Re: (ET) batteries

["Don Cohen" <bond007d netsync net>]

You should shell out the $300 because it is not good to mix batteries of
different ages. Your specific gravity readings after charging are probably
all over the place. You really need them to all be close to being the same
for good performance and it is doughtful that even with a good equalizing
charge that you will see that with mixed batteries.
Don Cohen

----- Original Message -----
From: <daveb seanet com>
To: <roden ald net>; Elec-trak <elec-trak cosmos phy tufts edu>
Sent: Tuesday, June 12, 2001 9:01 AM
Subject: Re: (ET) batteries


> Just now getting my ET12 out of winter storage.  Discovered two batteries
only
> putting out 2 volts under load (before charging).  I doubt they'll come
back to
> a usable state.  I've only had my ET for  a year and not really used it
much.
> I've no idea what these batteries in it are. There are 4 of the same
brand/type
> and two oddballs that don't match each other. So I have quite a variety.
My
> first thought was to just replace the two batteries with perhaps 2 used
golf
> cart batteries.  Can I expect to get some from a local golf course?  How
much
> should I expect to pay?  Maybe I should just shell out the $300(?) and
replace
> all six?
>
> comments suggestions appreciated.
> > 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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> > all
> > thou knowest."  Neither shalt thou send me any spam, lest I smite thee.
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