Living in Apartment Building - Charging questions

[Jctz1]

Hello,
We recently took the plunge and bought our first EV, a 2012 24kWh Nissan Leaf. It has 9 battery bars and overall is in great condition.
It drives so well, too, I am still getting used to it but even as someone who doesn't particularly like driving, I enjoy it immensely. It truly feels like gliding.
Our issue at the moment is that we live in a 30 year old apartment building, so we have no way of charging the car over night at home (no chargers or granny pins in the parkade). Luckily there's plenty of public chargers close by. The Level 2 chargers have a charge limit time of 2 hours, and the Fast DC chargers have a limit of 1 hour.
So far I have only charged the car twice, once at a level 2 charger for about 1:30hrs, which netted me around 4.3kWh of battery (how much charge is that in percentage? 17%?) just to test out the waters and learn how to charge it, and it went from 4 bars to 7 bars of charge.
The second time was the day after; I happened to hit a curb at low speeds (entry to parkade is stupidly designed) the previous day and was concerned about having damaged a tire in my new car, so I took it to a shop to get checked and while everything was fine, the person who drove the car drove it a bit recklessly and lowered it from 7 to 6 bars. I figured I'd try to get the car to 80%, so I went to the Fast Charging station and put 3.9kWh in the battery, from 6 bars to 11 bars.
All the stuff I have read about charging EV's say that the ideal situation is to charge using the granny pin or level 2 charging, from 20-80%, and to only use fast charging sparingly. We luckily don't drive a lot, maybe once or twice a week, though a couple of places we go to are between 20 and 30kms away (12-18 miles roughly, times two to account for the way back), and include a bit of highway driving, so I'd like to be sure that I am preserving those 9 bars of battery as long as possible. So I have a few questions:
1) What does "keep battery between 20-80%" actually mean? Does it mean to only use the car down to 20% and only charge it up to 80%? Or does it mean to keep the battery within that 20-80 range and charge as needed? for example, from 40-65 or from 50-80, etc.
2) Since we can't charge at home, and we can only charge in public stations 2-3 hours at a time, would that damage the battery, since we're not consistently getting to 80 or 100?
3) How often should we actually use Fast Charging? Once every few weeks? Only to make it back from a longer venture out?
4) Since the battery degradation for this used car is at 9 bars, I'm assuming it has degraded around 25%, which for a 10 year car sounds pretty good to me, though still concerning range-wise. Given this, what would be a good percentage equivalence per bar?
I'd appreciate any insight on any or all of these questions.
Thanks.
J.

 

[cwerdna]

2) No
3) Less is better. My last Leaf didn't even have a CHAdeMO inlet and I sold it when it turned about 8 years old.

Out of curiosity, what country are you in? Are you in Canada?

I wouldn't recommend Leafs to people w/o a means to charge at home, work or some place where you will be for hours at a time. You shouldn't have gotten a pre-'13 if you wanted to charge more quickly. '13 SV and '13 SL (and '13 S w/charge package) in the US have 6.6 kW on-board chargers so charging on L2 can be faster. On 240 volt L2s stations, you can hit 6.6 kW at 240 volts. If only 208 volts, it tends to be ~5.7 to 6.1 kW or so.

 

[Jctz1]

Hi cwerdna, thanks for taking the time to reply!

2) No

That's good to know! So theoretically we could just charge as needed within the 20-80 charge range, right?

Are you in Canada?

Yes, in BC.

You shouldn't have gotten a pre-'13 if you wanted to charge more quickly.

Unfortunately the 2012 is the only one we could afford. Leafs have gone up in price recently (20,000 CAD + for a 2015 with 100,000km in the ODO, for example), and this one seemed like a good deal. There is also a possibility of us getting to a place where we can charge overnight in the not so distant future, so we purchased with that in mind, but for the time being we are in an apartment building and that's why I have these questions. It's not like we need to fast charge every time, but we have the option to do so, hence why I was wondering how often it would be good to fast charge. Knowing that we can just level 2-charge when we need to is a relief, and it's what we would rather do.

