Cor, this just doesn't add up, for my case. Not the heaters, but the
difference in range between cold charging and warm charging.
Let's say I have about 2/3 the original battery capacity, which would be
16kWh. In warm weather, I'll guess I have a range of 50 miles, perhaps
60 if I go 40 mph without many stoplights. But, as I mentioned, in our
december cold snap, I was getting about 20. I came very close to running
out of energy, so I think 20 is pretty accurate. That's less than half
the range.
So, if the main culprit is internal resistance, then half the energy
would be going into warming up the battery. That's a hell of a lot of
energy. I would assume that one of two things would happen: the battery
would warm up and the resistance would drop (and range improve), or it
would become plasma.
In reality, I don't think either happens. That's why I made this post in
the first place. I have searched on the Internet but haven't found
anything beyond people's speculation. But I would think this is heavily
researched within the battery industry.
Peri
<< Annoyed by leaf blowers ? https://quietcleanseattle.org/ >>
------ Original Message ------
From: "Cor van de Water" <cor.vandewa...@gmail.com>
To: "Peri Hartman" <pe...@kotatko.com>; "Electric Vehicle Discussion
List" <ev@lists.evdl.org>
Sent: 06-Apr-22 17:27:23
Subject: Re: [EVDL] kWh versus charging temperature
I presume that there are 2011 with "winter package" and heaters in the pack.
They still have only a single HV connector on the front of the
battery, so the HV switching is done in the car.
I did find one inconsistency yesterday: I was taking a 2012 pack apart
and came across a total of 8 heaters, there was an extra pair between
the back of the quarter packs and the halfpack.
In contrast to the 2013+ heaters, they are not all the same
resistance: the two large heaters on the halfpack measured in at only
1kOhm at room temp (again, resistance increased quickly with
temperature). The 6 low profile heaters from around the quarter packs
measured close to 4kOhm each. The heating elements apparently are the
same, though at the large heaters the 2 power wires connect
alternating to 5 wires that power 4 elements, hence the 4 times lower
resistance. This also means that the power draw is much higher for the
earlier pack heaters: 2 of 1k and 6 of 4k parallel means around 285
Ohms at room temp (less in the cold) so this will draw about 1.3 Amps
at room temp which is almost 500 Watts, more when it is cold. This
means that in a cold and exposed location when the heater is running
the whole time that the car is plugged in, it can steal almost half
the power of a 110V charger.
Cor.
On Tue, Apr 5, 2022 at 7:06 PM Peri Hartman via EV <ev@lists.evdl.org> wrote:
So, even the 2011 has a modest heater, then ? I believe you. However,
how do you explain the vast difference between range (kWh during
charging) in winter 20F versus comfortable weather 70F ?
Peri
<< Annoyed by leaf blowers ? https://quietcleanseattle.org/ >>
------ Original Message ------
From: "Cor van de Water via EV" <ev@lists.evdl.org>
To: "Electric Vehicle Discussion List" <ev@lists.evdl.org>
Cc: "Cor van de Water" <cor.vandewa...@gmail.com>
Sent: 05-Apr-22 18:47:53
Subject: Re: [EVDL] kWh versus charging temperature
>Every battery I have taken apart that has heaters, has a total of 6:
>2 on top of the halfpack,
>2 midway between the quarterback stacks and
>2 in the front of the battery, next to the first high stack of the
>quarter packs.
>The resistance is in the order of 10kOhm and all heaters are in
>parallel, connecting to the full battery voltage when the heater relay
>closes.
>At an average 375-ish Voltage, the current is around 37mA which
>translates into a max heating power of around 12W per heater.
>Each heater is built up with a plastic carrier, a thin alu sheet het
>spreader and all have the same resistive heating element, though the
>resistance is strongly temp related.
>At room temp I measured about 8.7 kOhm, but even putting my hand on
>the heater element the meter quickly rose to near 10kOhm, so at any
>decent heat produced the resistance is likely to rise sharply and the
>power to fall, so they intrinsically avoid thermal runaway.
>The power likely falls to around 7 Watts per heater in operation, so
>about 40 Watts total for a pack. but a cold pack may start at more
>than 100W of power draw for heating.
>Cor.
>
>On Mon, Apr 4, 2022 at 3:31 AM Jay Summet via EV <ev@lists.evdl.org> wrote:
>>
>>
>>
>> On 4/4/22 00:54, Peri Hartman via EV wrote:
>> > I'm not sure about the newer models, but definitely no battery heater
>> > (or cooler) for the 2011 model.
>> >
>>
>> 2013 Leaf has (four) resistance heaters inside the main battery case.
>> They turn on if the temp gets below freezing.
>>
>> No active cooling in any Leaf battery so far.
>>
>> Jay
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