Re: drain current Alfa 90

[Lars Arvidsson <arvid@domain.elided>]

[Anthony wrote:]
Hi all,
My Alfa 90 seems to drain the battery after about a week of sitting
around
in the garage. The Battery is new and the altenator is charging. If I
use it
everyday, it is fine. But when it sits for a week, there is not enough
juice
to crank the motor.
I have measured the drain current with everything off, and it's about
26mA.
Is this excessive, or am I to expect this due to drain from clock and
odometer?

[Lars replies:]
Well, 26 mA is not that much. It corresponds to 0.3 watts at 12 V.
On a week it drains the battery with : 0.026 x 24 x 7 = 4.37 Ah
I guess your battery is somewhere 55-75 Ah, so there should be plenty
left.
Could it be something intermittent that discharging the battery?  Brake
lights contact ?

Measuring on the battery, you should get abt. 14 volts with engine
running.
Try to disconnect the battery for a week,  then see what's happening.
If it works OK, then something is draining far more than 26 mA
sometimes.
If not OK, the battery is no-good, or the generator is bad.
Charge the battery with a mains-connected charger, until it's fully
charged.
Then let it rest for a week, with disconnected cables.
Then repeat above, if it's OK, your generator/charging circuits is bad,
if not OK, the battery is bad.

Also, check the grounding wire between the engine and the negative pole
of the battery.
This can cause strange behavior when starter is engaged, since there is
a lot of current floating, well over 400 A.

All the best
Lars in Sweden
Alfa 75 TS 1990
E-mail: arvid@domain.elided

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