Live Help - Voltage Drop while stopped, nearly stalls - on Cross Country Road Trip (1 Viewer)

[duggy]

I have found that those on-board testers are junk as you cannot properly test an alternator or battery just by hooking up the tester to the terminals.

FWIW I had 2 DHP that a local Sears would refuse to warranty because they would charge them and say it was good. I took both of them to another Sears and they both tested bad, which yielded me 2 new Die Hard AGM Golds and a refund on the difference of price.

 

[suprarx7nut]

Update for tonight: after a combined 90 minutes of driving at night including downtown driving, all is well. I think it's too soon to say the issue is 100% resolved, but as far as I can tell right now it's fixed. Voltage hovers around 12.5 while cruising, drops to 12.4 or so at idle.

It could be that the testing performed during my Sears trip topped off the battery and the problem has only been masked, but only time will tell. I fly out of Denver for a couple days starting tomorrow morning. in that time my wife will have the Cruiser to get around town. I get back Saturday night and we leave for Phoenix Sunday morning - assuming all is well, that is.

Thanks all for the help and I'll continue to update as news breaks. If nothing else, I've learned a lot about the group 31 AGM and its associated charging needs.

 

[montegofd3s]

Yeah, this evening will provide some good time to test for any existing problem. If it persists I'll be at Sears tomorrow morning at open demanding an alrernator swap back to my old one and a refund on the labor. If the problem is gone... Maybe it was the alternator.

Fighting this same issue. I am pretty sure it is the battery, but Sears refuses to say it is. They don't load test them (which is the problem here) they just test them for holding a charge. I promise you mine has a dead cell in it, and that is our shared issue. Getting people to understand that there is almost impossible.

Low Voltage Fight (searched to death)

Read that....sound familiar?

Update for tonight: after a combined 90 minutes of driving at night including downtown driving, all is well. I think it's too soon to say the issue is 100% resolved, but as far as I can tell right now it's fixed. Voltage hovers around 12.5 while cruising, drops to 12.4 or so at idle.

It could be that the testing performed during my Sears trip topped off the battery and the problem has only been masked, but only time will tell. I fly out of Denver for a couple days starting tomorrow morning. in that time my wife will have the Cruiser to get around town. I get back Saturday night and we leave for Phoenix Sunday morning - assuming all is well, that is.

Thanks all for the help and I'll continue to update as news breaks. If nothing else, I've learned a lot about the group 31 AGM and its associated charging needs.

Was it cool out? When its cool I get this because the battery stay cool, but as soon as it heats up it will drop.

 

[suprarx7nut]

Issue appears to be fully resolved. Voltage while driving is now 12.8 or 12.9 via my bluetooth OBD2 adapter. The alternator seems like the culprit. I think the low voltage after leaving the Sears where it was replaced was just due to the battery needing to charge back up. After many hours of driving in the last couple of days (~1000 miles) it's nice and stable and the voltage dips are gone.

The O'Reilley false pass really threw me for a loop on this. My first thought when the voltage dipped was that the alternator was going out. I quickly dropped my wife off and hit the local parts store. Their tester said all was well and I started chasing other leads and started this thread. If the O'Reilley tester could have found the fault I would have bought an alternator and replaced it myself in the street/parking lot and saved the $260 in labor from Sears. Oh well.

So as a PSA to everyone else... Don't necessarily rely on the handheld alternator tests!

 

[Sandroad]

Fighting this same issue. I am pretty sure it is the battery, but Sears refuses to say it is. They don't load test them (which is the problem here) they just test them for holding a charge. I promise you mine has a dead cell in it, and that is our shared issue. Getting people to understand that there is almost impossible.

Low Voltage Fight (searched to death)

Read that....sound familiar?



Was it cool out? When its cool I get this because the battery stay cool, but as soon as it heats up it will drop.

Fighting this same issue. I am pretty sure it is the battery, but Sears refuses to say it is. They don't load test them (which is the problem here) they just test them for holding a charge. I promise you mine has a dead cell in it, and that is our shared issue. Getting people to understand that there is almost impossible.

Low Voltage Fight (searched to death)

Read that....sound familiar?



Was it cool out? When its cool I get this because the battery stay cool, but as soon as it heats up it will drop.

I hear ya. I have a DHP 31 sitting on my garage floor right that will hold a charge, but has essentially 0 capacity. The Sears test shows good. I'll get $15 for it when I get a non-Sears new battery.

 

[suprarx7nut]

Well go figure my problem has returned. I noticed tonight the cruiser was a little off when I started it warm. Idle was around 450-500 and voltage was low (10.7-11V at idle). Once I give it some gas voltage comes back to 12.5 or higher.

This time around it happened near my home, but I'm mid-move. My tools aren't packed yet, but I can't exactly tear into the engine bay on a week-long search for problems. I need to move out of state in two weeks with no real spare time to speak of.

Either I managed to kill a new alternator in 5-10k miles or I have another problem plaguing the cruiser.

