This is getting rediculous. I go through 1 battery a year. I had a mazda guy look over all the grounds when i had it serviced last...he didnt find anything wrong. Well, SOMETHING IS. A damn battery should last more than 1 year, and this has been my 4th battery in 5 years. Im driving a 84 GSL and i replaced the alternator about 2 years ago.

 

ahhh the love of rx7's,and the things we put up with.yes it happens to all rx's.well at least first and second gens.im surprised no one has replied to this already.heres the deal.you CANNOT leave an rx7 not to be started for more then a week.sometimes even three days will do it.dont know why it does it.just does.did it on both my first gens.my second gen and my buddies second gen.ill have to give you the name of the battery im using.its nothing spectacular but has held up very well.ive let it almost die four times already.jumped it and it fired right up.drove it for a couple of miles and it held the charge everytime.my last batteries once they died they were dead.no bringing them back.and they were expensive 950 cca batteries.put in a battery cut off switch,run a seperate wire to your radio and clock,diode isolate the two wire against feeding the rest of the car and it will solve the problem,if it is bothering you that bad.good luck.

 

Well, i drive it EVERY day except sunday pretty much. And im not getting onough power through the entire system, as u turn more stuff on, volatge drops like a 747 on 1 engine. Im going to try replacing the battery terminals and the grounds this weekend..any good ideas how to make a better battery and alternator ground?

 

Well, hopefully atleast the batteries should be replaced with no charge if they are only lasting a year. One of the problems I could also see is where they are and the fact the rotaries apparently get a little warm. Heat will kill a car battery. You could always try putting something to act as a heat shield around it. A piece of plastic or a piece of tin would probably help.

And if you are just drawing too much power for your altenator to handle (like big stereo or something) you may just want to getting an altenator that will put out a little more juice if that is actually the problem.

 

Do the second gen alternator upgrade, you find the info in archived posts.
hanman

 

Replacing the terminals and ground wire should do it. Be sure to clean the grounding points with light sandpaper.
You can add a ground from the alternator mounting bolt to the battery ground, but it should not be necessary if the existing grounds and the wire are good.

I was going to suggest the battery was being overcharged, but you have replaced the alternator so it's not likely the problem now. Have you had it load tested? It will tell you if the alternator is charging the battery properly. If you do not have extra equipment (large amplifiers, etc.) you would not need a larger alternator.

If you have a voltmeter, you want about 13.6v (at around 1500 rpm. Voltage will vary with engine speed.) at the battery terminals when running: much more will overcharge the battery and kill it. If it is high, the alternator is not regulating properly.

-John.

 

when charging i get around 12.8. When i got accesories on i get little under 12. I do got a Sony Xplod radio..the silver one with the red lights (matches the other lights almost perfectly), but i dont have any amps because i dont WANT subwoofers that shake your car apart. At night, when idling, the headlights are dim, yet when i am going, they brighten up....im thinking that prehaps the alternator isnt turning fast enough? My idle is around 800...900 with A/C on.

 

two things kill batteries fast: heat and vibration. we can't do much about heat but you can at least make SURE the battery can't move around. it must be securely fastened down... if you can grab an edge or a corner and make it move it's not secured good enough!

my SA would dim the lights like you describe, at idle... I had a 65amp alternator that I put in because I do lots of night driving and I had some high power accessories (MSD ignition and electric fan - 30+ amps right there)