Phoenix and Hot Climate Leafs - Try L1 Charging

[phxsmiley]

Since tracking my Gid count daily in June and July here in Phoenix (South Chandler area), I've been losing approximately 1 GID a day, L2 charging to 80%, particularly on the hot days. My garage temperature has been sitting around 92 degrees at night, very close to the outside temperature, as I'm trying to use a fan to keep the garage.

This past Monday evening, I parked outside and L1 charged at night to 80%. And since then, I've not lost 1 GID yet.

Monday and Tuesday were particularly hot days, also. Driving home Monday, with the car parked in an outdoor parking lot, my car registered 120 degrees. Then it cooled down to 116 on the drive home. Based on my previous readings, I fully expected to lose 1 GID by the next morning. Tuesday was a little cooler, but still in the 115 range. Nighttime temperature only got as low as 93 degrees.

My GID count this morning, after 80% L1 charging both evenings, is still at 185.

This is hardly scientific (sample size of 1), but I wanted to pass this along so that those with GID meters in Phoenix could try L1 charging to see if it helps.

A co-worker here has a Leaf that has not lost a capacity bar, parks outside during the day, and uses L1 charging at night.

I know that based on discussions here, the L2 charging shouldn't be contributing to significant heat gain, but I thought my findings might be helpful, and we could get other users to chime in.

 

[Volusiano]

I wonder if it's not because L1 charging contributing to less heat gain, but because since it's twice as slow as L2, it gives time for the battery to cool down more during the charging process so that a good part of the charging is done when the battery is cooler.

 

[phxsmiley]

Whether doing L1 or L2 charging, I've been using an end timer to try and get the charging done during the coolest part of the night. And, I think L1 is 3x slower, isn't it? - 1.1KWh versus 3.3KWh.

When L1 charging, it seems to have to start around 10PM.

 

[adric22]

I have also wondered for a long time if L1 would be better on the battery long-term. I know Nissan has denied this, but it really only seems logical. Slower charging and slower discharging of a battery is typically good for it. The only example that comes to mind that is contrary to that is when purposefully boiling a lead-acid battery to knock some of the sulfate buildup off of the plates. But I don't see that as an issue with lithium batteries.

 

[Volusiano]

I think L1 is 3x slower, isn't it? - 1.1KWh versus 3.3KWh.

You're probably right. I was just thinking about L2 being at twice the voltage of L1. However, I think L2 draws 16A while L1 draws only 12A, so this would compound the difference in charging time as well.

 

[Volusiano]

I have also wondered for a long time if L1 would be better on the battery long-term. I know Nissan has denied this, but it really only seems logical. Slower charging and slower discharging of a battery is typically good for it. The only example that comes to mind that is contrary to that is when purposefully boiling a lead-acid battery to knock some of the sulfate buildup off of the plates. But I don't see that as an issue with lithium batteries.

Slower charging may be better for the battery, but it may not be better in terms of charging efficiency because L1 charging may waste more energy than L2. So it depends on what's more significant. If the difference in prolonging battery life between L1 and L2 is significant enough to be worth the difference in charging efficiency, then sure. The big question is how do we calculate this?

 

[phxsmiley]

L1 charging is definitely less efficient, I know I've read some estimated measurements from other forum members.

And I believe part of that inefficiency comes from two factors:
- The 'charger cooling pumps' are running the whole time charging is occurring, whether at L1 or L2. Since they draw the same power whether on L1 or L2, but run for less time on L2, L2 charging is more efficient.
- Voltage converter efficiency. I would think the charger is more efficient at 220V than 120V, probably by a small factor.

 

[Volusiano]

Whether doing L1 or L2 charging, I've been using an end timer to try and get the charging done during the coolest part of the night.

I think using the end timer only puts a different twist on things.

For example, let's say it takes 4 hours to charge up on L2, and 12 hours on L1. Let's also say it takes 4 hours for the battery to cool down, to keep it simple.

If you don't use the end time only, so you'd be charging right away, so your L2 charge duration is while the battery is hot. Your L1 charge duration is 1/3 of the time when the battery is hot, and 2/3 of the time when the battery is cool. So it's better to use L1 in this case.

