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2018 Chevy Bolt EV
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Discussion Starter · #1 ·
Hello and happy November!

Do you charge at home using a Level 2 charger? What charger would you recommend and why?

We received a question about this from a Kia Niro EV owner and while we cannot endorse any brand, we can certainly pass on recommendations from our coaches.

Please comment below!
 

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2018 Chevy Bolt EV
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Discussion Starter · #2 ·
Virtually any L2 EVSE will work. Before spending the money on an electrician and equipment, the owner should answer: is it necessary?

An EV owner who drives less than 40-50 miles daily can charge overnight on a standard 120V outlet. If charging is available at work, at least double this.

If L2 is necessary due to longer daily driving routines, there are several factors to consider. Does your utility offer rebates on certain units? If so, choose one of these to save hundred(s) of dollars. Also realize, the charger and electrical work may be eligible for up to 30% tax credits (Federal) and many utilities will also offer rebates on the electrical work.

Can the home's Main breaker panel handle an additional 40Amp circuit? The Niro has a 32Amp (32A) onboard charger, so a 40A circuit would be adequate to charge at the fastest possible rate at home (always overrate the circuit to remain safe - 80% is the safe load). L2 chargers range from 16 - 48A typically. While higher speed chargers will still work (Niro will only draw the amount of current it is capable of accepting), the higher powered units tend to be costlier.

Generally, home chargers come in two plug types, Tesla or J1772. J1772 is nearly universal, even Teslas can use it with an adapter that comes with their car. All other EVs use J1772. While it is possible to use a Tesla AC charger with an adapter on J1772 equipped cars, it may end up costlier to go this route.

To determine minimum charging speeds needed to "fill the tank" nightly, use the following guidelines. These assume an average driving efficiency of 4 miles/kWh.

L1: 120V (12A) - 1.44 kW or 14.4 kWh over 10 hours. This would yield about 55 miles of range added overnight, maybe less in winter weather.
L2: 240V (16A) - 3.84 kW or 38.4 kWh over 10 hours. This would yield about 150 miles of range overnight.
L2: 240V (24A) - 5.76 kW or 57.6 kWh over 10 hours. This would yield about 230 miles of range overnight.
L2: 240V (32A) - 7.68 kW or 76.8 kWh over 10 hours. Note, Niro pack has a 64 kWh capacity, so 0-100% in about 9 hours.

Another way to look at it is to use the formula miles (per day) / 4 = kWh consumed. So, a 100 mile daily routine would use roughly 25 kWh. Then, divide 25 (kWh) by charging speeds from above. So, a 32A EVSE would take 25/7.68 or 3.25 hours to replenish daily use. This is well within Time of Use schedules typically.

The AC charger is onboard all EVs. So the charging cord or wall unit is effectively simply supplying power to the car, almost like an extension cord. For this reason, the cord or wall unit is referred to as EV Supply Equipment or EVSE.

Most EVs have smart charging scheduling built in, so the EVSE doesn't need to be smart (WiFi enabled), though some owners like having this option. For those with Time of Use utility rates, the off-peak lower rates may be less than 10 hours, so do a little math to determine if a high powered charger would save money on utility rates.

Finally, there are dozens of good quality EVSEs in the market. Electrify America, Chargepoint, JuiceBox, Grizzl-e and a few others are generally good bets. Don't go too cheap, some foreign nock off units have been known to cause issues like melting charge ports. You spent premium dollars on your EV, why wouldn't you buy a quality charger?

Amazon can be a good source of reviews, they sell nearly every brand of charger. Also, consider an account on the Niro forum or Facebook group and ask other owners for input on EVSEs and why they like them. Or join the Colorado EV Owners forum to interact with EV enthusiasts here in the state.
 

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Hello and happy November!

Do you charge at home using a Level 2 charger? What charger would you recommend and why?

We received a question about this from a Kia Niro EV owner and while we cannot endorse any brand, we can certainly pass on recommendations from our coaches.

Please comment below!
Hello I have a Juice Box 40 amp. Works great. I don't always need the speed so I set mine to charge at about 5 kwh. I'm the rare occasions when I need a faster charge. For example when friends come into town and I pick them up from the airport and then we head out again 2 hours later it's nice to have 10 kwh charging possibilities.
 

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2018 Chevy Bolt EV
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Discussion Starter · #4 ·
I assume you mean 5 kW (~24Amps), and for 1-2 hours, that would add 5-10 kWh to the EV pack.

I only correct the terminology because it is confusing to prospective and new EV owners. As EV advocates, it is probably important to speak clearly about these terms.

For clarification, the rate of charge or discharge at any given point in time is expressed as kW, and the cumulative energy stored is expressed in kW per hour, or kWh.

