Parasitic Loads

Buick vehicles may have several electrical devices which result in continuous current drains on their batteries. Batteries in vehicles not being used for an extended period may become discharged by these small current drains called parasitic loads.

Any battery discharged by parasitic loading and then allowed to stand in this condition for a period of time, may not readily accept recharge. However, if properly recharged, batteries will return to a good usable condition.
Extremely discharged batteries can freeze at temperatures as high as +20F, and freezing can also cause permanent damage. Permanent damage to discharged batteries can also be accelerated by high temperatures.

FIGURE 1 - BATTERY POWER:

Figure 1 shows what happens to available battery power and the power required to start the engine at different outside temperatures.

FIGURE 2:

Figure 2 shows a typical amount of current used in getting a vehicle built and delivered to the dealer, how much is available for electrical devices, and how much is necessary to start the vehicle. The battery begins to be discharged at the time it is connected. Current is used during plant build, carrier handling, dealer storage, and new car preparation. During this entire period, the vehicle is never driven long enough nor at a high enough RPM to bring the battery back up to a full state of charge.
A vehicle sitting for 2 months at 32~F most likely will not start due to parasitic load and self-discharge.

Examples of parasitic loads:

Device Milliamp Draw

Voltage Regulator 1
Digital Clock 3-4.5
Quartz Clock 7
ECM 6.5-8
ETR Radio & Clock 7
Load Leveling 4
Memory Seat 3
Twilight Sentinel 3

TYPICAL PARASITIC LOADS

Load (Milliamps) At
Model 12.6 Battery Volts

Skyhawk 7
Somerset & Skylark 9
Century 2.5L 10
2.8L 5
3.8L 16
Regal 5
LeSabre 9
Electra 13
LeSabre & Electra Estate Wagon 16
Riviera 23

Chemical reactions take place in all batteries, even if they are not connected to a load. Therefore, a certain amount of self-discharge is always occurring. The higher the ambient temperature, the greater the amount of self-discharge. This explains why the number of discharged batteries increases in very hot weather. The Delco Freedom battery has a much lower rate of self-discharge than conventional batteries. The chart at top of next page demonstrates how the increased temperature affects self-discharge.
Rate of
Temperature Self-Discharge (Milliamps)

120 11.2
100 6.8
70 1.8
50 .8


To prevent battery damage and difficulty in recharging, any vehicles that are not going to be in service within a 30-60 day period should have ground cable(s) disconnected to remove the constant drain on the batteries. If this is not possible, batteries should be recharged periodically every 30-60 days until the green dot is visible. The longer a vehicle sits on a dealer's lot with the battery cables connected, the higher the probability that it will have to be recharged due to the drain caused by parasitic loads and self-discharge.

CHARGING TIME REQUIRED

The time required to charge a battery will vary, dependent upon the following factors:

^ Capacity of Battery - A completely discharged large heavy-duty battery requires more than twice the recharging as a completely discharged small passenger car battery.

^ Temperature - A longer time will be needed to charge any battery at 0~F than at 80~F. When a fast charger is connected to a cold battery, the current accepted by the battery will be very low at first, then in time, the battery will accept a higher rate as the battery warms.

^ Charger Capacity - A charger which car supply only five amperes will require a much longer period of charging than a charger that can supply 30 amperes or more.

^ State-Of-Charge - A completely discharged battery requires more than twice as much charge as a one-half charged battery. Because the electrolyte is nearly pure water, and a poor conductor in a completely discharged battery, the current accepted by the battery is very low at first. Later, as the charging current causes the electrolyte acid content to increase, the char in current will likewise increase.