Cooling time for Zebra batteries in Th!nk City

[Electric Aid]

Originally posted by Sven Forsberg

Hi,

For how long can a fully charged Th!nk City stay parked without charging before the Zebra battery becomes solid/cold/unusable ?

It is interesting to know for how long you can manage without access to a charging socket.

/Sven

[Electric Aid]

Reply by Tom Roy on April 6, 2009 at 9:09am

One member at the Norwegian EV forum reports that he parked his car on Friday at 6 pm and the meter indicated 70 %. Next Monday at 8 am the meter indicated 40 %.

Think Global has confirmed that this is normal and that about 10 % energy per day (24 hours) is used to keep the battery hot - minimum 270 degrees centigrade.

[Electric Aid]

Reply by Andrew on April 6, 2009 at 11:17am

Mes-Dea have informed me in the past that the 19Kw/h zebra cell uses approx 1Kw/h of its
own energy in a 24hr period to maintain its temperature . Obviously in summer it will use
less and in the colder periods more , but on average 5% per 24 hrs .

[Electric Aid]

Reply by Øyvind Lunde on June 21, 2009 at 9:37am

By definition its unusable under 270°C If you park the car with "hot" batteries you have etablished (buffered) about 50-60°C . It cools down pluss minus 5°/hr So it would not normaly spend any ekstra power to heat it self for at least 6-10hr if the batteries where "hot" when you parked it. Logged data shows that power to keep it hot after this period is aproximently 100W or 2,4kWh /24hr. Mesured at a prototype car and it is possible that this powerloss is redused in the later produktionmodel?

I belive that a fully charged Zebra batterie will "stay alive" with av steady decline in capasity for at least 10 days.

Tom Roy estimate make sence ;-)

[Neil Blanchard]

Hello Richard,

It is really 270°C? That is scorching hot! That's 518°F which is hot enough to cook pizza...

I had no idea. Will the first imported City car into the USA use the Zebra battery? Does it heat up when it is being driven?

Sincerely, Neil

[Dahl]

Zebra batteries keeps temp. between 270-350 degrees celsius all the time, but it stands total discharge also. Then it would take quite some time to awake it .The temperature keeps the battery stable and is good to have in either very cold or very hot climate because the outside interferes very little with the battery(it is vacuum insulated) . Downside is of course that it uses a bit of electricity to keep the battery warm , about 10% per 24h. Litihum is supposed to be better in a more tempered climate , but I am curious to the lifespan of lithium compared to Zebra. Zebra is supposed to do 10 years with about 10-20 reduction of capacity towards the end, with lithium i dont know, but i guess lithium batteries on pcs and macs would give you a clue. Our preference is the Zebra battery because of greater range , cheap electricity(Norway) and reliability.
Good Luck
D

P.S. Maybe a useful link : http://cebinew.kicms.de/cebi/easyCMS/FileManager/Files/MES-DEA/Elec...
Also, did you know : It takes about 3 kilowatts to refine a liter of petrol , but you will travel longer in a Th!nk with 3kw than in a gasoline car with one litre of petrol...