Hi All:

Is it possible for a C5 starter to slowly drain the battery and not throw any codes? My 2000 C5 has always lost a charge after 30+ days with no use, hence I always use a trickle charger. But there have never been any codes thrown...

Best Regards,
Garibaldi

 

Anyone? Smoot-Hawley?

 

Im still wondering about that starter, guys.
GP

 

The starter does not draw any current until the key is turned. There are three wires on the starter solenoid one for ground, one for energizing the solenoid which is only hot when the key is turned to start the car. The third wire is the primary power to the starter motor which only draws current when the solenoid is engaged.

It is common to have the battery drain after long periods of time since the computers are monitoring things like the alarm,

 

It could cause chargin problems that won't show up as an error code if your alternator works fine, but it should not drain your battery.

 

The starter shouldnt cause any current drainage issues. Nor will it cause any DTC's. There are a bunch of things that will cause excessive current draw after shut down. You need to conduct a battery current draw test to see what the actual draw is. It should be right around 20 milliamps.

I have answered numerous post on this issue and you should be able to find them in the archives. Just do a search in the C5 tech section on current or current draw.

BC

 

Bill [and others]:

Thanks for the response[s]. I was asking the question because I had been advised by a tuner that the starter needed replacing because the battery was losing charge. Bill, I looked through your posts, but evidently skimmed over the important parts!

 

Theres one of three things that may be happening:

1- The wire that comes from the alternator (FAT RED WIRE) and goes to the battery actually connects to a terminal on the solenoid. If that connection is bad/loose/corroded, it could effect the output of the alternator and not properly charge the battery. It wont discharge the alternator!

OR

2- You misunderstood what the tuner stated.

OR

3- He has NO EARTHLY IDEA what he is talking about!

RUN FOREST RUN!

BC

 

In automotive terms, a parasitic drain is an electrical load that draws current from the battery when the ignition is turned off. Some devices, such as the PCM and the radio memory are intended to draw a very small amount continuously. These draws are measured in milliamps (mA).

In normal use, parasitic drains aren't usually cause for concern, because the battery is replenished each time the vehicle is driven. But, in long-term parking situations, parasitic drains may discharge the battery enough to cause a no-start condition. New vehicles in dealer stock and airport long-term parking are two such situations.

An abnormal parasitic drain could be a glovebox or luggage compartment light that remains on but undetected. Or an electronic component may malfunction and cause a parasitic drain that is larger than normal specification.


Parasitic Drains and On-the-Lot Battery Discharge


Important: In most cases of discharged batteries in low-age, low-mileage vehicles, proper charging procedures with approved charging equipment is the only repair necessary.

Here are some rules of thumb that might help relate parasitic drains to how long a battery would last on a parked vehicle.

The Reserve Capacity (RC) rating multiplied by 0.6 gives the approximate available ampere-hours (AH) from full charge to complete rundown. Somewhere between full charge and complete rundown, the battery will reach a point at which it can no longer start the engine, although it may still operate some of the electrical accessories.

Using up about 40% of the total available AH will usually take a fully-charged battery to a no-start condition at moderate temperatures of 25°C (77°F). Put another way, for a typical battery in a storage situation, depleting the available AH by 20 to 30 AH will result in a no-start condition.

Important: If the battery begins storage at 90% of full charge, reduce the available AH accordingly.

The recommendation for maximum parasitic drain is around 30 mA (0.030 amp). A typical drain today actually falls into the 7-12 mA range, even though some vehicles do approach the maximum. Multiply the drain (in amps) by the time (in hours) the battery sits without being recharged. The result is the amount of AH consumed by the parasitic drain. The actual drain may be small, but over time the battery grows steadily weaker.

Here's an example: a vehicle with a 30 mA drain and a fully-charged 70 RC battery will last 23 days. But if that battery is at only 65% of full charge (green dot barely visible), it is going to last only 15 days before causing a no-start.


Effects of Temperature on a Standing Battery
The parasitic drain will be fairly constant over a range of temperatures. The important temperature is that of the vehicle at the time a start is attempted. Colder temperature raises the threshold of a no-start by increasing the residual power needed. When the temperature falls to 0°C (32°F), the battery will be able to put out only about 85% of its normally available starting power, and the engine may need as much as 165% of the usual power to start.

The combined effect of these two factors is to reduce the number of days the battery can stand with a parasitic drain. At 0°C (32°F), the battery can stand only half as long as it could at 25°C (77°F). And at -19°C (0°F), the standing days are reduced to one-fourth.

Temperatures above the moderate climate of 25°C (77°F) increase the battery's internal self discharge. If the battery is in a locale where the temperature is averaging 32°C (90°F), an additional 5% to 10% of the available ampere-hours will be lost in a month due to self-discharge within the battery. At temperatures below the moderate range, self-discharge will be low enough to be negligible compared to the parasitic loss.


What the Policies and Procedures Manual Says About Parasitic Drains
Because determining how long a battery may last in a storage situation is not precise, the P& P manual provides a clear-cut policy, excerpted here.

"Discharged batteries can freeze at temperatures as high as 0°C (32°F), causing permanent damage. Other permanent damage may result from allowing batteries to stand discharged for extended periods."

"To alleviate this condition, the negative battery cable should be disconnected on vehicles which are not going to be in service within a 20 day period, beginning from the time the vehicle is shipped. If this is not possible, batteries should be recharged periodically, every 20-45 days, until the green eye is visible."

"Disconnected batteries will slowly discharge, especially with higher temperatures; therefore, even disconnected batteries should be checked every four months and recharged if necessary."

"Vehicles on display are subject to battery discharge due to drains from courtesy lights and other accessories. Provision to maintain battery state of charge for these vehicles will be necessary."

Consult your P& P manual for full details.


Tracking Down the Source of a Parasitic Load
If the battery in a vehicle becomes discharged in a shorter time than described earlier, the vehicle may have an out-of-specification parasitic load. Refer to Service Information (SI) for procedures for locating parasitic drains. Follow these steps:

Build the vehicle.
Select the Engine section.
Select the Engine Electrical sub-section.
Select Diagnostic Information and Procedures.
Select Battery Electrical Drain/Parasitic Load Test.
You will need the J 38758 Parasitic Draw Test Switch and a digital multimeter set to the 10A scale.

Important: Read the procedure and follow the steps exactly as described in SI. The following is a summary, not the complete procedure.

The test switch permits you to place an ammeter in series with the battery negative cable. Before performing the test, the engine must be run and all accessories must be operated as instructed. After shutting the ignition off, turn the test switch off. Now, all the current being used by the vehicle is shunted through the ammeter where it is measured. If the reading is out of specification, the procedure explains how to pinpoint the cause.

 

99ssconv

EXCELLENT Response!!! BROVO!

BC