cold batteries

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cold batteries

Jeff Shanab
I am suffering because of cold batteries. They are not makeing the drive
to and from work without sagging terribly in the last few miles. It took
a few days of cold weather to get here but I need to find a way to warm
them up.

Unfortunantly I underestimated the effect cold would have and my EV gets
terrible mileage to begin with which I need to work on. but I put the
batteries in angle iron racks I welded up when I had access to a shop.
They are orbitals and I took the option to bold down thru them.

13  batteries are in the cabin area behind the seats and 8 of those the
rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
The 8 elevated batteries I can get to most the sides so adding
insulation should be easy. Although the cabin is not heated so just
preheating the entire cabin is an option :-)

The other batteries are under the hood. 4 in a rack above the motor in
which the back side is up against the controller box. I can only get to
5 of the 6 sides here (no picture)

The last 7 are stuffed in the front grill area and are hard to get to.
http://cvevs.jfs-tech.com/dsc00004.jpg


It has been getting below 30degrees at night and only up to 50-55 during
the day and it is gonna get colder over the next few months. Not colder
at night, but less warming during the day.

I was hoping some people could offer up some ideas.
Is insulating going to be sufficient? I only charge the pack with a
maximum of 5 amps so not much warming going on there.
I do pull 240-350 Amps on acceleration regularly.
Do I need waterbed heaters? Are they something I would use every night,
or just once a week.


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Re: cold batteries

Roland Wiench
Hello Jeff,

Never have your batteries get below 60 degrees.  When they are at 60
degrees, then charge the batteries at at 7.4 volts per 6 volt battery or
14.8 volts per 12 volt plus add 0.028 volts per 10 degrees drop below 80 F.

Right now it is 10 degrees F and my batteries are at 75 degrees in a super
insulated non-conductive battery box with no battery heat on.  I normally
will charge about 1 hour before I leave in the low temperature at 40 amps at
222 volts for a 180 volt pack which warms them up from 65 to 75 degrees.

I have at times park outside in temperatures of -35 below and after four
hours the battery temperature will be down to 60 degrees.  When I was park
outside at work, I then will have a thermostat turn on a battery heat
blanket that is made by the KAT's company which all kinds of engine heaters
that a lot of auto parts store stock.


----- Original Message -----
From: "Jeff Shanab" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, December 01, 2007 9:14 AM
Subject: [EVDL] cold batteries


> I am suffering because of cold batteries. They are not makeing the drive
> to and from work without sagging terribly in the last few miles. It took
> a few days of cold weather to get here but I need to find a way to warm
> them up.
>
> Unfortunantly I underestimated the effect cold would have and my EV gets
> terrible mileage to begin with which I need to work on. but I put the
> batteries in angle iron racks I welded up when I had access to a shop.
> They are orbitals and I took the option to bold down thru them.
>
> 13  batteries are in the cabin area behind the seats and 8 of those the
> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
> The 8 elevated batteries I can get to most the sides so adding
> insulation should be easy. Although the cabin is not heated so just
> preheating the entire cabin is an option :-)
>
> The other batteries are under the hood. 4 in a rack above the motor in
> which the back side is up against the controller box. I can only get to
> 5 of the 6 sides here (no picture)
>
> The last 7 are stuffed in the front grill area and are hard to get to.
> http://cvevs.jfs-tech.com/dsc00004.jpg
>
>
> It has been getting below 30degrees at night and only up to 50-55 during
> the day and it is gonna get colder over the next few months. Not colder
> at night, but less warming during the day.
>
> I was hoping some people could offer up some ideas.
> Is insulating going to be sufficient? I only charge the pack with a
> maximum of 5 amps so not much warming going on there.
> I do pull 240-350 Amps on acceleration regularly.
> Do I need waterbed heaters? Are they something I would use every night,
> or just once a week.
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

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Re: cold batteries

Rush Dougherty
In reply to this post by Jeff Shanab
Jeff,

Could you make the photos that you put up a little smaller? The dsc00004.jpg
is 1.5 MB, it really needs to be no more that 500 kb, when you keep it big
and people with dial up go to down load it takes so long that they stop the
process and you never get feedback from them.

