CJ Rodarme
Full Access Member
I just installed the big 3. My voltage is definintely raised but it fluxuates. Between 14.4-15.0 or around that. Is this normal or is something wrong?
Big 3 Help
- Thread starter CJ Rodarme
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might want to have your battery tested, my experience with the nbs's is when the voltage starts wiggling then the battery is getting weak, but aside from that just double check that you didn't leave a ground loose somewhere namely on the battery terminal.
OP
OP
CJ Rodarme
Full Access Member
Well hopefully it’s a battery so I have an excuse to get a new northstar for it
There is always a bright side.
HiHoeSilver
Away!
that's weird thought they didn't start that till 07
HiHoeSilver
Away!
I thought that too before, but noticed my truck deciding on its own to flip between 12+ and 14.5ish on its own. I asked about it and remember getting the answer that I had it. I think from James. Now you got me guessing again. Lol. I'll have to look.
Can you be more specific? Does it have an aftermarket alternator? If so you will want to verify on there website. I have a 300 amp mechman that stays right at 14.8v (which is right at where there website says it should be). You're not too high at all, that's right where you should be, but the fluctuation could be a problem. What year?
What kind of alternator do you have? (amperage and brand)
When does it fluctuate, when idling, when driving, or depending on the RPM? (If you got a cheaper rebuild you might have a low (even lower than factory) amperage output at low RPMs. Some of the cheaper alternators will just have a really low amperage output at lower RPM. Could you be trying to draw too many amps at a low RPM and fluctuating voltage?
HiHoeSilver
Away!
I found where I asked before. James said no, but a couple posts down, Jason had some insight but not sure. I don't think I ever actually went looking for it in my truck, either. If I did, I don't remember, but my gauge sure acts like it does.
https://www.tahoeyukonforum.com/threads/useless-information.97483/page-29#post-1242922
This might make sense. I wonder if e-fans had anything to do with it?
HiHoeSilver
Away!
I think what @adriver said makes sense. A few things changed for 05-6, including the fans. Maybe the RCV was part of that, too. I'll look closer this afternoon to refresh my memory and report back.
even if so the op's truck is a 03
HiHoeSilver
Away!
True dat. Good advice to check all terminations regardless.
OP
OP
CJ Rodarme
Full Access Member
It’s a 150 amp, I think from the 3500 6.0 trucks. So it’s more than stock but its still OEM. My bet would be that it’s the battery. It’s old stock and I’ve beat on it. I’m resting at about 14.6, maybe a little higher. It’s at 15.0 ish when I first start it. I’m not concerned with where the voltage is but it’s the fluctuation that I’m concerned with. My best bet is the battery.
