Re: (ET) Chargers

["David Roden" <etpost drmm net>]

I agree that if you're going to tap the battery for lights and lift, 
charging the battery all in series at 36 volts isn't ideal.  Imbalance is 
just about inevitable, and you need heavy overcharge to correct for it.  
Thus modular charging can be beneficial. (So can a DC:DC converter, but 
that 
adds some cost.)

For about 10 years I've been using 3 automatic 10-amp Exide brand 
chargers, 
made by Cliplight in Canada, to charge my ET.  I have 12 volt gel 
batteries 
and the GE charger would have ruined them.  These chargers cost about $50 
each, IIRC.

Since I'm using 12v batteries in series-parallel, I've had the front lift 
tap at 24 volts all this time.  Others have warned me about this, but so 
far 
so good.  

The downside of modular charging are :

1. Balance.  You have to do one of the following:

A. Use six 6v chargers, not three 12v; OR

B. move the lift tap to 12 or 24 volts; OR

C. Derive the lift voltage from some kind of DC:DC converter

2. Reliability. Three or 6 chargers are at least 3 or 6 times as likely to 
have a failure.  If a series charger fails, you know it pretty promptly 
because the tractor doesn't have any range.  

But if one battery in the pack doesn't charge, you're less likely to 
notice. 
 If you don't realize it, that battery is apt to be reversed and damaged 
on 
the next use of the ET.  Thus, with modular charging, you should  check 
every individual battery to make sure it's fully charged before operating 
the tractor.  Do I?  Um, well ... ;-)


David Roden - Akron, Ohio, USA

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