Re: (ET) Wanted, information on installing Lithium cells in my EGT 200

["David Roden" <etpost drmm net>]

On 11 Apr 2013 at 5:01, RJ Kanary wrote:

> I would check with the engineers at Boeing before proceeding. :)

I didn't miss the smiley, but let's put things in perspective.  Millions 
of 
lithium ion batteries are serving safely in electronic devices of all 
kinds 
all over the world.  When they're properly managed and supervised 
(electronically) they're safe.  Judging whether Boeing did this "properly" 
will be left as an exercise for the reader.  ;-)

Lithium ion secondary cells are fussy.  That's why they're not sold in 
your  
local drugstore alongside the ones with the pink bunny.

Unless you're an engineer, you're probably best off (and safest) buying a 
complete, matched, properly configured lithium battery system - cells, BMS 
(Battery Management System) and charger.  Such systems are offered by some 
of the EV parts vendors, but it adds significant cost to those direct-
imported, Chinese-made $1.30-per-amp-hour LiFePO4 cells.

Someone may come along here and argue that some EV hobbyists are doing 
fine 
without any BMS.  Actually, these folks DO have BMSes - THEY are the 
BMSes, 
testing and monitoring their own cells.  

This requires care and attention, not unplug and go.  It's for the kind of 
guys who, 40-50 years ago, couldn't go 24 hours without popping the hood 
of 
their cars to tinker with something. For those of us who just want to USE 
the tractor, and not worry about whether the garage might burn down or we 
might kill an expensive cell or two, a BMS is mandatory.

All in all, I'm with the folks who suggest that lead batteries remain the 
better choice for ETs.  Their weight is a good thing in this application.

Also, thanks to use that's mostly weekly or less, and reasonable discharge 
currents, lead batteries have a quite satisfactory lifetime in ET service, 
despite abuse from that blunderbuss of a charger.


David Roden - Akron, Ohio, USA

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