Charging

[limey5]

My batteries are a year old and about three months ago my charger had a new rectifier (?) fitted. Now all of my batteries show 6.3 v when fully charged. However, I lose three bars on my capacity gauge in 9 holes of golf. The cables look ok and the tires are all pressured correctly, do y'all think it could be something else, like another problem with the charger? Should I change the cables just to be safe?

[JohnnieB]

Something is amiss somewhere because 6.3V is only about 90% charged. (SoC chart attached - Note: The voltages given are taken 12 hours after charging.)

As for the LED bargraph type battery meter, they tell more lies than politicians, so if you want to know what the actual battery pack voltage is, use a DVM.

If your cart is old enough for the batteries to have been replaced, the stock cables most likely need to be replaced.

To figure out what the problem is, of even if there is one, we need to know the particulars about the cart and charger and batteries.

What is the cart's year, body style and drive type?
Which charger is being used?
What make and Amp-Hour rating are the batteries?

[limey5]

The cart is a 2003 TXT
regular golf cart
107 min @75 amp
energizer
Power Wise charger

The cgrger went bad a couple of months ago and the $60 internal part was replaced. When it went bad, it was humming but would not get the meter up to full - could it have gone bad again??

[Sir Nuke]

limey5, as far as the drive type system Johnnie was talking about......look at the first post of this thread and tell us what you have....

http://www.buggiesgonewild.com/elect...en-system.html

[JohnnieB]

107 minutes @ 75A matches up with the economy grade Energizer (208AH)
That is 17AH less than standard grade batteries, so the run-time would be less, but you should still get at least 18 holes without recharging.

Of course, the batteries probably aged rapidly while the charger wasn't working, so they are probably older electrochemically than their one year chronological age.

If the tires are taller than stock (18") that will also reduce runtime.

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What does the charger's ammeter climb to when first plugged into cart?
Should be about 18A.

What is the battery pack's On-Charge voltage right before charger shuts off automatically.
Should be in the 44 to 46 volt range.

What is the battery pack voltage 12 hours after the charger shuts off?
Should be 38.2V, each battery should read 6.37V and all batteries should be within 0.1V of each other.

What is the At-Rest voltage before and after playing 9 holes?
Note: At-Rest voltage is 12 hours after charging or half an hour after discharging.

[limey5]

At the moment the batteries are charged, but if I plug in it jumps to about 18 and drops immeadiately to a constant 11. The rest will have to come later, maybe Monday when I use the cart again. With a friends help I might also try to get a voltage drop under load to see if one is bad.
I comfortably get 18 holes out of a charge, with about a four bar (halfway) drop on the gauge, it's just a lot more than I'm used to.

[JohnnieB]

Originally Posted by limey5

1. At the moment the batteries are charged, but if I plug in it jumps to about 18 and drops immeadiately to a constant 11. The rest will have to come later, maybe Monday when I use the cart again. With a friends help I might also try to get a voltage drop under load to see if one is bad.

2. I comfortably get 18 holes out of a charge, with about a four bar (halfway) drop on the gauge, it's just a lot more than I'm used to.

1. Sounds like the charger is working normally, but the batteries aren't fully charged.
If the batteries were close to being fully charged, the amps would drop from about 18A down to around 11A or so quickly as the ON-Charge voltage climbed to about 42.3V, and then, after a few minutes, the amps would continue to decrease as the On-Charge voltage climbed into the 44-46 volt range and the charger shut off automatically.

2. Bar graph type battery meters, when working right, provides an approximate guesstimate of the amount of charge left in the battery based on what it thinks 100% is, rather than reality.

The fact that the meter is now reporting a lower SoC (State of Charge) after nine holes than it used to means either the meter has changed its mind as to what 100% is, or the batteries storage capacity has gotten lower, or the cart is now using more energy to move the same distance.

To determine the battery pack's true SoC, a DVM with at least 1/10 volt resolution is needed and to determine an individual battery's SoC, 1/100 volt resolution is needed.
(IE: 38.2V for the pack and 6.37V for each battery)

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Plug the charger into the cart again and let it run until it shuts off automatically.
Measure the pack voltage with a DVM before using the cart Monday and after it is used. (Take the after reading no sooner the 15 minutes after the cart stops)

[kernal]

Limey, you didn't say where you are but if the average temperatures are dropping typical of fall weather then this could be normal. Flooded batteries have about 10% less capacity at 60° than at 80°. For a person who uses his cart on the same course or over the same route frequently, you notice when the battery meter is lower than it usually is at the same point than it was other times. After living with 2 carts for 13 years I can tell almost to a specific tree when my meter should drop a bar. So when it gets cold you can interpret this as an indicator that the batteries are beginning to deteriorate when in reality they are operating normally. This can be exaggerated if normal summer temps are 80° + because the batteries have higher capacity at temps above 80 so the drop in range looks even more severe as the temps drop. I through this out only as a possibility. In any case, the bar graph battery meters should be verified with a digital volt meter and frequently be re-verified to insure their accuracy.

I suggest you follow JohnnieB's instructions.