If you use end time only, and also assuming your end time is 12 hours from when you plug in (to keep it simple). Then the L1 charge duration will be 1/3 time while battery is hot, and 2/3 time like battery is cool. But L2 charge duration will be when the battery is cool.

So now the question is, is it better in this situation to use L2 to delay the charging until closer to the end time so the battery has had a chance to cool down enough? Or is it better to use L1, knowing that 1/3 of the charging cycle will be while the battery is still hot?

What I'm trying to get at here is, which is the lesser of the 2 evils? Charging while the battery is still hot and hasn't had a chance to cool down? Or charging at a slower rate because the rule of thumb is that it's better for battery life than charging at a 3x faster rate?

 

[smkettner]

I am thinking parking outside to get maximum overnight cooling has more effect than the L1 vs L2.
But if you need to use L1 to park outside I certainly would consider it.

 

[jspearman]

We charged L1 until about 2 months ago when our solar, new 200amp service and L2 charger were all installed together. So, for the first 8 months we charged L1, but we started charging L2 when it got warmer. Still lost a bar, but we weren't charging L1 when it reached the 100's, so maybe there's something to this.

I encourage everyone to make sure your circuit can handle the draw before plugging in. When rewiring my last house I found that part of my kitchen, including the dishwasher and disposal (which should have their own 15-amp circuits), were on the same circuit as half the kitchen lighting and all the garage outlets. On top of that, the circuit breaker was bad, meaning if I would have been driving an EV then, I could have easily burned my house down in the middle of the night if running the dishwasher at the same time. So grab a couple of toaster ovens and see if you can trip the breaker before plugging in your $35K car. Nissan certainly doesn't need a fiery garage to complement the degradation.

 

[Weatherman]

I am thinking parking outside to get maximum overnight cooling has more effect than the L1 vs L2.

This is, probably, true.

Not only is it likely to be cooler outside than in an enclosed garage at night, objects outside can radiate their heat into space on a clear night.

For those of us in more humid climates, it’s why dew forms on outside objects on clear nights. The object is, actually, cooler than the air temperature.

 

[RegGuheert]

A co-worker here has a Leaf that has not lost a capacity bar, parks outside during the day, and uses L1 charging at night.

Interesting! Can you please tell us when your co-worker purchased the car?

 

[phxsmiley]

I am thinking parking outside to get maximum overnight cooling has more effect than the L1 vs L2.

This is, probably, true.

Not only is it likely to be cooler outside than in an enclosed garage at night, objects outside can radiate their heat into space on a clear night.

For those of us in more humid climates, it’s why dew forms on outside objects on clear nights. The object is, actually, cooler than the air temperature.

This is likely true. I measure about a 2-3 degree difference in temperature between the outside and garage, despite fan cooling - probably need a better fan.

But, the better ability to radiate the heat is probably key here. That, in combination with the almost negligible heat gain from L1 may be making the difference.

It's difficult to test the combination of L2 charging outside, and keep all the other conditions the same (outside temp) so I can clearly see the effects. I do have a EVSE-upgraded unit, but finding two non-GFCI and opposite phase outlets nearby is pretty difficult.

If other Phoenix/Texas users could try this, then watch with their GID meters and see if things improve (improved GID loss) that would help.

 

[09Bamb00]

My 240V EVSE charger should be here any day now so for now I charge with 110 over night and 240 during the day at work.

Because I live in sunny Florida, I can't leave the car charging outside at night as I never know when a thunderstorm might decide to visit. (I'm paranoid about waking up to no electricity and a car fire.) And I'm not too happy about leaving a door ajar to accommodate the cord as the sole single use outlet is directly under the electrical panel. On the 110 charger I have to start within the first hour that I get home otherwise it doesn't make enough electricity to get me to work the following day. My commute is 47+/- one way.

I find that the stated 'range' has nothing to do with reality. In the morning the Leaf states that I have an 87 mile range. By the time I've backed out of the garage and driven the four blocks to the first light doing 35 mph, the range has dropped to 69 miles. When I arrive at work, it reads 29 mile range. Meanwhile the actual miles is 47+/-. Most of the commute is on a highway at 70 mph (minimum speed limit), with the radio. Sometimes with lights on and sometimes with the air conditioning running. On those days I have a 19 mile range by the time I get to work.

