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Hey experts, quick question. I just got my Level 2 charger installed today. What do most of you do, drive it until 25% to 50% then recharge to 100% or top it off daily or what seems to be best for the battery?
 

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I'm with NewJag though -- I read that thread all the way through, and there is lots of talk about temperature and the rate at which the onboard charger will charge, but I didn't see an answer to the question. Clearly the car wants to charge to 100% every time you plug it in. I know that is a buffer that prevents the car from over charging, but does everyone actually charge to 100%? If you take a drive and come back at 90% do you plug it in, or wait until it's below 50% unless you know you have a longer drive soon?

edit -- looks like this thread covers it Recharging to 100%?
 

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I'm with NewJag though -- I read that thread all the way through, and there is lots of talk about temperature and the rate at which the onboard charger will charge, but I didn't see an answer to the question. Clearly the car wants to charge to 100% every time you plug it in. I know that is a buffer that prevents the car from over charging, but does everyone actually charge to 100%? If you take a drive and come back at 90% do you plug it in, or wait until it's below 50% unless you know you have a longer drive soon?

edit -- looks like this thread covers it Recharging to 100%?
I allow the SoC to drop to 20% before recharging to 100% on the home charger. Others have pointed out the battery "memory" effect and recommend taking the battery below 20% perhaps down to 5% but I am not comfortable doing this yet. JLR says that it's okay to charge to 100% using a home charger and it's not detrimental to the battery health to use a 50 kWh fast charger which most US chargers are. Battery longevity is affected by charging at 100 kWh or above even though the car limits the rate to below that. Studies have shown that EV batteries have a life of about 2700 cycles which means 2700 charging/discharging cycles so if I am charging every 10 - 15 days 2700 cycles this will get me past 70 years.... :). Another good recommendation is not to allow the battery to sit at 100% SoC for many days to reduce heat.
 

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Another good recommendation is not to allow the battery to sit at 100% SoC for many days to reduce heat.
Can you remind me on the heat thing? Heat means energy, energy would mean a drop in battery SoC. Or is it just retaining the heat from when it was charging to 100%?

Thanks Curt!
 

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Can you remind me on the heat thing? Heat means energy, energy would mean a drop in battery SoC. Or is it just retaining the heat from when it was charging to 100%?

Thanks Curt!
I wish I knew more about lithium ion batteries! Someone else will have to help here but I think it has something to do with battery chemistry at various states of charge. I just remember the recommendation.
 

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I wish I knew more about lithium ion batteries! Someone else will have to help here but I think it has something to do with battery chemistry at various states of charge. I just remember the recommendation.
I'm sure it is probably a good practice. I'm just trying to wrap my head around the "heat" aspect and where the energy is coming from. I'll see if I can dig anything up.
 

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I'm sure it is probably a good practice. I'm just trying to wrap my head around the "heat" aspect and where the energy is coming from. I'll see if I can dig anything up.
I'll find the online source. I know the link is buried somewhere on the forum because the subject was heavily discussed about a year ago. Memory fails me, damned West Nile virus!
 

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In this context it's not a battery generating heat ... it's simply high ambient temperatures.
It's not good to cook the battery hot by fast charging in high heat, but that's only for relatively short time periods.
It's also not good, for long time periods, to keep a fully charged battery at high ambient temps.
Yes it's chemistry.
For example, Temperature effect and thermal impact in lithium-ion batteries: A review
 

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I have no way to measure the battery temperature, but I have noticed that a couple of times , this month (quite hot in Quebec these days), after a ride of 100km and more on the highway at 100-110km/h, when I got back home and tried immediately to recharge, I got the red flashing led and could not charge, but when I retried 10 or 15 min after, it was successful. I had the same problem last week-end, I was on the highway, wanted to charge at a 350kw charger, no success (red flashing light), 30 km away I retried on a different 50kw charger, same issue, then I came back home, same issue on my 7kw charger. 15 min after I retried on a 50kw charger close to my home, and it was ok, but the car was only taking 40kw at 20% of SOC. I have never experiment any charging issue in winter.
I have never heard the fan trying to cool down the battery while I was trying to charge.
 

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I'm with NewJag though -- I read that thread all the way through, and there is lots of talk about temperature and the rate at which the onboard charger will charge, but I didn't see an answer to the question. Clearly the car wants to charge to 100% every time you plug it in. I know that is a buffer that prevents the car from over charging, but does everyone actually charge to 100%? If you take a drive and come back at 90% do you plug it in, or wait until it's below 50% unless you know you have a longer drive soon?

edit -- looks like this thread covers it Recharging to 100%?
I'm like Curt, I let it drop to about 20-25% and then recharge to 100%, knowing 100% is not 'really' 100%.

One clarification I seem to recall from charging & recharging, is that when a manufacturer states a certain # of lifetime charge/discharge cycles, they're not talking about charging to full, letting it drop to say 60% and then recharging. That wouldn't account for 1 charge/discharge cycle in their specs any more than letting it drop to 90% and then recharging to 100% would. My understanding is that it's predicated on the cumulative effects of multiple charges & discharges at varying percentages that would simulate a full charge/discharge cycle.

So it may take several of a given owner's charge/discharge cycles to account for just 1 cycle. Obviously if you let the battery drop to near 0 and then recharge to 100%, that would count as a full cycle. Not sure if that makes any sense the way I described it.

I was also under the impression that lithium ion batteries don't have a 'memory effect' like NiCads do.
 

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Interesting article about lithium ion memory effect: Memory effect now also found in lithium-ion batteries
Yikes! Now they do mention, since this article is quite old (written before widespread use of these batteries in BEVs), that it's possible that good battery management will eliminate this effect. I wonder if that's what's happened with our cars since I can't recall hearing about it as a significant issue in BEVs?
 

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Yikes! Now they do mention, since this article is quite old (written before widespread use of these batteries in BEVs), that it's possible that good battery management will eliminate this effect. I wonder if that's what's happened with our cars since I can't recall hearing about it as a significant issue in BEVs?
I think the key take away is that the memory can be reversed with a deep discharge and full recharge hence Sciencegeek's recommendation to take the SoC to 5%. I have seen the effect in my lawn mower and trimmer Li batteries and haven't been able to recover them but I'm sure they weren't designed to last as well as they do in an EV.
 

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I think the key take away is that the memory can be reversed with a deep discharge and full recharge hence Sciencegeek's recommendation to take the SoC to 5%. I have seen the effect in my lawn mower and trimmer Li batteries and haven't been able to recover them but I'm sure they weren't designed to last as well as they do in an EV.
Yup, there is probably little to no battery management in appliances like trimmers, lawn mowers etc. The sophistication of BM in BEVs is probably day & night compared to those appliances.
 

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Yup, there is probably little to no battery management in appliances like trimmers, lawn mowers etc. The sophistication of BM in BEVs is probably day & night compared to those appliances.
The technology is better but the chemistry and physics is the same. I need to man-up and take the car to 5% every now and then.
 

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The technology is better but the chemistry and physics is the same. I need to man-up and take the car to 5% every now and then.
The last couple of times I took it down to 5% or less the car recharged just fine, but that also seemed to put the car into some sort of re-balancing at the end of the cycle. This made the car extremely hot on the hood, but also seemed to give me more miles on the GOM and in reality. I am typically now at 272 miles when I do a full recharge and it holds pretty close to reality.
 

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OK, you guys have me convinced to get down to 5%. Now is a good time since I'm at about 13%. I'll stay close to home...really close. ;)
 
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