One of Lee's suggestions (for battery cooling) was to sandwich a .065 or so
thick aluminum sheet, a copper cooling coil, a layer of soft crushable foam
insulation between the battery bottom and the supporting insulation.

I've made a web page -
http://ironandwood.org/CoolingCoil.html

What you might do is instead of using a cooling coil, just put heating pads
under the alum sheet. It would conduct the heat better to more batteries.

HTH

Rush
Tucson, AZ
2000 Insight, 66.7lmpg, #4965
www.ironandwood.org
www.Airphibian.com
www.TEVA2.com


----- Original Message -----
From: "Jeff Shanab" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, December 01, 2007 9:14 AM
Subject: [EVDL] cold batteries


>I am suffering because of cold batteries. They are not makeing the drive
> to and from work without sagging terribly in the last few miles. It took
> a few days of cold weather to get here but I need to find a way to warm
> them up.
>
> Unfortunantly I underestimated the effect cold would have and my EV gets
> terrible mileage to begin with which I need to work on. but I put the
> batteries in angle iron racks I welded up when I had access to a shop.
> They are orbitals and I took the option to bold down thru them.
>
> 13  batteries are in the cabin area behind the seats and 8 of those the
> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
> The 8 elevated batteries I can get to most the sides so adding
> insulation should be easy. Although the cabin is not heated so just
> preheating the entire cabin is an option :-)
>
> The other batteries are under the hood. 4 in a rack above the motor in
> which the back side is up against the controller box. I can only get to
> 5 of the 6 sides here (no picture)
>
> The last 7 are stuffed in the front grill area and are hard to get to.
> http://cvevs.jfs-tech.com/dsc00004.jpg
>
>
> It has been getting below 30degrees at night and only up to 50-55 during
> the day and it is gonna get colder over the next few months. Not colder
> at night, but less warming during the day.
>
> I was hoping some people could offer up some ideas.
> Is insulating going to be sufficient? I only charge the pack with a
> maximum of 5 amps so not much warming going on there.
> I do pull 240-350 Amps on acceleration regularly.
> Do I need waterbed heaters? Are they something I would use every night,
> or just once a week.
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.503 / Virus Database: 269.16.12/1163 - Release Date:
> 12/1/2007 12:05 PM
>
>

_______________________________________________
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Re: cold batteries

John-435
In reply to this post by Roland Wiench
I have no advice for Jeff (sorry) but I do have a question about  
battery temperatures.

Lets say for example you grossly underestimated how long it would  
take to get you conversion on the road and you have 24 Interstate  
2400 (US battery  U2-145) batteries sitting in your garage.

I have taken the EV on a few test drives in the driveway and down the  
street (less than about 1/4 mile in total) and about once a month I  
put the PFC-30 to them with a setback voltage of 185.

Now that it is getting colder in MA I realize I need to up the voltage.

If I have not driven or charged for 1 week do I assume the batteries  
are at the garage temperature when calculating my temperature?

Then once I get the truck legal and on the road, Phase may not have  
insulation at first, but I will be charging and discharging the  
batteries daily (fingers crossed). How to I take the battery  
temperature then; can I just stick a thermometer in the space where 4  
of the batteries in the pack meet?

Thanks.

On Dec 1, 2007, at 12:21 PM, Roland Wiench wrote:

