Controller protection circuit ?

JohnnyCRash

I'm speculating here and I'm sure many here can set me straight.

Cart runs fine and performs as I would expect except for immediately after removing the charger after a full charge. Charger shuts off on its own when it believes the batteries are charged. Some times I will then get on the cart and try to take off, but the cart does not go. I hear the solenoid click but there is no motor response. If I wait a few minutes (5-10) it will eventually start working. It's almost as if there is a short period of time after charging that the controller says "nope.....volts too high....not going to allow current to the motor."

I will get voltage readings for this thread soon. I need to borrow a meter and get into this scenario again before I can do it.

I am experiencing this symptom and it is happening to my buddies cart as well. Two CC DS carts having the same symptom makes me wonder. We both have 6 year old trojans and we both have the same 700Amp BU controller.

BGW

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scottyb

sorry to hear you have BU controller No. Really.... you didn't say what make controller and yes some do have over voltage protection. When batteries just come off the charger they will have a very high false reading which will settle in about 30
inutes to a true reading......

JohnnyCRash

So after a much closer look at the post-charging voltage and the safety circuit behavior, here is what I found....

Right after the charger shuts off, voltage can be as high as 58+ volts......
Within 5 min. the voltage gets down below 55 volts.
At 54.5 volts, the controller starts allowing power to the motor.

Thanks for the insight Scottyb!

gornoman

Nice call, scottyb.

roady89

If the controller is rated for 48 volt usage and it's doing this return it and demand your money back. If you KNOW of 2 identical controllers doing the same thing these controllers obvously have issues.

From Trojans site.
Charger Voltage Settings for Flooded Batteries:
Charger Voltage Setting 48V
Daily Charge 59.2
Float 52.8
Equalize 62.0

As you can see, Daily Charge and Equalize are well above 54.5 volts. If the controller can't be used with standard charging procedures it's useless.

JohnnyCRash

roady89,
Now you've lost me.....sorry if I'm slow on the uptake here.
The charger seems to be doing the 59.2 daily when I check it with a meter while charging. I Wait for the charger to finish it's cycle, remove the charger, then need to wait for a few until the pack voltage settles to 54.5 before the cart will move. This happens within about 5 min. or less.
This is usually not a problem due to the fact that the cart finishes charging over night sometime and has "settled" long before I jump on and go.

What is it that I am missing that your pointing out about the controller/charging functionality? Thanks in advance roady89!

gornoman

The charger is not online when the cart is being driven, Roady. Those higher voltages you quoted from Trojan are only applied during the CHARGE cycle, and they dissipate quickly once the charger finishes the cycle. The controller is acting correctly. My Alltrax would do the same thing if I had the HighVoltage threshold set low enough via the software.

roady89

I dis-agree that the controller is acting correctly. What I'm trying to say is, you should not have to wait for the batts to settle down before the controller will operate. If it were a programable Alltrax your settings would be off and it would be a simple matter of setting the voltage limit up a little. You cannot do this with the BU controller. (that I'm aware of)

Now, if the charger is "Overcharging" the batteries then the problem is not with the controller but with the charger. The numbers are not high enough to throw a controller into overvoltage protection.....at least they shouldn't be.

phasetim

Good controllers usually have a variable working range.. Such as alltrax's 36-72 range..

I concur with Roady, I wouldn't settle with having to wait 10 minutes.. Not to mention that if you do this in the morning your charger has likely already been off for hours.

gornoman

Let me rephrase this:

The controller is acting correctly as defined by it's design and operating parameters.