Not sure what I'm doing

reinman88 · 04-05-2015, 09:03 AM

Thought I knew what I was doing but I'm not sure now.

I have an 08 drive with 4 one year old 12 volt batteries. I have used the cart some all winter and put it on the charger at least once a week.

About 3 weeks ago I cleaned all terminals, and added distilled water as needed. Last Tuesday I made a run that's about 2 miles almost all off road with a big, 25% slope, hill and all was fine. Yesterday I made the same run with a friend along, so we had extra weight. I had charged the cart the night before, so fully charged. We made it up the hill, but I could tell the last stretch we were losing power. I had to flip the tow switch 4 or 5 times to make it home. Temp outside was about 50.

Put the charger on, orange charge light came on. After 2 hours the green light started blinking. After 4 hours the green light was solid and orange light was still on. 6 1/2 hours after starting, about 7 pm last night, just a solid green light no orange light so charger was shut off.

This morning I took my voltage tester and added some longer leads so I could test the batteries while driving. When I first checked before starting I had 51 volts. This is where I thought I knew what I was doing. I thought I could check voltage while driving, but it was jumping all over the place. It was in the 20s, the 30,s the 40s, 80s, 100s, not what I was expecting. If I stopped it would go to 49 or 50. I drove a little more, maybe another 200 yards, and the same thing jumping all over and once I stopped it would sit at 49 or 50.

So am I doing something wrong or is a voltage meter not designed to do what I was trying? And with so little driving, maybe 400 yards, should my pack drop to 49 or 50 that fast, or is that temporary and it will go back up some if it sits a while?

sportcoupe · 04-05-2015, 10:59 AM

Change the battery in your voltmeter.

reinman88 · 04-05-2015, 12:09 PM

I will do that, but I went back out and did each battery separately. This time things went about the way I'd planned.

All four batteries were 12.4 or 12.5 sitting. My driveway is about 200 yards long so I tested going back and forth down the drive at full speed. Three of the batteries would move from 11.8 to 12.3 as we went down the drive. This is a gravel drive so there is some bouncing as we go. Battery four was a different story, it would drop down to 8.5 and go up to maybe 11.2 spending most of the time in the 9 to 10 range. I'm guessing this is my problem.

I am going to go out now to pull and clean all cables again to make sure there is no problem there. I'll run the test again, and then put the charger back until everything is fully charged again. The bad battery is the one where the negative charging wire goes so I want to make sure that battery is getting a full charge like the others. Then I will test one more time after all cables are cleaned and all batteries are charged. I assume results will be the same, but I want to make sure before I take the battery back.

Volt_Ampere · 04-05-2015, 12:35 PM

Sounds like at least one of your batteries may be bad. You are seeing way too much drop on that one.

sportcoupe · 04-05-2015, 12:48 PM

You shouldn't drop to 10.5v (1.75v per cell) on any battery. Dropping further then 9v (1.5v per cell) on a battery is doing damage or the battery just can't hold the load. Replace it if the rest are under 2 years old. If the others are 3+ years old consider replacing the whole pack.

reinman88 · 04-05-2015, 01:45 PM

Thanks, all batteries are one year old.

If my voltage tester says the batteries are 12.3 to 12.5 sitting, what would the proper voltage be for a battery if I am driving down the road?

Before I do anything I think I may get a new voltage tester. I replaced the batteries in this one as suggested, and where I was getting 12.4 while driving, now it says 16 or 17.

sportcoupe · 04-05-2015, 01:54 PM

Yes I would suggest a new voltmeter. It should not be reading 16 or 17 volts on a 12v battery of course.

There are "at rest" volt readings, usually taken 15-30 mins after use as the batteries will bounce back up some.

Under load volt readings should avoid dropping below 1.75v per cell (10.5v for 12v battery) or never be allowed below 1.5v per cell (9.0v for 12v battery). Internal physical damage occurs below 1.5v per cell.

reinman88 · 04-05-2015, 02:26 PM

Thanks for the help, I'll pick up a new voltmeter tomorrow and try again.

Bronco Barney · 04-05-2015, 03:58 PM

If you have a hydrometer check the cells when full charge to see what it says. Maybe a cell is weak on that one battery. Also volts around when driving is maybe your meter if its digital...?

It seems to me if I remember right a guy that used to do my specialty circuits for slot car racing said some digital volts meters have problems reading during a changing load and said a analog meter will work when digitals have a problem. Not sure but a cheap analog meter on fleaby for 5-$10.00.
Good luck.

meangreenmachine72 · 04-05-2015, 05:10 PM

It sounds to me that you have a bad battery, if one is bad it will slow you down big time. If after checking and it's bad you should be covered under warranty but I would not replace just one. I tried that once and then it was like a domino effect for the others having trouble. Good luck and keep us posted.

