Upon returning yesterday from a 12-day vacation, I got home to find my `05 wouldn't start. I could get the blue glow from the gauges, but when I turned the key to the on position they didn't switch to white; instead the gauges would jump around erratically and everything would dim. I double-checked, and I'm 99% sure everything (including the trunk) was closed before I left.

No big deal; I figured maybe I was due for a new battery (I just bought the RX-8 a few months ago used) and pulled my wife's Mazda3 over for a jumpstart. Now comes the weird part. When connected to the 3 (bought new a couple of months ago; the battery should be fine) with booster cables the way the manual describes, I still couldn't start the RX-8. The headlights would come on, the fans would blow, the gauges & display would act normally, but when trying to turn it over I would just get a clicking/snapping sound repeating quickly. I'm guessing that was the starter, but I'm not 100% sure.

I have the battery out of the car and on a charger since last night. The charger put it at 6% charged when I tested it; I'll try it again in a while once the charge is complete. My worry is this: why couldn't I jumpstart? Do I have another issue? Would the Mazda3's stock battery not be powerful enough to start the RX-8? If I need a new battery, should I get another Panasonic from the dealer or go with an Optima red-top?

 

Red top

 

Once your battery falls below 5 volts, the chances of recharging greatly diminishes.
You can take it to Autozone and see if they can recharge it (its free), but you might be looking into a new battery.

 

Get a new battery. Batteries are never the same after letting them discharge that much. you might be able to recharge it but it will leave you stranded somewhere in a few months.

 

possible reasons for not being able to jumpstart:
-the mazda 3 battery's output may be too small for the rx-8
-the jumper cables are crap(rusted connections, too thin, etc)

You could take out the mazda 3's battery and put it into the rx8 temporarily and see if it would work.

 

Try it again after the battery is charged.

Very often when a battery is way down a car won't start even with a jump. When that happens, the customary procedure is to leave the cables hooked up with the donor car running for about 10 minutes, then try again.

I've had that happen a few times over the decades. No need to panic.

Ken

 

Wait a minute, you have a Panasonic battery in your car?

if thats the case, that simply means the car has NEVER got the Engine No-Start TSB done.

If you're still within the bumper to bumper warranty, go visit the dealership ASAP. they might want you to pay for the battery, just deny that, the new starter alone is worth it. Then go get Optima Red-Top (Make sure its the one with reverse terminals, the regular D35 wont fit correctly)