Low Voltage Beep Code

ubstung71

Hello;

Background Info:

2004 EZ-GO TXT PDS 36V.
Basically all stock wheels, motor, controller. Batteries two years old.
Added lights radio, etc. but all run off an aux. battery and are isolated from the main drive battery pack.

I have owned the cart for the last year, P.O. bought the batteries in 4/2013 (and batteries stamped as such) and claimed to take good care of them. I tend to believe him. I have been maintaining the batteries as per procedures outlined in the forum here.

Cart used primarily for golf, a full trip to clubhouse, 18 holes and back is between 8-10 miles depending on my slice and bar side trips.

Over this winter too cold and snowy to golf but I kept the batteries charged by hooking up the charger every two weeks or so.

A couple of weeks ago I placed the cart in diagnostic mode before the first run of the season. Just 4 beeps for freedom mode and no other codes. I forgot to toggle the tow/run switch afterwards so it stayed in diag. mode.

Last week did 18 holes after a full charge and around the 16th hole I started to hear 2-1 'low voltage' beep on hills. The cart seems a little slower but was nowhere near dying or anything like that.

So I decided yesterday to do a thorough test of batteries, following are the pack voltages.

Immediately after full charge:

pack: 40.71V
Batt 1: 6.79
Batt 2: 6.79
Batt 3: 6.78
Batt 4: 6.77
Batt 5: 6.75
Batt:6: 6.76

20 hours later and just prior to golf:

Pack: 38.8
Batt 1: 6.46
Batt 2: 6.48
Batt 3: 6.46
Batt 4: 6.46
Batt 5: 6.45
Batt 6: 6.47

1 hour of rest after golf and bar side trip (total trip distance of 8.9 miles based on my hunting GPS).

Pack: 36.83
Batt 1: 6.13
Batt 2: 6.15
Batt 3: 6.12
Batt 4: 6.14
Batt 5: 6.13
Batt 6: 6.14

I heard a few low voltage beeps codes around the 17th hole and a few times driving home on the steeper hills. I have a voltmeter across the main pack and the voltage would dip into the 35V range when the cart was beeping. The cart seemed a little low on power as normal but it was nowhere near grinding to a halt and I made it home with no problems.

So finally my questions are:

1. Based on these numbers I think the battery pack is OK. Agree? Based on the charts I was still above 60% charge percentage.

2. Based on my readings of other threads the code doesn't necessarily mean low voltage on pack but a difference between controller pins voltage and main pack voltage.

3. So the beep could be due to corroded wiring between the controller and package - right?

I also never really drive it in diag. mode before so it could have always given the code but I had the mode off so I just never heard it.

Thanks for any/all replies.

BGW

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JohnnieB

1. You cart's range (run-time) isn't very good. I was getting about 25 Miles with 2 year old T-105 batteries that hadn't been well cared for during their first 18 months, while my cart was part of a golf course fleet. Except for 2Ga cables, my cart was stock at that point in time.

What make/model batteries do you have?
What make/model charger do you have?

The pack voltage immediately after a full charge is low. Ought to be closer to about 45V, which is the typical 36V charger cut-off voltage.

The pack voltage after 20 hours rest is high. Ought to be about 38.2V for Trojan batteries and their clones and about 38.5V for US Battery batteries.

2. You right. I'm not sure where a PDS controller measures the voltage, but the three most likely places are the B+ Terminal on top and J1 Pins 4 & 5. Those test points are used for other error code like welded solenoid contacts.

3. Yes, excessive resistance in the cables and connections can cause a voltage error code.

Another thing is the temperature. In cooler weather, the batteries have less storage capacity and with less capacity, the pack voltage drops further with the same amount of amps being drawn.

ubstung71

JohnnieB;

I have Energizer batteries a photo is included. it says "GC2" 107 RC Minutes @ 75 Amps

The P.O. included his PowerWise 36V, 21 Amp charger with the cart. Photo also included.

If the pack voltage is low immediately after charging is there a recommended way to test the charger itself? Thanks a lot...

Attached Images

	GolfCartBattery.jpg (159.0 KB, 0 views)
	GolfCartCharger.jpg (247.3 KB, 0 views)

JohnnieB

Energizer has two grades of 6V cart batteries, standard (215AH) and premium (232AH). Looks like you have their standard grade, which is a bit less than the 225AH of the T-105 batteries that came in the cart from the factory. They are fine, but will have about 5% less range and useable lifetime.

