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Comment by taneq | Hacker News Reader

> Electric engines do indeed release a lot less waste heat than internal combustion engines, but they also can't tolerate nearly as high of temperatures.

Eh? I thought both topped out around ~100 degrees C? Not that water cooling isn't a good idea for automotive electric drive motors.

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Rechargeable batteries of most designs are pretty heat sensitive. Too hot or too cold and the maximum range of the electric vehicle suffers. The drop off can be as high as 30% or so too, especially if you live somewhere with regular seasonal extreme temperatures.

This is why as well as cooling systems, some EVs even heat the battery in the cold.

The same thing affects Lithium Ion batteries in phones, cameras, laptops etc too.

Hah, sounds kind of like LED lights -- way less waste heat, way more sensitive to what heat there is.

> This is why as well as cooling systems, some EVs even heat the battery in the cold.

IC cars have that feature too, if you live somewhere like Saskatchewan. You need to plug the heater in at night (https://info.kaltire.com/wp-content/uploads/2015/03/Jan-6-Pl...) or the battery will be too cold to start the car in the morning.

Block heaters are used in somewhat milder climates as well – even though a modern ICE will start quite fine at even below -20°C (increasingly more unreliably the lower you go), doing so is somewhat harmful for the engine. (Also, by heating the engine fluids you can also blow some warmer air into the cabin to prevent the windows from frosting when you get inside – not to mention the added comfort.) Actual battery warmers are much rarer I think, but that isn't often an issue as long as you keep your battery well charged (and obviously have a more capable battery to begin with).

The usual recommendation is to start using the block heater even before temperature gets below freezing (for convenience reasons not many people do so).

Sorry, I guess I worded that poorly. In the electric case, it's specifically the batteries that need to be kept cooler. So while the whole system puts off less heat, at least the battery portion also withstands less, so still needs a significant radiator.

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