Charging System Questions

[KnockingDiesel]

I am sorry if this has been posted but a 2 hour search answered most of my questions but I still have a few.

1. Will removing any of the relays under the steering wheel cause the batteries to weaken and/or alternator not to charge.

2. Would driving it for 4 or 5 days and parking it for 2 or 3 cause the batteries to drain. (when I drive it its at least run for 30 mins, and when parked its not started at all for 2 or 3 days).


The reason I pull the relays is, someone tried to break into it and drive off with it about a month ago, and I cant afford a quality anti theft device (I am considering a Revelco). Since then I pull the relays IDM, Starter and PCM Power relays. Around this time I noticed the batteries slowly weakening each time it starts (both less than a year old) and once in a while the battery light comes on for like 30 secs then goes off, so after parking it for two days I went to start it this evening and it barley turned over, I jump started it took about 10 mins ran it for about an hour and a half non stop (went to autozone got a battery brush, some cleaner, a battery tester, distilled water and baking soda). I got home and checked the alternator and got 11.5v to 12v, turned it of disconnected the batteries cleaned them all off along with the connectors tested them seperatly and both got 10v. so the altenator is not charging the batteries, the batteries were weak but the truck started will run for hours. I pulled off the alternator and batteries will have them tested tomorrow. I have owned this truck since new, the original batteries and alternator went out about 3 years ago, so I replaced them with motorcraft parts (expensive) and got 2 years out of the new batteries and replaced them under warranty last year.


So is it coincidence that this happened, have the parts lived out their service life, whats your opinion?

Thanks
TJ

[Tj Krawler]

Originally Posted by KnockingDiesel

I am sorry if this has been posted but a 2 hour search answered most of my questions but I still have a few.

1. Will removing any of the relays under the steering wheel cause the batteries to weaken and/or alternator not to charge.

2. Would driving it for 4 or 5 days and parking it for 2 or 3 cause the batteries to drain. (when I drive it its at least run for 30 mins, and when parked its not started at all for 2 or 3 days).


The reason I pull the relays is, someone tried to break into it and drive off with it about a month ago, and I cant afford a quality anti theft device (I am considering a Revelco). Since then I pull the relays IDM, Starter and PCM Power relays. Around this time I noticed the batteries slowly weakening each time it starts (both less than a year old) and once in a while the battery light comes on for like 30 secs then goes off, so after parking it for two days I went to start it this evening and it barley turned over, I jump started it took about 10 mins ran it for about an hour and a half non stop (went to autozone got a battery brush, some cleaner, a battery tester, distilled water and baking soda). I got home and checked the alternator and got 11.5v to 12v, turned it of disconnected the batteries cleaned them all off along with the connectors tested them seperatly and both got 10v. so the altenator is not charging the batteries, the batteries were weak but the truck started will run for hours. I pulled off the alternator and batteries will have them tested tomorrow. I have owned this truck since new, the original batteries and alternator went out about 3 years ago, so I replaced them with motorcraft parts (expensive) and got 2 years out of the new batteries and replaced them under warranty last year.


So is it coincidence that this happened, have the parts lived out their service life, whats your opinion?

Thanks
TJ

#1. Not sure, but I don't see how it could.


#2. No, unless something was left on. I had to let mine sit a week at 10* outside. Cranked fine, without being plugged in.


It sounds like you're getting 11.5-12 volts at idle? Sounds like the alternator to me. Should charge at 13.5-14.5 volts.

It could be a bad charging wire. (The wire that goes from the alt to the battery) Did you check voltage at the alternator or battery?


Mine charged at 10-12 volts for 150 miles or so. It gave out on my way to the pick up the new alternator.



If you decide it is the alternator, I would recommend buying a part store NEW one. For me it was only $20 more than rebuilt ones. Most of the part stores will have a lifetime warranty. I'm happy with my Napa one.

[Schnot]

I drove my truck with the batteries so low that the interior lights and gauges went off so i know it will run with weak batteries for a long time.

You definitely got a weak alternator though.

[KnockingDiesel]

thanks for the reply guys, i guess it was just coincidence pulling the relays. I barley got a ride to the parts store today the alternator was bad and the batteries were dead and need to be charged before they can say if they are good or not.

How long is the service life of the motorcraft alternator and 850 batteries?

Thanks
TJ

[Tj Krawler]

Mine went out at 97k or so. Replaced the batteries at the same time.