Is it better to completely drain my rechargeable batteries every time?

Battery drain: '98 sebring convertible

• QUESTION: Hi Roland, you have helped me before, and I need your assistance again. I have a battery drain issue on my 1998 Chrysler Sebring Convertible. If I let the car sit for a few days, I can't start it without jumping. Once it starts, it charges again. So the charging system seems OK, but something is causing the battery to discharge. After charging it, I removed the battery, and the next day it was still at 11.8 volts, which is where it was when I left it the day before. I am assuming the battery is not the problem. I looked at some of your suggestions to others for the same problem, and checked resistance on the underhood fuses. This was done with the battery removed from the car - I connected my ohmmeter to the "battery posts" under the hood (as you know, the battery is in front of the driver's side wheel, and inaccessible, so I used the positive and negative posts under the hood). Of the 19 underhood fuses, I was able to put 15 of them back in, and the ohmmeter still showed infinite resistance. I got these numbers when inserting each of the other four individually: I've gotten pretty far, but am unsure what to do next. I opened the drivers's side door, and the number went down further. I closed the door and the number went back to 1.9 K ohms. I opened the trunk, and the number went down again. I'm not sure what this means. I guess the resistance should go down when the door or trunk is opened, as the circuit is closed. So does that mean the door and trunk lights are not the problem? How can I further troubleshoot this to find the problem? If there is a short in the wiring somewhere before the light itself, how would I locate that? I could use some advice on how to proceed from here. Thanks very much. Bill ANSWER: Hi Bill, That is good sleuthing but I don't believe you have found the problem yet. The 1.9K ohms would only produce a current draw of 1 mA, and typically the car will draw 20-50 mA when shut down AND the battery is connected. I think you need to do the measurement of the current being drawn between the remote - post stud on the strut tower and the - wire after you have separated them for purpose of making the current measurement. The ignition off draw is the issue, and that requires that the battery be in the circuit. See what the mA is to begin, then start removing fuses one at a time to find the ones that cause the mA to drop significantly into the normal range. I think this will reveal the cause. ---------- FOLLOW-UP ---------- QUESTION: Roland, this reply is very late, but I just wanted to tell you how I fixed my battery problem. Maybe somebody else will benefit from this as well. I used my ammeter to measure current by disconnecting the negative battery cable and wiring the ammeter in series between the battery cable and the post under the hood. This let me put the meter where I could see it, and it seemed to be more accurate than the clamp meter my friend loaned to me. My car has 19 fuses under the hood. I found that if I removed #4 (Stop Lamps and Interior Lamps) and #11 (Seat Belt), the current draw was 0.00 A. (Both are 20A fuses.) When I put just #4 back into place, the meter jumped wildly between 0.50 and 1.2 A. After 2 minutes and 15 seconds, it dropped down to 0.02 and stayed there. I don't know what it does for 2:15, but the result was easily repeated numerous times. - - - - - - - - - - 1997-1999 Chrysler Sebring Convertible STRUCTURAL SEAT BELT SYSTEM (WITH SEAT BELT CONTROL TIMER MODULE) The structural seat with integrated Retractor Integrated Height Adjuster allows the seat belt to comfortably fit a large range of occupants. The seat belts are attached to the seat instead of the body which allows better passenger access to the rear seat. Since the retractor is mounted to the seat back that can recline, a typical seat belt g-sensor cannot be used in the retractor. Instead, a solenoid inside the retractor is used to lock and unlock the seat belt when electronically signaled by a remote g-sensor. The remote g-sensor is located inside the Seat belt Control Timer Module (SCTM). The SCTM is located under the center console. The seat belt retractor solenoid is located in the seat back and is serviced as an assembly. When the solenoids are powered, the seat belt can be moved. When the solenoids are not powered, the seat belts can not be extracted. This is necessary to ensure that occupants are always safe, even in the case of a power loss during an accident. Whether the seat belts are in lock or unlock position, an occupant can always release the seat belt and it will retract. The SCTM controls the seat belt solenoids. It supplies power continuously to the seat belts whenever the ignition is in the RUN or ACCESSORY position. The module has two other unique functions: that of a time and g-sensor. The SCTM was designed with a timer function so that when the vehicle is not in use, the battery would not be prematurely drained. The module times out after approximately 30 minutes if no inputs are sent to the module. The module will power the seat belts for a period of time when there is an input: 1. from either door ajar switch (open or closed), or 2. the ignition switch is moved from RUN or ACCESSORY to the OFF position. Each time one of these inputs occurs, the timer is reset to keep the belts powered for 30 minutes. The g-sensor function of the SCTM will cut power to the seat belts whenever: 1. the vehicle accelerates or decelerates at a rate greater than or equal to 0.7g in any direction, or Input of ignition switch in the RUN or ACCESSORY position will cause the module to power the seat belts as long as the condition exists. The SCTM incorporates limited diagnostics. The detectable faults include solenoid short to ground, open or shorted to battery, internal fault, or no acceleration within the past 10 timer cycles. Faults are communicated to the seat belt lamp via a single fault line to the body control module. The body control module communicates the fault on the bus to the cluster/lamp. - - - - - - - - - - With that knowledge, I was able to perform some more tests, and saw nothing unusual about the current draw. If I pulled both #4 and #11, and put them back in, I ended up with either 0.02 immediately, or 0.45 for 30 minutes, after which it returned to 0.02. In the end it was just a bad battery. Costco doesn't replace batteries - you have to return the bad one and then buy a new one, but that fixed the problem.

• Answer:

  Hi Bill, Thanks for that report. It is good to have that explanation of the special seat belt arrangement in the convertible Sebring. By the way, I did notice in your report one other possible cause for the battery to drain other than a bad battery: "The module will power the seat belts for a period of time when there is an input: 1.from either door ajar switch (open or closed),..." My thought is that given the very common maladjustment of the door ajar switches in this rather flexible convertible body, it might be the case that you have an intermittent malclosure of one of your latches such that an ajar switches is falsely sending an "open" signal that causes the module to power up for 30 minutes, occasionally or inconsistently during the shutdown time of the vehicle. Other owners have told me about the interior lights going on and off for example even though the vehicle is at rest So you might want to move the door latch striker located in the door frame in-board a few mm on the driver door or the passenger door as that might also be the cause of quick draining of the battery. It is very helpful for you to provide this discussion. Please 'rate' my answer. Thanks, Roland