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Via a super nice customer service rep I finally got some answers from JLR engineering on batteries and charging. My questions were motivated by the observation that my battery temperature was at 108F for 20 min during my first trip at an EA DCFC charger, which seemed high to me. Batteries should just not be cooked like that. Engineer said that this was within spec, which is fine, but I really want to avoid such high temperatures if possible. Soooo ... after a bit of back and forth I learned this:

1. Charging and battery temperature
Facts
: The battery cooling system will kick in at some point to prevent 'overheating' when on a charger. The battery energy control module (BECM) expects higher temperatures during charging.
My take: Well-known fact: DCFC charging is detrimental to battery life, and especially so at high temperatures. There's a tradeoff between using energy to cool the battery and how long we have to stay at a charger. The BECM is tuned so that temperatures are tolerated that do not do outright damage, but that are not really good for battery life. The logical conclusion is that charging the I-Pace at DCFCs at high battery temp (for example after a high speed freeway run when the battery is already hot, and then heats up more during fast charging) reduces battery life.

2. Preconditioning
Facts
: While charging, the battery is held to a “better” temperature with preconditioning running than without preconditioning running. (This verbatim statement was definitively affirmed by the engineer). This is to get "optimum performance" (i.e., range) after unplugging. Preconditioning consists of both cabin and battery components.
My take: Why JLR decided to couple cabin and battery preconditioning is beyond me, but given the facts, here is the practical suggestion: Always have preconditioning running while you're on a fast charger. Anecdotally (from my very limited experimentation) you'll "lose" about 6kW or so, so on average you might spend 10% more time at the charger if you do that. You will extend battery life because the battery temperature will be "better". I suspect the same is true at low temperatures, though less of an issue because just charging produces heat after all.

3. Cell balancing
Facts
: If the variation between cell voltages exceed a pre-defined threshold, the BECM will initiate balancing. This is regardless of charger or charging rate. There is no SoC threshold to initiate cell balancing.
My take: Whew, glad to hear that; you don't have to charge to 100% for balancing to occur. If you're charging on a Level 2 charger at home and notice that the rate is varying, with charging perhaps even stopping and starting, it means it's doing its thing. Leave it alone. That said, it might take a bit longer to get to your desired SoC because charge rate varies.

HTH
 

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.

3. Cell balancing
Facts
: If the variation between cell voltages exceed a pre-defined threshold, the BECM will initiate balancing. This is regardless of charger or charging rate. There is no SoC threshold to initiate cell balancing.
My take: Whew, glad to hear that; you don't have to charge to 100% for balancing to occur. If you're charging on a Level 2 charger at home and notice that the rate is varying, with charging perhaps even stopping and starting, it means it's doing its thing. Leave it alone. That said, it might take a bit longer to get to your desired SoC because charge rate varies.

HTH
This post reminded me of an earlier thread where you were commenting on L2 charging and how the rate of charging dropped off at times - presumably to balance the cells. This was with your original car and the bad battery I believe. Perhaps this behavoir - balancing before reaching near a full charge - is indicative of a battery management issue that leads to bad batteries over time.
 

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This post reminded me of an earlier thread where you were commenting on L2 charging and how the rate of charging dropped off at times - presumably to balance the cells. This was with your original car and the bad battery I believe. Perhaps this behavoir - balancing before reaching near a full charge - is indicative of a battery management issue that leads to bad batteries over time.
Or maybe it was just going crazy to keep a bad cell in balance.

I find #2 very interesting to keep the cooling system running. Some of these operations show how there is still a bit to catch up to Tesla technology.
 

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This post reminded me of an earlier thread where you were commenting on L2 charging and how the rate of charging dropped off at times - presumably to balance the cells. This was with your original car and the bad battery I believe. Perhaps this behavoir - balancing before reaching near a full charge - is indicative of a battery management issue that leads to bad batteries over time.
It may also mean that a bad battery may trigger rebalancing but not succeed, so a bad battery may trigger a rebalancing but a rebalancing may not indicate a bad battery.
 

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How are you able to monitor your battery temperature? Is there an OBD/App combination that works with I-Pace?
 

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Fantastic thread. Very helpful
 

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How are you able to monitor your battery temperature? Is there an OBD/App combination that works with I-Pace?
yes but it's in limited beta: powercruisecontrol.com
i was hoping it would be public by now but it isn't yet as far as I know
 

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yes but it's in limited beta: powercruisecontrol.com
i was hoping it would be public by now but it isn't yet as far as I know
Excellent. Thanks. One of my biggest gripes with the car is the complete lack of access to basic useful information like charging speed. The car's interface is so overly dumbed down that it makes me feel like it's trying to hide something.
 

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Q: when parking into the garage after driving, I can hear the noise coming from front part of the car and I was told it is battery cooling. Should I not turn the car off to keep the cooling running? Thanks.
 

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Q: when parking into the garage after driving, I can hear the noise coming from front part of the car and I was told it is battery cooling. Should I not turn the car off to keep the cooling running? Thanks.
Is this during hot days after fast driving?
 

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Under those circumstances the battery should not be too hot. The loud fan noise is not just the battery, I think it's the cabin AC too.
 

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Under those circumstances the battery should not be too hot. The loud fan noise is not just the battery, I think it's the cabin AC too.
I am not sure if it is ac fan. It is quiet inside and only hear it when I step out and it just happened the car was still turned on otherwise I won't have noticed. Could this indicate a problem? Thanks.
 

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There's cooling for the battery, the electric motors and the cabin. Three different cooling systems and there's a link somewhere to Jaguar explanation of them. This is normal for the fan to run as required.
 