04-05-2015, 09:03 AM	#1
reinman88 Gone Wild Join Date: Jan 2011 Location: Nebraska Posts: 665	Not sure what I'm doing Thought I knew what I was doing but I'm not sure now. I have an 08 drive with 4 one year old 12 volt batteries. I have used the cart some all winter and put it on the charger at least once a week. About 3 weeks ago I cleaned all terminals, and added distilled water as needed. Last Tuesday I made a run that's about 2 miles almost all off road with a big, 25% slope, hill and all was fine. Yesterday I made the same run with a friend along, so we had extra weight. I had charged the cart the night before, so fully charged. We made it up the hill, but I could tell the last stretch we were losing power. I had to flip the tow switch 4 or 5 times to make it home. Temp outside was about 50. Put the charger on, orange charge light came on. After 2 hours the green light started blinking. After 4 hours the green light was solid and orange light was still on. 6 1/2 hours after starting, about 7 pm last night, just a solid green light no orange light so charger was shut off. This morning I took my voltage tester and added some longer leads so I could test the batteries while driving. When I first checked before starting I had 51 volts. This is where I thought I knew what I was doing. I thought I could check voltage while driving, but it was jumping all over the place. It was in the 20s, the 30,s the 40s, 80s, 100s, not what I was expecting. If I stopped it would go to 49 or 50. I drove a little more, maybe another 200 yards, and the same thing jumping all over and once I stopped it would sit at 49 or 50. So am I doing something wrong or is a voltage meter not designed to do what I was trying? And with so little driving, maybe 400 yards, should my pack drop to 49 or 50 that fast, or is that temporary and it will go back up some if it sits a while?

04-05-2015, 10:59 AM	#2
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: Not sure what I'm doing Change the battery in your voltmeter.

04-05-2015, 12:09 PM	#3
reinman88 Gone Wild Join Date: Jan 2011 Location: Nebraska Posts: 665	Re: Not sure what I'm doing I will do that, but I went back out and did each battery separately. This time things went about the way I'd planned. All four batteries were 12.4 or 12.5 sitting. My driveway is about 200 yards long so I tested going back and forth down the drive at full speed. Three of the batteries would move from 11.8 to 12.3 as we went down the drive. This is a gravel drive so there is some bouncing as we go. Battery four was a different story, it would drop down to 8.5 and go up to maybe 11.2 spending most of the time in the 9 to 10 range. I'm guessing this is my problem. I am going to go out now to pull and clean all cables again to make sure there is no problem there. I'll run the test again, and then put the charger back until everything is fully charged again. The bad battery is the one where the negative charging wire goes so I want to make sure that battery is getting a full charge like the others. Then I will test one more time after all cables are cleaned and all batteries are charged. I assume results will be the same, but I want to make sure before I take the battery back.

04-05-2015, 12:35 PM	#4
Volt_Ampere Gone Wild Join Date: May 2012 Location: Rio Verde, Az Posts: 7,190	Re: Not sure what I'm doing Sounds like at least one of your batteries may be bad. You are seeing way too much drop on that one.

04-05-2015, 12:48 PM	#5
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: Not sure what I'm doing You shouldn't drop to 10.5v (1.75v per cell) on any battery. Dropping further then 9v (1.5v per cell) on a battery is doing damage or the battery just can't hold the load. Replace it if the rest are under 2 years old. If the others are 3+ years old consider replacing the whole pack.

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04-05-2015, 01:45 PM	#6
reinman88 Gone Wild Join Date: Jan 2011 Location: Nebraska Posts: 665	Re: Not sure what I'm doing Thanks, all batteries are one year old. If my voltage tester says the batteries are 12.3 to 12.5 sitting, what would the proper voltage be for a battery if I am driving down the road? Before I do anything I think I may get a new voltage tester. I replaced the batteries in this one as suggested, and where I was getting 12.4 while driving, now it says 16 or 17.

04-05-2015, 01:54 PM	#7
sportcoupe Gone Wild Join Date: Sep 2012 Location: Savannah, GA Posts: 2,760	Re: Not sure what I'm doing Yes I would suggest a new voltmeter. It should not be reading 16 or 17 volts on a 12v battery of course. There are "at rest" volt readings, usually taken 15-30 mins after use as the batteries will bounce back up some. Under load volt readings should avoid dropping below 1.75v per cell (10.5v for 12v battery) or never be allowed below 1.5v per cell (9.0v for 12v battery). Internal physical damage occurs below 1.5v per cell.

04-05-2015, 02:26 PM	#8
reinman88 Gone Wild Join Date: Jan 2011 Location: Nebraska Posts: 665	Re: Not sure what I'm doing Thanks for the help, I'll pick up a new voltmeter tomorrow and try again.

04-05-2015, 03:58 PM	#9
Bronco Barney Gone Wild Join Date: Mar 2015 Location: El Rancho en Debto, So. Cal. Posts: 886	Re: Not sure what I'm doing If you have a hydrometer check the cells when full charge to see what it says. Maybe a cell is weak on that one battery. Also volts around when driving is maybe your meter if its digital...? It seems to me if I remember right a guy that used to do my specialty circuits for slot car racing said some digital volts meters have problems reading during a changing load and said a analog meter will work when digitals have a problem. Not sure but a cheap analog meter on fleaby for 5-$10.00. Good luck.

04-05-2015, 05:10 PM	#10
meangreenmachine72 Gone Wild Join Date: Apr 2011 Location: New Jersey Posts: 999	Re: Not sure what I'm doing It sounds to me that you have a bad battery, if one is bad it will slow you down big time. If after checking and it's bad you should be covered under warranty but I would not replace just one. I tried that once and then it was like a domino effect for the others having trouble. Good luck and keep us posted.