jinman
Rest in Peace
- Joined
- Feb 23, 2001
- Messages
- 21,008
- Location
- Texas - Wise County - Sunset
- Tractor
- NHTC45D, NH LB75B, Ford Jubilee
A couple of years ago, I bought my brother a used golf cart for his birthday. It's a 2007 model Yamaha YDRE 48 vdc cart. It worked well until a couple of months ago and then just quit. He isn't very technically inclined and so I figured the battery terminals were just dirty based on what I'd seen a few months earlier. To make a long story short, I checked his batteries and found one that read 10.9 volts. That made me think he had a dead cell and so I brought the whole cart home with me to work on because he lives 1-1/2 hours away. Besides, I've been wanting to surprise him with a cargo box for the back instead of the golf bag well which he never uses.
After getting the cart home and disconnecting all batteries, I found that three of them maintain at least 12.5 to 12.75 volts under load. When I tested the suspicious battery, it read about 11.2 volts. That tells me that something internal is probably beyond hope, but I thought I'd give it a try with the Epsom salts solution and try to see if I could get it back to a usable state. As it is, when I put the charger onto it, I cannot get charging current of much more than 2 amps. The internal resistance of this battery is extremely high. If hooked in series with the other batteries, it will kill any high current flow in the cart and the cart just shuts down. I'd normally just replace the battery, but these darn things are over $225 each after core exchange (Trojan T-1275, 280 hours at 25 amps, 83 lb battery. . . Whew!). I might as well give this one a good try before giving in.
Yesterday morning, I mixed up two quarts of distilled water and 16 oz of Epsom salts. I heated it to around 175 F and got it completely dissolved in the water before putting it into my battery filler pitcher. Then I used a battery bulb to suck out the old acid and put it into a clean poly container. I couldn't get more than about 1-1/2 quarts out of the battery without emptying them out and I didn't want to do that. I refilled with the strong Epsom salt solution and started the charging. Right away, I noticed the cells were bubbling a bit. I know nothing happens really quickly with this method, so I left the charger running. After 18 hours, it was up to about 4 amps charge current. After 36 hours, it was about 8 amps charge current. I could never get it to charge at that rate before the Epsom salt.
So after 36 hours, I decided to give the battery a load test. I have a 34 lb thrust trolling motor that I hooked to the battery. Of course, the motor is just spinning in the air, but before the rejuvenation, that motor would drop the battery straight to 9 volts. This morning it ran strong and I measured 12.5 volts while it was running. To add additional load, I hooked up a 12 volt headlamp and let it run. Between the two, the battery had no problem keeping them going for 1-1/2 hours. Since I don't have a load tester to put on that battery, I decided to increase the load by holding the propeller on the trolling motor for maximum current drain. I held the prop while flicking the switch up to 3. The motor hummed and the battery held. I went all the way to 5 (maximum speed) and suddenly the battery output dropped to 8.5 volts and the light got dim. It was like a switch had been turned off. I shut off the motor and the battery jumped back up to 9.5 volts and the light illuminated. I started the motor again without holding the prop and it ran slowly for about 30 seconds and then started whirring at full speed. I looked back at my meter and it said 12.5 volts.:confused3:
Just to ensure I was not seeing things, I tried the loading several more times and made sure the contacts were good on my battery clips. As before, the load would drop the batter output suddenly to 9 volts and then with less load it would run a few seconds and then pop back up to 12.5 volts like I had turned on an internal switch. I decided to let the battery run the motor and light for several hours and then recharge the battery more. This is starting to sound like a cell may be shorting out instead of just being sulfated. I don't expect to ever get this battery restored, but found it interesting to monitor its operation and see how it reacted so quickly to loading and then restored itself. It just appears that under light loading the battery works fine, but will not take a heavy charging or load current. I'll keep trying for awhile and see what happens when I charge it again after being discharged.
In the meantime, I have a friend who works at a golf cart sales place. He's checking on a battery for me and may be able to get me a good deal. He volunteered to check on it for me and I really appreciate his efforts. I'm just glad all four batteries aren't bad. A full set is around $1k by the time you pay shipping.:shocked: The things you do for family. . . .
After getting the cart home and disconnecting all batteries, I found that three of them maintain at least 12.5 to 12.75 volts under load. When I tested the suspicious battery, it read about 11.2 volts. That tells me that something internal is probably beyond hope, but I thought I'd give it a try with the Epsom salts solution and try to see if I could get it back to a usable state. As it is, when I put the charger onto it, I cannot get charging current of much more than 2 amps. The internal resistance of this battery is extremely high. If hooked in series with the other batteries, it will kill any high current flow in the cart and the cart just shuts down. I'd normally just replace the battery, but these darn things are over $225 each after core exchange (Trojan T-1275, 280 hours at 25 amps, 83 lb battery. . . Whew!). I might as well give this one a good try before giving in.
Yesterday morning, I mixed up two quarts of distilled water and 16 oz of Epsom salts. I heated it to around 175 F and got it completely dissolved in the water before putting it into my battery filler pitcher. Then I used a battery bulb to suck out the old acid and put it into a clean poly container. I couldn't get more than about 1-1/2 quarts out of the battery without emptying them out and I didn't want to do that. I refilled with the strong Epsom salt solution and started the charging. Right away, I noticed the cells were bubbling a bit. I know nothing happens really quickly with this method, so I left the charger running. After 18 hours, it was up to about 4 amps charge current. After 36 hours, it was about 8 amps charge current. I could never get it to charge at that rate before the Epsom salt.
So after 36 hours, I decided to give the battery a load test. I have a 34 lb thrust trolling motor that I hooked to the battery. Of course, the motor is just spinning in the air, but before the rejuvenation, that motor would drop the battery straight to 9 volts. This morning it ran strong and I measured 12.5 volts while it was running. To add additional load, I hooked up a 12 volt headlamp and let it run. Between the two, the battery had no problem keeping them going for 1-1/2 hours. Since I don't have a load tester to put on that battery, I decided to increase the load by holding the propeller on the trolling motor for maximum current drain. I held the prop while flicking the switch up to 3. The motor hummed and the battery held. I went all the way to 5 (maximum speed) and suddenly the battery output dropped to 8.5 volts and the light got dim. It was like a switch had been turned off. I shut off the motor and the battery jumped back up to 9.5 volts and the light illuminated. I started the motor again without holding the prop and it ran slowly for about 30 seconds and then started whirring at full speed. I looked back at my meter and it said 12.5 volts.:confused3:
Just to ensure I was not seeing things, I tried the loading several more times and made sure the contacts were good on my battery clips. As before, the load would drop the batter output suddenly to 9 volts and then with less load it would run a few seconds and then pop back up to 12.5 volts like I had turned on an internal switch. I decided to let the battery run the motor and light for several hours and then recharge the battery more. This is starting to sound like a cell may be shorting out instead of just being sulfated. I don't expect to ever get this battery restored, but found it interesting to monitor its operation and see how it reacted so quickly to loading and then restored itself. It just appears that under light loading the battery works fine, but will not take a heavy charging or load current. I'll keep trying for awhile and see what happens when I charge it again after being discharged.
In the meantime, I have a friend who works at a golf cart sales place. He's checking on a battery for me and may be able to get me a good deal. He volunteered to check on it for me and I really appreciate his efforts. I'm just glad all four batteries aren't bad. A full set is around $1k by the time you pay shipping.:shocked: The things you do for family. . . .