But, you raise an important point. Fast isn't always necessary. I suspect 90% or more of EV owners could get by on 120V wall outlets as average daily commutes in the US are somewhere under 40 miles round trip. But it is nice to have a faster option for the quick turnaround trips.

Thanks for your input!
 

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I assume you mean 5 kW (~24Amps), and for 1-2 hours, that would add 5-10 kWh to the EV pack.

I only correct the terminology because it is confusing to prospective and new EV owners. As EV advocates, it is probably important to speak clearly about these terms.

For clarification, the rate of charge or discharge at any given point in time is expressed as kW, and the cumulative energy stored is expressed in kW per hour, or kWh.

But, you raise an important point. Fast isn't always necessary. I suspect 90% or more of EV owners could get by on 120V wall outlets as average daily commutes in the US are somewhere under 40 miles round trip. But it is nice to have a faster option for the quick turnaround trips.

Thanks for your input!
Yep you are right. I only plug in twice a week. When I get close to 20 percent and I charge up to 80 percent. I would say about 8 times a year I need the quick turn around if 10 KW power.
 

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2018 Chevy Bolt EV
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Discussion Starter · #6 ·
Yep you are right. I only plug in twice a week. When I get close to 20 percent and I charge up to 80 percent. I would say about 8 times a year I need the quick turn around if 10 KW power.
Lessons learned from the Chevy Bolt battery recall... When SoC drops below 30%, some expansion occurs in Li-Ion cells. Same when charging to near 100%. So GM has suggested owners attempt to keep SoC in the 30-90% range to minimize battery issues due to the expansion and contraction, which has apparently exasperated the defects in the LGE cells. Other EV makers offer similar guidance, though most don't make a big deal about it as the impact may be minimal in the short term that many keep their cars.

This article touches on swelling that occurs in Li-Ion batteries: Why Do Lithium-Ion Batteries Swell?

The fact that you use lower Amp settings may help, but plugging in a bit more often and keeping SoC a little higher on the low end might to worth considering.

Also, as temps drop, being plugged in may enable the EV to draw a little grid energy to run battery heating\cooling cycles to minimize extreme pack temps. Think of the battery pack like a human, it prefers ~60-80F temps for optimal performance and health. Storing at high or low SoC when temps are outside of the preferred temp range may have some minor negative effect on long term health. Again, using the Bolt as a reference, GM has programmed the BMS to run conditioning less often when unplugged (to preserve range), so remaining plugged in ensures conditioning can occur anytime it would be favorable for battery health.

Using the car's Time of Use (TOU) scheduling could help. You could make a habit of always plugging in, but set schedules to charge Mo, We, Fr only for instance. In other words, trick the car into thinking peak utility rates are all day on Tu, Th, Sa, Su.

With the Bolt, there is a simple way to override the schedules if circumstances warrant. To override, simply plug in, wait a few seconds, unplug, then plug back in again within ~10 seconds and the charging will start immediately and disregard the schedules (but still honor the target charge level (80% for instance).

The other benefit of more frequent, shallow cycle charging is you can avoid peak rate period charging because you won't need to charge as long each time. Even if you are not on a TOU utility rate plan, avoiding peak period charging may help utility keep rates lower for everyone.

My attitude is, keep it simple and don't get too worked up about the little things WRT battery health. But, knowing some of the tips like above if they can easily be worked into a routine might be helpful if you intend to keep the car for a long time. I set mine to charge to 90%, only between 10PM and 5AM 365 days per year. This way, I can always plug in and know it will remain ready for anything that comes my way.
 

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I have to admit I didn't know the swell at 30% and 100%. I heard something once about sitting at 100% in hot weather but nothing beyond that before your post. I am used to that for old electronics. I'll have to read that linked article thank you.

One other thing is if you are going to have an electrician come I'd at least put in a 50amp circuit for future proofing if not 60A like Tesla often does as labor is the biggest cost there unless you got a real nice buddy. This does not mean you need an EVSE that can do that yet. I agree most people can get by with l1. One advantage is when the spouse or you forget to plug in and then you want to make a long drive l2 can help you get more sooner. Even I probably only need the full l2 speed 10 times a year to be honest, usually so I can go on errands before a road trip and have it full up to leave early in the morning to put off a DC fast charger. I also have been recommending people do l1 for a while before hiring an electrician, some people seem to think they need to do that before they take delivery of the car and that is just not the case.

I use an OpenEVSE kit I got on a discount they had, I would not recommend that to most people it is more like a hobby for me. Some utilities are offering and looking into offering rebates on chargers and programs where they can control when you care based on peak loads and such, I assume there is an override when you really need it like I am about to leave on a road trip. Some have a solar divert too where instead of to the grid you can go to your car, I see it in the software for mine but it is not connected for it.
 
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