How does 48V 2001 Club Cart OBC function?

[gaston]

I love this thread, thanks Doc! Reaaaally helpful

[wpns]

I still can't figure out what the SCR does, unless it's in series with the charge cable it can't control the charge current...

Still, lotsa good info, thanks Dr. Bob! I'll probably have more comments after I look over the patent in greater detail.

My local buggy repair shop tells me they've successfully installed a "field kit" computer (new computer, with new BWL (including IR emitter), replacement charger control socket in the charge plug, and fuse) in old carts and they work fine. Still not clear why there are at least three different part numbers for the computers, though I know the new Villager 6 carts use T-145 batteries, so they'd at least have to know about the different battery capacity...

[scottyb]

This comes from the CC IQ Manual..... it may help someone with something?

OBC WIRES function explained

Red(18-gauge) Main power supply for the onboard computer. The vehicle
batteries provide +48 volts to the onboard computer.
White (18-gauge)
The Tow/Run switch provides +48 volts to the OBC through the
white wire when the switch is in the RUN position. When the
Tow/Run switch is in the TOW position, the OBC locks out the
speed controller by not sending a +48 volt signal through the
light blue OBC wire.
Yellow (18-gauge)
Enables the OBC to power-up (brings the OBC out of sleep
mode) when the accelerator pedal is pressed. The MCOR limit
switch provides +48 volts to the OBC when the accelerator pedal
is pressed.
Brown/White (18-gauge) Controls the battery warning light by providing a ground to the
light through a transistor inside the OBC.
Light Blue (18-gauge) Solenoid lockout circuit – the OBC provides a +48 volt signal to
the speed controller when the battery charger is disconnected.
Green/White (18-gauge) Reserved for future use. Wire serves no function at this time
Gray (18-gauge)
Provides a ground for the charger relay when the battery charger
is connected to the vehicle. Also enables the OBC to power-up
(brings the OBC out of sleep mode).
Black (10-gauge) to battery charger receptacle Battery charging current is controlled by the SCR (siliconcontrolled
rec Black (10-gauge) to B– terminal of speed controller tifier) inside the onboard computer.
Black (6-gauge) through onboard computer Allows the hall-effect sensor inside the OBC to measure the
amount of current passing through this wire.

[pizzamaker]

thats some learnin' right there

[scottyb]

Originally Posted by pizzamaker

thats some learnin' right there

All of which was totally uncalled for on Club Car's part in the first place..... Everybody else has done just fine leaving the charger brain in the charger .....
CC got the great idea to seperate them

[wpns]

Originally Posted by scottyb

Black (10-gauge) to battery charger receptacle Battery charging current is controlled by the SCR (siliconcontrolled
rec Black (10-gauge) to B– terminal of speed controller tifier) inside the onboard computer.

I stand corrected, turns out the OBC does indeed control the charge current, as the negative lead from the charger is connected to the OBC. Somehow my brain was convinced that the OBC only turned the charger on and off via the control lead.

Thanks for the correction!

[wpns]

Originally Posted by scottyb

All of which was totally uncalled for on Club Car's part in the first place..... Everybody else has done just fine leaving the charger brain in the charger .....
CC got the great idea to seperate them

Not sure I'd agree with you, putting the charge controller on the cart allows the cart to keep track of how many EU (KWHR) go into and out of the batteries, and allows the other functions (*) of the OBC to be implemented easier.

(*)
Wake up every 2 weeks for equalization charge
Various charge termination scenarios
Drive lockout when charger connected
Total EU per battery bank for warranty and fleet load leveling using the CDM
"Charge" light functions.
Reduce cost of charger by a hundred bucks or so.
increase reliability of charger (especially when left out in weather).

not that you couldn't do most of these things with the computer in the charger (or computers in both places), but it's not a bad thing to put it in the cart.

[scubabud]

Originally Posted by scottyb

All of which was totally uncalled for on Club Car's part in the first place..... Everybody else has done just fine leaving the charger brain in the charger .....
CC got the great idea to seperate them

In essence it does the same thing that a microprocessor does on a non proprietary charger. And Club Car uses Lester Chargers without the microprocessors... Hummm... can we say MONEY was the reason?

[DrBob]

Originally Posted by wpns

I still can't figure out what the SCR does, unless it's in series with the charge cable it can't control the charge current...

If you look at the wiring diagram of the 2001 DS (and probably any other year using the Club OBC), you will see that the charging current enters the 3-prong plug and goes directly to the OBC on a 10 gauge black wire referred to by scottyb above. On the disassembled OBC, I can see that the black wire lead directly to the input of the SCR and another #10 black wire connects to the output side of the SCR. The output black wire goes to the controller B- terminal where it meets with the 6 gauge black wire that runs back to the battery pack negative terminal by passing through the hole on the OBC where the charging current is measured. This measurement allows the OBC to apply the proper voltage to the gate of the SCR to control the current.

So the SCR is in series with the wire carrying the charging current.

Note that the SCR does not control the running current. I have measured the running current at over 500 amps if you floor the cart from a standing start going up a hill. This current is only for a few seconds of course, or it would fry the controller.

[DrBob]

Originally Posted by scottyb

All of which was totally uncalled for on Club Car's part in the first place..... Everybody else has done just fine leaving the charger brain in the charger .....
CC got the great idea to separate them

I guess I have a different take on it.

Overcharging is one of the worst things you can do to your battery pack. If you know the amount of energy expended since the last charge, you can limit the amount of energy you use to recharge the cart to prevent overcharging the batteries. The Club Car/Lester patents refer to 110% as the amount energy replaced - probably providing 10% "excess" charge to allow for inefficiency in the process.

A separate charger is at a sever disadvantage without this knowledge.