Re: (ET) First mowing of the year (at last!) and questions

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

On 11 Apr 2002 at 9:27, Christopher Zach wrote:

> 
> 1) The battery voltage fluctuates ...

This is normal.  It's a voltmeter -- the markings notwithstanding, it 
doesn't really work like a gas gauge.  After a while you'll learn to 
interpret what it's saying.

> 
> 2) The E20 doesn't steer as well with the mower on. 

My E15 doesn't steer very well no matter ~what~ is on the front.  <g>

> 3) What is the recommended speed for mowing the lawn? 

I usually use L, with the speed lever on one of the top 2 steps.

> ... D speed
> drives the batteries into the red when climbing the hill. 

That won't hurt anything if it doesn't last more than several seconds.  
Don't take the red too seriously (but also try not to pin the ammeter and 
don't keep it in the red continuously).

> Also L seems to
> do nice amounts of regen, while D doesn't do much regen braking at *all*.
> Is this normal?

Same with mine.  There's no controller to boost motor voltage at low rpm 
so 
low gearing is necessary to keep rpm and therefore regen voltage high 
enough 
to stuff electrons back in the pack.

> 
> 4) How noisy should the deck be? I don't hear any mechanical whines, but
> the blades do appear to make a lot of air noise (roar). Would new blades
> be a good idea; do I have an aerodynamic issue here?

They're never silent.  Don't worry about it unless you're getting 
excessive 
vibration (bent shaft or imbalanced blade) or howling bearings (if they 
get 
loose you can break a field magnet => $$$).

> 
> 5) To increase the range (and decrease the voltage drop under load) I 
> have
> been thinking of adding three 12 volt Dynasty AGM batteries

Unless you really don't have enough capacity to mow the lawn, I wouldn't 
do 
this.  In fact, if you do need more capacity, I'd suggest changing to  
high 
capacity batteries, such as T-145s or US145s.  

If you decide to add a second, parallel set (some people have done this), 
I 
would try to match them as closely as possible to the main set so they 
share 
the load better.  AGMs have lower internal resistance and will thus bear 
the 
brunt of the load.

In general I don't recommend using AGM batteries in the ET.  Their 
greatest 
strength is the ability to deliver huge currents with aplomb, which really 
isn't necessary for an ET.  They cost a lot more and don't last as long; 
golf car batteries are much more cost-effective.


> 
> My thought is the AGM batteries can provide a lot more amperage over a
> short period of time than the lead acid batteries and this might help
> smooth out the voltage fluctuations when going up a hill.
> 

Don't worry about the voltage sag unless it gets so bad that you can't 
climb 
a hill with a fresh charge.  If that happens, either one or more batteries 
is/are toast, something's wrong with the motor or wiring, or the brake is 
dragging severely.

Golf car batteries are just about ideal for the ET.  This is one thing 
that 
GE did right.


David Roden - Akron, Ohio, USA
1991 Solectria Force 144vac
1991 Ford Escort Green/EV 128vdc
1970 GE Elec-trak E15 36vdc
1974 Avco New Idea 36vdc
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