 

[Marktm]

Doing a little research on your "granny" issue (being from US), I found this interesting article. Appears the easiest, but likely not the most recommended is an "extension" for your granny charger (actually charge controller). If that's just not possible, you are stuck with area charge stations.

https://toughleads.co.uk/pages/safely-charging-your-electric-vehicle

Having owned a 2012 for about a year with (eventually) 9 bars, I had to fully charge or to 80% anytime that I could - seems a little too late to worry to much about battery degredation :|. Having LeafSpy will be helpful in estimating trip limitations for sure.

 

[Jctz1]

Doing a little research on your "granny" issue (being from US), I found this interesting article. Appears the easiest, but likely not the most recommended is an "extension" for your granny charger (actually charge controller). If that's just not possible, you are stuck with area charge stations.

https://toughleads.co.uk/pages/safely-charging-your-electric-vehicle

Having owned a 2012 for about a year with (eventually) 9 bars, I had to fully charge or to 80% anytime that I could - seems a little too late to worry to much about battery degredation :|. Having LeafSpy will be helpful in estimating trip limitations for sure.

Hi Marktm! Thanks for taking the time to reply.

We are actually located in Canada, though a lot of information on EV's I found was from the UK, so I kind of adopted the term "granny pin" for the 140V charger (directly from an outlet) without noticing.

Thanks for your suggestion! Sadly there's no way we can charge using that even with an extension. :/

The only reason I am worried about battery degradation is that I want to keep this car as long as possible, at least 3-5 years. Obviously if as we use it we find it doesn't fulfill our needs, we might wind up switching to a different EV, but that is a last resort situation. Thanks again for replying!

 

[cwerdna]

I'm only guessing Canada due to the use of parkade. In the UK, they seem to call parking lots/garages car parks.

 

[LeftieBiker]

If you didn't live in Canada, I'd be encouraging you to resell the 2012 ASAP. Why? because the 2011 - 4/2013 Leafs have batteries that use a fast-degrading chemistry that is especially vulnerable to heat.(I dubbed them "Canary packs" in my buying guide, which I will link below.) If you are in a cooler part of Canada, you may get a few more years out of the battery. If you have Hot (28C+) Summers, you are going to see significantly more loss of capacity, and should then consider selling it.

Used Leaf buying guide: https://www.mynissanleaf.com/viewtopic.php?p=538030

 

[goldbrick]

The advice to stay within 20%-80% charge is meant mostly to prevent the car from sitting at very low or very high states of charge since either extreme is hard on the battery and accelerates its degradation. In either case, time is also a factor so not much damage will be done by charging to 100% if you drive away immediately or running the battery down to 0% if you charge right away.

What you want to avoid is letting the car sit for a long time at very high % SOC or very low % SOC. Under your circumstances, I would focus more on convenience and trying to leave the car between 20% and 80% only when it's parked for a while. If you're driving around feel free to run it from 100% down to 0% if you need to, just don't park it at 99% or 1% for a week and let it sit there.

 

[LeftieBiker]

I'd offer slightly different advice: don't worry about charging to 100% as long as you use the car soon after it's charged, and don't worry about driving it down to 10-20%, as long as you recharge immediately afterward when it's less than 20%. Running it to an indicated 0% (actually a bit higher in reality) can let any weak cells in the battery trigger a shutdown, even if you have a significant amount of range left. The car will slow and then shut down to protect the weakest cell(s) in the battery.

 

[cwerdna]

Household voltages in the US are most certainly not 140 volts! I doubt they are in Canada. 140 volts coming out of 120 volt outlets could let out the "magic smoke" (http://www.catb.org/jargon/html/M/magic-smoke.html) out of some items.

 

[Jctz1]

@LeftieBiker Thanks for your input!

If you have Hot (28C+) Summers, you are going to see significantly more loss of capacity, and should then consider selling it.

Thankfully summers here don't usually go over 28 or 30C. Last year we had a heat dome that pushed us to 40C and it sucked, but hopefully that doesn't repeat. And it's not really that hot for super long. In case of a super hot summer, would it be best to not drive the Leaf or to drive it very little?