> Hello Jeff,
>
> Never have your batteries get below 60 degrees.  When they are at 60
> degrees, then charge the batteries at at 7.4 volts per 6 volt  
> battery or
> 14.8 volts per 12 volt plus add 0.028 volts per 10 degrees drop  
> below 80 F.
>
> Right now it is 10 degrees F and my batteries are at 75 degrees in  
> a super
> insulated non-conductive battery box with no battery heat on.  I  
> normally
> will charge about 1 hour before I leave in the low temperature at  
> 40 amps at
> 222 volts for a 180 volt pack which warms them up from 65 to 75  
> degrees.
>
> I have at times park outside in temperatures of -35 below and after  
> four
> hours the battery temperature will be down to 60 degrees.  When I  
> was park
> outside at work, I then will have a thermostat turn on a battery heat
> blanket that is made by the KAT's company which all kinds of engine  
> heaters
> that a lot of auto parts store stock.
>
>
> ----- Original Message -----
> From: "Jeff Shanab" <[hidden email]>
> To: <[hidden email]>
> Sent: Saturday, December 01, 2007 9:14 AM
> Subject: [EVDL] cold batteries
>
>
>> I am suffering because of cold batteries. They are not makeing the  
>> drive
>> to and from work without sagging terribly in the last few miles.  
>> It took
>> a few days of cold weather to get here but I need to find a way to  
>> warm
>> them up.
>>
>> Unfortunantly I underestimated the effect cold would have and my  
>> EV gets
>> terrible mileage to begin with which I need to work on. but I put the
>> batteries in angle iron racks I welded up when I had access to a  
>> shop.
>> They are orbitals and I took the option to bold down thru them.
>>
>> 13  batteries are in the cabin area behind the seats and 8 of  
>> those the
>> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
>> The 8 elevated batteries I can get to most the sides so adding
>> insulation should be easy. Although the cabin is not heated so just
>> preheating the entire cabin is an option :-)
>>
>> The other batteries are under the hood. 4 in a rack above the  
>> motor in
>> which the back side is up against the controller box. I can only  
>> get to
>> 5 of the 6 sides here (no picture)
>>
>> The last 7 are stuffed in the front grill area and are hard to get  
>> to.
>> http://cvevs.jfs-tech.com/dsc00004.jpg
>>
>>
>> It has been getting below 30degrees at night and only up to 50-55  
>> during
>> the day and it is gonna get colder over the next few months. Not  
>> colder
>> at night, but less warming during the day.
>>
>> I was hoping some people could offer up some ideas.
>> Is insulating going to be sufficient? I only charge the pack with a
>> maximum of 5 amps so not much warming going on there.
>> I do pull 240-350 Amps on acceleration regularly.
>> Do I need waterbed heaters? Are they something I would use every  
>> night,
>> or just once a week.
>>
>>
>> _______________________________________________
>> For subscription options, see
>> http://lists.sjsu.edu/mailman/listinfo/ev
>>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev

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Re: cold batteries

Roland Wiench
Hello John,

You have 24 each 6 volt batteries, than the normal charge is about 7.4 per
battery or 24 x 7.4 = 177.6v at 80 degrees F.

For every 10 degrees drop below 80 F. you add 0.028 charging volts per cell.
This makes 24 x 3 cells or 72 cells.  72 cells x 0.028 = 2.016 volts

For 70 F battery temperature, this makes 177.6v + 2.016v = 179.61V

At 60 F battery temperature, its becomes 181.63 volts

At 50 F it is 183.64 and at 40 F it becomes 185.66 volts.

The temperature is normally taken from one of the lead battery post.  How
this is done, is that you get a one of those indoor/outdoor thermometers
that has a sensor on the end of a wire that is made out of plastic it has a
stick on pad on it.  You can get these units from WalMart.

Another way to connect this sensor to a battery post that has a bolt stud on
it, is place the plastic sensor in the a cable terminal barrel and pot it
with some J-B Weld and bolt the terminal to the battery stud.  This is the
way the Link 10 E meter temperature sensors are done.

As you charge the battery, it may raise the battery temperature about 10
degrees, so you may have to adjust the charging voltage to compensate for
the charging rate.

If I start to charge my batteries that may be at 60 F, I will only increase
0.028 per cell, because they will end up at 75 F at the end of charging.

If you batteries are charge, but are at a low temperature.  They are not
discharge, only the electrolyte is not as conductive at the low temperature.
The only other thing you can do, is just leave them, because you are not
using them or if you want to use them, just warm them up with a electric
battery blanket or wrap them with a heat tape so they do not go below 40 F
degrees.

Roland




----- Original Message -----
From: "John" <[hidden email]>
To: "Electric Vehicle Discussion List" <[hidden email]>
Sent: Saturday, December 01, 2007 6:01 PM
Subject: Re: [EVDL] cold batteries


