From: Dr. Bob [dr.bobf@worldnet.att.net] Sent: Sunday, September 03, 2000 10:53 AM To: 928 Subject: [928] re: not starting Tom shouted to the list (release the 'caps lock' key please...): >'89 S4, HAD THE SEATS OUT TO REWIRE THE AUDIO. TOOK OUT THE FACTORY AMP AND >ALL SPEAKERS AS WELL AS THE HEAD UNIT. NOW WHEN IT TRY TO START IT CLICKS >RAPIDLY (PLENTY OF JUICE I THINK), THE DIGITAL DISPLAY LIGHTS UP COMPLETELY >THEN WHEN I RELEASE THE KEY IT SAYS "NO. 4" IN THE DISPLAY AREA. ANY IDEAS? All the symptoms point to a low battery. Clicking solenoid means low current. The dash controller reset confirms it. That indication on the dash is the firmware code and revision date for the digital display computer. I'll speculate that your audio install was done with the battery still connected. While working on the car all afternoon with the doors open, the interior lights drained the battery some. If your install went like mine, it also included some "testing" of the new system without the engine running, a procedure which drained the battery even more. What to do now: Disconnect the battery ground strap at the rear pan, easy to access with the tool kit panel removed. 8mm Bolt (13mm head) screws into the rear pan through the end of the braided ground strap. Others have mentioned that it's good to make a clean break when lifting the cable off-- Don't let the end bounce on the pan as you lift it. Same when you install again, by the way. After the strap is lifted and covered with a rag to keep it isolated, go ahead and pull the spare tire cover, remove the tire, and open the battery cover. Check the water levels in the battery cells, and top up with distilled water as necessary to get the water level ups to at least the bottoms of the cap tubes in each cell. Replace the caps. Only at this point is it OK to hook up the battery charger and plug it in. Most chargers have a meter that shows charging current. A very dead battery will show a small current initially, and the current will rise as the battery charges some, then falls off to just an amp or two as it approaches full charge. A low battery like yours will start off at the higher rate, and fall off as it becomes fully charged. So plan on having the charger on for a while to make sure the battery is pretty well charged before removing the charger. Safety dictates that the charger be disconnected from the wall plug first to avoid any sparks in the battery well. With the charger disconnected, let the battery sit for a while, then recheck the water levels in the cells before replacing the cover, the spare tire, belts, tools, gloves, plastic bag, rags, etc that live in the spare well, and the cover. It's not a bad idea to clean the battery terminal connections while all is apart too. With all that back together, reattach the ground strap at the rear pan, replace the covers, and the car will start and run just fine. ******* I have a seat-of-the-pants theory that batteries left to drain very low somehow manage to lose about 20% of their remaining capacity at each episode. That doesn't mean that you can do it only five times in the life of the battery, since it eats at the --remaining-- life. A little math, carry the two... about 35% of original capacity after five drain-downs. 35% is enough to start a car that starts quickly, so you may not even notice the loss. One day, after sitting with the radio playing or parking with the corner lights on for a while, the low battery will strand you. I know I have about a 30% chance that it will happen in my own garage, and a 100% chance that it will happen someplace a little further away. That's just how the odds stack up I'm afraid. Owners can check the battery capacity using an inexpensive hydrometer. With the battery fully charged, draw a sample of the electrolyte and watch the float. It gives you a color indication, and also a specific gravity number to show the capacity. Look for the hydrometer at you parts store. They start out at around a dollar for the one with the lottle floating balls, and go up to maybe six to ten for the more deluxe version with the calibrated float. Using the hydrometer at least twice a year when you check the water level will give you fair warning of battery problems. Oh-oh-- did you by a non-maintainable (also called 'maintenance free') battery?? Hmmm. Can't add water when it's low, can't test for capacity, more likely to get stranded.... But you can just attach the charger I guess. Sorry if this is a more extensive post than you had in mind. ;-) dr bob From: Wally Plumley [wplumley@bellsouth.net] Sent: Friday, December 01, 2000 10:40 AM To: 928 Subject: [928] RE: Battery boost '89S4 At 03:48 AM 11/30/00, Ian wrote: >I had to deal with a flat battery even after I put