Robert, the energy needed long term would be determined by the heat
loss, not the mass being heated. Thus, if perfectly insulated there
would be no heat loss and thus no energy needed to keep the battery
warm.
So, my question persists. Why didn't BYD put thermal management into
their battery?
Peri
------ Original Message ------
From: "Lee Hart via EV" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Cc: "Lee Hart" <[email protected]>
Sent: 29-May-19 2:43:40 PM
Subject: Re: [EVDL] BYD's(style.cn) inflated range ratings - how about
fossil fuel heaters?
Robert Bruninga via EV wrote:
wouldn't it be just as easy to insulate the battery and
provide a small electrical heat source. 100W or so?
Lets say a 1000 lB battery. It takes 1 BTU to raise one pound one degree.
To raise 1000 lbs say 40 degrees from 0F to 40F would take 40,000 BTU or
about 11 kWh. Or about 33 miles of range given up to heat the battery.
True enough if you're warming up a cold battery. But it would be foolish to
heat the battery with its own charge.
Instead, you would use AC mains power to heat it. In that case, you'd be
charging the pack at the same time. So heating the battery from a cold start
just adds to the charging time. When the charge cycle finishes, you have a
fully-charged, fully warmed up battery; so no loss of range.
The battery pack has so much thermal mass that if it is well insulated, it will
stay warm all day, without any supplemental heating. Wait until the next time
it's plugged in to warm it back up.
-- In software development, there are two kinds of error: Conceptual
errors, implementation errors, and off-by-one errors. (anonymous)
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
_______________________________________________
UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub
http://lists.evdl.org/listinfo.cgi/ev-evdl.org
Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
