Alltrax setting and low controller voltage...

[Jake_Daddy]

Did an Alltrax install last weekend and just now got around to hooking up to computer and tweaking settings and have a few questions.

1. In the SPM window it says 48V 500amp, it doesn’t look like it’s adjustable but is that just stating model? I’m 36V currently and didn’t know if I need to adjust to tell controller I’m 36V or where to do that.

2. In the gauges section it says 37.1V my dash and DVM both read 38.3V, where should I be checking voltage on the controller to see why I’m reading low?

Thanks!

[scottyb]

The controller evaluates and knows what voltage you run on. No user setting needed there.
There is an under voltage setting which can be set to a low 36 or low 48v battery. Default is around 20v which allows both 36 and 48 to run... Bump it up to 36 or 38v and only a 48v pack can run.

meters connected to power sources obtained through F&R micro switches wires and key switch are often .5 to 1v lower than actual pack voltage... adjust your readings and go with it. If 37v at the dash = 38v at the pack adjust your thinking accordingly

[Jake_Daddy]

The gauges window in the alltrax toolbox is saying 37.1V, my pack reading with a DVM and my dash reading are 38.3V. I’m wondering why the controller is reading lower.

[Fairtax4me]

Two different things probably.
One is the way the Alltrax determines voltage compared to the way your meter does.
The other has to do with where the alltrax measures that voltage. If I remember right Alltrax measures the displayed voltage from the KSI pin. This typically has to go through at least two switches before it gets to the controller, so that’s about a dozen different points of contact where some voltage is lost along the way, combined with a normal loss through the 15 feet or so of small gauge wire along the path where key+ comes from.
It doesn’t have to be an exact science, because the voltage changes by more than that during operation of the cart.

[Jake_Daddy]

Yea I was curious where the B+ came from. When I am looking at the Alltrax tool box I just have the computer plugged in and not running the cart so there really isn’t any key voltage at that time because the way I wired it it has to run through the FnR micro and the Vglide micro befor it gets to the controller.

Tinkering around today I found one of my battery cables was a little lose and one of my selonoid cables was just slightly lose. I haven’t plugged the laptop yet to see what it’s reading now.

[Fairtax4me]

Ok, which controller are you using?
The XCT has several pins where it gets power from.
An SR series controller can read pack voltage from the B+ terminal with the key Off, but it will only be reading voltage coming through the pre-charge resistor which would account for the drop. If that’s the case then the displayed voltage would go up when the solenoid is engaged.

[Jake_Daddy]

I’m using an SR controller and that makes perfect sense with the precharge resistor! I haven’t had a chance to jack it up and play with the settings with the throttle engaged yet which should show full pack voltage. Now that I have a good understanding it won’t bug me anymore, I have been thinking about how the circuit made it back to the controller for two days and not once did I think about that new resistor!

Thanks

[Fairtax4me]