Battery

[sailsmen]

Drove the Marauder on Wednesday and all good.

Saturday tried to start and battery dead.

Charger showed 8% and 11 volts. Charged 1.5 hours @15amps = 40%.

Due to rain unhooked charger. 13 hours latter with no charger 10% and 11 volts.

Reinstalled charger, 14 hours latter 90% and 12 volts. Marauder started up, drove on and off tow truck to shop.

Next day a shop starts right up, which is Friday. Monday at shop starts right up.

Battery is ~6 months old. Any ideas?

Thanks in advance for your response.

[azgolfrat]

I'm a newb, but here is an idea...when I put in the fuel pump I ran a line from the battery...and through a relay before onto the pump (essentially). The relay only allows power to the pump when the key is turned, otherwise the pump (and maybe the fuel pump driver?) is getting voltage/current all the time (though not running), and I was told this would run the battery down.

[SilverPhoenix]

When you drove it on Wednesday, how long did you drive it?
It started up just fine Friday and Monday at shop...did it sit at the shop over the weekend? Did they put a charger on it?

I'm thinking 1 of 2 things...battery is defective or the alternator is not working 100%. Don't know where you got your battery from, but since it's only 6 months old I'd get it tested and/or swap it out for another one. If the issue persists, then have alternator checked out. Parasitic drain is also a possibility, but if it sat at a garage over the weekend and cranked right up then that eliminates that.

[sailsmen]

On Wed 45 minutes. Yes, sat at shop over weekend w/ no charger.

[GreekGod]

Battery drain can be difficult to diagnose - especially if intermittent.

An experienced tech told me that an 8 hour day of diagnosis may not be enough to find an intermittent drain.

Newer cars have many computers on board.