Thanks George.  Great explanation!

Looks like I have to start ordering some components and test out my battery
over the winter.  

Anyone want to compare draw times when the tester is completed?  I'd like to
know how the draw time with 1.5 Ohms of resistance compares to real life for
a Dacor/Apollo.  Unless someone knows the draw of the Dacor motor on it's 3
settings?  Naturally averaged with the typical stokified gear setup.....
:-)  Anyone from a shop know the typical draw of the motor, maybe someone
who sells them?  

Thanks again George!
Art.


		-----Original Message-----
		From:	kirvine@sa*.ne* [mailto:kirvine@sa*.ne*]
		Sent:	Monday, November 22, 1999 3:40 PM
		To:	Paltz, Art
		Cc:	techdiver@aquanaut.com
		Subject:	Re: Question about the battery tester....

		That is my battery tester you are looking at. It is simply
two 300 watt
		3 ohm resistors in parrallel giving 1.5 ohms of resistance .
The voltage
		is not an issue. If you burn a 12 volt battery it is still
subject to
		V=IR, and you merely time how long that "R" goes for and
compare it to
		the curve supplied with the batteries.

		We chose that combination of resistors to match the draw of
a DV100
		scooter motor. The new motors that I make draw 2 amps less
for the same
		thrust, and peak much lower. This test gives us a "worst
case" burn for
		our scooters, which actually floats with drag, which of
course the DIR
		system minimizes.

		In your case, as you said, the objective is to just see how
the battery
		compares to its rating.

		For 12 volt light battery testing, the array happens to
mimick a 100
		watt halogen bulb time-wise, and if you just use one of the
resistors (
		there is a disconnnect bettween them in my setup), you will
get the 50
		watt light time or the Mako motor time. Howver, why do the
long test
		when you can factor the times using the discharge curve of
the battery.

		If you really want to roll on the floor laughing, look at
how the usdct
		tested theirs or how the other guys who make them test
theirs. I came up
		with these numbers based on dynamic testing using a long
harness and
		remote guages so I could ride the scooter at different
settings and gear
		configs. As you know, doing what I do with a scooter means I
need to
		know exactly what that piece of equipment will do, and our
tests turn
		out to be right on the money in real life diving.

		I am used to claiming ignorance on issues of cave trade
secrets, but
		that is not so necessary anymore. Actually , all of my stuff
is
		incorporated into the GUE scooter course , and we even
filmed me
		teaching part of it with Errol , but that is not available
outside of
		the organizations.


		Paltz, Art wrote:
		> 
		> George,
		> 
		> It's mentioned at the bottom of this web page that you're
the EE guru.
		> Being that you make your scooters I'd say that makes you
pretty much a guru.
		> 
		> The battery drain/tester on
http://www.bentleytech.com/resistor/index.html
		> <http://www.bentleytech.com/resistor/index.html>  says
it's for 24V
		> Gavin/Mako scooters.  Can it be used to test a 12V Dacor
if it's drained to
		> 10V?  I have a new battery in the scooter and I'm getting
poor performance
		> from it.  This gizmo looks simple to make and test.  I
just don't know if I
		> would need to modify the resistors to account for a 12V
battery.  As you can
		> tell, I'm not an EE type.  I just know how to solder
wires....
		> 
		> I also assume it won't accurately mimic a Dacor motor for
burn time but at
		> least I can cycle the battery and assume I've got an
optimal charge.  Might
		> be fairly close though.
		> 
		> Thanks,
		> Art.
		
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