Re: (ET) When did they start making car batteries out of gold?? :-)

["David Roden (Akron OH USA)" <etpost drmm net>]

On 15 Aug 2013 at 18:44, Theoldcars aol com wrote:

> Its a good thing battery chemistry has improved because now there are  
> better options. 

Completely passing over the political comments in Don's post, I must say 
that while batteries HAVE indeed improved, and while I think lithium 
(particularly LiFePO4) batteries are crucial to building successful road 
EVs, lead batteries are still the better option for most ETs.  

For one thing, in most cases, we WANT the mass lead provides.  That's 
definitely not the case in a road EV.

Lead is also far more forgiving of careless charging.  Flooded lead 
especially will shrug off all but severe overcharging.  Overdischarging 
will 
shorten its life, but it's not catastrophic.  Compare that with the 
babying 
a lithium battery needs.  

When you change to a lithium battery, don't forget to count the cost of 
the 
cell-level BMS (battery management system) it requires.  Hobbyist users 
sometimes leave the BMS out.  In some cases this is because they want to 
save money.  Others just don't know or think it's necessary.  Some think 
they can do manually what a BMS does.  A few actually think a BMS is 
counterproductive.  

Not that I want to be alarmist, and I know things can also go wrong with 
lead, but lithium systems DO have to be managed. Lithium batteries have 
shown not only a propensity to die when improperly charged, but to do so 
in 
a violent manner at times.  The good news is that lithium stores a lot of 
energy and can produce a lot of power.  That's also the bad news.

You have to watch them all the time - or your BMS does.  I really don't 
think you can be your lithium battery's manual BMS unless you don't have a 
life.  

Besides its forgiving nature, lead remains a very low use-cost battery, 
especially for the generally relaxed life it lives in an ET (compared to a 
road EV).  

The roughest part of a lead battery's life in an ET is being charged by 
that 
blunderbuss of a GE charger.  Despite that, lots of ETers get 10 year 
battery life.  Replace the GE charger with something gentler and smarter, 
and I'd guess you'd see a good 15 year battery life.  In fact, I've been 
using the same East Penn gel batteries in my ET now since 1997 or 1998, 
and 
my chargers aren't even that smart (though smarter than the GE).  

Meanwhile, as I understand it, lithium batteries have a calendar life 
apart 
from their cycle life.  

There may come a time when large lithium batteries are produced in 
quantities as massive as golf car batteries are now.  Maybe then they'll 
be 
as much of a commodity as lead batteries are now.  When that happens, we 
might find ourselves using lithium in places where lead actually is the 
better choice, just because lithium is so cheap.  But not now.