Hi guys. Im needing to put a new alternator in my 07 2500hd lt. I think anyways? I put in a relay isolator and a second battery and for a while everything was fine but now im getting a service battery charging system message and my voltage wont gi above 11.5v . I think, well i hope rather its just my curesnt alternator not beingnpowerful anough? What would yiu guys recommend for a stronger alternator? I was looking around online but do t know one from rhe other?
Hate to say it but looks like the rectifier on your alternator has gone out causing the no charge issue. I would check all your connections at the battery and alt, also check the actuall votalge with a volt meter. Ive ran two batteries directed connected in my last 3 trucks and never had a issue with the stock alternator not being powerful enough. If you use your truck with the engine off alot then I would recomend a 140a factory alt. Just so the batterys will charge faster and be less worry about waiting with the motor running trying to get the batteries charged. Any alt above 140-150a will start to have reliability issues. I would look around for a local shop that knows what there doing when it comes to rebuliding alts. A good shop would charge you about $100 and take about 2 hours if they have to remove the alt. If you take it out about 45 mins for them to rebulit it.
So youre saying that theres no chance at fixing my problem with a new alternator? Ive never even heard of a rectifier before? Everything was working fine untill i added that stupid relay isolator and then i started to have problems. At first i thkught it was the battery so i changed it out yesterday. It was fine for an hour or so and then it started giving me that code again.
Did you check the isolator? What kind is it? How old?
Could it have malfunctioned and be draining the main battery at the wrong time?
You could temporarily rewire back to the old way (single battery) and see what happens. Of coarse if the battery is shot from the isolator draining it incorrectly, you would need a new one.
The isolator was installed in october and the battery was put in on sunday. Yesterday when i left for work in the morning me battery only reached 11.5v and slowly drained while i was driving to and from work. My commute is about 30 min in both directions and in the total of 1 hour driving my voltage dropped to just over 9v. I didnt think i was gonna make it home yesterday. It looks like the battery is no longer being charged at all. It shouldnt be the isolator because he alternator is still hooked up directly to the main battery and the isolator only seperates tue two batteries. This truck is 6years old and has close to 200,000 miles on it so would it be possible that this alternator just needs to be replaced?
The isolator would have nothing to do with your alt not charging. I suggested that the factory one could be rebulit at about half the price of a compleat replacement. If the copper coil in the old one is intact and test fine there is no reason why the old one couldnt be used. The rectifier is what changes the ac current the coil produces into dc current. It also regulates the voltage that the alt puts out by reading the voltage from the battery and charges according to the charge demand your truck. Your alt isnt charging at all. When you replaced the battery, your truck was running off the battery only If you would have continued to drive the truck would have eventualy left you stranted once the battery was dead. If you do get a new aftermarket alt makes sure to get one with a decent replacement warranty and keep your recept for proof incase it goes out on you in the future. A isolator is good for seperating two batteries when the truck is off to keep your starting battery charged while the accoreries are being used while the truck is off. Isolaters can be good and bad at the same time depends on how its hooked up. If the second battery is compleatly drained and the isolater is wired to connect the batteries as soon as the key is turned on. The isolater is connecting a dead battery to a charged one putting extra strain on the starting battery but trying the charge the dead one and also trying to start your truck. If its wired with a delay then the strain isnt as bad but the dead battery is seeing a very harsh and fast charge. That would be fine if its is a gel cell or another type of battery that can handle a rapid charge. I would personaly get rid of the isolater and get two matched batteries ( same type, brand and ratings) and hook them up directly. Put a fuse in line at both batteries 20-50 amps above what your alts is rated. Granted if you run your lights for a long enough time both batteries will drain. Keep in mind that at that point your are running two batteries with double reserve power of one so the likely hood of it happing is a slim one. If you have any questions pm me. I would be glad to help you out.
Long story short, I can't afford to accidentally kill my starting battery if I'm 60 miles down a one-way beach road and if I'm out fishing for a week or more there's a pretty good chance I can kill two batteries in one night. I can't risk having them connected in tandem.
I tried putting in a diode isolator so that each battery would be completely separated but I couldn't find one that would work with my alternator. I did buy two and try to instal them myself to no avail. I settled for a relay isolator instead and had a car audio shop install it for me. It will only charge the secondary battery once the main battery is charged. If the main battery dies it will allow power from the secondary battery into the main. I killed my starting battery as I was installing those diode isolators to the point that it wouldn't hold a charge. But even tho it was dead every time I started the truck, the new relay isolator would allow power from my auxiliary battery (optima yellow top) to jump the starting battery. Once the truck was on the alternator would bring the starting battery up to 14v. It would then die again overnight and the process would then repeat. Is it possible that I just overwork the hell out of the alternator by doing this over and over again since October?
I read your isolator thread and watched your video. People need to know that when you use the solid state (diode) isolators, there are "complications". See this link, and you will see how complicated it can get for the average joe DIY'er. http://www.cooperindustries.com/content ... 80012q.pdf
You hooked up the SS isolator in the video incorrectly IMO and you may very well have damaged your alternator, battery and anything else that was hooked into it.
Now that you have found the easier way to install an isolator (smart solenoid), it should work fine (if hooked up right), but you will have to replace the damaged equipment.
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Any isolator that involves hooking into the alternator or ignition circuit is going to be more complicated with more chance for error.
My suggestion for isolators if you are a DIY'er, is to use the ones that do not involve any alternator rewiring. Stick to the ones that just hook into the batteries like the T Max or the powerstream smart isolator solenoids. http://www.powerstream.com/battery-isolator.htm
The SS type is fine if you know how to hook it up right but the solenoids are for us electro-idiots, who are not electrical engineers or GM techs.
Those diode isolator wanted me to rewire crap into the fuse box and tie into ignition wires and stuff.
this relay isolator was installed by a car audio company. I would hope that it's done right? It's a unit that they sell and install all the time so it should be good? I hope...
I went ahead and picked up a Duralast Gold 165amp alternator and threw it in the truck. The battery was dead after my last trip so I had to jump it from my s10. Once started, the charge warning came on for 15-20 seconds while the voltage was around 11v. Then the voltage jumped up to 14v and the warning turned off. I drove around for a bit and the voltage never dropped below 14v. Turned the truck on and off a few times and the battery never started with less than 14v. It used to start with 11v and then climb up to 12.5v - 13.5v.
when removing the old alternator I noticed that the terminal was melted. And I also noticed that this new alternator runs very hot. Not too hot to touch hut deffinitely too hot to keep your hand on. Is that normal?
Looks like you had a loose connection causing arcing and heat. More than likely melted the solder joints inside the alt. Glad the new one solved your issues. The heat is normal especially if the alt is having to charge a low battery or a few charge cycles from the starting during testing.
Looks like you had a loose connection causing arcing and heat. More than likely melted the solder joints inside the alt. Glad the new one solved your issues. The heat is normal especially if the alt is having to charge a low battery or a few charge cycles from the starting during testing.
Arcing is what I thought too. There used to be a washer in there but it was completely melted out! :lol: been driving it for a couple days now with no issues. Feels good to have my truck back! Now to fix the evap code on my '03 s10...
Please explain this statement "Any alt above 140-150a will start to have reliability issues". Why would a new or rebuilt alternator rated over 140A have reliability issues?
I'm interested in that also because I'm thinking about putting a 145 amp one in my 04 2500 HD
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