[Mg-t] Battery issue

[Stuart C. Keen, Jr.]

I9m having an issue with batteries in my TD. Hopefully someone has an
answer. I am going though Optima batteries like they were the greatest thing
since sliced bread. Why are Optima batteries failing so frequently (every
2.5 years or less) when placed in my TD?  Perhaps the below facts and data
will reveal cause of problem. Please let me know of any other tests I should
be making.

FACTS:  Four and a half years ago I installed an Optima Red Top. Two years
later it failed. Replaced and also installed a solid state voltage
regulator. Two and a half years later the second Optima failed. It was just
replaced with a third Optima. Chronologically:

6/28/04    54,187 odometer    Installed Optima #1. Original 5-terminal relay
voltage regulator installed.

6/02/06    64,487 odometer    Replaced Optima #2, installed Solid State
Regulator

1/03/09    78,807 odometer    Replaced Optima #3

Is this an Optima problem or a MG problem?

DATA:  (Digital voltmeter readings taken at dashboard TEST POINTS while
driving)

MG at idle  @ 1000 rpm    charging voltage 11.9 vdc

MG @ 2000 - 3000 rpm    charging voltage 14.00 to 15.00  vdc  (seems to
depend on how close the battery is to being fully charged)


STATE OF BATTERY #3 (voltage reading made after letting battery
3stabilize/settle2 for 15 minutes)

Battery was first charged on work bench to        12.74 vdc

The CHARGE on battery after driving 1 hour       12.78 vdc

CHARGE on battery after 12 hours of non-use    12.60 vdc

CHARGE on battery after 36 hours of non-use    12.25 vdc

The Optima web site states the battery should maintain a voltage of 12.6 to
12.8. It should NEVER be allowed to fall below 12.6 volts, otherwise it will
start to sulfate. If I don9t drive for a couple of days, the battery will
drop to 12.00 or lower! Is this normal?

With ignition OFF, drain on battery in the MG is 16 MA (0.016 Amps). This
is from a car alarm and standby voltage  for Radio and CD Player.  When
driving (without lights) the dash ammeter charging amperage looks approx
Plus 3 amps. With lights on, the dash ammeter reads basically ZERO.

I checked this morning  the status of the battery in my General Motor9s CTS
after non-use for 2.5 days. It reads 12.01 vdc. However, when I start the
CTS, the charging voltage jumps to 14.5 vdc @750 rpm. The MG only shows a
charging voltage of 11.9  at start up (idle) unless revved to 2000 rpm. Is
the MG suppose to show full charging voltage (14 - 15 vdc) when starting and
idling or is this normal for 3unsophisticated2 classic cars?

PS I changed to Optima because I had one lead-acid battery leak from a
pin-hole on the side and a second that was leaking from the top.

Stuart Keen
1951 MG TD Mark II