65mA = normal standby current on V70XC?

sugarfreejazz · Post by **sugarfreejazz** » 10 Dec 2012, 05:20

Dear all,

New to this forum, although I did successfully perform the ABS module revision. So now it's on to the next problem.

My battery drains to the point of not being able to start the car in about four days. The battery is about two years old. A quick check tells me that there is about a 65mA current flow, measured at the positive terminal, with the car in standby and not having driven it for hours. Standby voltage is 12.1V, going up to 14.0V when idling. This drops 0.1-0.2 volts after turning on blower and headlights.

My question is: what would be a normal, reasonable standby current? (I measure about 65mA.) I appreciate any answers.

I will first disconnect the battery for a few days just to check if it loses its charge anyway. If it holds its charge then, depending on your answers, I will have to check connections and wiring to the alternator first (using "Alternator and Regulator.pdf") and start pulling fuses I guess. Would this be the correct troubleshooting order?

Post by **rmmagow** » 10 Dec 2012, 07:27

Good or bad I don't know, but if you can leave this setup hooked up, pull fuses one at a time and see if it drops to near 0. That would let you know which circuit is in used with the car off.

Post by **jblackburn** » 10 Dec 2012, 08:11

That's too high. Normal standby current is around 25 mA.

Pull fuses randomly and see if that number drops. Start with the alarm system.

12.1V means that your battery isn't holding a proper charge and is very low on cranking power. It either needs to be hooked to a charger and charged back up to 100% capacity, or may have a dead cell. (12.8V is 100% charged).

sugarfreejazz · Post by **sugarfreejazz** » 15 Dec 2012, 14:46

I believe to have found the culprit: an orphaned cell phone carkit left behind by the previous owner.

Once I pulled fuse #16 (power antenna + amp, power to caravan/trailer, accessories) the standby current dropped from 65mA down to 10mA. It was my SC-805 that pointed me in the direction of the carkit because it displayed TEL and would not be persuaded to do anything else. Knowing about the left-in carkit I suspected that perhaps a telephone mute signal was causing the stereo to enter 'TELephone' mode. So I cut the power to the carkit and in-line adapter module and thus regained my stereo for its intended purpose. I removed the carkit stuff and isolated and neatly tucked away the leftover wiring, mic, antenna etc.

The only thing that's left me a slightly confused is that I now measure no standby current at all (0mA) anymore?! In fact, I got that measurement already before even cutting the power going to the carkit (but after having located it underneath the dash.)

I can only explain this assuming that by fiddling with the carkit wiring I may 'inadvertently' have removed the short that was causing the leakage current in the first place. (Or perhaps the current has dropped below the resolution of my meter - I may have only had the meter at the 10A scale setting.)

It's got me puzzled, mainly because no leakage current at all would be hard to believe. That, and I would have like to have been able to confirm the root cause by seeing the current drop by cutting the wires to the carkit with fuse #16 in. Of course I could try with a second multimeter I guess. Now I cannot exclude the possibility of a short in the antenna amp or trailer power circuitry (even though my V70XC has no tow bar.)

Any thoughts?

For the record, and for the remote possibility that this information may serve others with ancient carkits I will include the type numbers of the carkit: Ericsson 5020018 - BV and adapter module Grundig TA-1.

Post by **Pauloil** » 16 Dec 2012, 07:17

something is always running, security etc, so you will have 10-15mA. do a Voltage Drop test on your B+ cable from the batt to the fuse box, it that is bad the batt. voltage drops also. look for corrosion at the grommet at the end of the cable by the fuse box.

https://www.matthewsvolvosite.com/forums ... =1&t=35208

sugarfreejazz · Post by **sugarfreejazz** » 03 Jan 2013, 04:17

Thanks for your suggestion Pauloil. Due to personal circumstances I have not gotten around to testing the B+ cable running to the fuse box. Fortunately, the battery has not died on me since I removed the carkit; it seems to have plenty of juice whenever I start the car. So I will put the cable test on the todo list for this Summer and check/replace all the battery / starter / alternator / fuse box cabling. Should I find anything worth mentioning I will post it here. Thanks again for your help.