Parasitic battery drain

[jp2dunk]

parasitic battery drain Volvo 2002 s60 I have had this problem for 3 years found it to be fuse number 1 in the cargo(trunk) a 10amp fuse. when fuse is pulled goes down to .002 when in drain is .100 when it drops. #1 fuse in my car booklet says rear electrical module(REM),trunk lighting. I pulled the bulb in the trunk light then pulled the connection to the lights and trunk release.No change in the .100 drain. that tell me the problem is the rear electrical module. where do I go from here. this module seems to be connect to every wire and light in the rear of the car?

[abscate]

That 0.1 Amp might be the REM signaling the trunk lid is open to the CEM

That isn’t a huge drain , either, about 10% of battery in a week sitting without running.

If that’s Williamstown MA, keep an eye out for aNautic Blue V70 just east of the “ Lions”, about 100 meters!

[RickHaleParker]

That isn’t a huge drain , either, about 10% of battery in a week sitting without running.

0.1 Amp X 168 Hours = 16.8 Amp-Hours. For it to be 10% per week, the battery would need to be a capacity of 168 amp-hours.
Most of the starter batteries are around 60 Amp-Hours. 16.8/60 x 100% = 28% DOD in a week or 4% per 24 hours.

[RickHaleParker]

I pulled the bulb in the trunk light then pulled the connection to the lights and trunk release.No change in the .100 drain. that tell me the problem is the rear electrical module. where do I go from here. this module seems to be connect to every wire and light in the rear of the car?

Check for corrosion at the light bulb sockets and electrical connector to the trunk latch. Corrosion can be semiconductive and create leakage currents. Grease, grime and other contaminants can also create leakage currents.

[jp2dunk]

This what I found so far. 1)The battery is old and as it ages the problem seem to have gotten worse. So has everything else. pulling the relays I found a green matter on the outside of the plastic relay. I then took the worst looking one apart finding green mold I think it's mold, impacting the copper coil, points, wire. My brother says it looks like it came out of an old boat. So I believe the way of a attack is 1) get a new battery 2) replace most of the relays 3)pull rear fuse, relay board out 4) look for a spray to clean and coat the wires of that board! Question as for battery, lead-acid or AGM?? SPRAY cleaner CRC qd electronic cleaner,CRC SPRAY LUBE, WD-40 Thank you all for much help

[abscate]

If you have green corrosion you have excess moisture in that area , make sure you solve that.

How old is the battery? In northern climates, 3-5 years is the norm for battery life.

Best value is conventional lead -acid. Make sure you have a battery hold down and good cables

[RickHaleParker]

I then took the worst looking one apart finding green mold I think it's mold, impacting the copper coil, points, wire.

It is called Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion). It originates at the junctions of the copper and lead solder or where the two are bridged by an electrolyte. You can find Galvanic corrosion on old copper pipes where they are soldered together.

Two things are needed for Galvanic corrosion to happen. Two dissimilar metals and a electrolyte. The electrolyte was formed out of the water and salts that got in there. After you get it corrected you need to figure out where the water is getting in and fix that also. Is the car on a salvage title? Cars that have been flooded have a lot of this type of problems.

Two dissimilar metals and a electrolyte is the chemistry of a corrosion cell, like one of the non-rechargeable batteries you might put in a flashlight. You folks that live where they salt the roads in the winter need to be vigilance to this. Salt water is an electrolyte.

Contrary to popular belief, pure water is an excellent insulator. Impurities dissolved in water that make a water solution conductive.