Amp Leech
05-08-2014, 04:43 PM
#1
RL Community Team
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Amp Leech
My 02 S has managed to suck the battery dry in less than two days parked. I purchased a new Optima thinking the battery was at fault. Same issue. thinking it might be a bad VR on the Alternator I ran a voltage test which read normal voltage range to low, but no over charge and it did not register soley low. I went through the fuse box and with the exception of the secondary air pump fuse which I could not read, the only fuse I found with an active load was C1: 'Engine Electronics.' I plan on breaking out the Bentley diagrams this evening, but I'm interested in hearing about any experiences anyone has had with this rather all encompassing circuit. I've also got a very noise actuator on startup, but we'll save that for another day 
05-08-2014, 06:50 PM
#3
Race Director
Check the car after a few minutes with it locked. I think you'll find the current load way down. Just a few 10's of milliamps.
If you check the current load too soon after engine shut off and with the car unlocked the ECU can be awake and really sucking the juice. My Turbo requires 3 minutes of time before the ECU goes into low power mode after I turn off the engine and *lock* the car.
My 02 Boxster's ECU goes into low power mode almost before I can remove the key from the ignition switch.
If you check the current load too soon after engine shut off and with the car unlocked the ECU can be awake and really sucking the juice. My Turbo requires 3 minutes of time before the ECU goes into low power mode after I turn off the engine and *lock* the car.
My 02 Boxster's ECU goes into low power mode almost before I can remove the key from the ignition switch.
05-09-2014, 12:12 PM
#7
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Sometimes random battery kills are the result of a bad grounding strap or a loose terminal/cable connection.
Your alternator may be producing the right output during a stationary measurement, but the grounding strap/cable keeps 'making and breaking' a solid connection as you bounce down the road. This will limit the alternator's effectiveness.
Start with a fully charged battery @ 12.6V or thereabouts, make sure the cables are tight, *lock the car* (for reason previously noted) , and wait (if you can) a few days. You shouldn't move much lower than a 12.5V reading in only a few days.
BD
* be prepared for emergency battery access or jumping
Your alternator may be producing the right output during a stationary measurement, but the grounding strap/cable keeps 'making and breaking' a solid connection as you bounce down the road. This will limit the alternator's effectiveness.
Start with a fully charged battery @ 12.6V or thereabouts, make sure the cables are tight, *lock the car* (for reason previously noted) , and wait (if you can) a few days. You shouldn't move much lower than a 12.5V reading in only a few days.
BD
* be prepared for emergency battery access or jumping
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05-14-2014, 08:38 PM
#8
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I've got a kit for diaconnect though I haven't installed it yet. I noticed reference to one primary grounding point on the top of the engine. Given what was mentioned earlier is that my next focus? Identify, clean up and make certain its torqued properly? Been driving the car daily with my other wheels in the shop and no problems at all.
05-14-2014, 09:28 PM
#9
Burning Brakes
Maybe something here would help.
Your battery is fine when jump started and charges fine but discharges quickly with the key is turned off and removed?
disraeli posted this on www.ppbb.com
"The factory technical manual (Section 97-07 page 2) has the following table of total electrical load after the car has been shut off (ModelYear 02):
(electrical current is worst case, i.e. car loaded w/all options...)
FROM TO mA
0 min 5 min up to approx. 950
6 min 15 min up to approx. 900
16 min 20 min up to approx. 750
21 min 60 min up to approx. 50
61 min until the battery is empty up to approx. 30
1000mA equals, of course, one amp.
If the car had no options whatsoever, the load after 60 min would be 17mA instead of 30mA.
From this table you should be able to insert an amp-meter between the battery and battery cable and tell if the car is within spec before you begin pulling fuses or removing the battery to get it tested."
And once you see the draw is beyond spec, you pull one fuse at a time noting if the current draw drops within spec when the fuse is removed. Find the one that causes the excess draw and you have located the circuit that is causing your problem.
Your battery is fine when jump started and charges fine but discharges quickly with the key is turned off and removed?
disraeli posted this on www.ppbb.com
"The factory technical manual (Section 97-07 page 2) has the following table of total electrical load after the car has been shut off (ModelYear 02):
(electrical current is worst case, i.e. car loaded w/all options...)
FROM TO mA
0 min 5 min up to approx. 950
6 min 15 min up to approx. 900
16 min 20 min up to approx. 750
21 min 60 min up to approx. 50
61 min until the battery is empty up to approx. 30
1000mA equals, of course, one amp.
If the car had no options whatsoever, the load after 60 min would be 17mA instead of 30mA.
From this table you should be able to insert an amp-meter between the battery and battery cable and tell if the car is within spec before you begin pulling fuses or removing the battery to get it tested."
And once you see the draw is beyond spec, you pull one fuse at a time noting if the current draw drops within spec when the fuse is removed. Find the one that causes the excess draw and you have located the circuit that is causing your problem.