[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

RE: N.O.S. Wheelhorse

"Pestka, Dennis J" <Dennis Pestka mkg com> wrote:

>  I may still look for a battery upgrade although for
> greater range. I'm hearing a lot about Optimas. They are supposedly
> maintenance free.

Well, they don't need watering.  But they're not exactly maintenance 
free.  You still have to check the terminals and test them now and 
again.  <g>

If you use any "maintenance free" (sealed, or more accurately, valve 
regulated) battery you will need to replace or modify the ET charger.  It 
is designed to charge flooded batteries which can gas freely at the end 
of charge.  Its finish rate is much too high for valve regulated batteries.

Valve-regulated batteries have a catalyst and operate under pressure to 
re-combine the hydrogen and oxygen evolved at the end of charge into 
water.  If you push too much current into them during the last 20% of 
the charge, you can overwhelm the catalyst.  This will cause too much 
pressure, so the battery must vent (the "valve regulated" part comes 
into play here) so it doesn't explode.  Then you lose the water.  Do this 
enough times, and the battery dries out.  There's no way to replenish 
it, so at that point the battery is junk.

Optimas are beautiful batteries.  However, they require special care in 
charging.  They are at their best in extremely high-current (600 amps 
and up) applications like high-performance on-road electric vehicles.  
And they are very costly (about *triple* the cost of a golf car battery).

All other things being equal, range is roughly proportional to pounds of 
lead.  So, because they are smaller and have less lead, you will 
actually have *less* mowing capacity with 6 Optimas than with 6 golf 
car batteries.

There may be situations where valve-regulated batteries are appropriate 
-- for example, where you know the user won't water the batteries 
regularly.  For such cases, there are less expensive (and larger) VR 
batteries available than the Optimas.  In most cases, conventional 
flooded golf car batteries are by far the most economical choice for this 

     David Roden          THE VIRTUAL PD         
     Services for radio broadcasters targeting educated adults
 Programming   Air talent development   Research   Classical music