Re: (ET) batteries

["David Roden (Akron OH USA)" <roden ald net>]

On 1 Jun 2001, at 12:29, Neil Dennis wrote:

> The only thing I'm not sure i like is the "sealed" feature, no way to
> check the fluid

If it's a gel or AGM type, you shouldn't ever have to if the charger is 
set up correctly.  They use catalytic recombination to change the H2 and 
02 back into water.  But you need a proper charger -- if you use the ET 
charger, you literally dry them out.

If the Voyager is a sealed, flooded battery, it is probably not a true 
deep-cycle battery but rather a "combination" (starting/cycling) marine 
battery.  True deep cycle batteries have antimony-doped grids for cycling 
durability.  Combo and starting batteries have calcium-doped grids to 
reduce gassing and water usage.

They don't last very long if cycled deeply and/or used at high currents, 
so I recommend keeping discharges shallow.  I would not exceed 50% DOD. 
At 12.1v after mowing, you are taking them to about 65% discharged 
(assuming that your meter is accurate), so 4 years of life so far is 
pretty good.

If you want good life and no mess, I recommend East Penn (Deka Dominator) 
gel batteries or Concorde AGMs in a group 27 or 31 size.  They are not 
cheap, around $150-$175 each.  You will have to make a battery box for 
them to mount in place of the weight box.  

Optima yellow tops are also quite good but are rather small for this 
application.  Someday Optima are supposed to start selling their group 
31s that they prototyped a couple of years ago.  These would be good.

Better yet for range extension would be 6 volt golf car batteries in a 
trailer.  Any time you run parallel packs, you're better off matching the 
aux batteries with the main.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1979 General Engines ElectroPed 24vdc
1974 Honda Civic EV 96vdc
1970 GE Elec-trak E15 36vdc
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