Thanks for the link to your buying guide!

I'd offer slightly different advice: don't worry about charging to 100% as long as you use the car soon after it's charged, and don't worry about driving it down to 10-20%. Running it to an indicated 0% (actually a bit higher in reality) can let any weak cells in the battery trigger a shutdown, even if you have a significant amount of range left. The car will slow and then shut down to protect the weakest cell(s) in the battery.

So, for example, charging to a 100% in the morning using a DC Fast Charger before a longer drive instead of charging it to 100% the night before at a Level 2 station and leaving it fully charged over night would be the course of action you'd take?

@goldbrick Thanks also for replying!

The advice to stay within 20%-80% charge is meant mostly to prevent the car from sitting at very low or very high states of charge since either extreme is hard on the battery and accelerates its degradation. In either case, time is also a factor so not much damage will be done by charging to 100% if you drive away immediately or running the battery down to 0% if you charge right away.

What you want to avoid is letting the car sit for a long time at very high % SOC or very low % SOC. Under your circumstances, I would focus more on convenience and trying to leave the car between 20% and 80% only when it's parked for a while. If you're driving around feel free to run it from 100% down to 0% if you need to, just don't park it at 99% or 1% for a week and let it sit there.

This goes in line with what LeftieBiker was saying, so I appreciate the consistency and will take both your advice to heart! Thanks!

Thank you both again!!

@cwerdna

Household voltages in the US are most certainly not 140 volts! I doubt they are in Canada. 140 volts coming out of 120 volt outlets could let out the "magic smoke" (http://www.catb.org/jargon/html/M/magic-smoke.html) out of some items.

That was my bad! I totally meant 120V, not 140V. Thanks for your concern and letting me know about the magic smoke. That's concerning!

 

[LeftieBiker]

So, for example, charging to a 100% in the morning using a DC Fast charger before a longer drive instead of charging it to 100% the night before at a Level 2 station and leaving it fully charged over night would be the course of action you'd take?

No, not at all. DCFC heats the battery substantially, while L-1 and L-2 charging don't. We are talking about not leaving the car at 100% for long periods after charging ends, not suggesting that the less time spent charging the better. Leaving it at 100% for a few hours, with a cool battery, isn't a big deal.This does bring up the role of heat in battery degradation, though. Heat above, say, 5 temp bars on the dash display is bad for Leaf batteries - especially older ones - and combining a hot battery with a high state of charge (90-100%) is probably the best way to cause degradation. Or it's a tie between that and leaving a Leaf charged to 100% for weeks or months.

 

[Jctz1]

No, not at all. DCFC heats the battery substantially, while L-1 and L-2 charging don't. We are talking about not leaving the car at 100% for long periods after charging ends, not suggesting that the less time spent charging the better. Leaving it at 100% for a few hours, with a cool battery, isn't a big deal.This does bring up the role of heat in battery degradation, though. Heat above, say, 5 temp bars on the dash display is bad for Leaf batteries - especially older ones - and combining a hot battery with a high state of charge (90-100%) is probably the best way to cause degradation. Or it's a tie between that and leaving a Leaf charged to 100% for weeks or months.

Ok, I get it. For example, my charge right now is at roughly 59% (drove up a long, steady incline yesterday and it took a bite out of the charge, plus lots of red lights), and if I wanted to charge today knowing I will drive tomorrow, I could charge up to even 100% and be sure that it would be ok, preferably with Level 2 charging. The ones around my place charge at 7.20kW, I think it'd take roughly 7 hrs to charge it fully.
Is it more common for the battery to drain faster at the top of the charge and stay steady in the middle of it longer? Like, you start driving, goes from 11 to 8 bars at the beginning but remains in a 7 to 5 bar range longer than it does at the top?
Thanks again!

 

[cwerdna]

I could charge up to even 100% and be sure that it would be ok, preferably with Level 2 charging. The ones around my place charge at 7.20kW, I think it'd take roughly 7 hrs to charge it fully.

