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Allow me to apologize in advance if this info already exists. I did a search in this forum and possibly the information exists in many pieces and many threads but thought it might be good to have it in one place.

As far as thermal management of the battery pack is concerned this is what I understand -

- putting a lot of power into or taking a lot of power out causes a built up of heat in the battery pack. ie. heavy and sustained acceleration and regen, and also rapid charging
- batteries perform badly when very cold. ie in snowy conditions
- not managing the thermal requirements of the battery pack will effect the performance and possibly cause lasting damage

- battery packs that get too hot will need a cooling system, either air or liquid, otherwise their output will need to be artificially throttled
- battery packs operating in cold temperatures will need battery heating to operate efficiently

Next question: what are the ideal operating temperatures? (Nissan Leaf gen 1 or 2 battery)

Is a car that is used for steady speed commuting (100kph) ever likely to produce excessive heat in the battery pack that will require a cooling system?

Would a medium speed charger (6-10kw) require active cooling of the battery pack or is that just necessary for ultra high speed charging (50kw etc)?
 

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Such questions cannot be answered in general.

Huge variability in chemistry's properties.

Lots of other variables.

C-rates not kW.

The makers send millions on engineering the cars' thermal management systems, and not for nothing.

Going bareback "safely" means IMO

using new packs not salvaged EoL


not striving for performance, and

at least solid monitoring, ready to pull over and stop.

Each hobbyist-built vehicle will have its own thresholds, and they change with aging.
 

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OEMs (well, smart ones at least; see Leaf fiasco) also have cooling and heating systems also because their cars need to work in wildly different climates without any special care from the owner.

Conversions are different. A cooling system in Phoenix seems like a requirement. Here in Seattle, not so much, particularly if your charging rate is moderate.
 

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Except even at the North Pole, sustained high discharge rates can be even more stressful than fast charging.

As these batts age out, their failure modes can be "not so gentle", and how far are they from your beloved humans' flesh?

Just saying, nice hobby, but be careful out there.
 

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Except even at the North Pole, sustained high discharge rates can be even more stressful than fast charging.

As these batts age out, their failure modes can be "not so gentle", and how far are they from your beloved humans' flesh?

Just saying, nice hobby, but be careful out there.
True, if you are going to race you definitely have different equipment requirements than if you are commuting.
 

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IMHO the problem is not high temperatures so much as localised high temperatures so any cooling system simply by transferring the heat will tend to avoid a local hot spot

I'm using a small dc water pump that pumps an antifreeze water mix though my batteries cooling system and through the heat plate under my controller

I'm effectively warming my battery and cooling my controller

Living in Southland I would add an additional heater if anything
 

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I would not add any heat once running until ambient got way low near 0°C.

Above that point, cooler the better for batt longevity.
 

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That likely relates to maximum power.

Which conditions are always in opposition to those conducive to greatest longevity.

Not saying it isn't valid to favour the former, but realize it's a trade off.
 

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This all depends on the battery type and design. In e-golf they don't do any active cooling/heating. They may run a control loop over the battery temperature and throttle the motor performance though.
 
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