Page 5 of 5

Re: Details on Nissan Leaf battery pack, charge rates, lifespan

Posted: Tue Jun 01, 2010 8:51 am
by garygid
Just because the EVSE signals it can provide 40 or 50 amps of 240v AC does not in any way require the cars to use that much.

In this case, it appears that the initial LEAFs would only "sip" 15 or 16 amps (about 3.3 kW charging).

We hope that later versions of the LEAF's internal charger will be able to "eat" something like 32 amps (approx. 6.6 kW charging) off the 240v "plate".

Re: Details on Nissan Leaf battery pack, charge rates, lifespan

Posted: Tue Jun 01, 2010 9:29 am
by LEAFer
Yeah ... I wasn't ignoring that initial 3.3kW limitation. But I was hoping that 16A at level 1 (120V) is possible (120V*16A=1.92kW) rather than being limited to 12A. Of course ... all this speculation can go further.
a. How about TT-30 ("30 amp service") at RV parks ? (120V * 30A * 80% = 2.88kW)
b. How about 208V service at higher amps, but still under 3.3 ? (e.g. 15.9A * 208V = 3.3kW)

Note: Many current EV charging locations only provide 208V rather than the nominal Level 2 240V capability. The first public J1772 charging location was unveiled in Woodland, CA recently. It is 208V (now we just need a LEAF to test it !). Click Here. (Ignore the "Woodside" typo. It's Woodland.)

So ... we need to know a little more than "3.3kW limit" ... we need to know current limit or how the car determines and/or possibly limits it. (Was this already published somewhere else and I missed it?)

Re: Details on Nissan Leaf battery pack, charge rates, lifespan

Posted: Tue Jun 01, 2010 9:54 pm
by garygid
In charging, the charger usually tries to regulate the DC current going to the battery pack, gradually tapering off as the SOC of the cells nears "full".

In the EV with EVSE case, the EV's charger would also have to monitor the input AC current, to avoid drawing more current than the EVSE-indicated maximum.

If the input is a lower-than-expected voltage (208v), the charger would usually try to draw more AC current (up to the EVSE max. value) if necessary to charge the battery pack with the "intended" DC current. If the EVSE max. current is reached before the charging DC is high enough, the charger will just need to charge the battery "slower" (less DC current).

NIssan Bets on the Electric Car - designnews.com

Posted: Thu Jun 24, 2010 10:40 am
by sparky
Nice article talking about the battery breakthroughs and work that Nissan put into battery tech.
"We had a huge number of engineers dedicated to the (battery) project," recalls Shinohara of Nissan. "It was the largest scale engineering focus we've ever had on a single technology, outside of engine design."
The big breakthrough, though, was the energy density. Energy density, which translates directly to driving range, had suddenly jumped two-fold. Nissan still won't say what their energy density is, but experts estimate it to be between 140-150 W-hr/kg, a gigantic leap beyond what was used in earlier EVs.

"An energy density of 150 (W-hr/kg) is a great number," says David Swan, founder of DHS Engineering, which specializes in battery-related research and development. "It's a number we would have given our front teeth for back in the ‘90s."
http://www.designnews.com/article/50951 ... ic_Car.php

Re: NIssan Bets on the Electric Car - designnews.com

Posted: Thu Jun 24, 2010 1:42 pm
by Bicster
Thanks for sharing that one.

Re: Details on Nissan Leaf battery pack, charge rates, lifespan

Posted: Thu Jun 24, 2010 4:48 pm
by mwalsh
Some interesting stuff on how Nissan ended up with the batteries they're using in the Leaf:

http://www.designnews.com/article/50951 ... ic_Car.php

Re: Details on Nissan Leaf battery pack, charge rates, lifespan

Posted: Thu Jun 24, 2010 5:25 pm
by evnow
Merged.