> I have no advice for Jeff (sorry) but I do have a question about
> battery temperatures.
>
> Lets say for example you grossly underestimated how long it would
> take to get you conversion on the road and you have 24 Interstate
> 2400 (US battery  U2-145) batteries sitting in your garage.
>
> I have taken the EV on a few test drives in the driveway and down the
> street (less than about 1/4 mile in total) and about once a month I
> put the PFC-30 to them with a setback voltage of 185.
>
> Now that it is getting colder in MA I realize I need to up the voltage.
>
> If I have not driven or charged for 1 week do I assume the batteries
> are at the garage temperature when calculating my temperature?
>
> Then once I get the truck legal and on the road, Phase may not have
> insulation at first, but I will be charging and discharging the
> batteries daily (fingers crossed). How to I take the battery
> temperature then; can I just stick a thermometer in the space where 4
> of the batteries in the pack meet?
>
> Thanks.
>
> On Dec 1, 2007, at 12:21 PM, Roland Wiench wrote:
>
> > Hello Jeff,
> >
> > Never have your batteries get below 60 degrees.  When they are at 60
> > degrees, then charge the batteries at at 7.4 volts per 6 volt
> > battery or
> > 14.8 volts per 12 volt plus add 0.028 volts per 10 degrees drop
> > below 80 F.
> >
> > Right now it is 10 degrees F and my batteries are at 75 degrees in
> > a super
> > insulated non-conductive battery box with no battery heat on.  I
> > normally
> > will charge about 1 hour before I leave in the low temperature at
> > 40 amps at
> > 222 volts for a 180 volt pack which warms them up from 65 to 75
> > degrees.
> >
> > I have at times park outside in temperatures of -35 below and after
> > four
> > hours the battery temperature will be down to 60 degrees.  When I
> > was park
> > outside at work, I then will have a thermostat turn on a battery heat
> > blanket that is made by the KAT's company which all kinds of engine
> > heaters
> > that a lot of auto parts store stock.
> >
> >
> > ----- Original Message -----
> > From: "Jeff Shanab" <[hidden email]>
> > To: <[hidden email]>
> > Sent: Saturday, December 01, 2007 9:14 AM
> > Subject: [EVDL] cold batteries
> >
> >
> >> I am suffering because of cold batteries. They are not makeing the
> >> drive
> >> to and from work without sagging terribly in the last few miles.
> >> It took
> >> a few days of cold weather to get here but I need to find a way to
> >> warm
> >> them up.
> >>
> >> Unfortunantly I underestimated the effect cold would have and my
> >> EV gets
> >> terrible mileage to begin with which I need to work on. but I put the
> >> batteries in angle iron racks I welded up when I had access to a
> >> shop.
> >> They are orbitals and I took the option to bold down thru them.
> >>
> >> 13  batteries are in the cabin area behind the seats and 8 of
> >> those the
> >> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
> >> The 8 elevated batteries I can get to most the sides so adding
> >> insulation should be easy. Although the cabin is not heated so just
> >> preheating the entire cabin is an option :-)
> >>
> >> The other batteries are under the hood. 4 in a rack above the
> >> motor in
> >> which the back side is up against the controller box. I can only
> >> get to
> >> 5 of the 6 sides here (no picture)
> >>
> >> The last 7 are stuffed in the front grill area and are hard to get
> >> to.
> >> http://cvevs.jfs-tech.com/dsc00004.jpg
> >>
> >>
> >> It has been getting below 30degrees at night and only up to 50-55
> >> during
> >> the day and it is gonna get colder over the next few months. Not
> >> colder
> >> at night, but less warming during the day.
> >>
> >> I was hoping some people could offer up some ideas.
> >> Is insulating going to be sufficient? I only charge the pack with a
> >> maximum of 5 amps so not much warming going on there.
> >> I do pull 240-350 Amps on acceleration regularly.
> >> Do I need waterbed heaters? Are they something I would use every
> >> night,
> >> or just once a week.
> >>
> >>
> >> _______________________________________________
> >> For subscription options, see
> >> http://lists.sjsu.edu/mailman/listinfo/ev
> >>
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>

_______________________________________________
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Re: cold batteries

Cor van de Water
In reply to this post by Jeff Shanab
That is not the problem, the loading of that one 1.5MB picture
took over 1 minute for me, while I am on a high-speed cable modem.
The reason for it to load so slow, is that it is hosted from a
web server at home and the typical UP-link speed of a provider is
only several tens up to a few hundred of kb/s, so transferring
these 12 megabits easily takes a minute or more.

Reducing the size down to 200kB will reduce the time to a
more reasonable few seconds.

