-----Original Message-----
From: Xebra_EV@yahoogroups.com [mailto:Xebra_EV@yahoogroups.com]On Behalf Of John Gipson
Sent: Monday, January 22, 2007 5:22 AM
To: Xebra_EV@yahoogroups.com
Subject: RE: [Xebra_EV] Re: Xebra Overdrive Project

 Hey, if the price of the kit is about $500 for the controller isolation relays

 and cables and extra charger count me in as very interested.  Can hardly

 wait to test out 120-volt system....

 

 The kit will be using a Changeover type relay system to isolate the low

 voltage controller, right?

 

Sean <x@losthighway.us> wrote:

Sounds like it would work, but I am leaning toward simple; have Damon bump the limiter to 99v (the controller is using 100v components).

Sean Rarey
Grants Pass Electric Vehicles
145 Redwood Highway
Grants Pass OR, 97527
gpev@losthighway.us
(541) 218-8850

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From: Xebra_EV@yahoogroups.com [mailto:Xebra_EV@yahoogroups.com] On Behalf Of bortel
Sent: Sunday, January 21, 2007 8:51 PM
To: Xebra_EV@yahoogroups.com
Subject: RE: [Xebra_EV] Re: Xebra Overdrive Project

Sean,

Here’s something else you might try. Instead of running the extra voltage through the controller, series it with the output of the controller. That way the controller stays within it’s limits and you can add as much extra voltage as desired. This will require a couple of relays to implement. I’m sure Damon has seen this done or he can figure out how to do it. In operation you just run the controller up about half way, let off on the pedal, push a button to switch in the additional pack, and then run it like normal in the upper range. Of course, it should be wired to drop out when braking. One of the guys in NEDRA has been using this scheme to use 144v with a 72 v controller.

Dan

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From: Xebra_EV@yahoogroups.com [mailto:Xebra_EV@yahoogroups.com] On Behalf Of Sean
Sent: Sunday, January 21, 2007 4:45 PM
To: Xebra_EV@yahoogroups.com
Subject: RE: [Xebra_EV] Re: Xebra Overdrive Project

Ok folks XOP (Xebra Overdrive Project) update.  I have to tell you that we have had some extremely unexpected results (at least for me, the electrical engineers involved don’t seem so surprised).

Here is the one that really got me excited:  Temps are pretty warm here today, about 65 degrees.  In run after run, the XOP Xebra’s motor is running *COOLER* then the stock one.

??!!

Here is how the smart guys are explaining it to me.  The Xebra motor is a 72 volt 82amp motor.  Under load, the volts are dropping well below 72, so more amps have to be fed to it to go X speed.  Going the same speed, the XOP is using a fraction of the amperage, because it has all the volts it needs.  Result:  cooler, more efficient running motor.

Stay with me, because this is where things start to get really fun.  Everybody involved was *so* impressed with the performance boost of the XOP that we took the idea over to the house of a customer of ours that also happens to own K-fab, an after-market company that makes cool stuff for everything from off-road vehicles to cranes.  Anyway, he looked at what we had done, took it apart & re-did it.  By the time he was done, we had a dash-selectable, thermal-protected overdrive system in a plug&play kit.

The XOP now has a 7^th battery where the spare tire used to be (the spare is now in a rack at the front of the bed).  This battery is separate from the main traction pack and has its own charger which kicks in anytime the main pack is being charged.

The XOP looks and functions just like stock, except there is an extra switch on the dash.  Activating this switch adds the 7^th battery into the pack in series, giving the traction pack a 12 volt boost.  If you don’t need it, don’t use it.  If you want more speed/range, flip the switch & off you go.

SAFETY.  You can never feed the motor more then 90 volts, the controller takes care of that.  Because of that, when all the batts are on their “just charged high”, you cannot activate the overdrive as it puts you over that limit (the vehicle will not move).  In addition, the overdrive circuit runs through the thermostat on the motor, so when the cooling fan kicks on the OD kicks off.  This will keep the OD system from ever overheating the motor.

DRIVING THE XOP.  I can pull hills at 38MPH, keeping the motor cooler then the stock Xebra pulling the same hill at 25MPH.  I can run across the flats at 45MPH (13” wheels).  All of that is kind of cool, but here is the kicker for me; efficiency.  I can maintain speeds of 30 to 35MPH with a fraction of the pedal (hence a fraction of the amps) I am using on the stock unit.  There must be a lot of waste in the low volt/high amp way the Xebra is running stock, because adding one more battery *should not* double my range, but at this time it appears to be doing exactly that!  I did well over 20 miles on a test today, and my main traction pack was still well over 72 volts.  Oh, and much of that was on the highway at 40MPH +.

Yes, I will be sure to tell you Joseph if I burn up a motor.  However, with the numbers we are seeing and the safeties on the system, I am betting you will sooner burn up a motor running the bad voltage sag from the stock setup then you will with the XOP.

So.  As a dealer I have to tell you that this type of mod will likely void at least part of your warrantee.  As a Xebra driver, I am never going back!!  I’m keeping my nitrous switch!!  J  I am getting a massive performance boost with a fraction of the cost of pack replacement.  This is a no-brainer.

K-fab is now onboard with us, and is doing our power-dump kit for the PK.  They will also produce a plug&play XOP kit if there is interest.  The kit would consist of a drop-in battery box, master control unit, charger, cables, wiring, switches and instructions.  You would need a drill, a wrench and the battery.  You would need about the same skill level as it would take to put in a stereo to install such a kit, & about an afternoon’s worth of time.  I am told price for the kit would be about $500.

Let me know if there is interest.  I think if he got 5 orders he would put it out.

The XOP is charging, when it is done I’ll go do some more range testing.

Sean

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From: Xebra_EV@yahoogroups.com [mailto:Xebra_EV@yahoogroups.com] On Behalf Of gotinc
Sent: Sunday, January 21, 2007 10:29 AM
To: Xebra_EV@yahoogroups.com
Subject: [Xebra_EV] Re: Xebra Overdrive Project

Hills that drop you below 30? ha. We have hills here that I snail down
to below 20. Sean, get a temperature probe on the motor and see how
it's doing. You can see what change ambient temperature has and find
out what temps are too hot to drive it in overdrive.

Glad you did it. We were going to, but now we don't have to risk one
of our machines. Awesome work! Let us know when the motor craps out.

How do you handle charging? Are you just running the BC2 right into it?

-Joseph

_,_._,___

 

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