Computerdoctor
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 1:47 am

ebill3 wrote:
Computerdoctor wrote:A poor consolation to my stupidity is that i probably won´t need a battery cooling system anyway. This morning the temp here below 0 C/32 F. Winter is coming!
Agree that you might not need battery cooling, but I'll bet you are going to wish you had some battery heating. ;)
Well, as a matter of fact I DO have some kind of battery heating. At least that´s what I have figured out since I have a 2012 for the "cold" markets. Or is this just another misconception of mine...?
Read somewhere that it will heat the battery from -4 F to 14 F whenever needed. I figure that once I start driving the chemical process itself will warm the batteries?

This leads me to another thought of mine : Is it possible to (generally) store more power in cold batteries than hot? That the electrons will be more compact stored in the battery but on the other hand they will move slower and therefore give less power? Then when the battery is used it heats up and releases more of the stored energy?

DaveinOlyWA
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 9:20 am

Computerdoctor wrote:
ebill3 wrote:
Computerdoctor wrote:A poor consolation to my stupidity is that i probably won´t need a battery cooling system anyway. This morning the temp here below 0 C/32 F. Winter is coming!
Agree that you might not need battery cooling, but I'll bet you are going to wish you had some battery heating. ;)
Well, as a matter of fact I DO have some kind of battery heating. At least that´s what I have figured out since I have a 2012 for the "cold" markets. Or is this just another misconception of mine...?
Read somewhere that it will heat the battery from -4 F to 14 F whenever needed. I figure that once I start driving the chemical process itself will warm the batteries?

This leads me to another thought of mine : Is it possible to (generally) store more power in cold batteries than hot? That the electrons will be more compact stored in the battery but on the other hand they will move slower and therefore give less power? Then when the battery is used it heats up and releases more of the stored energy?
the batteries will warm when charging or discharging but that should be relatively minor which is probably one of the main reasons Nissan elected not to provide active thermal management. the pack is relatively massive and it appears it may take several hours or days for the temperature to regulate so heat of normal charging is not likely to make a difference.

FYI; i did a QC from 18% to 80% the other day. started with 5 TBs ended with 5 TBs, temps upper 50's

in comparison, did a QC same station about 10 days ago, temps were mid 70's.

started at 38% stopped at 76% (both times machine said 89%) and ended with 6 TBs from 5.
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 11,333.1 mi, 93.73% SOH
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SierraQ
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 9:25 am

Computerdoctor wrote: This leads me to another thought of mine : Is it possible to (generally) store more power in cold batteries than hot? That the electrons will be more compact stored in the battery but on the other hand they will move slower and therefore give less power? Then when the battery is used it heats up and releases more of the stored energy?

The colder the battery the less capacity it can hold. On a Leaf without a battery heater it is common to lose 10-20 miles of range in close to freezing temps when you combine the ineffecient cabin heater and the temporarily reduced capacity--mostly due to the cabin heater. Also the battery heater only activates around -10C/14F. The main reason for it is to allow the car to operate in very cold temps since these batteries cease to function if they get too cold. Acceleration can also be reduced but i dont know if it is significant.
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DaveinOlyWA
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 10:12 am

This leads me to another thought of mine : Is it possible to (generally) store more power in cold batteries than hot? That the electrons will be more compact stored in the battery but on the other hand they will move slower and therefore give less power? Then when the battery is used it heats up and releases more of the stored energy?
if non vibrating molecules is how a battery worked the answer would be yes. however, battery works on moving stuff around changing from one chemical to another. when its cold, the change happens at much lower rate. iow; molecules are like Humans, when they are cold they want to sit and bundle up and not move.

during my relatively mild winters i estimated my pack capacity to be in the 19 Kwh range. this was done by driving from full charge to turtle and NO HEAT other than occasional bursts of defrost.

granted part of this was using the miles/kwh gauge. during Summer i am more in the 21-21.4 Kwh range. this figure is extrapolated since i no longer value the goal of stressing my pack so i dont do range tests any more especially when its hot.

i might consider doing one near the end of this coming winter.

my Winter range test was done with temps in upper 20's low 30's. it is unusual to get temps that low. we are generally in mid 40's
2011 SL; 44,598 mi, 87% SOH. 2013 S; 44,840 mi, 91% SOH. 2016 S30; 29,413 mi, 99% SOH. 2018 S; 25,185 mi, SOH 92.23%. 2019 S Plus; 11,333.1 mi, 93.73% SOH
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dgpcolorado
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 11:54 am

Computerdoctor wrote:Well, as a matter of fact I DO have some kind of battery heating. At least that´s what I have figured out since I have a 2012 for the "cold" markets. Or is this just another misconception of mine...?
Read somewhere that it will heat the battery from -4 F to 14 F whenever needed. I figure that once I start driving the chemical process itself will warm the batteries?