I noticed your domain's IP address reverse lookup resolves into
a modem in the Sprint domain, not sure what kind of uplink
speeds Sprint is offering.

Regards,

Cor van de Water
Systems Architect
Proxim Wireless Corporation http://www.proxim.com
Email: [hidden email]    Private: http://www.cvandewater.com
Skype: cor_van_de_water     IM: [hidden email]
Tel: +1 408 542 5225    VoIP: +31 20 3987567 FWD# 25925
Fax: +1 408 731 3675    eFAX: +31-87-784-1130
Second Life: www.secondlife.com/?u=3b42cb3f4ae249319edb487991c30acb

-----Original Message-----
From: [hidden email] [mailto:[hidden email]] On Behalf Of Rush
Sent: Saturday, December 01, 2007 4:36 PM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] cold batteries

Jeff,

Could you make the photos that you put up a little smaller? The dsc00004.jpg is 1.5 MB, it really needs to be no more that 500 kb, when you keep it big and people with dial up go to down load it takes so long that they stop the process and you never get feedback from them.

One of Lee's suggestions (for battery cooling) was to sandwich a .065 or so thick aluminum sheet, a copper cooling coil, a layer of soft crushable foam insulation between the battery bottom and the supporting insulation.

I've made a web page -
http://ironandwood.org/CoolingCoil.html

What you might do is instead of using a cooling coil, just put heating pads under the alum sheet. It would conduct the heat better to more batteries.

HTH

Rush
Tucson, AZ
2000 Insight, 66.7lmpg, #4965
www.ironandwood.org
www.Airphibian.com
www.TEVA2.com


----- Original Message -----
From: "Jeff Shanab" <[hidden email]>
To: <[hidden email]>
Sent: Saturday, December 01, 2007 9:14 AM
Subject: [EVDL] cold batteries


>I am suffering because of cold batteries. They are not makeing the drive
> to and from work without sagging terribly in the last few miles. It took
> a few days of cold weather to get here but I need to find a way to warm
> them up.
>
> Unfortunantly I underestimated the effect cold would have and my EV gets
> terrible mileage to begin with which I need to work on. but I put the
> batteries in angle iron racks I welded up when I had access to a shop.
> They are orbitals and I took the option to bold down thru them.
>
> 13  batteries are in the cabin area behind the seats and 8 of those the
> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
> The 8 elevated batteries I can get to most the sides so adding
> insulation should be easy. Although the cabin is not heated so just
> preheating the entire cabin is an option :-)
>
> The other batteries are under the hood. 4 in a rack above the motor in
> which the back side is up against the controller box. I can only get to
> 5 of the 6 sides here (no picture)
>
> The last 7 are stuffed in the front grill area and are hard to get to.
> http://cvevs.jfs-tech.com/dsc00004.jpg
>
>
> It has been getting below 30degrees at night and only up to 50-55 during
> the day and it is gonna get colder over the next few months. Not colder
> at night, but less warming during the day.
>
> I was hoping some people could offer up some ideas.
> Is insulating going to be sufficient? I only charge the pack with a
> maximum of 5 amps so not much warming going on there.
> I do pull 240-350 Amps on acceleration regularly.
> Do I need waterbed heaters? Are they something I would use every night,
> or just once a week.
>
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
> --
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.503 / Virus Database: 269.16.12/1163 - Release Date:
> 12/1/2007 12:05 PM
>
>

_______________________________________________
For subscription options, see
http://lists.sjsu.edu/mailman/listinfo/ev

_______________________________________________
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Re: cold batteries

John-435
In reply to this post by Roland Wiench
Thanks Roland,

I am familiar with the temp compensation procedure (However I use the  
US Battery recommendation of 2.583 per cell at 80 since, 7.7  V per  
battery, since I have not found any recommendations on the interstate  
site and I understand  they are a re-branded US battery product)

Taking the temp at the post was the info i was missing.

Much appreciated.

