Re: (ET) New Member

["David Roden" <etpost drmm net>]

On 2 Jul 2008 at 12:44, Michael S Briggs wrote:

> I'm not planning on getting new lead-acid batteries, since there
> *should* be some significantly improved Li-ion battery technologies
> coming onto the market over the next few years - which would be great
> not only for full electric vehicles, but also for ETs. 

I think this isn't all that advisable, and here's why.

1. The main advantage of Li over Pb is much higher specific energy (Wh per 
kg), so they are light for the amount of energy they store.  This is vital 
for road EVs.  However, a tractor, like a forklift, THRIVES on weight.  
And 
for the way we use ETs, how often do you really need more energy than 6 
golf 
car batteries can store anyway?

2. Flooded Pb batteries can be charged with the dumbest gear in the world 
and survive.  The GE charger is a perfect example.  ;-)  OTOH, Li needs a 
smart, sophisticated charger that monitors >every single cell< or the 
battery will be destroyed, possibly catastrophically.

3. Li batteries have a limited >calendar< life.  Cycles are not as big a 
deal for them as for lead.  Because most ET owners cycle their lead 
batteries about once a week, they usually get a good 10 years out of them. 
 
It's possible that a Li battery would last only half that long, or less, 
regardless of how much it's used.  

4. Lead batteries are reliable, proven, conservative technology.  They are 
a 
commodity using an old principle that's public property, sold by the 
millions. OTOH, Li batteries show great potential for uses where light 
weight and small size are crucial.  However, they're new, unproven, and 
may 
>never< become a commodity, depending on how the licensing situation pans 
out.  

I agree, lead batteries are too expensive right now.  Be patient, they 
will 
come back down in price eventually.  Lead prices are already falling. 


David Roden - Akron, Ohio, USA

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