

 

[JohnWasser]

My i3 is on the charger now and it's only 3.82kw. Maybe I didn't run my battery down enough. I'm at about 3/4 full battery.

Unless your battery is very hot it is unlikely your charge rate would be throttled anywhere below an 80% charge.

3.82 kW is about 16A at 240V. Could you have told the car to use the "Reduced" charging rate? The Level 2 charger draws 32A/240V by default but if it is set to "Reduced" instead of "Maximum" it draws 16A/240V.

 

[protonic]

My i3 is on the charger now and it's only 3.82kw. Maybe I didn't run my battery down enough. I'm at about 3/4 full battery.

Unless your battery is very hot it is unlikely your charge rate would be throttled anywhere below an 80% charge.

3.82 kW is about 16A at 240V. Could you have told the car to use the "Reduced" charging rate? The Level 2 charger draws 32A/240V by default but if it is set to "Reduced" instead of "Maximum" it draws 16A/240V.

Thank you. Is this done in my car settings or somewhere in the chargepoint app? I looked through the app and didn't see anything other than where you select the breaker amp.

 

[alohart]

3.82 kW is about 16A at 240V. Could you have told the car to use the "Reduced" charging rate? The Level 2 charger draws 32A/240V by default but if it is set to "Reduced" instead of "Maximum" it draws 16A/240V.

Thank you. Is this done in my car settings or somewhere in the chargepoint app? I looked through the app and didn't see anything other than where you select the breaker amp.

iDrive includes maximum charging power settings for both AC Level 1 (120 V) and AC Level 2 (208 V - 240 V) but not for DC Levels 1 or 2 (a.k.a., DC fast charging).

 

[protonic]

3.82 kW is about 16A at 240V. Could you have told the car to use the "Reduced" charging rate? The Level 2 charger draws 32A/240V by default but if it is set to "Reduced" instead of "Maximum" it draws 16A/240V.

Is this done in my car settings or somewhere in the chargepoint app? I looked through the app and didn't see anything other than where you select the breaker amp.

iDrive includes maximum charging power settings for both AC Level 1 (120 V) and AC Level 2 (208 V - 240 V) but not for DC Levels 1 or 2 (a.k.a., DC fast charging).

I had to google iDrive. Haha. I thought it was an app. Both the 240 and 120 charging was set at reduced! Thanks for the info John and Art! Is there any risk with setting both at MAX or is that the default setting?

I was already excited about the increase in charging speed. Can't wait til my next charge!

 

[jadnashuanh]

Some feel that the maximum charging rate will decrease battery life, but with the logic in the car and the liquid cooling, if any, it's not huge.

The limitations are more for if the device is on a shared circuit to prevent you from overloading it. Say you were using the included 120-vac EVSE and plugging it into the garage. That circuit might be the same one that supplies the lights and maybe garage door opener. Things might be fine until you tried to open or close the door...so, BMW gives you a way to lower the maximum draw of the car so you don't pop the breaker. On a dedicated circuit, usually, your best bet is to let the car decide, so choose maximum. It will throttle down if the battery is too hot or even too cold as required to maximize the life. Life's too short to sweat the small stuff.

 

[protonic]

I've read on forums (maybe this one) that you should wait for the car to cool down before charging. Is this not needed then? The i3 automatically does this to some extent? It would be way more convenient of course if I didn't have to back out to the car. How long does it take to cool down anyway?

On a side note, the Chargepoint app does allow you to manually enter your rates. I called my power company and found out I'm paying 6 cents per kW. Is this pretty average? I've never paid attention to my power usage, just the total bill amount. Kind of embarrassing but I always though 240 volts was more "expensive". True in the sense that it costs more to run the clothes dryer than your hair dryer, but I guess it makes sense that the i3 would cost the same to fill up whether it's with the 120 plug or 220 level 2 charger.

It seems my commute to work and back costs me about 50 cents. This seems to good to be true. lol

 

[Anonymous]

No need to wait to charge. The car will cool the battery if needed, as soon as you plug in the charger. You will hear it

Your electric rate is good. In my area varies from 5 to 13 cents per kwh, depending on the plan and usage (how many kwh per month used).

 

[Pahaska]

My electric supplier provides an analysis of whether a flat rate or a time-dependent rate is better. The analysis showed that I have saved over $100 in the last 12 months by using the flat rate.

However, we never used significant power after midnight. The AC is pretty much idle then and AC is the biggest use here in central Texas.

I'm still using the slow charger until it cools enough that I can ask an electrician to run wires in our attic. My conscience will not allow me to ask someone to work up there now.

I have had the I3 for 6 weeks now and I set it to charge from 11 PM to 7 AM, the lowest rate period. I'm curious to see whether if I run the analysis again in a couple of months, whether the timed rate would then turn out to be better. The rate during those hours is $0,032819.

