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This topic is PHEV-specific. HEV owners don't have an external charging option, and EV owners are likely to have solid reasons for wanting Level 2 charging in their homes. But PHEV owners have to make a decision and the choices are hardly self-evident.

PHEV owners receive a level 1 charger when they purchase their Niro. We can plug it in to standard household electrical outlets, it takes longer to charge our PHEV than level 2 would take, but given that our maximum EV range is 26 miles and we can get a full charge overnight on Level 1, most of us are content with the level 1 charger's performance. Not having to hire an electrician and pay significant sums of money to install level 2 charging equipment reinforces that perspective.

But the owner's manual recommends level 2 and describes the level 1 charger as an "emergency charger". Many of us are concerned about maximizing the lifetime of our PHEV battery, and we're left questioning the owner's manual guidance because conventional wisdom suggests that slow (level 1) charging is likely to be better for battery longevity, but the owner's manual seems to contradict that conventional wisdom.

There are a lot of other threads on this forum that discuss these sane questions. My hope is that this thread will give this specific topic a home for future discussion.

In this post, lafe005 points out some level 2 advantages, in terms of both time and temperature. It's worth considering if you live in a cold climate, are concerned about charging efficiency/economics, or if your situation would allow you to avoid depleting the charge in your PHEV battery if you can use a level 2 charger, when you would be more likely to (almost) fully deplete it with a level 1 charger. That's because depleting the battery is not great for longevity either, although I think most of us PHEV owners are inclined to do that when exceeding our 26 mile range, because that's kind of the point of owning a PHEV. It would be interesting to see a scientific study on which is worse: depleting or avoiding depletion by fast charging.

Several threads speculate that Kia recommends level 2 not because it's necessarily better for your battery, but because of corporate liability concerns. The thinking seems to be that if you install a level 2 charger, it's going to land on a brand new dedicated circuit in your garage, because not many people have 240 V outlets in their garage and so level 2 likely requires an electrician to install new wiring that conforms to modern electrical codes, but if you use the level 1 "emergency charger", you might plug that in to old, substandard, house wiring and because the level 1 charger pulls a lot of current, if you have crappy or overloaded wiring in your garage, it could lead to a house fire which could lead to a lawsuit against Kia. I don't completely buy that theory, because it's not like the level 1 charger is necessarily pulling more current than is "legal" or "standard". The draw is comparable to a high powered hair dryer, although it's different from a hair dryer in that it runs for hours, rather than minutes. So yeah, if you have crappy garage wiring, that long high current draw could heat up your house wiring and start a fire when a hair dryer would not, but I don't really think that this is the reason why Kia recommends level 2 in the PHEV owner's manual. Which is not to suggest that I know what their real motivation actually is.

Looking forward to reading what others might be thinking on this topic.
 

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This topic is PHEV-specific. HEV owners don't have an external charging option, and EV owners are likely to have solid reasons for wanting Level 2 charging in their homes. But PHEV owners have to make a decision and the choices are hardly self-evident.

PHEV owners receive a level 1 charger when they purchase their Niro. We can plug it in to standard household electrical outlets, it takes longer to charge our PHEV than level 2 would take, but given that our maximum EV range is 26 miles and we can get a full charge overnight on Level 1, most of us are content with the level 1 charger's performance. Not having to hire an electrician and pay significant sums of money to install level 2 charging equipment reinforces that perspective.

But the owner's manual recommends level 2 and describes the level 1 charger as an "emergency charger". Many of us are concerned about maximizing the lifetime of our PHEV battery, and we're left questioning the owner's manual guidance because conventional wisdom suggests that slow (level 1) charging is likely to be better for battery longevity, but the owner's manual seems to contradict that conventional wisdom.

There are a lot of other threads on this forum that discuss these sane questions. My hope is that this thread will give this specific topic a home for future discussion.

In this post, lafe005 points out some level 2 advantages, in terms of both time and temperature. It's worth considering if you live in a cold climate, are concerned about charging efficiency/economics, or if your situation would allow you to avoid depleting the charge in your PHEV battery if you can use a level 2 charger, when you would be more likely to (almost) fully deplete it with a level 1 charger. That's because depleting the battery is not great for longevity either, although I think most of us PHEV owners are inclined to do that when exceeding our 26 mile range, because that's kind of the point of owning a PHEV. It would be interesting to see a scientific study on which is worse: depleting or avoiding depletion by fast charging.

