Battery short? I did a bad thing.
03-12-2019, 01:25 PM
#1
Rennlist Member
Thread Starter
Battery short? I did a bad thing.
87 S4. I had to jump the battery (sat for too long) and when I removed the positive jump cable I must have pulled one of the clustered hot red leads slightly upwards in doing so. The terminal connection was slightly loose. Put everything back, drove out onto the street and hit a bump. Car instantly died, lost all power. I went back to the battery compartment and lifted the lid, noticing a severely arced area on the bottom of the lid and the elevated red lead. The battery is very secure, hold down was tight. Towed it back to garage and by the time I got it there battery went from totally dead to having enough juice to produce a weak chime.
All my tools, multimeter are in storage and I have not done anything with it yet. My question is- what have I fried? The brains? Battery? Anything I need to look for? I'm not very good with electricity so any advice is appreciated.
Don
All my tools, multimeter are in storage and I have not done anything with it yet. My question is- what have I fried? The brains? Battery? Anything I need to look for? I'm not very good with electricity so any advice is appreciated.
Don
03-12-2019, 02:09 PM
#3
Rennlist Member
Given you shorted the battery directly to earth chances are no damage was done other than perhaps the battery may be toast. On the bright side of life you got away relatively "Scot free".
When this happened to me it happened at night, at speed in the outside lane with my wife and two small daughters in the car. No engine, no lights, no indicators - absolutely squat electrics- had to barge my way over from the third lane to the hard shoulder- real scary on a busy motorway! The battery compartment lid was welded to the positive post of the battery. Had to drill the lid to get it open! ******** here had forgotten to fasten the hold down strap. The battery was more or less new so after cleaning up the post a bit I took the battery back to the shop that sold it complete with the warranty slip- told them it had packed up- they tested it, said it was buggered and gave me a new one. They never asked what happened! Stuck the new battery in and no other problems whatsoever.
I regularly advise folks to put a sheet of rubber between the positive post and the lid.
When this happened to me it happened at night, at speed in the outside lane with my wife and two small daughters in the car. No engine, no lights, no indicators - absolutely squat electrics- had to barge my way over from the third lane to the hard shoulder- real scary on a busy motorway! The battery compartment lid was welded to the positive post of the battery. Had to drill the lid to get it open! ******** here had forgotten to fasten the hold down strap. The battery was more or less new so after cleaning up the post a bit I took the battery back to the shop that sold it complete with the warranty slip- told them it had packed up- they tested it, said it was buggered and gave me a new one. They never asked what happened! Stuck the new battery in and no other problems whatsoever.
I regularly advise folks to put a sheet of rubber between the positive post and the lid.
03-12-2019, 02:16 PM
#4
Rennlist Member
Thread Starter
Thank you guys, that's a relief. I'm glad I was 200 yards away from the garage and only doing 10 mph! It's a fairly new Die Hard AGM so hopefully they will just replace it. I don't even know if Sears is still in business around here. Heard they closed a bunch of stores. I'm going to take your advice Fred and put some rubber pads on the underside of the lid.
03-12-2019, 03:05 PM
#5
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Don --
A common telltale of internal battery damage is that the case is "swelled" on the sides. An internal explosion results from the sudden hydrogen evolution and the heat generated. If you are getting any voltage at all now, and it sounds like you are, try opening the battery well and connecting your smart charger/maintainer for a day or three to get the battery voltage back up.
----
When we moved north almost five years ago now, the car ended up sitting for a couple weeks with the glovebox door not fully closed. The bulb in there ran the battery down pretty far, like to virtually dead. When we came back with furniture and stuff and found it dead, I scrounged around and found a small 6-amp conventional charger in my storage boxes to bring it back to life. The math might tell us that a 6-amp charger should take less than a day to restore a discharged battery, but in fact the charge rate drops off quickly as a dead battery starts taking the new charge. I ended up leaving that charger connected for almost three days, monitoring terminal voltage regularly so it didn't cook. By then a new CTEK maintainer with higher current capacity arrived in a brown truck, and it was tasked with the smart part of bringing the last bit of life back to the battery. The battery is now seven (7!) years old, and well past its statistical end-of-life. The car missed it's annual electrical maintenance last spring since I was off on a project until August, so no specific-gravity readings yet that would warn of its impending demise. The battery does live in the car with the "smart" maintainer continuously attached when it isn't being driven. Regardless, we are definitely into bonus time. Lesson: add a good smart maintainer to your tool collection if you don't already have one. Then use it religiously.
Also... The Group 48/H6 battery used in our cars includes a plastic shield that fits over the positive terminal. I get to snip a little relief in it to fit over the cable itself. With that shield correctly installed, there's no chance of a short-to-lid in the well. Lots of folks like to throw those away, thinking it's a shipping shield of some sort protecting the post.
A common telltale of internal battery damage is that the case is "swelled" on the sides. An internal explosion results from the sudden hydrogen evolution and the heat generated. If you are getting any voltage at all now, and it sounds like you are, try opening the battery well and connecting your smart charger/maintainer for a day or three to get the battery voltage back up.
----
When we moved north almost five years ago now, the car ended up sitting for a couple weeks with the glovebox door not fully closed. The bulb in there ran the battery down pretty far, like to virtually dead. When we came back with furniture and stuff and found it dead, I scrounged around and found a small 6-amp conventional charger in my storage boxes to bring it back to life. The math might tell us that a 6-amp charger should take less than a day to restore a discharged battery, but in fact the charge rate drops off quickly as a dead battery starts taking the new charge. I ended up leaving that charger connected for almost three days, monitoring terminal voltage regularly so it didn't cook. By then a new CTEK maintainer with higher current capacity arrived in a brown truck, and it was tasked with the smart part of bringing the last bit of life back to the battery. The battery is now seven (7!) years old, and well past its statistical end-of-life. The car missed it's annual electrical maintenance last spring since I was off on a project until August, so no specific-gravity readings yet that would warn of its impending demise. The battery does live in the car with the "smart" maintainer continuously attached when it isn't being driven. Regardless, we are definitely into bonus time. Lesson: add a good smart maintainer to your tool collection if you don't already have one. Then use it religiously.
Also... The Group 48/H6 battery used in our cars includes a plastic shield that fits over the positive terminal. I get to snip a little relief in it to fit over the cable itself. With that shield correctly installed, there's no chance of a short-to-lid in the well. Lots of folks like to throw those away, thinking it's a shipping shield of some sort protecting the post.