On the drive home, I almost always run the air conditioner, the lights and the windshield wipers because the afternoon monsoon rainy season is upon us. So I start out at around 101-87 mile range (for some reason I get these numbers when I use 240v charger). Once again, I'm down to 35-19 mile range when I get home. Some days when I have used the constant wiper setting, I have had to stop to a car charging station about 20 miles from home to get enough juice to make it home.

Anyway, it will be nice to be able to go out further than walking distance when I get home, which is why I'm looking forward to the 240 charger arrival.

 

[RegGuheert]

This past Monday evening, I parked outside and L1 charged at night to 80%. And since then, I've not lost 1 GID yet.

Four thoughts on this:

1) Perhaps L1 charging permits better cell balancing than L2. (Although I have no idea whether or not any cell balancing is done during an 80% charge.)

2) Similar to 1) above, perhaps the temperature rise in the pack is uneven such that the charging creates more unbalance each time an L2 charge is done. If so, perhaps the apparent drop in capacity with L2 is not real (or mostly not real).

3) Perhaps an EVSEUpgrade without the Rev 2 to get 16A at 240 VAC would be better? (Although I believe Phil said that the LEAF only draws around 13A anyway.)

4) I have always felt a 6.6kW charger would be a liability for home use and I would want to be sure to use a 16A or lower EVSE with a LEAF with such a charger. Maybe I haven't taken my thinking far enough on this topic!

 

[mkjayakumar]

I find that the stated 'range' has nothing to do with reality. In the morning the Leaf states that I have an 87 mile range. By the time I've backed out of the garage and driven the four blocks to the first light doing 35 mph, the range has dropped to 69 miles. When I arrive at work, it reads 29 mile range. Meanwhile the actual miles is 47+/-. Most of the commute is on a highway at 70 mph (minimum speed limit), with the radio. Sometimes with lights on and sometimes with the air conditioning running. On those days I have a 19 mile range by the time I get to work.
.

Starting your commute with GoM reading 87 miles and if you see 29 miles range remaining, after you have driven 47 miles mostly at highway at speeds in excess of 65 mph - that means you are doing pretty good. Remember, the 87 miles initial reading is under the assumption that your driving efficiency is atleast 5.0 miles/kWh or more.

What is your miles/kWh on a one way trip to office ?

 

[adric22]

I am thinking parking outside to get maximum overnight cooling has more effect than the L1 vs L2.

I will never park my car outside. I'm more worried about break-ins, hail storms, etc. However, I do have a thermometer on my garage wall and I've noticed that it takes a very long time for the garage to cool down. Even after the sun has been down for hours and the outside temperature has sunk to 90 degrees, it is still often 103 inside the garage. Even in the mornings when the temperature has reached 80 degrees outside, it is still close to 90 in the garage.

So the last week or so I've been leaving the garage door open just a tad, around 6 inches or so. It is enough to allow air to circulate through the garage some.

If this turns out to be a real issue (hot garages, that is) then I'll look into adding some forced-air ventilation to the garage.

 

[09Bamb00]

What is your miles/kWh on a one way trip to office ?
47 miles +/-

I understand the amount may work out, it's just the silliness of saying I have 87 mile range and four blocks later I have 69. Or in the garage I start with 101 and when I roll down the incline to the exit I have 97.

 

[Deleted member 3147]

(Although I believe Phil said that the LEAF only draws around 13A anyway

Actually, the amperage is limited (to 12A) only for L1 (120V). At L2 voltage, the Leaf will draw 16A at 240V and up to 18A (possibly more) if the voltage sags to keep the 3.8KW AC draw all limited by the EVSE pilot signal, of course). I mentioned to Phil once that I'd be charging at work on 208V and he said that he'd experimented with setting the EVSE pilot to 18A and that wiring is marginal at that amperage; it'd work if you were careful not tightly coil the cable or cover the connector, etc.

 

[smkettner]

What is your miles/kWh on a one way trip to office ?
47 miles +/-

I understand the amount may work out, it's just the silliness of saying I have 87 mile range and four blocks later I have 69. Or in the garage I start with 101 and when I roll down the incline to the exit I have 97.

Yes I agree the GOM could just as easy tick off miles with the odometer at least during the first 10 miles of 100% charge. Then adjust to reducing range (never increase) at 50% to 200% of odometer miles.