Trouble Starting - Battery

[jpperry]

I posted this message earlier today but it may have gotten lost when the site went down. Anyway, a few months back I had signs of a battery getting low (trouble starting or not starting at all after not being driven for a while). I tested the battery and it was on the low side of being good and was the original battery (2001 Disco 2 with 80,000 miles). I put in an Optima Red and the problem seemed to go away, but perhaps I was driving it more often, I don't recall. Anyway, the battery drain is back, and the car can not sit more than a day or two without being unable to start. If I jump it and drive it everyday it will start but is noticeably worse in the morning. I checked for current draw on the negative lead of the battery and didn't measure anything out of the ordinary. I pulled all fuses and didn't see any big change. It normally was registering 20 - 40 mA. I've never gotten a battery light to come on and it seems fine after driving; the alternator also tests good. I've read that it is possible for the diodes to go bad in the alternator allowing the battery to drain back to the alternator when the vehicle is not running, wouldn't this show up when I was checking for current draw? Also, I checked the alternator to feel if it was warm in the morning after sitting overnight and it was not noticeably warm. This weekend I will test the voltage and then unplug the alternator and see if I get drain over the weekend. Any other ideas or suggestions?

Thanks.
Joe

 

[Chongo]

Diodes and rectifiers

Hey Joe…. The diodes you are referring to is part of the rectifier in the internal regulator. The rectifier usually consist of 3 diodes, one for each electrical field. If one or more of these fail, the alternator will only produce AC current. When the alternator produces only AC current, the internal regulator will no longer work, and the end result is it will not recharge the battery. Take the Alternator off and take it to the nearest auto parts store, they usually check them for free. I hope this helps……. Chongo

 

[joey]

Also nothing against Optima batteries, but I know several people that have not had good luck with them... in one case the Rover burnt to the ground due to the battery. I would also have the battery checked.

 

[jpperry]

Chongo

Thanks for the advice, I should take the alternator in to have it checked, but I know that it is currently charging the battery as I have not had it go flat on me while driving since the issue has started and after driving the battery is rechared and starts up with no problems.

Joey

I thought I was buying a good battery but have seen more notes like yours since I have bought it. Perhaps it is the battery draining itself, I just thought it was too much of a coincidince to have the problem with my previous battery causing me to buy the new battery and then have the problem still but think it was the one thing I changed, you know what I mean?

Thanks for the suggestions, I will keep you posted.

 

[Chongo]

Hey Joe.................

Hey Joe………………….. By the way, I like that Hendrix song………………. To buy sealed optima batteries is probably the best advice you can get in a 4x4, although not the highest ampere hour rating battery money can buy, I use them extensively. I’ve been running them for almost a decade now. When My wife first got her 04 discovery, I put the optima battery in that week. The main desirable point with the optima batteries it that there is no corrosion or acid spillage. And since you put the optima red one in your half way there. Although it's only a few months old, Joey is right Have it checked, and recharged


Thanks for the advice, I should take the alternator in to have it checked, but I know that it is currently charging the battery as I have not had it go flat on me while driving since the issue has started and after driving the battery is rechared and starts up with no problems.

Alternator:
Just because the alternator charges the battery on frequent usage, doesn’t mean the alternator is working up to par. You also need to check the cables and connections, at the battery as well as the alternator itself. And the activation wire, the small wire at the back of the alternator, check for 12 + volts. This can be done at a garage or some parts stores for little money, and you don’t have to remove it from the vehicle.

Power drains:
Power drains are best isolated by pulling fuses to see which ones are affected. When the draw goes away, that is the circuit affected.
Also by pulling the ground cable and leaving the positive one connected, if you have a electrical current meter, measure the amp draw value between the ground end and the neg. battery Post. This value should be in lower milliamp range with the doors closed and the key out. If the value is high, you have a heavy draw on the battery while the key is out. Normally battery draws are related to electrical accessories or alterations installed, repaired, messed with etc. prior to the problem.

Hope this helps……………… Chongo

 

[jpperry]

Chongo...I like that song myself. I did try pulling all of the fuses and checking for amp draw but everything seemed good. I took the battery in and had it charged and checked and.....it wouldn't hold a charge. I guess I shouldn't have ruled out the obvious right away just because it was new. I have a battery checking device but it just measures output voltage, which was always good because I checked after it had been recharged. Anyway, I put the new battery in so we'll see how it goes.

Thanks for the help.