I finally got serious on trying to track down my battery draining problems over the past year or so.
I was hoping it was something easy like a bad headlight retractor motor, but that would've been too easy.

Measuring current draw with KEY OFF, the DMM showed 0.25A draw.
Just a little too high...
It was enough to kill a bunch of batteries over the course of sitting around over a period of 3 days.
You would not have noticed if you drove the car daily or every other day, but after the 3rd day, cranking was significantly slower.
If I tried to leave it for more than the 4th day, the battery was dead enough to not be able to turn the starter at all.
The car has gone through 4 - 5 batteries during this time.
I can easily recharge the batteries using an external charger, but deep cycling automotive batteries like this is a slow death.

I had the FD alterator wired up correctly (constant +12VDC for the exciter lead), but it looks like the exciter field wasn't dropping when the alternator stopped turning.
Killing the power (I've got a relocated battery with two manual-reset CB's) would "reset" the alternator, and current draw would drop to a normal 0.03A.
Just disconnecting the exciter lead with main power still active would not drop the exciter field, and the current draw would still be high at 0.25A.
So putting the exciter lead to switched ignition +12VDC isn't the solution.

I dunno how the FD charging system is wired, but I can't believe that Mazda would be stupid enough to allow this to happen.
BTW, this is a silverrotor FD alternator.

For now, I can always kill the CB to band aid solution this problem, but this will keep reseting my clock. :P


-Ted

 

Hmm, that's too bad. I may have to rethink my plan to upgrade to an S6 alternator.

Any of the others who converted having problems?

 

I have an S6 alternator on mine, but I havent noticed any battery drain. I just wired it up in the "accepted" way on here with the exciter wire running to fused 12V too. I dont know where the alt came from as it came on the engine (but un-wired), but it seems to work fine

 

No, but my car is a DD and has never yet sat for even three days unstarted.

RETed didn't mention what series his car is...mine is a S5 and I was under the impression that the conversion was plug-n-play...

 

I haven't had any drain issues yet. Im running silverrotor's FD alt as well.

 

I installed an OEM not rebuilt FD alt in my S4 when I replaced the engine. I wired the S terminal to the fuse box and the L terminal to the original L terminal. The lights no longer dim when you operate the windows at night time! I haven't had a problem with it yet

Vince

 

Sorry, it's a 1987 Turbo II.
I do have an Alpine alarm that I usually arm, so that might add a tad bit to the current drain while it's just sitting there.

Or am the only one that leaves their FC's parked for that long?


-Ted

 

mines a DD now, but before that while i was still working on her she sat around untended for 2 weeks without starting (and id play the radio occasionally while working too), and I didnt have a problem trying to start the next time.

 

I had the same problem with a Silverotor alternator and a Bosch unit. I did the 12v constant fix and that worked for me and I've had my car sit for a week at a time with a Braille sized battery and it still starts.


Maybe a bad alt? Have you tried a different FD alt?