I'm going to start by replacing the air filter and cleaning out the TB and MAF. I hear those are potential low idle causes and should be easy to try out.

I also recently bought a CTEK 25000 battery charger and just did the "Recondition" mode charge on the battery. It tested good and the recondition didn't take long, indicating battery voltage was already fine.

Perhaps part of the problem is the ECU "relearning" fuel trim and idle settings? The battery has been reconnected for a handful of short trips, but maybe that's not enough to settle into good settings?

 

[montegofd3s]

It is your battery.

 

[spressomon]

If you've spent the last "5-10k miles" in alternator deep mud/goo/stream crossings you might have another alternator problem. Otherwise look to the battery side. Be sure to check terminals for tightness as well as ground cable & all alt & battery terminusses.

 

[Sandroad]

I'm with @montegofd3s. If you still have that DHP 31 in there, it could likely be the culprit. Get it out of there with an OEM 27F for now since you're mid move. I think It will be $120 well spent. IF the problem persists, you can go from there.

 

[abuck99]

I think that running voltage you report is slightly low. At idle it should be closer to 13.5. What is your static voltage with engine off? Should be at least 12.1 but closer to 12.3 or greater.

My voltages range from 13.3 to 14.1. At start up its typically 14.1 and after warm up it settles down to mid 13's.

If your battery is perfect, and the alternator still checks out, then something elsewhere is sucking amps.

 

[2001LC]

I don't think I used any dielectric grease when I put this battery in. The posts look very dry and clean.

 

[suprarx7nut]

It is your battery.

This is my cautious assumption at this point, but I'd like to rule everything else out that I can.

If you've spent the last "5-10k miles" in alternator deep mud/goo/stream crossings you might have another alternator problem. Otherwise look to the battery side. Be sure to check terminals for tightness as well as ground cable & all alt & battery terminusses.

Nope, no off-roading (queue sad face) since the alternator replacement.

I'm with @montegofd3s. If you still have that DHP 31 in there, it could likely be the culprit. Get it out of there with an OEM 27F for now since you're mid move. I think It will be $120 well spent. IF the problem persists, you can go from there.

I do have a second battery tray (slee, old version) waiting to be installed so I'll get a battery sized for that if it'll work in the 31 tray with my existing cables. Worst case I could swap that into the second tray and get a new interstate group 31 if it comes to that.

I think that running voltage you report is slightly low. At idle it should be closer to 13.5. What is your static voltage with engine off? Should be at least 12.1 but closer to 12.3 or greater.

My voltages range from 13.3 to 14.1. At start up its typically 14.1 and after warm up it settles down to mid 13's.

If your battery is perfect, and the alternator still checks out, then something elsewhere is sucking amps.

I'll report on that as soon as I measure.

 

[suprarx7nut]

Lol. To make matters worse, the Sears mechanic that did all my alternator work galled the nut on the post adapter trying to remove it AND didn't use any grease, either.

 

[2001LC]

Lol. To make matters worse, the Sears mechanic that did all my alternator work galled the nut on the post adapter trying to remove it AND didn't use any grease, either.

I've seen this so many times with standard type lead battery post. If not cleaned and greased it will just keeping coming back (oxidation). I felt you wasted your money while here in Denver going to Sears, by not tying this first. KISS.

 

[suprarx7nut]

I've seen this so many times with standard type lead battery post. If not cleaned and greased it will just keeping coming back (oxidation). I felt you wasted your money while here in Denver going to Sears, by not tying this first. KISS.

I'll make a point to get some dielectric grease on there soon. My reason for not making that a priority earlier is that I would expect some sort of visual indication before it would affect performance to any significant degree. The terminals look absolutely spotless - both on the outer surfaces and the contact surfaces on the post and ring. They could pass for brand new.

Never-the-less, totally agreed it's a no-brainer first step that I've put off.

 

[2001LC]

I'll make a point to get some dielectric grease on there soon. My reason for not making that a priority earlier is that I would expect some sort of visual indication before it would affect performance to any significant degree. The terminals look absolutely spotless - both on the outer surfaces and the contact surfaces on the post and ring. They could pass for brand new.

Never-the-less, totally agreed it's a no-brainer first step that I've put off.

I learned this lesson as a teenager, I've not owned jumper cables since.

They'll (lead post & clamps) may look clean, but under closer inspection will have a slight gray appearance. That gray is oxidation. Just that nearly indistinguishable gray from clean silver will cause issues. Even brand new battery post need cleaning then greasing before attaching cables. It generally takes one to three months before issue becomes apparent if not done correctly.

This is total different from the white corrosion buildup on battery post. That white stuff is acid and needs neutralize with baking soda before rinsing off. Washing without neutralize will eat paint and metal wherever rinse water flows onto.

I wash battery with baking soda, clean & grease post each year as PM while doing MAF, PCV valve and throttle body and inspecting all hoses. I always start with washing & disconnecting battery, then finish job with clean & greasing post & cable clamps then connecting battery.

Hopefully this will solve your issue, regardless it's best to start with simplest smallest stuff first.