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. -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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