a new Bosch Silver in - I >left my car with the hatch not shut fully and the alarm/interior lights >drained it over a day. I tried jump starting off the post in the engine bay, >but it's quite hard to find a good negative (ground/earth) connection with >regular jump lead clips, especially if you don't want to scratch paint >anywhere. With a fully charged BIG battery I couldn't start it, just got the >usual clicks and a bit of engine rotation. Even off the battery directly >connected it wouldn't go. In the end I only got it going by jumping it >straight off my Wife's car, and leaving the connections on for a couple of >minutes with hers running before I tried the 928. > >I suspect there's a LOT of resistance (or something) between the post and >the battery, and between the battery and the motor. I assume these are the >same wire though. It is possible that you do have high resistance somewhere in the battery circuits on your 928, and this should be checked. There is another possibility, however. There are few consumer items sold in the USA that have a higher percentage of pure crap than jumper cables. I saw a set in a major discount store this week that were good looking, heavy cables - but the conductors were 14 gage wire! That isn't heavy enough to run your headlamps, much less crank the car. It is common to find jumper cables with 10 or 12 gage conductors. A good set of jumper cables with long 2 or 4 gage conductors and good clamps is expensive, bulky and heavy - but they WORK, and are a very good investment. >I plan to buy a boost charger and use the cigar lighter if I ever need to do >this again - unless anyone knows that this is a bad idea! I suspect that this is another case of words changing meanings over borders. In the USA, a "boost charge" is equivalent to a "jump start", a high-amperage, fast charge to get the car going NOW. A "battery charge" is usually a two to eight hour slow charge to recharge a dead battery, or top off a low battery, when there is no particular hurry. A "trickle charge" or "battery maintainer" is used for long-term battery maintenance. They are not the same thing in most cases, however. A trickle charger usually can and will overcharge and damage a battery over extended periods, while a proper battery maintainer is safe for indefinite usage. I believe that a "boost charge" to Ian is equivalent to our trickle charge or maintainer charge. In any case, as several members have pointed out, the 928 cigarette lighter isn't suitable for any of that. We sell the Porsche Battery Maintainer together with the adapter kit, which includes wire and connectors to hook the maintainer to the battery circuits. The jump start terminal is suitable for connection of a battery charger or maintainer. Wally Plumley 928 Specialists From: Wael Mansour [wael@nova.net.ng] Sent: Sunday, December 09, 2001 12:39 AM To: 928 Subject: [928] Any1 with Battery Draining Problems? Hello lister, This message is to anyone with battery draining problems, I thought I'd share this experience. My battery was draining out in a couple of days after charging it. SO I thought to tackle the problem with my little tools that I have, no need of any electronic gadget!: All you need are long nose pliers and an Amp-meter and someone to help you. Put the amp-meter in series with one of the battery cables. Close the doors, put the alarm off, shut down every electrical item that can consume electricity (all the cabin lights should be off, even the back light coz you'd be reading the ampmeter while the glass hatch is open).The reading should be 60milli-Amps. If it is more then you have electrical leakage. If it is more than 60milliamps, start removing the fuses ONE BY ONE and at each time you remove a fuse check the reading if it has gone down to 60milliamps. When you remove the 'suspect' fuse, then you'll find the leak problem. I did this on my car, and my ampmeter was reading in excess of 500milliamps, then I started removing the fuses till I got to fuse no.23 which is the cabin lights. I found out there is a leak somewhere and I am going to revise the circuitry now to find it! Hope this will help someone out there, call me if you want I'll be glad to help! Wael From: Wally Plumley [mailto:wplumley@bellsouth.net] Sent: Sunday, June 30, 2002 2:31 PM To: 928 Subject: [928] Re: Batery Drain Current At 02:04 PM 6/30/02, Rick Slater wrote: >What is normal battery drain current for an 84? I am measuring 47ma. Is >this excessive? No. A 928 battery should have around 90 amp/hours capacity. If we assume that we can crank the engine after half of that capacity is drained, we have 45 amp/hours available. 45 divided by 0.047 equals 957 hours, or almost 40 days. Long enough? Wally Plumley 928 Specialists