Re: (ET) Elec-trak Digest, Vol 14, Issue 37

["Robert" <euclid delhitel net>]

You can use SLA's in an ET you just need a different charging algorithm. The 
original charger is sort of OK but remember it's very old technology. L/A 
batteries should optimally be charged with a 3 stage algorithm and equalized 
every 30 or so charges for best life and performance. The original charger 
does not have current limiting. A 100A battery should be charged with C/10 
to C/20, that means 100/10 = 10 amps max charge current. It's also better to 
charge each battery individually or in pairs of two. A string of 6 batteries 
has all kinds of charging anomalies, that's why equalization charges are 
important.

Rob
-----Original Message----- 
From: elec-trak-request cosmos phy tufts edu
Sent: Tuesday, March 29, 2016 12:00 PM
To: elec-trak cosmos phy tufts edu
Subject: Elec-trak Digest, Vol 14, Issue 37

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Today's Topics:

  1. Re:  Charger question (Christopher Zach)
  2. Re:  Darn, E15 motor out too (Chris Tromley)
  3. Re:  Darn, E15 motor out too (james)
  4. Re:  Darn, E15 motor out too (John Jeno)
  5. Re:  Darn, E15 motor out too (tb)


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Message: 1
Date: Mon, 28 Mar 2016 18:35:12 -0400
From: Christopher Zach <cz alembic crystel com>
To: elec-trak cosmos phy tufts edu
Subject: Re: (ET) Charger question
Message-ID: <56F9B1A0 6080201 alembic crystel com>
Content-Type: text/plain; charset=windows-1252; format=flowed

On 3/28/2016 6:31 PM, Charlie wrote:
> What keeps the OEM Elec-trak battery charger from overcharging the
> batteries?  The manual says you are "automatically protected" or
> something equally vague.

The transformer tapers down the charge current as you hit 42 volts. 42v
on a 36v system is 7 volts per 6 volt battery, which is about the
gassing point of the cells. Left too long the water in the cells will
boil away, thus the timer. You of course need to keep adding water,
that's part of the reason why you don't use SLA type batteries in an
Elec-trak.

C