Subject: it could be as simple as a dead battey Author: shogun (moderator) : member since March, 2004 : 12550 posts Posted on: 2009-09-30 00:31:58

make a load test, not only checking with a multimeter for 12V.

http://www.batteryfaq.org/

Inspect

4.1 Visually inspect for obvious problems such as a low electrolyte levels; loose, corroded or swollen cables, corroded battery terminals or posts; loose or broken alternator belt; frozen battery; loose hold-down clamps; dirty or wet battery top; or a leaking, cracked, bulging or damaged battery case. If the electrolyte levels are below the tops of the plates, add enough distilled, deionized or demineralized water to cover the plates and recharge the battery, allow to cool to room temperature and then top off the levels. The plates need to be covered at all times to prevent sulfation and reduce the possibility of an internal battery explosion. Please see Section 3.2 for electrolyte fill level information.

If electrolyte has been spilled, please see Section 9.14 for more information on adding electrolyte or adjusting the Specific Gravity within a cell.

4.2. Charge

Charge the battery to 100% State-of-Charge in a well ventilated area. If non-sealed battery has a .030 (sometimes expressed as 30 "points") or more difference in Specific Gravity reading between the lowest and highest cell or if a cell is .010 or 10 "points" below the reading for a fully charged cell, then you should equalize the battery using the battery manufacturer's procedures. (Please see Section 9. for more information on equalize charging.)


4.3. Remove Surface Charge

Surface charge (or "counter voltage") is the uneven mixture of sulfuric acid and water along the surface of the plates as a result of charging or discharging as the electrolyte has an opportunity to diffuse in the pores of the plates. It will make a weak battery appear good or a good battery appear bad. Larger wet lead-acid batteries (especially over 100 amp hours) could also have electrolyte stratification where the concentration of acid is greater at the bottom of the cell than near the surface. Open Circuit Voltages (OCV) will read higher than they actually are. Stratification can be eliminated by an equalizing charge, stirring or shaking the battery to mix the electrolyte.

The surface charge can be eliminated by one of the following methods after recharging a lead-acid car battery:

Allow the battery to sit (or rest) without discharge or charge for between six to twelve hours at room temperature, if possible, to allow for the surface charge to dissipate. (Recommended method.)


Turn the headlights on high beam for five minutes, turn them off, and wait ten minutes.


With a battery load tester, apply a load at one-half the battery's CCA rating for 15 seconds and then wait ten minutes.


Disable the ignition, turn the engine over for 15 seconds with the starter motor, and wait ten minutes.


Apply a load that is 33% of the ampere-hour capacity for five minutes and wait ten minutes.


With a battery load tester, apply a load is one third the battery's amp-hour rating for five minutes and wait five minutes.


4.4. Measure the State-of-Charge (SoC)

The State-of-Charge acts like a "battery fuel gauge", but it only measures the state of the battery's charge and not it's storage capacity or state of health to produce rated current. For storage capacity measurements, please see Section 4.5, below. For example, a 50% SoC reading does not necessarily mean that a 100 amp hour (C/20) battery will produce 50 amp hours at five amp discharge load (with five amps being the 20 hour discharge load) because the battery might not have a 100 amp hours of storage capacity to begin with. Depth-of-Discharge (DoD) is the inverse of State-of-Charge (SoC) as shown in the following graphic.

E32 750iL 11/88, E32 750iL Highline 03/90
SHOGUN'S TRICKS AND TIPS FOR THE SEVEN SERIES

• Electrical Problem - abracadabra 2009-09-28 15:02:12 (54 views)
  • Re: Electrical Problem - Additional Info - abracadabra 2009-09-29 22:55:36 (56 views)
    • it could be as simple as a dead battey (url) - shogun 2009-09-30 00:31:58 (53 views)
      • Re: it could be as simple as a dead battey - abracadabra 2009-10-03 12:08:17 (40 views)