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Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 2:45 pm
by SageBrush
LeftieBiker wrote:The reason that even the Prime has lower efficiency than a residential unit is that EVs,unlike houses, have to be heated quite a lot in a matter of minutes - or even a single minute - while units heating houses can take a little longer without complaints. So EVs use their resistance heating units (which are a backup only with residential units, IIRC) to speed up heating the cabin. The resistance heaters then shut down after the cabin has gotten warm enough for the heat pump to maintain the set temp. That's why we call the system in the Leaf a "hybrid" heating system: both heating units work together, speeding heating but lowering efficiency.
A heat pump can work "faster," (meaning transfer more heat/time) but at reduced efficiency

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 3:27 pm
by LeftieBiker
I just came here to correct what I wrote earlier: as far as I can tell the Prime doesn't have a resistance heater - it gets cabin heat from the heat pump at more moderate temps, and they assume you'll be running the ICE at temps below the mid teens F. That makes for a very efficient heater, but one with a definite lower temp limit on its usefulness.

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 4:08 pm
by jjeff
LeftieBiker wrote:...... as far as I can tell the Prime doesn't have a resistance heater - it gets cabin heat from the heat pump at more moderate temps, and they assume you'll be running the ICE at temps below the mid teens F. That makes for a very efficient heater, but one with a definite lower temp limit on its usefulness.
Interesting, not sure I like that :(
In my climate we can goes days below zero, weeks + in the low teens and single digits, so it sounds like the Prime wouldn't give us any heat in those cases, unless the ICE ran? If this is the case the Prime loses some of its charm for us as I'd prefer a vehicle we could run EV in all temps(and get heat) albeit at a much-reduced range. Reminds me of a Volt and plug-in Ford C-max we tried in a cold winter day 5 years ago, neither ever shut off the ICE due to cold temps, at that point we tried the Leaf and it had nice heat, even in the single digits(we later bought the Leaf). Personally if it's true the Prime doesn't have a resistive type of heater I think it's a mistake, some EV range is better than none :)

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 4:19 pm
by LeftieBiker
I asn't able to get a definitive answer from my reading on this - just a lack of any mention of a resistance heater. There doesn't seem to be one integrated into the heatpump, either, as I looked at the schematic for that, too. Others should look into it as well, and ask at dealerships. (caveat emptor there!) And yes, it does suck terribly if there is no resistive heater. Our PIP has no electric heat of any kind, and no heated steering wheel, so I drive it only rarely in Winter, and often have to wear my electric heated gloves when I do. I don't know why they just didn't add a little resistance heater to the heat pump on the heat side. Maybe it's because it's actually made by Denso, IIRC, and they didn't want to do it.

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 5:17 pm
by LeftieBiker
NO resistance heater. I downloaded and searched the owner's manual. Here is the relevant section:

...

Crap. I can't get $#@!@ windows to copy and paste this as plain text, even after pasting the PDF copy into Open Office and saving it as plain text. I'll work on this later. It's section 4946-1 in the manual. Here is a SHORT, manually typed quote:

"When the outside temperature is low or it is snowing, (!!!?) compared to conventional vehicles, heating may be less effective and warm air may not come out." Yikes. I added the parenthetical part.

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 6:15 pm
by iPlug
Appreciate the input of all.

We have a PiP as well. It is neither cold enough here nor does the PiP have long enough EV range for us to need resistive or heat pump heat. Seat heaters are fine during the short EV interval getting me to and from my 7 mile round trip work commute. If in the car long enough and it's cold enough, EV range is already depleted and on the ICE comes and behold ICE heat.

Feeling bad for the rest of youse guys up in the northeastern parts. Technology has a way to go up in those parts.

Even home heat pump works great here and never need resistive backup except for a few minutes a year to keep the heat on while the defrost/de-ice coil cycle momentarily runs on the coldest pre-dawn mornings.

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 6:24 pm
by SageBrush
LeftieBiker wrote: "When the outside temperature is low or it is snowing, (!!!?) compared to conventional vehicles, heating may be less effective and warm air may not come out." Yikes. I added the parenthetical part.
I owned the Prius Prime for about a year in Colorado. Heating was fine.

Re: AAA confirms what Tesla, BMW, Nissan electric car owners suspected — cold weather saps EV range

Posted: Sat Feb 16, 2019 7:16 pm
by LeftieBiker
SageBrush wrote:
LeftieBiker wrote: "When the outside temperature is low or it is snowing, (!!!?) compared to conventional vehicles, heating may be less effective and warm air may not come out." Yikes. I added the parenthetical part.
I owned the Prius Prime for about a year in Colorado. Heating was fine.
Were you able to run it in EV mode without engine starts, in sub-20F weather? I'm guessing that the hills forced regular ICE starts...?