 

[alohart]

I've read on forums (maybe this one) that you should wait for the car to cool down before charging. Is this not needed then? The i3 automatically does this to some extent? It would be way more convenient of course if I didn't have to back out to the car. How long does it take to cool down anyway?

As was pointed out, the battery management system will turn on the AC compressor to cool the battery pack while charging, if necessary. However, this would result in more electrical energy being consumed to charge the battery pack. This would also increase the charging time because an i3 can be charged at a maximum of ~7.2 kW (30 A at 240 V). When battery pack cooling is occurring, some of the charging power is being used for cooling instead of for charging the battery pack.

On a side note, the Chargepoint app does allow you to manually enter your rates. I called my power company and found out I'm paying 6 cents per kW. Is this pretty average? I've never paid attention to my power usage, just the total bill amount.

You are paying 6¢/kWh (energy), not kW (power). If you look at your electricity bill, you will see that your energy consumption is measured in kWh. In the internal combustion vehicle world, kWh is analogous to gallons or liters of gasoline where kW is analogous to the engine's horsepower.

Hawaii has very high electricity costs. I have a time-of-use electricity rate schedule in which the lowest cost, ~16¢/kWh, is between 9 am and 5 pm when extensive rooftop solar power reduces demand for the electricity power company. The most expensive period, ~44¢/kWh, is between 5 pm and 10 pm when solar power generation has ceased and demand increases when residents return home after work. Between 10 pm and 9 am, I pay ~25¢/kWh. I almost always charge our i3 between 9 am and 5 pm. So your 6¢/kWh rate is very low in my world.

Kind of embarrassing but I always though 240 volts was more "expensive". True in the sense that it costs more to run the clothes dryer than your hair dryer, but I guess it makes sense that the i3 would cost the same to fill up whether it's with the 120 plug or 220 level 2 charger.

For example, the charger in your i3 can consume a maximum of ~30 amps (A). If that 30 A is on a 240 V charging circuit, the charging power would be 240 V x 30 A = 7,200 W = 7.2 kW. If that 30 A were on a 120 V charging circuit, the charging power would be 120 V x 30 A = 3,600 W = 3.6 kW. If your i3 were charged for 1 hour at 7.2 kW, the energy consumed would be 7.2 kW x 1 h = 7.2 kWh vs. 3.6 kWh at 3.6 kW. Because your electrical power company charges you for the energy that you consume, you would pay twice as much when charging for 1 hour at 7.2 kW vs. 1 hour at 3.6 kW. However, your i3's battery pack would have had twice the energy added at 7.2 kW vs. at 3.6 kW assuming that the charging losses are the same. It's actually slightly more efficient to charge at 7.2 kW than at 3.6 kW due to the i3's high-voltage system being on twice as long when charging at 3.6 kW compared with 7.2 kW.

 

[jadnashuanh]

Fine point, but the internal charging of the i3 is limited to 7400W, two 3700W devices. My soon to be i3 replacement X5 45e uses one of these, for a maximum of 3700W. So, while the EVSE sends out a signal that says how many amps (to protect the wiring to it) it has, how much power is actually transferred is up to the car up to 7400W. My nominal acv=247v, and I have a 30A EVSE, so I can max out the i3 where others may require a 32A unit. A typical US commercial supply might end up being 208V, so amps is the limiting thing, but the amount of power supplied is limited by the applied voltage.

208*30=6240
247*30=7410
240*32=7680

The later two will max out the charging capacity of the i3, the first, will not. Most newer units went from 30A to 32A to maximize a 40A circuit. It doesn't hurt the vehicle if you have a larger EVSE, it just won't use more than it needs like plugging in a 10W phone charger doesn't care much about the input being 120vac.

Places where three-phase power is the norm, BMW can charge at a higher rate (I think it's around 10400W).

 

[protonic]

Wow, that is crazy that some people are paying that much for electricity!

I am charging at 7.47 kW nos so that is awesome.

Random question...I have a friend with an RV, 30 amp 3 prong (standard I think). Would he be able to change his plug and plug into my 50 amp outlet when he visits?

 

[alohart]

Random question...I have a friend with an RV, 30 amp 3 prong (standard I think). Would he be able to change his plug and plug into my 50 amp outlet when he visits?

A better solution would be for your friend to purchase a plug adapter with a receptacle end into which his 30 A plug would plug and a plug end that would plug into your 50 A outlet. Your circuit is protected by a circuit breaker, so there's no danger.

 

[jadnashuanh]

As was stated earlier, at least in the USA, the breaker is to protect the wiring, not the device plugged into it. Same idea when you plug in a 100W lamp into a circuit capable of 15A (nominally 15*120=1800W). Using less of the available power is normal, and perfectly fine.

 

[protonic]

Sweet, thanks guys. have one in order from Amazon for $20 prime. Will be here tomorrow (Fri).

 

[protonic]

Does anyone have a Chargepoint charger at home and at work (your own business)? I'm wondering if I can use the same app for both chargers or if it would be better to go with a different brand.