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Via a super nice customer service rep I finally got some answers from JLR engineering on batteries and charging. My questions were motivated by the observation that my battery temperature was at 108F for 20 min during my first trip at an EA DCFC charger, which seemed high to me. Batteries should just not be cooked like that. Engineer said that this was within spec, which is fine, but I really want to avoid such high temperatures if possible. Soooo ... after a bit of back and forth I learned this:

1. Charging and battery temperature
Facts
: The battery cooling system will kick in at some point to prevent 'overheating' when on a charger. The battery energy control module (BECM) expects higher temperatures during charging.
My take: Well-known fact: DCFC charging is detrimental to battery life, and especially so at high temperatures. There's a tradeoff between using energy to cool the battery and how long we have to stay at a charger. The BECM is tuned so that temperatures are tolerated that do not do outright damage, but that are not really good for battery life. The logical conclusion is that charging the I-Pace at DCFCs at high battery temp (for example after a high speed freeway run when the battery is already hot, and then heats up more during fast charging) reduces battery life.

2. Preconditioning
Facts
: While charging, the battery is held to a “better” temperature with preconditioning running than without preconditioning running. (This verbatim statement was definitively affirmed by the engineer). This is to get "optimum performance" (i.e., range) after unplugging. Preconditioning consists of both cabin and battery components.
My take: Why JLR decided to couple cabin and battery preconditioning is beyond me, but given the facts, here is the practical suggestion: Always have preconditioning running while you're on a fast charger. Anecdotally (from my very limited experimentation) you'll "lose" about 6kW or so, so on average you might spend 10% more time at the charger if you do that. You will extend battery life because the battery temperature will be "better". I suspect the same is true at low temperatures, though less of an issue because just charging produces heat after all.

3. Cell balancing
Facts
: If the variation between cell voltages exceed a pre-defined threshold, the BECM will initiate balancing. This is regardless of charger or charging rate. There is no SoC threshold to initiate cell balancing.
My take: Whew, glad to hear that; you don't have to charge to 100% for balancing to occur. If you're charging on a Level 2 charger at home and notice that the rate is varying, with charging perhaps even stopping and starting, it means it's doing its thing. Leave it alone. That said, it might take a bit longer to get to your desired SoC because charge rate varies.

HTH
Don't be concerned about battery temperature on the IPace. The BMC will not permit charging if the temperature is too high so there is no risk of damaging the cells since it will shut down the charger prior to that happening. In addition, during battery charging the processor will start the AC compressor to chill coolant to control the temperature of the pack. Also, keep in mind, if you park your car in the sun while you're at work the battery temperature will be even higher than 108 degrees. Just enjoy the car, all is good with the battery thermal protection.

Stay Safe Mike
 

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Thanks Mike, I guess I'm not quite as sanguine about the BECM as you are, as there are choices JLR made that don't necessarily maximize battery life.

Note that the battery does not in fact reach 108 degrees when you're parked in the sun on a warm day. The cabin might get mighty hot but the battery insulation is good enough that the temperature while sitting is only slightly higher than outside air temperature. This is by measurement, by the way, not just my speculation. 🍺
 

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Thanks Mike, I guess I'm not quite as sanguine about the BECM as you are, as there are choices JLR made that don't necessarily maximize battery life.

Note that the battery does not in fact reach 108 degrees when you're parked in the sun on a warm day. The cabin might get mighty hot but the battery insulation is good enough that the temperature while sitting is only slightly higher than outside air temperature. This is by measurement, by the way, not just my speculation. 🍺
Sciencegeek unless you planning on keeping the car for 15-20 years, you should not worry about battery health - for the most part, you're only saving your battery for the next owner. Just use it and charge it!

Regretfully, you're incorrect on the battery not reaching over 108 degrees, on a 95-100 degree day this is very common when EV's are parked in the sun.
The problem stems from the interior of the car on a hot 90+ degree day, can reach 170+ degrees. This heat is trapped in the interior which is exposed to the floorboards so therefore convection heating reaches the aluminum battery case located directly below even with insulation. In addition, when its 90 degrees out, asphalt heats up to over 150+ degrees. This heat surrounds the the entire car to include underneath, rising to the bottom side of the aluminum battery case as well, heating the battery case.

EV's have been dealing with this heat for decades, the cars processor is designed for both heat and extreme cold weather. Just enjoy your car, the battery has plenty of protection, your worries are not warranted.

If you can park your car in a shaded parking lot when at work it will increase your range slightly as well.

Stay Safe - Mike
 

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Sciencegeek unless you planning on keeping the car for 15-20 years, you owner should not worry about battery health
Many of us, including you, have or have had compromised batteries after only a few thousand miles.There is such a thing as best practices. The main recommendations from my post above are:
1. Turn on preconditioning when you're on a fast charger
2. Leave your Level2 charger alone when it seems to do weird things

Regretfully, you're incorrect on the battery not reaching over 108 degrees, on a 95-100 degree day this is very common when EV's are parked in the sun.
I said "warm day" not "hot day". If it's 100 degrees out and the cabin is at 150, sure the battery gets a little hotter than 100. But the battery appears to be insulated quite well from the cabin, and therefore will be closer to outside temperature than cabin temperature unless you're fast charging, when the battery itself produces copious amounts of heat. Again, this is measurement, not speculation. See the attached screenshots. In the first one, during a fast charging session, the cabin temp was 79 and the battery was at 108. In the second one, during Level 2 charging, the cabin temp was 104 and the battery was at 73.
3790
3789
 
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