Re: (ET) charger problem

["David Roden" <etpost drmm net>]

On 21 May 2009 at 9:51, tbamc wrote:

> I think U. S. Battery recommends about 46.5v for equalization, and as
> far as I know the E-T charger won't get there. 

I usually say "ask the manufacturer," but I think USBMC's charging 
directions are aimed more at users who need to get the highest possible 
capacity from their batteries on every single cycle, and are willing to 
sacrifice some cycle life for it.

They recommend constant current to 2.583 volts per cell, then constant 
voltage at this point for an additional 2-4 hours.  They suggest to reduce 
the voltage by 0.028 Volts per Cell for every 10 deg F above 80 deg F, and 
increase voltage by the same amount for temperatures below 80 deg F.  
(Following this algorithm to the letter requires a much smarter charger 
than 
the GE, by the way.)

I think this is needlessly aggressive for most users.  I wouldn't much 
exceed 2.5 volts per cell (45 volts for an ET), and stop the charge when 
the 
current falls to 0.05C regardless of time.  I'd probably add an 
equalization 
phase of perhaps 2 hours at 0.2C or so for the ET, since it taps the 
battery 
pack.  I would still use USBMC's temperature adjustment.  


David Roden - Akron, Ohio, USA

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