2005 S60R electrical problem

[ejsimcox]

Hello,


I have a 2005 S60R. I went out the other day to start it, and the battery was dead. Tested the alternator with and without load. It was fine.

I put a charge on the battery, and was able to drive it to the mechanic to have it checked. The car felt fine at idle and underway. Battery was full with a nice surface charge when I arrived. Alternator fine.

Drove for 40 mintes without issue. Again, it was fine under idle and underway. Parked for two hours. then it wouldn't start. Battery totally drained again. The window wouldn't even go down. Recevied a jump start in the parking lot. However, this time the enigine was hesitating. I barely made it to the other end of the parking lot before the engine died. Tried another jumpstart. I could get it to start, but could never get enough power to put it in drive and move.

Other fact: about 3 months ago, the security module started going out. I have been getting the security system console message ever since. I have been meaning to replace it DiY. Could the security module be affecting the battery that aggressively, or screwing with the computer? Other than that, I have not had any computer or electrical issues.


Any ideas?


Thanks!

[jimmy57]

I would start by unplugging the alarm siren. You can do this by pulling back the forward part of plastic RH front fender liner and then unplugging electrical connector from the siren that is mounted up high behind that liner. You will have a message about alarm service required from doing this but if the siren circuit has been shorted by the failed battery within this will stop the battery dead problem.
A dealer can download a software to remove alarm function and that will make message go away without replacing siren (500 US dollars for part).

By the way, charge your battery with a battery charger on a lower rate (6-12 amps) for 12-36 hours or you will shorten the life of the battery significantly. Alternators keep a fully charged battery charged but will not bring a flat battery back to full charge. Car may start but that is not an indicator of the battery having been returned chemically to full charge state.

[coflynn]

Killing the battery that fast would suggest something else, although perhaps it is the siren! One thing I would check is if the alternator is warm after the car has switched off.

I had an issue with my voltage regulator failing. It would still regulate OK meaning the car was charging & diagnostics said everything OK. But it failed to switch off one of the windings in the alternator when turning off the car, so you'd get a huge draw that would quickly kill the battery.

See https://www.matthewsvolvosite.com/forums ... =9&t=51058 .

Having a current clamp meter is best since you can quickly figure out where the current is going and what the draw is.

The 'warm' test is the fact if you are drawing a high current (~4A) @ 12V, it's something like 50W being dissipated in the alternator. Of course once it's killed the battery that isn't the case!