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Discussion Starter #1
I want to test for a battery drain issue. If I disconnect the negative terminal to put my multimeter between, will that screw up my settings and require some resetting/reprogramming?

I've disconnected the RF receiver antenna already. I am also having and issue with the driver's side direction indicators being stuck on so I've removed the bulbs. I believe a transistor is shot in the BECM and have ordered parts to replace the transistor. Is it possible this would be my drain?

Thanks for the help.
 

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Discussion Starter #2
An additional piece of info.

I tested the battery with the multimeter and it was at 12.48v (low) and when I started the vehicle the charging read 13.98v(low).

That leads me to believe the alternator could be faulty but will it read lower if it's trying to charge a low battery? Any way to determine which oen is faulty for sure?

I went to the local auto parts place and their meter said the battery and the alternator were good but I don't think it displayed actual numbers. It just indicates good or bad.

The vehicle would lose charge even while driving. Today I was driving it around town running errands and by my last stop, it barely turned over so I could make it home.

My charger charges the battery up to a point where I can restart the vehicle.
 

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1995-2002 Range Rover P38A
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Year model....cant help if you arnt bothered to supply the info..

Your charge rate is fine, test and check main earth cables, if you have a pre 99 then its worth adding the link cable direct from alt to battery, its an official LR update and it works.
In effect when you add this link cable it double's up your starting circuit
 

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Discussion Starter #4
viperover said:
Year model....cant help if you arnt bothered to supply the info..

Your charge rate is fine, test and check main earth cables, if you have a pre 99 then its worth adding the link cable direct from alt to battery, its an official LR update and it works.
In effect when you add this link cable it double's up your starting circuit

Sorry about that. I'm a little frustrated with the vehicle at the moment as I need it for transportation. It is a '99 4.6 HSE. It has 103000 miles.

Just so I understand. You are talking about moving the negative (earth?) cable that comes from the alternator directly to the battery rather than to the frame where it's connected now?

Thanks
 

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Discussion Starter #5
The battery dropped from 12.75 to 12.49v overnight. I'm guessing a drain but am not confident in the battery either. I had it tested at the local parts place and he said it was good but I had just charged it. I'm not sure that makes any difference.
 

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do like you said in the first post.. check to see if you have a parasitic drain on the battery. Put a meter between the negative battery post and negative cable with the car off. Make sure the number isnt 4 amps or seomthing. When i was diagnosing charing problems in my 96 i cleaned up the grounds (earth, negative) and gained over half a volt on my voltage readings. First thing you should do is clean all the grounds.

Also, the other member who sugested to put a cable between the alt and the battery, he meant between the positive output on the alt to the positive on the battery. I have done this on mine and it shows improvement. Much easier than replacing the wire that runs all the way down to the starter.
 

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Given that you have a multimeter and a range rover, you may as well start by posting the results to ALL the electrical sticky tests here. I know you have other problems as well but honestly it does help us help you.

Multimeters connected the way you have in mind can read up to 10 amps before blowing their internal fuse. You need to be careful to avoid doing anything that might draw more than 10 amps.

I prefer to use a clamp meter. This type of meter is almost as accurate and can read up to 200 amps. All you do is open the C in the clamp up, put it around one wire - eg the positive wire and close the C. It literally takes 1 second and you can start taking readings and you don't need to disturb anything to do it.

Forget about your battery shop tests, do the RR specific ones to find out what is going on.

Your multimeter test will be useful to help verify battery drain so go ahead with that too.

Do you park it in PARK or do you sometimes leave it in a gear or neutral? Do you ever have to move the gear lever or wiggle it to make the car start?

To keep it going in the meantime you will need to fix your basic electrical fault and keep it on a charger when not in use for more than a few hours.

Please post the results of the sticky tests here.
 

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Discussion Starter #8
I will try to complete the electrical sticky tomorrow. Today I tried the drain test and found the following:

After about 2 minutes the draw dropped to 0.04. This indicates no excessive drain on the battery according to what I've seen on the forum.

I'm going to replace the battery and see what happens.
 

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Here are my results. The results involving the Alternator might be off since I'm not 100 sure I was hitting the positive terminal properly.

1. Engine off, all accessories on for 30 seconds, then off. What voltage ___12.10v (After sitting all night)
2. Voltage across battery at idle (no electrical load) ____________14.31v
3. Voltage across battery at 2000rpm (no electrical load) ________14.31v
4. Voltage across battery at 2000rpm (everything electrical switched on) _________13.91v
5. Voltage at ALTERNATOR at 2000rpm (everything switched on)___________________0.05v
6. Voltage drop between alternator body and battery negative (YES negative). Measure at max electrical load and 2000rpm _-138.1mv (millivolts please)
7. Voltage drop between alternator positive and battery positive. 2000rpm, max electrical load _____________-50.5mv
8. Check Voltage drop from Battery Negative terminal to 1st groundpoint on vehicle______________0.03v
9. Check voltage drop from 1st ground point to block__________0.08v
10. Check voltage drop from Alternator Housing to block__________0.0v
11. Voltage from alternator positive to alternator housing_____1.4mv

To me, it seems that the charging system is working properly. The battery drain test showed 0.04 draw after 2 minutes but the battery still lost charge while sitting. At this point I think the battery is suspect.
 

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dekeblue said:
Here are my results. The results involving the Alternator might be off since I'm not 100 sure I was hitting the positive terminal properly.
5. Voltage at ALTERNATOR at 2000rpm (everything switched on)___________________0.05v
11. Voltage from alternator positive to alternator housing_____1.4mv
To me, it seems that the charging system is working properly. The battery drain test showed 0.04 draw after 2 minutes but the battery still lost charge while sitting. At this point I think the battery is suspect.
I tend to agree with you, 40ma draw should not bother your battery even after a week.

Tests 5 and 11 were not done correctly. Those results are impossible.

5 measures the voltage between the alternator housing and the alternator positive at 2000rpm at full electrical load. I would expect it to be about 14 volts given your other numbers but it is a good, important checksum
11 is the same test, I better fix the sticky!
 
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