John



On Dec 1, 2007, at 8:49 PM, Roland Wiench wrote:

> Hello John,
>
> You have 24 each 6 volt batteries, than the normal charge is about  
> 7.4 per
> battery or 24 x 7.4 = 177.6v at 80 degrees F.
>
> For every 10 degrees drop below 80 F. you add 0.028 charging volts  
> per cell.
> This makes 24 x 3 cells or 72 cells.  72 cells x 0.028 = 2.016 volts
>
> For 70 F battery temperature, this makes 177.6v + 2.016v = 179.61V
>
> At 60 F battery temperature, its becomes 181.63 volts
>
> At 50 F it is 183.64 and at 40 F it becomes 185.66 volts.
>
> The temperature is normally taken from one of the lead battery  
> post.  How
> this is done, is that you get a one of those indoor/outdoor  
> thermometers
> that has a sensor on the end of a wire that is made out of plastic  
> it has a
> stick on pad on it.  You can get these units from WalMart.
>
> Another way to connect this sensor to a battery post that has a  
> bolt stud on
> it, is place the plastic sensor in the a cable terminal barrel and  
> pot it
> with some J-B Weld and bolt the terminal to the battery stud.  This  
> is the
> way the Link 10 E meter temperature sensors are done.
>
> As you charge the battery, it may raise the battery temperature  
> about 10
> degrees, so you may have to adjust the charging voltage to  
> compensate for
> the charging rate.
>
> If I start to charge my batteries that may be at 60 F, I will only  
> increase
> 0.028 per cell, because they will end up at 75 F at the end of  
> charging.
>
> If you batteries are charge, but are at a low temperature.  They  
> are not
> discharge, only the electrolyte is not as conductive at the low  
> temperature.
> The only other thing you can do, is just leave them, because you  
> are not
> using them or if you want to use them, just warm them up with a  
> electric
> battery blanket or wrap them with a heat tape so they do not go  
> below 40 F
> degrees.
>
> Roland
>
>
>
>
> ----- Original Message -----
> From: "John" <[hidden email]>
> To: "Electric Vehicle Discussion List" <[hidden email]>
> Sent: Saturday, December 01, 2007 6:01 PM
> Subject: Re: [EVDL] cold batteries
>
>
>> I have no advice for Jeff (sorry) but I do have a question about
>> battery temperatures.
>>
>> Lets say for example you grossly underestimated how long it would
>> take to get you conversion on the road and you have 24 Interstate
>> 2400 (US battery  U2-145) batteries sitting in your garage.
>>
>> I have taken the EV on a few test drives in the driveway and down the
>> street (less than about 1/4 mile in total) and about once a month I
>> put the PFC-30 to them with a setback voltage of 185.
>>
>> Now that it is getting colder in MA I realize I need to up the  
>> voltage.
>>
>> If I have not driven or charged for 1 week do I assume the batteries
>> are at the garage temperature when calculating my temperature?
>>
>> Then once I get the truck legal and on the road, Phase may not have
>> insulation at first, but I will be charging and discharging the
>> batteries daily (fingers crossed). How to I take the battery
>> temperature then; can I just stick a thermometer in the space where 4
>> of the batteries in the pack meet?
>>
>> Thanks.
>>
>> On Dec 1, 2007, at 12:21 PM, Roland Wiench wrote:
>>
>>> Hello Jeff,
>>>
>>> Never have your batteries get below 60 degrees.  When they are at 60
>>> degrees, then charge the batteries at at 7.4 volts per 6 volt
>>> battery or
>>> 14.8 volts per 12 volt plus add 0.028 volts per 10 degrees drop
>>> below 80 F.
>>>
>>> Right now it is 10 degrees F and my batteries are at 75 degrees in
>>> a super
>>> insulated non-conductive battery box with no battery heat on.  I
>>> normally
>>> will charge about 1 hour before I leave in the low temperature at
>>> 40 amps at
>>> 222 volts for a 180 volt pack which warms them up from 65 to 75
>>> degrees.
>>>
>>> I have at times park outside in temperatures of -35 below and after
>>> four
>>> hours the battery temperature will be down to 60 degrees.  When I
>>> was park
>>> outside at work, I then will have a thermostat turn on a battery  
>>> heat
>>> blanket that is made by the KAT's company which all kinds of engine
>>> heaters
>>> that a lot of auto parts store stock.
>>>
>>>
>>> ----- Original Message -----
>>> From: "Jeff Shanab" <[hidden email]>
>>> To: <[hidden email]>
>>> Sent: Saturday, December 01, 2007 9:14 AM
>>> Subject: [EVDL] cold batteries
>>>
>>>
>>>> I am suffering because of cold batteries. They are not makeing the
>>>> drive
>>>> to and from work without sagging terribly in the last few miles.
>>>> It took
>>>> a few days of cold weather to get here but I need to find a way to
>>>> warm
>>>> them up.
>>>>
>>>> Unfortunantly I underestimated the effect cold would have and my
>>>> EV gets
>>>> terrible mileage to begin with which I need to work on. but I  
>>>> put the
>>>> batteries in angle iron racks I welded up when I had access to a
>>>> shop.
>>>> They are orbitals and I took the option to bold down thru them.
>>>>
>>>> 13  batteries are in the cabin area behind the seats and 8 of
>>>> those the
>>>> rack is elevated. http://cvevs.jfs-tech.com/dsc00006.jpg
>>>> The 8 elevated batteries I can get to most the sides so adding
>>>> insulation should be easy. Although the cabin is not heated so just
>>>> preheating the entire cabin is an option :-)
>>>>
>>>> The other batteries are under the hood. 4 in a rack above the
>>>> motor in
>>>> which the back side is up against the controller box. I can only
>>>> get to
>>>> 5 of the 6 sides here (no picture)
>>>>
>>>> The last 7 are stuffed in the front grill area and are hard to get
>>>> to.
>>>> http://cvevs.jfs-tech.com/dsc00004.jpg
>>>>
>>>>
>>>> It has been getting below 30degrees at night and only up to 50-55
>>>> during
>>>> the day and it is gonna get colder over the next few months. Not
>>>> colder
>>>> at night, but less warming during the day.
>>>>
>>>> I was hoping some people could offer up some ideas.
>>>> Is insulating going to be sufficient? I only charge the pack with a
>>>> maximum of 5 amps so not much warming going on there.
>>>> I do pull 240-350 Amps on acceleration regularly.
>>>> Do I need waterbed heaters? Are they something I would use every
>>>> night,
>>>> or just once a week.
>>>>
>>>>
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>>>
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Re: cold batteries