Several threads speculate that Kia recommends level 2 not because it's necessarily better for your battery, but because of corporate liability concerns. The thinking seems to be that if you install a level 2 charger, it's going to land on a brand new dedicated circuit in your garage, because not many people have 240 V outlets in their garage and so level 2 likely requires an electrician to install new wiring that conforms to modern electrical codes, but if you use the level 1 "emergency charger", you might plug that in to old, substandard, house wiring and because the level 1 charger pulls a lot of current, if you have crappy or overloaded wiring in your garage, it could lead to a house fire which could lead to a lawsuit against Kia. I don't completely buy that theory, because it's not like the level 1 charger is necessarily pulling more current than is "legal" or "standard". The draw is comparable to a high powered hair dryer, although it's different from a hair dryer in that it runs for hours, rather than minutes. So yeah, if you have crappy garage wiring, that long high current draw could heat up your house wiring and start a fire when a hair dryer would not, but I don't really think that this is the reason why Kia recommends level 2 in the PHEV owner's manual. Which is not to suggest that I know what their real motivation actually is.

Looking forward to reading what others might be thinking on this topic.
Someone please contact KIA engineering and ask them why level2 is recommended over level1.
 

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Because the charger is only using 3.3 KWh, the load on a circuit of a 30 amp/240v is less than the 15 amp/120v.

You have to understand how a 240V circuit is wired for this to make sense. A 240V circuit is literally 2 120V circuits. A 120V circuit has Live and Neutral wires, a 240V circuit has 2-120V live wires. A 240 V circuit at the circuit breaker is literally 2-15 amp circuits next to each other.

A level 1 charger maxes out the live wire on 1-15 amp circuit. (15 amps)
A level 2 charger uses at most 90% of the capacity of the circuits. (13.5 amps each wire)

These are maximum possible current draws, with ideal wiring and minimal resistance (Ohms about 8 ohms for these numbers).


Watts = Volts x Amps
Volts = Watts ÷ Amps
Amps = Volts ÷ Watts
Ohms = Volts ÷ Amps

Cold weather makes Ohms rise, this is more resistance. More Ohms causes a much higher current flow to keep the same watts. Amps squares as ohms increases. Watts also equals the sqaure of Amps x Ohms. W=A² x O
 

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Because the charger is only using 3.3 KWh, the load on a circuit of a 30 amp/240v is less than the 15 amp/120v.

You have to understand how a 240V circuit is wired for this to make sense. A 240V circuit is literally 2 120V circuits. A 120V circuit has Live and Neutral wires, a 240V circuit has 2-120V live wires. A 240 V circuit at the circuit breaker is literally 2-15 amp circuits next to each other.

A level 1 charger maxes out the live wire on 1-15 amp circuit. (15 amps)
A level 2 charger uses at most 90% of the capacity of the circuits. (13.5 amps each wire)

These are maximum possible current draws, with ideal wiring and minimal resistance (Ohms about 8 ohms for these numbers).


Watts = Volts x Amps
Volts = Watts ÷ Amps
Amps = Volts ÷ Watts
Ohms = Volts ÷ Amps

Cold weather makes Ohms rise, this is more resistance. More Ohms causes a much higher current flow to keep the same watts. Amps squares as ohms increases. Watts also equals the sqaure of Amps x Ohms. W=A² x O
FWIW

level1 uses max 12a x 120v = 1440w. (Confirmed by measurement)

level2 uses max 16a x 240v = 3840w (IIRC)

1440w/3840w ~ 2.5hrs/6.5hrs respective charge time ratio
 

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I read an article about 120 vs 240 charging in regard to which is best for battery life. It stated that while 120 volt charging does not heat the traction battery as much as 240 charging does, it charges and heats the battery for a longer period of time makeing 240 volt charging slightly better for battery life in the long run. I am currently charging with 120 volts and it is working well for me but I will most likely install a 240 circuit in the near future to maximize battery life. I tried to find the articale to post a link but couldn’t find it second time around.
 

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Charging the last 10 or 15 percent is what shortens battery longevity (capacity). No issue there as the Niro has a substantial buffer in that charging to "100%" is actually around 80%. Excessive heat from fast charging can also shorten life, but it is hard to imagine that the small increase in heat from Level 1 charging over a longer time is worse that the higher increase for a shorter period. I'd have to see the research that supports it. It would have to be a long term lab test on individual cells controlling carefully the charging and noting the temperature, and the reduction in capacity a few thousand charging cycles later to be valid.

No special knowledge of the field, but of note in a college coop job, I programmed satellite battery testing routines (major issue was designing programs that would fit in the limited RAM of the minicomputers of the day). These were NiCad batteries and we tested the entire battery, not individual cells. What we were looking for cell voltage reversals and how to prevent them happening in space. Satellites were very expensive back then and a battery failure means you have to replace the entire satellite.
 