The bolded part isn't helpful for your car. '11 an '12 Leafs have a "3.3 kW" on-board charger that will pull from the wall at most 3.8 kW.

3.8 kW * 7 hours = 26.6 kWh out of the "wall".

If you wanted to charge faster on L2, you need a 6.6 kW OBC car, which didn't exist until model year '13 (for US: S w/charge package and standard on SV and SL).

 

[Jctz1]

I could charge up to even 100% and be sure that it would be ok, preferably with Level 2 charging. The ones around my place charge at 7.20kW, I think it'd take roughly 7 hrs to charge it fully.

The bolded part isn't helpful for your car. '11 an '12 Leafs have a "3.3 kW" on-board charger that will pull from the wall at most 3.8 kW.

3.8 kW * 7 hours = 26.6 kWh out of the "wall".

If you wanted to charge faster on L2, you need a 6.6 kW OBC car, which didn't exist until model year '13 (for US: S w/charge package and standard on SV and SL).

I can’t really charge on those for 7 hours since the time limit is 2 hours, so I would never really let the car sit there for 7 hours without supervision, haha. Thanks for that number! It actually helps me calculate how much battery can be recharged in the time I can actually leave it out: 3.8kW * 2 hours = 7.6 kWh, so almost 30% of the charge. That helps with planning, though I know charging tends to slow down towards the “end” of the charge… or is this a misconception?
We don’t really need to charge any faster than that, really, when I said 7 hours earlier I was just trying to estimate time to fully charge (based on the owner’s manual). I really appreciate all of your input, it’s helped a lot with my concerns and thoughts on the car and how to charge and drive it.

 

[alozzy]

Charging does slow down at the top end of the pack, but the 2011/2012 L2 charging rate is slow anyways so you won't really notice much tapering off until you get to high 90% SOC.

 

[goldbrick]

For better or worse, you will probably need a lot of small charging sessions. Keeping the battery near 50% SOC will enhance its life so if you can cover your driving by charging every day from 30-70% SOC or something similar it should work well. Everyone's use case is different and hopefully you can find something that works for you. Convenience is also a big factor but if it's easy to charge every day, then that is a good option.

 

[LeftieBiker]

The 2011-2013/2013+ S w/o Charge package charging rate is 3.3kw, so that's about 6.6kwh every two hours. Actually, I think the 3.3 figure includes losses, so probably more like 3.1kw x 2 = 6.2kwh every two hours.

 

[Jctz1]

Charging does slow down at the top end of the pack, but the 2011/2012 L2 charging rate is slow anyways so you won't really notice much tapering off until you get to high 90% SOC.

Gotcha, thanks a lot for replying to this. What about the battery use becoming more ‘steady’ as it is being used? Is that a thing or am I just being optimistic?

For better or worse, you will probably need a lot of small charging sessions. Keeping the battery near 50% SOC will enhance its life so if you can cover your driving by charging every day from 30-70% SOC or something similar it should work well. Everyone's use case is different and hopefully you can find something that works for you. Convenience is also a big factor but if it's easy to charge every day, then that is a good option.

Excellent, this is all good to know. Thanks!!

The 2011-2013/2013+ S w/o Charge package charging rate is 3.3kw, so that's about 6.6kwh every two hours. Actually, I think the 3.3 figure includes losses, so probably more like 3.1kw x 2 = 6.2kwh every two hours.

Oh ok, I’ll adjust my calculations accordingly. Just out of curiosity, does the degradation of a battery mean it effectively holds less charge? Like, a 24kWh battery can become an 18kWh battery when it has 25% degradation?

 

[LeftieBiker]

Just out of curiosity, does the degradation of a battery mean it effectively holds less charge? Like, a 24kWh battery can become an 18kWh battery when it has 25% degradation?

That's exactly what it means. Degradation reduces capacity.

What about the battery use becoming more ‘steady’ as it is being used? Is that a thing or am I just being optimistic?

I don't understand the question, I'm afraid.