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Re: [EVDL] Winter & EVs

Hi everybody-

Not to take anything away from the various battery heating/insulating
projects, but why not just use a NiCd pack? Just seems like less
trouble, and as a bonus they'd last way longer than lead acid and be a
lot cheaper than Li-ion.

Just a thought...


Roland Wiench wrote:
> Hello Nikki,
> In Montana, it only got down to -36 C for about 2 hours and than it normally
> steady outs at -18 C for about a month and 0 C for the rest of the winter.
> At one time I use one of those round heat tapes, that you can get in any
> length on a spool. My batteries were in aluminum boxes which were space
> about 1.5 CM from the inside edge of the box. The heat tape wrap around the
> batteries in this space starting at the bottom of the battery space about
> every 6 CM.
> One end tap off a 20 amp circuit breaker in the EV that then tap of the
> charging input cable circuit. A adjustable thermostat is install that is
> design for this cable with a sensor bulb that is place in the battery box.
> The outside of the battery box was insulated with soft 3/4 foam that had a
> sew on vinyl cover that can be snap together for removable and cleaning.
> I could not let this EV set out side more then 8 hours when the temperature
> got to -36 C even with this heat, because the battery temperature could drop
> to close to 0 C.
> I change the aluminum battery boxes with 1 CM thick fiberglass, and allow
> enough space around the outside of the box to install a layer of 6 CM (2
> ins.) foam board that is glue directly on the box with a 12 CM air space and
> another layer of 6 CM foam board. The outside of the foam board was then
> cover with a nylon marine carpet.
> A 1.5 layer of foam with the carpet is lay on top of a 1 CM think hinge
> cover. This battery installation sets inside a insulated pickup bed with a
> insulated hatch back that has a solar passive glass that allows sun light to
> come in.
> I park in a super insulated garage that is always heated to 22 C which
> maintains the EV and batteries temperature at about 22 C. If I had to let
> the EV set outside, I would use the round heat tape inside this battery box.
> When it got down to -36 C. last winter early in the morning, it was a clear
> day. About 15 minutes, before I left with the EV, it preheated the
> passenger cab to 27 C. and the battery temp was setting at 22 C. I drove
> about 8 km at 16 km/h and park the EV with the glass hatch back toward the
> sun. After about 2 hours of setting, the temperature below the hatch back
> glass and around the battery box, was about 27 C.
> So, there is many ways to keep up you battery temperature. The best way is
> to insulated a enclose battery box with a heat tap or even one of those
> battery heat blankets you can wrap around the batteries.
> Make sure you do not wrap this type of round heat tape tight around sharp 90
> degree corners of the battery box, this will cause hot spots in these areas.
> Roland
> ----- Original Message -----
> From: "Nikki Bloomfield" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Sunday, September 23, 2007 11:51 PM
> Subject: Re: [EVDL] Winter & EVs
> > I'm really interested in this thread.
> >
> > The City El of course suffers just like any other car in the winter
> > but this year I have some Thundersky lithium Ions in her. When I
> > installed the pack I used some thermal 'space blanket' style
> > insulation on each of the three packs ( see
> > aminorjourney/sets/72157600628045492/ for pictures of the upgrade )
> > but I didn't install heating pads for the cells. BIG MISTAKE!
> >
> > Since the average temperature has dropped from the high 20 degrees C
> > down to 15 degrees C my batteries have taken a big hit in performance
> > and the internal resistance has rocketed. The first few miles I tend
> > to try and get the batteries as hot as possible so that the car
> > doesn't get too rough a performance. Of course also recharging from
> > cold isn't that possible as the batteries won't accept charge so well.
> >
> > So, I'm going to try and install some heating pads this week from RS
> > components. It'll mean removing all of the cells fom the car and re-
> > packaging them but at least then I'll have heating for the
> > batteries. The sort of pads I'm getting are here:
> > 3xu3qw . 30 W of heating per four cells should be enough to keep the
> > cells from getting too cold.
> >
> > I'm also wanting to introduce some form of mains heating for the car
> > as we're about to move house and the garage isn't big enough really
> > to store the City El (it's not long enough as it's just a mini-garage).
> >
> > With those with heating what sort of performance drop do you get in
> > the winter even with heating?
> >
> > Nikki.
> >
> >
> >
> >
> >
> >
> > _______________________________________________
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> >
> >
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