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And the level1 isn't so bad for the battery, just not as good as a 240v level2 charger that requires a special type of plug that you most likely would not find inside an average garage
 

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Discussion Starter #12
Because the charger is only using 3.3 KWh, the load on a circuit of a 30 amp/240v is less than the 15 amp/120v.

You have to understand how a 240V circuit is wired for this to make sense. A 240V circuit is literally 2 120V circuits. A 120V circuit has Live and Neutral wires, a 240V circuit has 2-120V live wires. A 240 V circuit at the circuit breaker is literally 2-15 amp circuits next to each other.

A level 1 charger maxes out the live wire on 1-15 amp circuit. (15 amps)
A level 2 charger uses at most 90% of the capacity of the circuits. (13.5 amps each wire)

These are maximum possible current draws, with ideal wiring and minimal resistance (Ohms about 8 ohms for these numbers).


Watts = Volts x Amps
Volts = Watts ÷ Amps
Amps = Volts ÷ Watts
Ohms = Volts ÷ Amps

Cold weather makes Ohms rise, this is more resistance. More Ohms causes a much higher current flow to keep the same watts. Amps squares as ohms increases. Watts also equals the sqaure of Amps x Ohms. W=A² x O
I think you might have a typo in one of those equations.
I think when the resistance increases and the voltage stays constant, the current decreases.

Where did you get 3.3 KWh? Is that your estimate for energy to fully charge the PHEV battery? I thought it was a bit more than 8 KWh.
I agree that there's likely to be less current flowing in a level 2 charging circuit, and so a somewhat higher safety factor if you have concerns about the electrical wiring in your garage. But if you are using a dedicated 120V circuit that is in decent condition for Level 1 charging, I don't see that as a significant consideration.


I read an article about 120 vs 240 charging in regard to which is best for battery life. It stated that while 120 volt charging does not heat the traction battery as much as 240 charging does, it charges and heats the battery for a longer period of time making 240 volt charging slightly better for battery life in the long run. I am currently charging with 120 volts and it is working well for me but I will most likely install a 240 circuit in the near future to maximize battery life. I tried to find the articale to post a link but couldn’t find it second time around.

Interesting idea and one that I hadn't considered. I wish you could find that article. I've read that the cooling fan can come on when charging, but I've yet to hear any sound to indicate that it was running. On the other hand, I'm usually asleep by the time it reaches the end of the charging cycle. Perhaps I'll make a point of charging during the day some time and check on it near the end of the cycle to see.


Level 2 is slightly more efficient than Level 1. But only slightly. I estimated that if I fully charged the PHEV battery every day, level 2 would save me about five cents/day in electric bills. Considering only the savings on the electric bill, I estimated the payback period for installing Level 2 hardware at about 78 years. Of course, if there's a benefit in terms of battery longevity, that might be a different matter.
 

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I think you might have a typo in one of those equations.
I think when the resistance increases and the voltage stays constant, the current decreases.

Where did you get 3.3 KWh? Is that your estimate for energy to fully charge the PHEV battery? I thought it was a bit more than 8 KWh.
I agree that there's likely to be less current flowing in a level 2 charging circuit, and so a somewhat higher safety factor if you have concerns about the electrical wiring in your garage. But if you are using a dedicated 120V circuit that is in decent condition for Level 1 charging, I don't see that as a significant consideration.





Interesting idea and one that I hadn't considered. I wish you could find that article. I've read that the cooling fan can come on when charging, but I've yet to hear any sound to indicate that it was running. On the other hand, I'm usually asleep by the time it reaches the end of the charging cycle. Perhaps I'll make a point of charging during the day some time and check on it near the end of the cycle to see.


Level 2 is slightly more efficient than Level 1. But only slightly. I estimated that if I fully charged the PHEV battery every day, level 2 would save me about five cents/day in electric bills. Considering only the savings on the electric bill, I estimated the payback period for installing Level 2 hardware at about 78 years. Of course, if there's a benefit in terms of battery longevity, that might be a different matter.
FWIW, More current in L2 than L1, not less. Relative charge times prove this.

level1 uses max 12a x 120v = 1440w. (Confirmed by measurement)

level2 uses max 16a x 240v = 3840w (IIRC)

1440w/3840w ~ 2.5hrs/6.5hrs respective charge time ratio
 

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FWIW, More current in L2 than L1, not less. Relative charge times prove this.

level2 uses max 16a x 240v = 3840w (IIRC)

You can go up to a 30a fixed L2 charger at home, 16a chargers are more used for people that transports their 240v chargers to their cottage and other places that has a 240v plug installed.
 

