2007 Ez-Go TXT, PDS 36 volt all factory electronics.

bubba4dad

I am having issues with a golf cart that I just recently purchased. The guy I bought it from said it needed new batteries, however when I went to buy new ones the guy said they had been overfilled with water. He removed some of the water, tested each cell with a hydrometer, load tested each battery and said they were fine.

The cart has larger tires and a speed chip jumper (RED). The batteries have a date of Aug 2016 on them. They are the Energizer brand. Other than the speed jumper wire & tires everything in the drive train (controller, motor, wires, etc.) appears to be stock.

The issues I am having is that sometimes after driving it for a bit, when you press the pedal it just doesn’t do anything. I can hear the clicking of the solenoid as the pedal is pushed but the cart does not move. After several tries it will take off as though the batteries are fully charged. I have felt the wiring and the only wires I think are a little warm is the ones going from the controller to the motor. The ones from battery to battery seem to be ~ ambient temperature.

I am looking for some advice on what voltage I should be reading per battery at rest and as I am running it, how fast should the voltage fall off. What are the minimum voltages I should see, etc. I am also concerned if the charger is performing as it should be. It comes on when plugged in @ ~18 amps and works its way down slowly. I feel like this is correct but what voltage should the charger be putting out? The guy had told me also that the charger quit working and he had repaired it. I am leaning towards maybe his repair was not adequate.

Before I start mass replacing parts, I thought I would ask and do a little trouble shooting.

Thanks in advance for any help anyone might offer.

BGW

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orangeman6

Attached is an soc chart. I’ve heard the pack shouldn’t drop more than the value of one battery when it is under a heavy load.

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AAB2D4F4-5465-4AF1-BDA2-02C96EE73AFA.jpeg (127.1 KB, 0 views)

JohnnieB

Sounds like you have a legacy type charger such as a Powerwise 28115. (Attch-1)

They charge in accordance the attached charging profile (Attch-2)

The output amps are limited to about 18A until the On-Charge voltage gets above about 42V.

The On-Charge voltage begins at whatever the battery pack voltage is when charger is attached and climbs to about 45V when the charger shuts off automatically.

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A fully charged 36V battery pack using Trojan batteries or clones should be 38.2V or higher. Other brands have different 100% SoC voltages. US Battery being the highest at 38.5V. I'm pretty sure Energizer batteries are Trojan clones, so the SoC chart orangeman6 posted is probably the right one.

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Cart batteries ought to be charged after each use, or at least every night after the cart have been used.

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The amount the voltage drops depends on how many amps are being drawn and tires taller than stock (18") draw more amps because more torque is needed to turn them. (Tire height is a factor in the final drive ratio)

Under normal driving conditions, the battery voltage should not drop below 31.5V and the absolute minimum voltage is 27.0V. (Irreversible physical damage begins occurring at that point.)

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If you still have OEM cables they are 11 years old and a mix of 4Ga and 6Ga, so all ten of the need to be replaced with all 4Ga of thicker. My first upgrade was 2Ga with silver solder lugs. (Noticeable better acceleration and low end torque and cart was only 4 years old at the time - top speed stayed the same because a PDS controller RPM limits the motor to about 4400RPM with freedom chip)

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An Alltrax XCT48400-PDS controller (or larger), a compatible solenoid (stock is only rated for 85A continuous), good high current cables and a 42V battery pack (7 x 6V) is the sweet spot for a 36V PDS drive.

Attached Images

	PW charger - Faceplate.JPG (447.2 KB, 0 views)
	Trojan reccomended Charging Profile.jpg (136.6 KB, 0 views)

bubba4dad

Yes, that is my exact charger.

I had the cart on the charger until it shut off. I waited about 24 hours and checked the voltage and it is at 37.2 which based on the chart is between 70% and 80%. Also on a per battery voltage they are all in the 6.19-6.21 range each. Once again in the 70% to 80% range. I guess I need to check the output voltage on the charger to be sure it is high enough. After I am guessing this point towards the batteries being bad? > 1 1/2 years on a set of batteries isn't good. I am guessing Energizers are a cheaper brand?

I plan on doing upgrades as in larger gauge wires, maybe the controller, motor, etc. if need be. Just trying to get to an even playing field prior to upgrading and just changing parts for the sake of spending money. lol

Should I be thinking about a better charger or is the legacy charger ok?

Should I consider upgrading to a 48 volt system? I have read that the original motor will work with 48 volts.

I just want to make sure whatever I do is a step in the right direction for the end results.

JohnnieB

Try some back-to-back charges on your batteries. (IE: Restart charger a few hours after it shuts off automatically) That might get them to take more of a charge.

My cart had 18 month old Trajan T-105 batteries in it when I got it and thjey'd only charge to about 80% SoC. After a few week of back-to-back charging they were up to about 95% SoC. The problem isn't the battery brand so much as how well they were maintained and being overfilled isn't a good sign.

Your charger is probably working as designed, but battery charging technology has improved quite a bit since it was designed. More correctly, the size and cost of dV/dT (change in Voltage over change in Time) technology has become small enough and cheap enough to be used in golf cart battery charges.

In a nutshell, your charger only raises the On-Charge voltage into the 44V to 46V range before shutting off, which isn't fully charging your batteries, but ought to charge them very close to fully charged. Chargers using dV/dT technology keeps charging until the On-Charge voltage ceases to increase, which means the batteries are fully charged.

If you plan to increase the battery pack voltage, that is when to get a new charger to match the new battery pack voltage.

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As for leveling the playing field, the trick is to figure out what the end goal is and build towards that goal using stuff that works with 36V, 42V or 48V so you don't have to replace anything other than the battery charger when you up the battery pack voltage.

Like I mentioned, my first upgrade was the high current cables.
Next was an Alltrax controller (A DCX since the XCT wasn't out yet) and a 48V MZJ-400 solenoid (which will work at 36V).
After running at 36V for a while, I went to 42V and got a 42V charger.
Everything was fine at that point, but I did something stupid and had to replace the motor, otherwise I'd probably still be running a stock PDS motor.

With a XCT controller, it is safe to go to 48V since the XCT can RPM limit the motor to a safe max RPM. With tires taller than stock, the motor won't rev as high anyways.

What is your tire height?

bubba4dad

The tires are 23"

bubba4dad

I had to tow the cart home the other day bc it wouldn't move. I checked the voltage and it was 37.1 and I could here the solenoid click when pushing the pedal. I tried it several times, a couple of the times I tried, the cart would move a couple of feet and then stop. I felt all the wires and they didn't seem warm. Once I towed it home, I put it on the charger, after just a few minutes on the charger I tried it and it would go. I know I want to upgrade and improve the performance of the cart. I just don't know where to start. What should I change/upgrader first? What parts are recommended.

I was hoping to hear from Scottyb with suggested parts and part numbers...lol

radioman

In addition to the good information suggested in previous post you might not have a battery/charging problem at all. My old PDS golf cart had the same symptoms and it turned out to be caused by the controller overheating and shutting down to prevent controller failure. Next time it won't run let cart set about ten minutes. Lift the seat and feel the rear of the controller heat fins to see if they are real hot. If it runs after cooling down that could be your problem. I solved the problem on my cart by installing a small 3 1/8 inch fan atop the heat sink area to improve air circulation.

JohnnieB

With 23" tall tires, the controller will most definitely get hot.

VanillaXtract

I have recently upgraded my cart, so if you need I have a stock 36V charger, controller, motor, and solenoid. I even have a PowerPulse battery maintainer which increased my pack voltage by about 1 volt over the course of a couple of weeks.