Your battery voltage - truck off and at rest

[chorky]

Maybe its time to pay the dealer a visit and get those batteries replaced. They could be bad.....

Drove mine 180'ish miles on Friday. it sat all weekend. Sunday afternoon tested (with both together though) at 12.58. I was expecting at least 12.63. I certainly think there is a big factor in the systems that continue to run and 'monitor' draining these batteries.

Maybe these new vehicles should come standard with a solar trickle charger on the hood.... I think I'm going to get one for mine. You have me worried about inability to start if out camping in the middle of nowhere lol

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[ShadowsPapa]

You mean a DIFFERENT dealer -the close dealer said they tested fine (after a 38 minute charge to get up to 12.4 volts LOL - CLUE guys, you have to charge it before you could test it!)

 

[chorky]

I would be curious to see what the shop manual says about that. I wonder if it's within their specs they allow even though we all know its not ok.

 

[ShadowsPapa]

The criteria for the type of test and equipment they use state the battery voltage must be 12.4 before they load test the battery. The fact that they had to charge at all before they hit the minimum 12.4 volts is pretty telling, IMO .

You'd think that after running around, driving, etc. that the batteries would be at 12.4 and could be load tested but no, they had to get the batteries UP to 12.4 volts before they could even test them.
So I'd love to ask them - what's up if the truck doesn't even charge the batteries to 12.4 volts?

 

[chorky]

I don't disagree. I have a hard time trusting any tech these days. As a tech myself years ago I saw the super dumb and sketch some people did. Just hoping I dont ever need to have warranty work done - we all know vehicles are't treated the best in those shops. Some places are really awesome. But they're few and far between.

Not that it answers the burning questions you have but I wonder if its a weird combination of issues.

 

[just_another_guy]

My battery rests around 12.5v after sitting a day when fully charged and the auto start/stop works all the time. However, the "smart" alternator voltage is always pegged at the max and never throttles down like it thinks the battery isn't fully charged. I want to take it to the dealer to have it checked out but am at least 90% sure they won't actually fix anything.

 

[Erievon]

So after being out of town for 7 days, the reading at the main was 12.1. It was at 12.3 when I left. I was a bit worried if it would start. Somehow it started just fine, cranked at the same speed it always does. I've seen so many different diagrams, do we know for absolute certainty which of the two batteries it uses for a cold start? (Not an ess restart event).

 

[jebiruph]

So after being out of town for 7 days, the reading at the main was 12.1. It was at 12.3 when I left. I was a bit worried if it would start. Somehow it started just fine, cranked at the same speed it always does. I've seen so many different diagrams, do we know for absolute certainty which of the two batteries it uses for a cold start? (Not an ess restart event).

Both, they are connected in parallel for a cold start.

 

[ShadowsPapa]

I charged the main battery last night with the charger set at the 10 amp setting, and let it go through all of the tech phases of charging. It took over 7 hours to complete! It started out less than 70% as I recall - and that's after having driven it around yesterday.

This am I connected to the aux battery. I won't have time to finish that as I'm heading to get the truck "appraised" as the dealers here keep insisting they want to buy it. So I'll let them look and throw me a number then I'll tell them they are crazy.
I connected to the aux battery in the 10 amp setting and it started out at - get this - 45% and instantly went into repair mode (it detected a problem such as sulfating of the plates.
I will have to stop charging and put all the cables back in a few minutes but I find that very interesting - how very long it took to charge the main battery and the fact the aux battery was so very low (of course it had all of the parasites of the truck on it alone over night with the main battery disconnected - so that may be the issue) but the charger going into repair mode?
Hmmmmm.
Maybe I'm crazy, maybe it's all fine and normal, but when I get back I will isolate things a lot more, and do more testing.
Auto stop/start not ready, battery charging my whole driving around shopping yesterday.

