# Powerup Altrax 7245 question



## Gerrit (Jul 20, 2012)

I bought a Altrax AXE 7245 and I´m looking at the wiring diagram from Altrax

http://www.alltraxinc.com/files/Doc100-045-A_DWG-AXE-No-Reverse-wire-dia.pdf

The pin 1 wire (KSI) is used to powerup the controller. In the diagram the 12v goes trough a couple of switches with extra fuse and a diode to pin 1 but there is also wire to the diode at the contractor that end at B-. Why does this need to go the the B-? For ground or to have everything in a closed loop? Can't I just use it like in the scheme below? So from the ignition 12v to the controller. cause I want to switch the controller and the safety circuit separate. 










Who can give me an answer on if the diagram from Altrax is the only way or not?
Thanks in advance


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## major (Apr 4, 2008)

Gerrit said:


> I bought a Altrax AXE 7245 and I´m looking at the wiring diagram from Altrax
> 
> http://www.alltraxinc.com/files/Doc100-045-A_DWG-AXE-No-Reverse-wire-dia.pdf
> 
> ...


Are you using a contactor with a 12V coil? The Altrax diagram uses a contactor with a coil voltage equal to the high voltage battery and does not use an auxiliary 12V battery at all. Pin #1 needs the high voltage positive signal, not 12V. It looks to me like you are mixing the high voltage and 12V on your diagram. And there may be other problems with your diagram, like a ground connection on the potbox  Hopefully we'll see some members chime in here and help.


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## mechman600 (Oct 16, 2010)

The key switch signal on the 7245 needs to be higher than 12V. Alltrax actually wants pack voltage there. I power it with my pack through a regular old 5-pin relay switched by my 12V ignition source. No problems yet powering this 72V with a 12V relay.

Looks like you are powering your contactor with 12V. That's what I do, independent of the controller.


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## toddshotrods (Feb 10, 2009)

Yeah, Alltrax specifies a contactor rated for pack voltage, and it's a completely closed loop system - at pack voltage. That threw me for a loop when wiring Scrape, because I didn't catch it until my contactor's coil wouldn't budge with 12 volts.  That made me take a second look at the diagram, to see what I was doing wrong, and realize it. I was also trying to mix 12 and 48 volts. I had been sleeping for a couple/few hours a night for days, trying to get the bike to an event, and was in a sleep-deprived state of semi-consciousness - that's my story... 

My solution, because I wanted to use the bike's handlebar switch to power up (and it has really small wire) was to use a 12v Ford automotive solenoid to close the coil. So my 12v switch trips the Ford contactor (solenoid), which sends 48v to the main contactor coil. I was concerned about pushing 48v through a contactor rated for 12v, but people here have been using 12v switches to power up 48v contactors, for years, without issue.

I only have a few test cells in the bike, so far, and haven't been able to test this system for extended periods, but so far the 12v contactor doesn't heat up. It's rated for intermittent duty though, so I intend to replace it with essentially the same thing, but rated for constant duty. It works perfectly though.


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## Gerrit (Jul 20, 2012)

Alright that is where I was going wrong. So it needs high voltage at about 5a looking at the diagram. 
I like the 72 relay switched by 12v key, I made a quick sceme. Added the small box as relay, got a 72v wire from the fuse. 12v comes from the key and switch and goes to ground. This what you mean? Do I need more then the relay and you say a regular old relay, but that does not really help with my electrical incompliance 









I bought the Hall effect throttle box which has a +5v, 0-5v and ground. Thats why I have the ground in the scheme. Makes sense?
I'll get a relay to get the 12v from key to 5v for the throttle box.

Im not good at all with electrics. Need to figure everything out. So the help is appreciated!


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## mechman600 (Oct 16, 2010)

Yes, a 5 pin Bosch style relay like what is used in 90% of vehicles. It's only rated for 12V but the 72V keyswitch signal to the controller has so little current that it doesn't matter. Power pins 85 + 86 (signal) with chassis 12V and ground. 

Your pot ground must be grounded to the common pin on the controller, not to chassis ground. If there is no common pin, I think pack neg might me okay, but double check with Alltrax on that. You must keep pos and neg of your traction side completely isolated from the chassis for safety sake.


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## poprock (Apr 29, 2010)

The Alltrax instructions say to test at minimum. 18v then to run at pack voltage, which can be from 18v-90v for a 7245. Mine is set at 90 and running 84v nominal.


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## Coley (Jul 26, 2007)

I used 12 volt powered solenoids like your Ford, but from an ag store that are rated at over 72 volt continous use.
The Ford type kept burning out on me after a short while.


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## toddshotrods (Feb 10, 2009)

Coley said:


> I used 12 volt powered solenoids like your Ford, but from an ag store that are rated at over 72 volt continous use.
> The Ford type kept burning out on me after a short while.


Yup, that's why I intend to switch to one with a continuous rating. Scrape hasn't been able to run long enough at a time to burn this one out, yet!  I just have four tiny little scooter batteries to make it move, while I make decisions on where I want to go with it.

Funny you should post right now, because that is exactly what I was working on/thinking about.


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## Gerrit (Jul 20, 2012)

Alright nice, so if I understand correctly first obviously I´ll test it with 18v then I install the controller with the 5-pin relay from the + 72v wire to the pin 1 KSI on the controller. No need to go to the B- here now? Is that then grounded via the throttle box? There is no common pin so B- should be fine, but I'll check that. 
And the other things like a 5a fuse and 6a reverse diode, do I need to use them with this option?

Thanks for all your reply's!


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## mechman600 (Oct 16, 2010)

This is the Alltrax diagram off their website:








It doesn't look like there is a provision (common pin) for a three wire pot/hall effect sensor. But I believe you can use B- as the "common" (ground) source because these controllers do all their power and grounds through the traction side as opposed to the chassis side.
So connect throttle pin 1 to B-.


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## frodus (Apr 12, 2008)

You can't use a hall effect out of the box.... you need a 5V power supply (isolated).... and even then, it may not go all the way to zero. Best to use a 0-5k throttle pot, like they tell you.


Read this:
http://www.diyelectriccar.com/forums/showthread.php/alltrax-axe-7245-hall-effect-throttle-69237.html

and this:
http://www.elmoto.net/showthread.php?1013-Hall-Effect-and-a-Alltrax-AXE


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## poprock (Apr 29, 2010)

poprock1 said:


> The Alltrax instructions say to test at minimum. 18v then to run at pack voltage, which can be from 18v-90v for a 7245. Mine is set at 90 and running 84v nominal.


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## poprock (Apr 29, 2010)

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