Jeff Shanab
In reply to this post by Jeff Shanab
Sorry on the picture sizes and more importantly the slow connection.
When I changed careers I had to take that PC from the buisness dsl
(symetric 6mb/s) to the sprint bbd at my house. (3mb/s down but 15Kb/s
up, caugh, ack)

I never got around to making thumbs and smaller versions. If I don't
mention the pictures, people ask if there are any. Yes that POL (page of
links) needs to be turned into a web page, yes there needs to be more
versions of the images with thumbnails, and yes I need to get a better
internet connection.

I just solved a problem with googlebot changeing the way it reads
robots.txt and crawling the site that should help it out some.
Persistant little bugger.

This situation is not going to change anytime soon, no money. At least
the page front page loads quickly ;-)

The question still stands: is insulation sufficient or are heaters needed.

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Re: cold batteries

Lee Hart
In reply to this post by Jeff Shanab
Jeff Shanab wrote:
> I am suffering because of cold batteries... The 8 elevated batteries
> I can get to most the sides so adding insulation should be easy...
> The other batteries are under the hood. I can only get to 5 of the 6
> sides here... The last 7 are stuffed in the front grill area and are
> hard to get to.

I favor low density Styrafoam insulation; it has a high R value, is acid
proof, easy to work with, nonconductive, and inexpensive.

When I can't squeeze it in, I use fiberglass insulation. For example, I
lay fiberglass batts in a plastic bag on top of my batteries in winter.
They conform easily to the irregular shape. Maybe you can wrap it around
the battery boxes? Use the 3.5" thick x 14" wide rolls in plastic
sleeve, suck the air out with a vacuum to compress it, wiggle it into
place, then let it swell back up to its normal thickness.

I've also used the spray foam for insulation. In one case, I put the
batteries in my battery box, then sprayed foam into the spaces around
them to both insulate and anchor them in place. To get them out for
replacement, I dumped acetone in to dissolve the foam.

If you drive and charge every day, insulation alone may be all you need
to keep the batteries warm. Otherwise, you may need 10-20 watts per
battery from a heating pad or blanket.

--
Ring the bells that still can ring
Forget the perfect offering
There is a crack in everything
That's how the light gets in    --    Leonard Cohen
--
Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart_at_earthlink.net

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