 

[chorky]

I connected to the aux battery in the 10 amp setting and it started out at - get this - 45% and instantly went into repair mode (it detected a problem such as sulfating of the plates.

am I understanding you correctly that you mean 45% SOC? As in 45% charge remaining??

 

[ShadowsPapa]

am I understanding you correctly that you mean 45% SOC? As in 45% charge remaining??

Yes, it may or may not be accurate, but when first connected before I turned it on, that's what it said. And it makes some sense as once the vehicle goes into ESS mode at a stop, the voltage drops like a rock - I mean into the 11s.
It jumped up to 75% fairly quickly after it started charging.
I had to stop everything and put it back together and leave this AM - but it was close to being done.
Now the interesting part - driving up to the dealership to get their lame offer on my truck, the voltage read 14.5 the whole way. ESS was ready in 3 miles (cabin temp) and it worked. Once the engine shut down the voltage dropped and settled for a bit at 12.8, then 12.7, then dropped more quickly but stabilized at 12.2-12.3. It hasn't done that for - well, I can't recall the last time it stayed above 12 at an ESS stop. Each time it worked, it stayed above 12.2, generally 12.3 with 12.7 or so to start.
Since I won't be going anywhere with it the rest of today - until tomorrow, I pulled things apart, and am charging the aux battery by itself again. I'll let it get through all modes, let the charger tell me that it's all done and it's in rest stage, then I'll move it back to the main battery to do that one again. Then tomorrow it will go back together and I'll watch it from there.
It seems these batteries aren't getting a proper charge from the truck........... or the aux battery isn't truly holding a charge regardless of their "load test". I've seen batteries pass a load test and then 10 hours later they are drained, voltage low, due to issues inside the battery. This will be a test, I guess - properly, correctly charge them with a proper charger, all phases, over hours, not minutes like a dealership does with a "fast charge" which is really just a "this will get it to start" charge, then see how long that lasts.

 

[cb4017]

Got me curious so I just checked. 12.58 volts. Been sitting in the garage all night.
I've had no issues with the ESS or anything else.
I'm going to run to town soon and I'm going to check it after a drive.
Interesting thread.

 

[Gatorized]

.
Now the interesting part - driving up to the dealership to get their lame offer on my truck, the voltage read 14.5 the whole way. ESS was ready in 3 miles (cabin temp) and it worked. Once the engine shut down the voltage dropped and settled for a bit at 12.8, then 12.7, then dropped more quickly but stabilized at 12.2-12.3. It hasn't done that for - well, I can't recall the last time it stayed above 12 at an ESS stop. Each time it worked, it stayed above 12.2, generally 12.3 with 12.7 or so to start.

This is how mine has been functioning… 14.4 to 14.5 while driving, then dropping to 12.3 to 12.4 when ESS kicks in. Mine was at 12.4 after sitting more than a week last time I went for a ride.

 

[ShadowsPapa]

I have fully charged both batteries two times using a correct charger that goes through all of the phases of charging, including absorption, rest, etc. Twice for each battery. Last time I measured the main and it was 12.75 and the aux was close to that. I reconnected things last night. Today we went shopping, quite some long trips.
Right off the bat I noted the voltage was 13.5 while driving, not 14.5-14.6 like it has been. It stayed 13.5 for quite a ways.
ESS worked within 3 miles of leaving home (45 degrees outside)
Once we'd driven a ways and made a few stops I noted the voltage was sticking around 12.9-13.0 on the cluster. When stopped and ESS kicked in the voltage stayed above 12.0
It hasn't done either (be that low on the cluster while driving or stay above 12 with ESS working) for ages.
The voltage changes while driving reminded me of the first couple of years of ownership -we'd see voltages all over the place, including lower 13s. For weeks it hasn't done that.
It will be interesting to see if the batteries stay up and things keep working like they should.

 

[chorky]

That is very weird. and it bothers me. Tells me something with how this system is designed is not reliable and is going to forever cause battery issues by improper charging. I wonder if it would be the same or different if both batteries were the same size and capacity….

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