96 Volvo 850 Turbo Wagon Automatic
2 yr. old Farm & Fleet 600 CCA battery - 7 yr. Warranty
Weather: Cold - January and February in Midwest
Fluke 88 Digital Multi Meter for testing
NO Ammeter to test amperage over 10A

Wife's Car For Work - Drives to work 4 days a week about a 15-18 mile round trip on highway.

Problem: For last 2 + months battery will go dead (low enough not to crank over) if car sits for 2 or 3 days without being driven. If driven every day the car will start. I have had to recharge battery at 2A overnight 4 or 5 times over this period of time.

Took battery terminals apart (did not uncrimp wires though) and cleaned with wire brush and WD40. Put dialectic grease on all area's and reinstalled cable terminals on battery. Same results.

Tested Voltage output also by wiggling Positive cable as some problems in crimped wire have been a problem. No change to note.

Testing Part 1

1. Battery Test: Charged car overnight and brought to AutoZone to test battery and alternator. They tested battery in car and said battery was Bad and couldn't test alternator.

Removed battery next day and brought to F&F for test and return. They tested battery and said it tested Good with results:
Voltage: 12.37V
CCA: 545
Temp: 72 degrees

To double check these results I asked them to quick charge battery to full capacity (20 mins at store) and test under load. They did this and said battery was still Good. Assume the battery then is good?

2. Testing Voltage:
Next day installed battery.
Engine Off Battery Connected: 12.24 V

Engine On w/ Head Lights and Blower On:
First started and running the voltage was 14.4V at idle (about 700 RPM) and 2k RPM - both same results
1st test running for a short while was 13.99V at idle
2nd test running a little longer was13.95V at idle
3rd test running longer, about 10-15 minutes, 13.87V idle and 13.97V at 2k RPM

Voltages seem to be adequate for charging? but concerns about dropping voltage.

3. Ohm Testing For Short In Wiring: Disconnected battery cables. Placed DMM between pos. and neg. cables in ohm setting. Ohms steadily rose to 1.96 K ohms and held steady. Doesn't appear to be any direct short?

4. Testing For Parasitic Drain On Battery From Components: Installed meter wire in mA socket and set meter to mA.

A) Engine Off: Removed Neg. battery cable. Connected one lead to cable and the other to Neg battery post. Meter reading settled out on 23 mA and occasionally fluxuated to 29 mA. Appears to be within tolerances? I read somewhere this was within parameters of being normal component drain on car, so no parasitic drain? Reconnected battery cable to battery.

B) Engine Off: Removed Pos. battery cable. Connected one DMM lead to cable and other to Pos. battery post. Meter reading was at 23.3 mA and fluxuated to 29 mA. Same as above.

SUMMARY: It is a super pain to have to remove the alternator in this weather without doing the basics first. It's cold working outside on this and before I go into the next stage of testing cables, grounds and alternator would like some input on results and if they sound good or if there is a problem here.

Thanks to ALL in advance for your help and input.

Clark

 

I am also interested in this question. My 1997 850 battery drains when the car is not used for a while. I have no clue why, I have tested the battery as well, it is good. I have tried testing to see if a drain is happening using tools but I never can seem to find it. I have no clue if it is random, since it is not constant. It is something I would like to get fixed though.

 

these are a pain to find sometimes. In other stories I've seen where one person found it was the lamp inside their glovebox was staying on - and a friend of mine had some food dropped into his console that was enough to create a path of low resistance (cleaned it up and battery stayed good. you may want to try pulling fuses and testing for a current draw to see if you can isolate a circuit...or a bad connector somewhere.

 

Hi, thanks for the reply.

I am certainly no expert on any of this and am just trying to get answers for the test results I did from those who know before I continue with looking at other possible problems.

Do these test results look normal or is there a problem with any of them?

I did an ohm's test for a short in the system. I had read in a search that this was within the correct readings to rule out a short in the system.

Do the results of this ohm's test for a short I listed seem OK or is there a problem with that from the info above?

I did the test for a current draw (parasitic draw) and again from what I had read this seemed within the tolerances of normal current draw from components on the car. If I understood the amount of current normally being drawn correctly does this not eliminate the need to pull fuses?

What should the normal current draw tolerances be?

Thanks again,

Clark

 

QQ - did you put the dielectric grease on the posts or spray it on after you bolted the cables back on? the idea of the grease is to keep dirt and moisture out - not to aid conduction between the cables and the terminals - there you want shiny metal on metal and use the grease to coat once bolted back on.

Another area to check is the ground strap connection to the block and the big cable to the starter. it may be possible you're not getting all the amps to the starter. If you have access, you can try to clean those up as well.

You may need to drop into a shop to get your alternator tested as well. The voltages say all the battery cells are working and all the diodes in the alt are good but its possible the brushes are not producing enough amps but a more formal test may be required from a shop.

 

Hi, thanks for the reply,

I used a tube of Permatex Dielectric Grease and squeezed a little on cleaned connectors on the cables when I put them back together and coated the crimped wiring also. I did not put any on the battery posts or inside of the clamps that make the post connection. Is this a bad practice to implement?

On the second part of your post I have not cleaned any ground connections or tested the cables yet. I wanted to confirm that the tests I already performed showed no problems before I move on to the next phase.

So to double check... from what I posted of the tests I made, do you believe it does not sound like a direct short or parasitic battery drain? If not I will proceed to the next phase of tests. Otherwise I will try to fix any of these problems before I go on.

Thanks,

Clark

 

Your tests were excellent. You say you're not an expert but I was impressed. I would conclude from that battery drain through the car, 20-30 mA, is not the problem. There are people who will tell you to have your alternator "checked" and your battery "checked" but the people doing the checking don't know 1% as much about electricity as you have already demonstrated.

My next experiment, if I were you, would be to determine if the battery runs down while disconnected. I personally have never seen a slow internal battery drain, and I can think of several reasons why that might be a rare thing. If the battery is okay disconnected, then I think you have a conflict between certain things you have observed, but in the end there will be a rational explanation for that.

 

Hi, thanks for the encouragement.

The battery test you mention will be my next step in this process. If that tests out fine then I will move on to the next phase - Part 2 - and I will start a new thread on that portion of it as this one would get pretty long.

I will get back to all with the battery test results. It may be a little while as the weather here is brutal for the next week.

 

slow internal battery drains are not that rare - it can happen when impurities get into the battery cell to create a conductance path (Say when topping a cell with regular water). This is exactly how older NiCad PC batteries die... (impurities create "dendrites" which are like molecular level short circuits). Its a good suggestion since its cheap and easy...

 

As mentioned, the glove box light is know to drain batteries over a few days. Toss the phone in the glove box while it is recording a video. Close the box, open it back up and watch the video. If the light is ON while the glove box was closed, start there.

 

Hi all,

Finally back to report on this problem I had. It's finally warming up enough to work outside again.

For whatever reason the problem stopped and the battery has been holding a charge without going dead since the time I made the first postings on this subject even through the very cold weather. It's now a couple months later, April, and it is warm out so I will clean all the ground contacts anyway to be sure.

At this time I do not need to post the Part 2 of this problem as it seems to have been corrected (fingers crossed).

I just wanted to follow up on this post and thank everyone for the help and support.

Clark