Your Powerwise 28115 G04 charge is a good match for your batteries. (Attached is a service manual for it)

If you measured the pack voltage immediately after you unplugged the charger, you probably didn't measure the voltage immediately after the charger shut-off. If you started the charge the previous evening and then unplugged the charger and measured the voltage the next morning, the batteries most likely had not actually been on charge for several hours, so the voltage would be less than the final On-Charge voltage.

If you have a voltmeter that has a peak hold, or a Min/Max function, you can use it to capture the max On-Charge voltage reached in the charge cycle. Otherwise you have to monitor the voltage and read it when the relay in the charger clicks off, or when the transformer stops humming.

Easiest way is to put on charge in the evening, then initiate another charge the next morning while monitoring the voltage. With close to a full charge on the pack, the charger should shut off within half an hour or so. If it is in the 44V to 46V range, the charger is shutting off at the correct voltage.

When the charger is connected to a partially discharged pack, the ammeter should quickly climb to 18A or more and stay there until the pack voltage climbs to about 40V, then decrease down to less than 5A until charger shuts off at about 45V.


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Try a few back-to-back charges on your batteries. It won't hurt them any and it might improve the range a bit.

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BTW: Drop a DCX400 controller in your cart and it'll do about 24MPH.
The PDS controller limits the motor RPM to 4400, the DCX controller doesn't and the stock motor will turn about 5400 RPM at 36V.

My first upgrade was 2Ga cables (all ten of them) and then a DCX400 and 400A solenoid, and then I went to a 42V pack and got 28MPH.

Attached Files

PW Charger manual.pdf (3.02 MB, 0 views)

ubstung71

JohnnieB;

Yes good to know the charger is a match. I thought I might have measured the voltage too long after the charge so this morning I plugged her in again after my post-golfing charge yesterday. The cart was off charge for a few hours at least as it stopped sometime in the middle of the night.

This morning the charger immediately went up to 18-20A stayed there a short time (a minute or so) and the amperage started to steadily decrease to under 5 amps and settle in and quit around 2-3 amps. The voltage with the charger plugged in started around 44.5 and climbed to a max of around 45.6 or so and stayed there or slightly decreased until the charger shut off.

The voltage then started to decline immediately to 42 or so and then steadily decrease at a much slower rate. Not sure how long it will take to get to the 38.2ish range probably a few hours.

Anyway I think from all this the charger is probably OK, the batteries OK but could be better.

I will try to figure out from the posts what pins on the controller to monitor and see the voltage on the pins compared to the main pack voltage. I will check the wires and replace those if they look remotely bad.

I don't know my true range before 50% discharge but if I can get 10-12 miles on a charge to get to 50% it may not be the best range but good enough for what I use the cart for. I'll toggle out of diagnostic mode so my wife doesn't freak-out when she hears the beeps!

Once the batteries die in a year or two I will probably upgrade to 48V anyway.

Thanks for your input...

JohnnieB

Sounds like your charger is operating normally.

Your batteries have aged and will continue to age because the aging process (Sulfation of the plates) occurs whenever the batteries are not fully charged and the moment your charger shuts off, the batteries become less than fully charged. In fact, the batteries are never fully charged since the charger shuts off at a predetermined voltage rather when the batteries are actually charged to their maximum capacity. These are relatively minor issues that have existed since electric golf carts were invented, but have been resolved in later years as the technology to charge cart batteries to their max storage capacity (dV/dT -- change in voltage over change in time) and subsequent float charging became available at the consumer level.

When you go to 48V, you will have to get a 48V charger, so get one with dV/dT technology that float charges after the regular charge cycle terminates. I use a DPI Accusense charger, which keeps my batteries fully charged when I'm not driving my cart.

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Based on the voltages given and the distance traveled, your cart's range is ~12 miles to 50% SoC. I don't know what the temperature was that day, but if it was about 50°F, the range will be about 15 miles when it gets up to 80°F this summer.

As previously mentioned, doing some back-to-back charges may improve the range and performance some. What you did this morning to measure the cutoff voltage was essentially a back-to-back charge, so it might have turn the aging clock back a moment or two.

If possible and practical, initiate a charge before taking the cart out to the links or a neighborhood cruise. And be sure to recharge as soon as possible and practical after each use.

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When cleaning the battery cable connections, be aware that the max torque on the battery studs is only 8.75 Ft/lbs (95-105 in/lb). The stud is actually a hex-head bolt embedded in the lead battery post. Too much force will turn the bolt head in the soft lead and cause all sorts of problems, including melting the battery post.