Club Car 48V Runaway Charger??

[pharmsc]

I have a 1996 Club Car DS 48 volt that has a charging issue. The batteries are 20 months old. The cart is rarely used and it appears that my charger is cooking my batteries. I tested my batteries BEFORE charging today and the resting voltage across the pack was 52.2 volts. Upon hooking up the charger it drew 13 amps for a couple of minutes then settled down to 6 amps. I checked approximately 45 minutes after charging began and the voltage across the pack WITH THE CHARGER ON and was showing 59.7 Volts and was still charging at 4 amps!
I then disconnected the charger and let the pack rest for a few minutes and the voltage across the pack WITH THE CHARGER OFF was 55.7 volts!! I rechecked the resting voltage on the pack 3 hours later and show 53 volts across the pack. All of the batteries are within 0.1 volts of each other and all connections are clean and tight on battery terminals.

What should the charging voltage and the resting voltage be? The batteries are gassing and in the past if the charger is left on for a long time the batteries gas really hard.! The batteries are using a good bit of water.
How do I test the charger for proper operation

Please give me some insight. I really appreciate the help. Any diagrams or testing algorithms appreciated. Thanks Bob T

[NoleFan4Ever]

It sounds all correct. 50.93v is a fully charges pack 12 hours after the charge completed. If you unplug it and replug it, it is not working off energy unit counting it is just doing an equalization or manual charge. At the end of the charge cycle, you can have 61-63 volts and has high as 65 volts. That is all normal. If 12 hours after charge you are above 50.93, then your batteries are excellent. Sometimes that is just a little surface charge and will quickly drop as soon as you use it.

If you are unsure of how it is working, just reset your OBC and then plug the charger back in and do not take it off until it cuts off automatically. It will time out after 16 hours so if you still have a charge going after that point, there is a problem with the OBC.

And by design, the amperage drops as the voltage rises and over 60v, the amperage is very low....

[pharmsc]

Many Thanks! How does the charger "READ" the charge on the pack? Does it stop charging then take a reading or just measure charging units? If I understand correctly I should NOT unplug and re-plug the charger in during a cycle as this begins the timing of the units again?? It is supposed the continuously charge for up to 16 hours and then time out? The very first battery on the negative ground to the chassis uses more water than the rest? Thoughts again many thanks I appreciate this very much Bob T

[NoleFan4Ever]

Your charger is just the tool in this case. It gets its directions from the OBC (On Board Computer). The OBC as a sensor in it that the Main Pack Neg cable rus through on its way to the Controller B-. This sensor will "sense the energy taken or used by the pack and it counts these energy units and then replaces 110% when you plug it back in.

You can unplug it if need be during charging and it will pick back up, but if you unplug it after the charge has completed, and then plug it back in, it will not be using the algorithm to charge the pack. When this is done, we usually call it an Equalization charge.

And it will stop momentarily after it starts just to sense the pack and calibrate.

No, it will cut off when fully charged or time out at 16 hours if not fully charged.

Your Main Pack Neg should not be going to the chassis. If you check, it should be going thru your OBC and to the Controller.

[pharmsc]

Agreed!! Last question AS the charge tapers to about 2 amps or so, Is the charger a "Dumb charger" and automatically run for 16 hours or can the OBC determine that the pack is full and shut off after just a few hours? You've helped me so much thanks

[rib33024]

[NoleFan4Ever]

Originally Posted by pharmsc

Agreed!! Last question AS the charge tapers to about 2 amps or so, Is the charger a "Dumb charger" and automatically run for 16 hours or can the OBC determine that the pack is full and shut off after just a few hours? You've helped me so much thanks

It is dump in that is cannot control itself, but it does cut off via the OBC whenever the charge cycle completes. The only time it would go to 16 hours is if they were very low, very old, or a brand new set.

I am attaching a battery guide for you to read over.

And as you can see by Rib's meter his are at the top....

[pharmsc]

Thanks Buddy I've printed and filed all of the above. I learned much today! Peace

[Fairtax4me]

What batteries do you have? How much and how often do you add water?

[ThreeCW]

Here is a bit more information on charging voltage, charging profiles and state of charge that you can refer to. The US Battery paper has a pretty good description of three stage, two stage and single stage charging. The C/20 (or C20) rate they refer to is the capacity rating of the battery.

For instance, a common 6 volt battery is the Trojan T105 which has a 225 Amp-Hr at the 20 hr discharge rate (C20 rate).

The Trojan recommended Bulk Charging amperage is 10 to 13% of the C20 rate = 22 to 29 amps charging rate. During the Finish Charge, the charging amperage drops to 1 to 3% of C20 rate = 2 to 7 amps. Note that not all chargers are rates for the 22 - 29 amps that Trojan suggests. In in your case you mentioned drawing 13 amps which might be the maximum that your charger can put out ... and it will take longer to complete the charge cycle compared to using a 22 amp rated charger.