Saturday, October 6, 2012

TMS verses Bigger Battery

One of the main topics of conversation right now is how to deal with the long term limitations of driving electric.  Now, if you got the big bucks you dont have much to worry about. plop about 100 grand on the table, get the max'd out Tesla S and in a few years when the charging infrastructure is up, you are set, But...

That does not address what most EV'ers or wannabes are looking for.  For me, I am not in the upper income level of most of my EV brethren.  It was a major financial stretch for me to get rid of a lightly used 2006 Prius that was paid for to get the LEAF but I did it because Nissan specifically  marketed the car to people like me. Ones who want to drive EV who reside squarely in the middle class (on the lower end) and need to do it on a budget.

Just driving EV help tremendously with the budget. Once again, recent refinery issues has caused a very large spike in gas prices. For the budget-conscious, it can be difficult to account for the gas bill when you dont know if its going to be $200 this month or $300.  Driving electric eliminates that question. my cost to drive the LEAF has not varied more than $10 per month in the 20 months  and nearly 23,000 of my LEAF experience. eliminate the 400+ mile spread in distance driven from one month to another and the "weighted" difference per month is less than a buck. iow; very predictable!!

So the question now has become what should the right budget EV look like?  The LEAF has a 24 Kwh battery pack with no battery pack temperature management system and is good for 70-90 miles depending on season and driving styles.  Its advertised at 100 miles and I have done over that a few times but that is all street level driving with no freeways involved so a bit unrealistic for most.  Now if it stayed at that range, most would be ok with it, but degradation reduces that range and degradation starts on day one.

Now degradation has two different modes; permanent and temperature induced.  cold weather reduces range so when making a purchase/lease decision one needs to evaluate the weather as vigorously as their commute routes to determine viability of the LEAF. But the other loss which is permanent has several causes but the one with the most concern is heat related losses experienced by people in Phoenix, AZ.   Many battery experts questioned Nissan's decision to not put in TMS (temperature management system) for the battery pack especially when they did have it for the inverter, charger and AC/DC converter.

So the question;  What is most cost effective?  Bigger battery pack or TMS?

More batteries is the primary reason why other EV options are so spendy.  Toyota's new RAV 4 EV is reported to have the range that most say they would accept but at $50,000 before incentives that is out of my consideration.  Bigger batteries also mean more weight which can lower range and for me; I am not sure I want to carry that extra weight 24/7 when I would only need it a dozen times a year.

So back to TMS.  Why did Nissan elect to not put this into the LEAF?  Granted, Phoenix just went thru a much hotter than normal Summer but so did the rest of the country and we may need to face the fact that the Summer of 2012 just might be our new normal.  One would have to guess it was a budget decision.  Nissan already was concerned that the price point for the LEAF was probably too high and made the decision to leave TMS out and I have to wonder if that was a mistake?

Another thing to mention; I have seen only a 2-4% degradation so TMS would have been a waste of money in my case since cold weather degradation is only temporary.  Now, would I have liked to have the longer range in Winter? yes and Nissan did address that partially in the Cold Weather Package released for the 2012 model year.

Nissan has released some information on changes to the 2013 LEAF that includes efficiency gains by a yet to be specified. Rumors have a battery chemistry change to be introduced later to be available for 2014.  But Nissan has also decided to introduce a lower priced LEAF entry that removes features like the LED headlights and the NAV option. Coupled by lower American manufacturing costs and renegotiated prices from suppliers, they are aiming at a $31,000 price point which would put it in the low 20's after incentives for WA State residents.


Yesterday Nissan announced specs for the 2013 Japanese Market LEAF. It does get a bit more range (estimated 73 to 83 miles) but did it thru a more efficient motor, better regen and a reduction in weight.  No changes to the battery pack itself other than the weight loss due to lighter materials, etc.

Also no mention of a TMS but once again, this is the Japanese Market and expecting the American Market to be different since it always is. Several reports that 6.6 Kw charging was coming but not mentioned here. Hopefully the American announcement will arrive shortly!

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