RE: (ET) Batteries and lighting

["David Roden" <etpost drmm net>]

On 12 Mar 2005 at 7:26, Dave & Deb wrote:

> the surprise was this
> last battery which actually had more capacity than the the optimas in 
> fact
> more than any others but the genesis. 

Compared to flooded deep cycle batteries, and even some AGM deep cycle 
types, SLI (starting lighting ignition) batteries have very high specific 
power, and often comparable or better specific energy.  The compounding 
required to make a deep cycle battery survive cyclic use reduces both of 
these factors.  

Electric vehicle racers used to use SLI batteries for this very reason.

The GE charger will overcharge and damage AGM batteries unless you add a 
fairly sophisticated outboard charge controller to it.  I don't know where 
you'd buy one, and building a really capable one is not a trivial task.   

You could charge each module individually with a fully automatic charger 
appropriate for the batteries, ideally one approved by the manfacturer.

Or, you could use a 36 volt approved AGM type charger for the entire pack. 
 
In this case you would need to add a DC:DC converter to derive power for 
the 
lift, at least, and also for the lights if you used 12v lights, since 
tapping the pack would cause problems when using a 36v charger with AGMs.  

There are lots of things you can do to improve the ET, updating it from 
what 
Mark Hanson calls "Apollo era technology."  Of course none of this comes 
free!   Whether each possible change is worth the effort and cost is 
really 
a matter of personal preference - I like my gel batteries and Alltrax 
controller, for example, but they're not for everyone.  In fact, although 
age is catching up to it, there's much to admire in the relative 
simplicity 
of the original GE design.


David Roden - Akron, Ohio, USA

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