Alltrax SR 48300 not properly working

[yabert]

The controller in picture below who do strange things.
I connect it to the Alltrax toolkit V3.9 and use the monitor fonction.
Connected to a 48V battery after a default reset, everything seem to work properly. The led is green and from the monitor fonction screen the throttle operate, the voltage increase and some current increase.
But when I verify at the motor output, there is no voltage increase and no current increase.
Of course the motor don't turn. I tried with a PM motor, a forklift motor (serie would) and simple 12V two wire 120mm fan. Nothing work.

Can you suggest some other thing to try to have proper function or do this controller have to go to the garbage?
Is it a know problem for those SR controller?
Let me know.
Thanks
Yan

 

[amberwolf]

Does the current show increasing even without a motor connected? If so, it must not be measuring the actual current flowing in the system.

Are you sure the screen you're looking at isn't a settings screen, rather than an operational one?

 

[yabert]

Well, I retried to connect the controller and there is not really current flowing with or without a motor (pic-1).
There is few digits (1-2A) showed when I turn the pot, but it probably related to the sensitivity of the current sensor of the Alltrax.
You can see my little set-up in pic-2. I tried with the 12V fan, but also with some other motors.

One really strange thing I remarked, there is no spark when I connect the battery to the controller with a resistor (precharge), but there is also no spark if I connect the battery to the controller without precharge.
Not is there supposed to have caps inside this little blue box???

 

[amberwolf]

I'm sure there are caps in there, but maybe it has a precharge built in?

Just to be clear--did this unit ever work, or has it always had the problems described?

It sounds like it might have a blown internal fuse, if all of the connections are correct and complete.

Or perhaps blown FETs; this would prevetn current flow if they're not shorted on (a common failure mode of FETs).

 

[yabert]

I never had this controller in working order as I only acquire it few weeks ago from a guy who said it was not working since a while.

From what I know, the is not precharge inside those controller and they don't have internal fuse... so I guess it's the end.

What could be a remplacing solution for this controller? Alltrax SR new are 400$ and this is more cash than the entire tractor who will receive the electric powertrain. Kelly controllers never had a good reliability. Navitas controllers are expensive and not easy to program.
So, what are the choice to control an old forklift motor in 2020?

 

[amberwolf]

Well, you could look for used Curtis controllers. I don't know which model you need, but the Curtis site should still have info on even their discontinued models. They were commonly used on EV conversions with forklift motors on places like DIYElectricCar forums. (might still be)


In the meantime, you could also open up the casing of the Alltrax and see if there's anything obviously failed in it. The FETs can be tested via a procedure over on http://ebikes.ca at the Learn tab, troulbehsooting section. If they are bad, they can be replaced, probably cheaper than a new controller would cost. (though not necessarily a used one).

 

[yabert]

In the meantime, you could also open up the casing of the Alltrax and see if there's anything obviously failed in it.

I would like to open it and repair it, but I bet there is full of black potting inside masking everything.

 

[amberwolf]

One way to find that out.

FWIW, there are ways (some easy, some hard) to remove various kinds of potting material, if it does have any.

 

[yabert]

I expect the inside of the Alltrax SR controller to be similar to the Alltrax SPM: http://elmoto.net/showthread.php?t=2216

And there is similar, except the copper fins are potted inside the plastic housing.
I tried to cut the top of the plastic fins to unglue the copper parts from the plastic.
It was a really destructive process and I end by brocking many mosfet legs.
Too bad that Alltrax did unrepairable stuff who broke...