On 13 May 2009 at 23:07, Darryl McMahon wrote:
A couple of people have replied to me off-list pointing out that the
mower uses 48-volt batteries,
As I read the description, they appeared to be series strings of four 12
volt, 15 amp hour batteries, connected in parallel. Five strings! A total
of 20 batteries!
However, the website does seem to suggest that they want the user to replace
an entire series string at a time -- so perhaps they are building them into
48 volt modules. To me, that sounds even crazier, junking 3 good batteries
because the fourth flakes out.
Again, perhaps I'm being too negative, but I don't see this as a positive
development. at all. I'm sure they mean well, but I'm concerned that, as I
said before, this is going to flop and give electric yard machinery a bad
name. We do not need any more PR of that sort for EVs.
Over the years I've seen WAY too many poorly designed attempts at road EVs,
poorly maintained by poorly trained dealers. The designers don't realize
how accustomed today's drivers are to "steer and push the pedals" vehicles.
Water the batteries monthly? These are folks who never even check the tire
pressure on their ICEVs! And to their credit, the automakers have done a
remarkable job of building ICEVs that tolerate neglect and still run for
100,000 miles or more.
Almost inevitably, it's the battery in an EV. They're neglected and, with
nothing to stop the user, run down flat repeatedly. WIth this abuse, the
battery fails early, often in a year or two, or even less.
The proud owner, a bit rattled and concerned about whether he's made the
right decision in buying this EV, puts up the substantial cash to replace
the battery.
When the battery quits again in another year or two, he gets discouraged,
especially if the EV has left him stranded with a flat battery. He parks
the EV until he feels ready to spend several hundred (or a few thousand)
dollars on it again. It sits in his driveway or garage for months or years.
Finally he puts it up for sale: "Needs batteries." Someone else buys it
(at a fraction of the original price) and the cycle starts again.
With luck, someone with battery experience and EV interest eventually gets
the EV. Otherwise, it's finally junked, or else converted into an ICE
vehicle. Meanwhile, the first owner admits to friends and family that the EV
wasn't such a good idea, and "I guess they're not ready for prime time yet."
(Of course, it was the EV's manufacturer that wasn't ready for prime time.)
This is why any EV or electric tool that you (as manufacturer or designer)
hope will replace a fueled machine HAS to be at least as long lived,
reliable, and neglect-tolerant as the ICE device it replaces. Sure, battery
management systems and high-reliability electronics add to the cost. But
omitting them is false economy. It's a competitive marketplace. The
machine will fail.
But as I say, maybe I'm being too pessimistic.
David Roden - Akron, Ohio, USA
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