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I think you might have a typo in one of those equations.
I think when the resistance increases and the voltage stays constant, the current decreases.

Where did you get 3.3 KWh? Is that your estimate for energy to fully charge the PHEV battery? I thought it was a bit more than 8 KWh.
I agree that there's likely to be less current flowing in a level 2 charging circuit, and so a somewhat higher safety factor if you have concerns about the electrical wiring in your garage. But if you are using a dedicated 120V circuit that is in decent condition for Level 1 charging, I don't see that as a significant consideration.
Ohms law is empirical. It is the resistance of a material to conduct electricity that is based on the type of material, the length, and the diameter. Copper, Silver, Iron, Gold. 10 ft, 20ft, 50ft. 16 AWG, 12 AWG, 0 AWG, 00 AWG. All factor into the resistance of the current flow.

The 3.3 KW charger: (Typo was using KWh instead of KW)
3.3 KW is how fast it can charge.
8.9 KWh is how much charge it can hold.

https://www.plugincars.com/kia-niro-plug-hybrid
 

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There is energy in the home mains supply. The issue is that this AC energy has to be converted within the car to DC for charging. This in car AC to DC converter is rated at 3.3kw. Now in the US and Canada we have single phase supply 120v. Elsewhere it is often only240V. The in car converter is more suited to a 240v supply since it is designed to run at that rate given that the 240v is more universal.. It does allow charging at half the voltage but that also in North America means half the amperage given that 120v circuits come with thinner wiring.This about quadruples the charging time and impacts the service lifetime of the charging process. Probably this is the source of KIA preferring 240v level2 charging.
 

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You can go up to a 30a fixed L2 charger at home, 16a chargers are more used for people that transports their 240v chargers to their cottage and other places that has a 240v plug installed.
no doubt, but the niro prev only uses <16a x 240v = 3840w

8900Whr / 2.5hr = 3560W

8000Whr /2.5 = 3200W

3300W/240 V= ~ 14a

Charging times, L1 6.5hrs, L2 2.5 hrs
 

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Discussion Starter #18
FWIW, More current in L2 than L1, not less. Relative charge times prove this.

level1 uses max 12a x 120v = 1440w. (Confirmed by measurement)

level2 uses max 16a x 240v = 3840w (IIRC)

1440w/3840w ~ 2.5hrs/6.5hrs respective charge time ratio

I stand corrected. Thanks for pointing that out. Presumably, the level 2 charging circuit is using at least 10 gauge wire and is up for the increased current as a result.
 

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Level1/level 2

Haven’t been able to find that artical on level 1 vs level 2 charging. I wish Kia would give an explanation as to why they recommend level 2 over level 1. Theories range from legal to longevity. I asked my local Kia service manager but he had no clue and said the level one charger was fine. Heat is the enemy. Less heat over a longer period of time (level 1) or more heat over a shorter time (level 2), which is better? Based on what I’ve read in this forum and elsewhere and given the fact that Kia recommends level 2 I will be installing a 240 circuit and switch to level 2 before summer hits. Right now I have my charging programmed to be done at 5:30 Am. It’s been in the 20-30 degree range at night so not as worried about the battery heat issue at the moment.

Another factor in battery longevity is number of charging cycles. Right now I plug my car in after every days use whether I have 5 or 20 miles of range left. Should I be topping off the 20 mile range if I don’t think I’m going to need it the next day? Any thoughts?
 

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Haven’t been able to find that artical on level 1 vs level 2 charging. I wish Kia would give an explanation as to why they recommend level 2 over level 1. Theories range from legal to longevity. I asked my local Kia service manager but he had no clue and said the level one charger was fine. Heat is the enemy. Less heat over a longer period of time (level 1) or more heat over a shorter time (level 2), which is better? Based on what I’ve read in this forum and elsewhere and given the fact that Kia recommends level 2 I will be installing a 240 circuit and switch to level 2 before summer hits. Right now I have my charging programmed to be done at 5:30 Am. It’s been in the 20-30 degree range at night so not as worried about the battery heat issue at the moment.

Another factor in battery longevity is number of charging cycles. Right now I plug my car in after every days use whether I have 5 or 20 miles of range left. Should I be topping off the 20 mile range if I don’t think I’m going to need it the next day? Any thoughts?
batteries always prefer to be charged at slower charge rates

I would stay with L1 until Kia engineering explains their L2 preference

L2 is better (for the battery) than L3 and L1 is better than L2.
 
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