'08 PDS Charging Problem

[kent5757]

Sorry for the length, but I have been scratching my head over this for a while. I left my 2008 EZGO PDS plugged in over the winter at the golf course. When I went out for the 1st time, I lost a cable from the lead battery (corroded). Put on a new lug, and barely made 18 holes. Plugged in charger and it was only charging about 15 amps. I am used to over 20. Next time out, barely made 18 holes. Plugged it in with same results. Took cart home to clean the terminals and batteries (batteries are original). Took off all wires and cleaned them. Used small wire brush and scotch brite. Plugged in cart and still only charged at 15 amps. I had just put new batteries in my wife's Club Car last fall. She only uses it around the property, so thinking I had a bad battery, I swapped them out. Put the 6 month old batteries in my cart, and the older ones in hers. Plugged in her Club Car, and ammeter went to 25 amps, and completely charged the batteries. CC is running great. Plugged in the EZGO and only 15 amps and within a couple of minutes down to 12. I let it charge all night, took cart back to the course, and played 27 holes without a hitch. Ran like a champ. Plugged in charger, only 15 amps lowered to 10 to 12 within minutes. Found a fellow golfer who had an EZGO, borrowed his charger, and same result. So, now I am assuming charger is okay. I only have a Fluke TI-1000 voltmeter, so I can't read tenths, but each battery was reading 7 volts (after charge cycle complete). Whole battery was reading 40 volts. Checked the charging plug and looked pristine. Continuity good on all wires. Now my real question: What does the red/white wire from the Positive post of charging plug to the controller do? I was reading battery voltage from the red/white wire at the controller to negative on the battery. So a signal from this wire is getting to the controller. Would something in the controller be bad and somehow not allow full charge? Or with new batteries, should I only expect a 15 amp charge. I drew a wiring diagram before removing wires, and bounced that off of wiring diagrams I found on the net. So I am sure wiring is correct. I almost forgot, when I first charged cart, after 1st time out, I also had a blown 60 amp fuse that was terminated at the positive post of the lead battery. I replaced this fuse. I did not put Run/Tow switch into Tow before removing battery wires and had a good spark. I think that might have blown the fuse. After researching this on the net, found out that I needed to put switch in Tow.

[JohnnieB]

I suspect you have a Fluke T5-1000 since a "TI" prefix to the model number on Fluke test equipment means Thermal Imager.
The T5-1000 is a fine meter, but it doesn't do electric golf carts.

Since there is only 0.32V difference between the open circuit terminal voltage of a half charged and a fully charged 6V Deep-Cycle Lead-Acid Wet-Cell type battery, to determine SoC (State of Charge) you need a DMM that will define voltages below 10VDC, down to the nearest 0.01V. (If you are working with GC 12V batteries & chargers, up that to 20VDC)

An inexpensive DMM in a blister pack from Wal-Mart or Auto-Zone will suffice. Just as long as it will read individual battery voltage down to 1/100th volt.
See attached chart. (Note: Voltage readings are taken 12 hours after charger shuts off, so surface charge is depleted.)

(I have good meters, but use $15.00 throw-aways when working on my cart. They are surprisingly accurate.)

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Low initial amps while charging is typically caused by either bad batteries, bad charger or bad charging loop.
You have eliminated two of the three by switching batteries and trying a different charger.
So, the low amps is most likely due to high resistance in the charge loop somewhere.

The cart's charging loop consists of the radsoks (female brass terminals) in the cart's charge receptacle, the white and the black wires from charge receptacle to the main positive and negative terminals on the battery pack, (There may be a 50A or 60A on one of these wires) and the five heavy Ga cables connecting the batteries in series. (Plus the batteries themselves, but they have been eliminated.)

If the five interconnecting cables are original, they most likely need to be replaced.
Should be 4Ga or heavier and all 10 high current cables should be replaced. (There are five more that the drive current flows through, connecting battery pack to controller and controller to motor.)

Clean the radsoks and other connections.

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The small red/white wire coming from the charge receptacle, should have B+ on it. If it doesn't the cart will not run.
However, it doesn't have anything to do with charging the batteries, other than disabling cart when charger plug is inserted into receptacle.

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Ouch! Working on electrical system in a PDS cart without flipping the Run/Tow switch to Tow can get mighty expensive.
Hopefully, you licked out and didn't damage the controller too much.

[kent5757]

Yes, I think I got lucky with the Run / Tow Switch, as the cart is running very well. I bought this cart used, and never had a manual. But trying to troubleshoot this problem online, I now have a manual on the laptop, and have learned a few things.
I happen to be on vacation this coming week, so I think I will start with the digital meter and a new set of cables. I will keep you posted on my progress. Thanks for convincing me that I still have a problem. Other influences have been trying to tell me that everything is okay. Would like to keep these batteries for a while.

[JohnnieB]

You might have lucked out on the batteries also.

Winter storage kills, or damages, a lot of batteries if it isn't done right.

Very few of the automatic golf cart battery chargers in use today are capable of long term battery storage without human intervention every thirty days or so. This is because once the charge cycle completes, the charger shuts of and never comes on again until it is manually recycled and cart batteries self-discharge at about 1% per day. Sulfation of the plates actually begins the moment the SoC drops below 100%, but the heavy, irreversible, sulfation begins at about 70% SoC, and recharging back to 100% every month more or less keeps the natural aging process in sync with elapsed time on the calendar.

For the longest battery lifespan, keep the SoC as high as possible, or practical, whether in use or while stored.

It depends of which charger type you are using, but the low initial amps issue can mean the charger is shutting off before the batteries are fully charged and continuously undercharging batteries will shorten their lifespan, so it is a problem that needs to be fixed.

[kent5757]

Purchased DVOM. Battery readings: 1 - 6.40, 2 - 6.46, 3 - 6.45, 4 - 6.45,
5 - 6.46, 6 - 6.41. This was about 18 hours after charger shut off.
Had to order cables and new charger receptacle. Trying to eliminate everything. Will keep you updated

[kent5757]

It has been awhile, busy summer. Received new receptacle and new wiring from charging receptacle to battery. Swapped out. Plugged in charger and crossed my fingers. Nothing but disappointment. 15 amps down to 10 amps in less than 30 seconds.

Now, I need to tell you, been golfing twice a week all summer and cart is running good. One nice day got in 45 holes and cart was strong at the end.

Ordered and installed new jumpers on the battery cells. All connections pristine. Played golf, back to the shed, plugged in charger. 15 amps down to 10 in less than 30 seconds.

What is left? If cart is running strong, could I still have a bad cell not letting enough current flow through for charging, but good enough to run the cart? I am grasping at straws here and really need to get some good charges on this battery.

[JohnnieB]

The battery voltages listed in you're #5 post indicate the batteries are being fully charged and being able to play 45 holes on a single charge, substantiates it.

You've not mentioned the make and model charger you are using, but it sounds like you have a ferroresonant transformer type.

The amp flow on that type charger decreases as the on-charge voltage increases.

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The capacitor in the charger might be a little out of tolerance, but it appears the charger is doing its job.

Here is how to check it if you are curious.

[kent5757]

I am curious and will be checking it out. I am not the OCD type, but when things aren't what I expect, well...........