631G
Senior Member
We have a 963B (SN: 9BL02418) that we have had for probably going on 10 years with no problems electrically or mechanically until about a year ago. The machine was on a project working on clearing and feeding a burner and at the end of shift she wouldn't shut down. We found that the batteries were completely dead, to the point the fuel shut off would no engage, and one showed a bad cell when hooked up to a tester.
We initially though that we had a failed alternator and that had allowed the batteries to draw down during the shift and maybe the battery with the bad cell was just old. We replaced the bad battery pulled off the alternator and had it rebuilt, reinstalled it all and put it back to work. The same issue came up again at the end of the next shift. The machine wouldn't shut down and the batteries were weak. This prompted a swap on the fuel shut off solenoid because we thought that might be part of the issue. We pulled the batteries charged them up at the shop and no change. Then another battery but on the opposite side of the machine had a bad cell crop up. We realized that we must have a short somewhere and started tracing cables back from the batteries to the starter and so on until found one of the large jumper cables that run from side to side of the machine was worn in a spot and so changed it out. Nothing improved. Still killing one battery at a time about every two to three shifts.
We limped the machine through the job swapping batteries etc. and then pulled the machine into the shop and started working on the fuse panel and the control panel where the key switch is, thinking that the issue must be there. We replaced all the fuses and fuse sockets, key switch and repaired a few smaller wires where the wire jacket was cracked which we thought might be grounding out and pulling power. After this period in the shop we got some results. It stopped killing the batteries for about a month and then out of the blue, were back to square one with the same issue. What makes it worse is when it died this time it was being ran by the company owner on his place in Alabama trying to prep up an area prior to some bad weather. He was less than happy when it bit the dust on him before the site work he was doing was done.
So that epic story brings us to today. I have the machine back in the shop to begin again tracing wires to find this gremlin. My question to you is where do recommend we start based on what all we have already changed? I cannot sort out what is going on because when we have checked the voltage at the alternator and at the batteries everything is checking out. We have +/-26v out put at the alternator and the batteries when checked do show to be charging. What could be causing them to pull down and what could be causing the batteries to fail, one side then the next, each time showing a bad cell when they die? Could there be another short somewhere to the point that the load on the batteries is higher than the output of the alternator and batteries so that with time they are being over drawn to the point that they just give up?
Sorry for the novel. This one is a story best told over a beer at the end of shift at the shop....
We initially though that we had a failed alternator and that had allowed the batteries to draw down during the shift and maybe the battery with the bad cell was just old. We replaced the bad battery pulled off the alternator and had it rebuilt, reinstalled it all and put it back to work. The same issue came up again at the end of the next shift. The machine wouldn't shut down and the batteries were weak. This prompted a swap on the fuel shut off solenoid because we thought that might be part of the issue. We pulled the batteries charged them up at the shop and no change. Then another battery but on the opposite side of the machine had a bad cell crop up. We realized that we must have a short somewhere and started tracing cables back from the batteries to the starter and so on until found one of the large jumper cables that run from side to side of the machine was worn in a spot and so changed it out. Nothing improved. Still killing one battery at a time about every two to three shifts.
We limped the machine through the job swapping batteries etc. and then pulled the machine into the shop and started working on the fuse panel and the control panel where the key switch is, thinking that the issue must be there. We replaced all the fuses and fuse sockets, key switch and repaired a few smaller wires where the wire jacket was cracked which we thought might be grounding out and pulling power. After this period in the shop we got some results. It stopped killing the batteries for about a month and then out of the blue, were back to square one with the same issue. What makes it worse is when it died this time it was being ran by the company owner on his place in Alabama trying to prep up an area prior to some bad weather. He was less than happy when it bit the dust on him before the site work he was doing was done.
So that epic story brings us to today. I have the machine back in the shop to begin again tracing wires to find this gremlin. My question to you is where do recommend we start based on what all we have already changed? I cannot sort out what is going on because when we have checked the voltage at the alternator and at the batteries everything is checking out. We have +/-26v out put at the alternator and the batteries when checked do show to be charging. What could be causing them to pull down and what could be causing the batteries to fail, one side then the next, each time showing a bad cell when they die? Could there be another short somewhere to the point that the load on the batteries is higher than the output of the alternator and batteries so that with time they are being over drawn to the point that they just give up?
Sorry for the novel. This one is a story best told over a beer at the end of shift at the shop....