This leads me to another thought of mine : Is it possible to (generally) store more power in cold batteries than hot? That the electrons will be more compact stored in the battery but on the other hand they will move slower and therefore give less power? Then when the battery is used it heats up and releases more of the stored energy?
As others have said, the battery heater is to protect it from damage in very cold weather. Be aware, however, that the battery heater won't work unless there is more than 30% charge in the battery or the car is plugged-in. From the manual:
The Li-ion battery heater does not operate if the available Li-ion battery charge is less than approximately 30% and the charger is not connected to the vehicle. To help prevent the Li-ion battery from freezing, do not leave the vehicle in an environment if temperatures may go below -4ºF (-20ºC) unless the vehicle is connected to a charger.
So, if you expect your car to get to -20ºC it is best to be sure it is plugged-in. (For what it is worth, the battery heater draws 300 Watts, but it runs only as needed, so it isn't a continuous 300 W draw.)

Your range in winter will be improved if you can keep the car in a garage that stays warmer than outdoor nighttime temperatures. Another thing that will help cold weather range is to pre-heat the car while plugged-in (by using the Climate Control timer or by turning it on remotely or manually) before leaving home. Then you might be able to get by on cold weather days using just the steering wheel and seat heaters, which take very little power, rather than the power-hog cabin heater. Of course, whether or not this is practical depends on how long the trip and how cold it is. Around 0ºC it works well. At -15ºC the cabin would probably cool down too much to be comfortable. And if parked outside all day in very cold temperatures with no plug available, using the cabin heater will be necessary.

A lot of this depends on how far you have to drive each day. If you aren't close to stretching the range, say 50 km a day, run the heater and don't worry about it. Just be aware that pre-heating can help a lot if cold weather range is a problem. And it also is very nice to get into a warm car in winter! How long you will need to pre-heat depends on the car temperature and is something that you will need to experiment with. Also, the temperature for pre-heating is set to 25ºC and can't be adjusted.
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SanDust
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 1:18 pm

planet4ever wrote:Actually, the charger, inverter, and motor are cooled by that system.
Power electronics?

ericsf
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 1:32 pm

SanDust wrote:
planet4ever wrote:Actually, the charger, inverter, and motor are cooled by that system.
Power electronics?
By "power electronics" you probly mean the electronics that drive the motor. That's the inverter. It converts the DC to AC for the motor. The only thing you did not list here that probably needs cooling is the regen charger which is a different part the Level 2 charger. Patent issue I believe.

Was discussed here a while ago : http://www.mynissanleaf.com/viewtopic.p ... on#p141369
SL w/ QC (3/5/2011) - 11bars on 1/23/2014 @ 54k miles - 10 on 12/23/2014 @ 73k - 9 on 10/5/2015 @ 85k - 8 on 7/3/2016 @ 96k

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planet4ever
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Re: Coolant system(s), am I right or wrong here?

Sat Sep 15, 2012 9:49 pm

ericsf wrote:
SanDust wrote:
planet4ever wrote:Actually, the charger, inverter, and motor are cooled by that system.
Power electronics?
By "power electronics" you probably mean the electronics that drive the motor. That's the inverter. It converts the DC to AC for the motor. The only thing you did not list here that probably needs cooling is the regen charger which is a different part the Level 2 charger.
Actually, it is the inverter which converts regen AC from the motor to DC which can be sent to the battery*, but it doesn't matter, because both the inverter and charger are water cooled. SanDust may well have been referring to one other component I forgot to list: the DC/DC junction box which converts high voltage DC to low voltage DC to run electronics and charge the 12v battery. Yes, that DC/DC converter is also water cooled by the same system.

Ray

* If you are interested, here is a straight-forward explanation of that from the service manual.
End of April 2013: Traded my 2011 SL for a 2013 S with charge pkg.

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garygid
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Re: Coolant system(s), am I right or wrong here?

Sun Sep 16, 2012 7:17 am

The other fluid system, on the driver's side, uses the same fluid,
so it shares the same overflow / expansion reservoir, which is
also on the driver's side.

This second fluid system is not used as a coolant. It is used to
carry the HEAT from the high voltage heater element into the cabin.
So, it is a "heatant" instead of a coolant.
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