Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Richard230]

I have been collecting motorcycle brochures since the mid-1960's (I have a lot of them).  So naturally, I have been picking up Zero brochures each year. Going through the  2014 and 2015 Zero brochures, I notice that the specification for "estimated pack life to 80%" includes the word "(city)". While the battery life estimates likely will no doubt far exceed the life of the Zero motorcycle chassis and motor, I wonder what the significance is of the "city" in the estimate?  The logical reason for that word is that the battery pack life will be less when the bike is ridden at normal highway speeds.  I wonder what the battery life will be when the bike is used the way most owners do?

Who could possibly go the estimated distances at "city" speeds, anyway?

[RNM]

I think it's "city" range * number of battery cycles * 90%...

[steven_first]

An exact answer from a Zero tech when I asked about battery life:

the way we test and get the number for those battery life’s if by doing full battery cycles. It is strictly based on the size of the battery versus home many miles of range that power pack will produce times the amount of full battery cycles it can go through.

[Richard230]

An exact answer from a Zero tech when I asked about battery life:

the way we test and get the number for those battery life’s if by doing full battery cycles. It is strictly based on the size of the battery versus home many miles of range that power pack will produce times the amount of full battery cycles it can go through.

Which still doesn't explain what the "(city)" means when Zero describes battery life estimates.    The logical conclusion is that it means running the battery discharge cycle through the government's city performance routine until it is completely discharged and then recharging again, over and over .  But it would be nice if they offered an explanation to clarify the battery life estimate criteria - considering that battery life is an important issue with many potential purchasers of their vehicles.

[Falco]

I believe the life of pack is 2500 full cycles x by range of intended use. City range being the highest and used as a best case for life of pack to 80% capacity.

[steven_first]

I would assume that the biggest killer of the batteries is heat, discharge rate, and storage conditions.  Me personally I would rather have Li-Po batteries.  Sure it may explode in a crash but damn....it wold be light and fast. 

[Falco]

I would assume that the biggest killer of the batteries is heat, discharge rate, and storage conditions.  Me personally I would rather have Li-Po batteries.  Sure it may explode in a crash but damn....it wold be light and fast.

You would prefer a heavier pack? The cells in the zero 2014-2015 are 184wh/kg. Thats better than any li-po pouch cells I have used.

[steven_first]

I apparently need to brush up on my battery information as it is dated enough that I didn't know the energy density of the 2 batteries were about the same.  Can't sit on your hand even a year without falling behind.  I read up for a bit and couldn't find one reason to go to li-po.  But....I found this fuel that has 22,394,444,400 wh/kg I think I can make it work; everybody stand back!

[Doug S]

Last time I spoke with a manufacturer about batteries, it was explained to me that there is no difference between "Li-ion" and "Li-Po" except that the Li-Po battery has no hard shell. All rechargeable lithium cells need a hard shell to prevent expansion due to outgassing during operation; a Li-Po battery doesn't have a built-in hard shell for instances when the manufacturer is going to be installing it into a hard case anyhow...it just saves a few grams of weight.

So actually (unless I was misinformed), the pouch cells we're using are actually Li-Po batteries anyhow.

[Justin Andrews]

I apparently need to brush up on my battery information as it is dated enough that I didn't know the energy density of the 2 batteries were about the same.  Can't sit on your hand even a year without falling behind.  I read up for a bit and couldn't find one reason to go to li-po.  But....I found this fuel that has 22,394,444,400 wh/kg I think I can make it work; everybody stand back!

Yes, but 90% of the energy is lost in the form of non interacting Neutrinos, bear that in mind as you light the fuse. :p

[Richard230]

I apparently need to brush up on my battery information as it is dated enough that I didn't know the energy density of the 2 batteries were about the same.  Can't sit on your hand even a year without falling behind.  I read up for a bit and couldn't find one reason to go to li-po.  But....I found this fuel that has 22,394,444,400 wh/kg I think I can make it work; everybody stand back!

Yes, but 90% of the energy is lost in the form of non interacting Neutrinos, bear that in mind as you light the fuse. :p

And don't forget about that "dark energy" loss, too.   

[teddillard]

Last time I spoke with a manufacturer about batteries, it was explained to me that there is no difference between "Li-ion" and "Li-Po" except that the Li-Po battery has no hard shell. All rechargeable lithium cells need a hard shell to prevent expansion due to outgassing during operation; a Li-Po battery doesn't have a built-in hard shell for instances when the manufacturer is going to be installing it into a hard case anyhow...it just saves a few grams of weight.

So actually (unless I was misinformed), the pouch cells we're using are actually Li-Po batteries anyhow.

You were, in fact, misinformed. 

http://batteryuniversity.com/learn/article/types_of_lithium_ion

...very common misconception.  The Zero is running NMC: https://evmc2.wordpress.com/2013/12/01/2014-zero-battery-chemistry-z-force-power-tank-secret-sauce/  Virtually everything comes first in a soft pouch or may be put into a hard case, except cylindrical cells. It has nothing to do with the chemistry.

"Lipo" generally refers to "RC lipo" which Lithium Cobalt Oxide(LiCoO2), and is the stuff that's highly volatile.  Read all about it here: https://evmc2.wordpress.com/category/lipo-batteries/

And no, steven_first, you probably wouldn't use it on anything but a race bike, once you understand what it's all about.  Though it is among the most power and energy-dense, as well as some of the cheapest chemistry... I have two personal friends who I know did everything right, and one lost his bike, the other the entire contents of his garage.  Countless other stories are out there. 

I'd be really interested in what manufacturer told you that, even if its just to learn what market they are in.

[teddillard]

As far as energy and power density, the last calcs I did about a month ago, RC lipo still wins hands down:
https://evmc2.wordpress.com/2014/12/29/more-on-the-lipo-option/

Zero's NMC can't touch it.  LEAF cells don't even come close.  The A123 are the only thing that really are close, but very expensive. 

I don't want to take this too far off-topic, but all the reading is right there on my site. Andrew Rivers, part of the CBRe build team, just put together this amazing data modeling a month ago or so: https://evmc2.wordpress.com/2015/03/06/the-rivers-models-moar-batteries/

[Doug S]

You were, in fact, misinformed.

Well, I'd have to agree with you that someone's misinformed:  http://en.wikipedia.org/wiki/Lithium_polymer_battery

The phrase has changed meaning somewhat as Li batteries have become more prevalent, but in its most common usage, it does refer to a pouch cell rather than cylindrical or prismatic (i.e. hard-shelled) cell. In any event, I'd draw your attention to the end of the third paragraph, which states that the electrochemistries of Li-ion and Li-po batteries are the same. Li-po doesn't have some magic energy density fairy dust that Li-ion doesn't have. They're just packaged differently.

[teddillard]

Sorry, what you're concluding from this Wikipedia article is just wrong, though what they're describing is correct, but incomplete.  Li-ion is a general category, of which "lipo" is a particular chemistry. 

Believe what you want and call it what you will, but Battery U is pretty much the acknowledged resource for information on batteries, especially lithium. If you want to learn, I'd suggest you sit down and read through that site instead of poorly written Wikipedia posts.

But suit yourself, I'm sure you know more than I. If you want to continue to perpetuate misconceptions that have been hashed out in every EV forum on the web for the last ten years, be my guest.  That's what forums are for, right?

(That was sarcasm.)

(addl: If you want to read about lipo "care and feeding", I'd suggest Endless Sphere - the "brain trust" of the EV community, in case it's new to you - http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=9170&start=0 for actual factuals.)