Multiple Errors - Parking Brake, Suspension, Fun!

[greiswig]

I think raw voltage measurements on this system are dodgy, since the alternator does not work the same as an alternator from the ‘80s would have. It’s a PWM system, if I remember right, so that makes it difficult.

What the low voltage could be telling you is that the computer determined no charge is needed, because it’s a new battery.

 

[Abram]

Hm! So even if the voltage is reporting lower than what it “should” be, it’s still ok? I have it connected to my charger right now and it shows 100% though when I started it up yesterday it was definitely reading lower.

I guess I just want to be sure it’s not gonna crap out suddenly. I do at least have a 4 year replacement warranty on the new battery

 

[powershift]

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[greiswig]

Hm! So even if the voltage is reporting lower than what it “should” be, it’s still ok? I have it connected to my charger right now and it shows 100% though when I started it up yesterday it was definitely reading lower.

I guess I just want to be sure it’s not gonna crap out suddenly. I do at least have a 4 year replacement warranty on the new battery

I'm no expert on how the charging system is supposed to work. I'll defer to someone else with more knowledge here. But I believe that a really good, fully charged battery might not inspire the LR alternator to push out higher average voltages using its PWM system.

 

[Abram]

That’s fair, I suppose my concern is that I don’t know what to trust as to whether the battery IS fully charged or not. I left it on my charger for 10 hours today and in the initial driving I was doing it was a consistent 14.5v, perfect, but then on my way back home it’s back to 12.2-12.7v

So either something is not working, or it’s just not activating the alternator as you said.

 

[greiswig]

I’m not sure those are the only two possibilities. And I hope somebody with more expertise into this particular charging system weighs in. But…

1. You put battery on charger overnight, and battery is fully charged.
2. You start the truck, pulling hundreds of amps in doing so. Battery is no longer fully charged.
3. The charging system either sees that latter fact or goes into an automatic “top off” mode, which you see as 14.5V*
4. In short order the battery is topped off again, so the charging system drops the voltage to 12.5V*

*in both these cases, I think you’re reading RMS voltage, but it is actually just the effect of the variance in PWM. PWM light dimmers don’t lower the voltage to the bulb, they just vary the “on time” of a set voltage, but the effect is virtually identical if the drain on the voltage acts like a filament or battery.

I would think that going to a dealer and having them check the charging system would be relatively cheap? Might give you peace of mind.

 

[Abram]

Super educational response thank you! I’ve only been using a local Land Rover shop but I do have at least 6 dealers in my area. I’ve not used them as of yet, just my local shop. But yes it might be worth having someone test just to rule things out (and ideally not add to my growing list of repairs lol)

 

[itsaguything]

In another forum, someone coined the acronym "ITBS". (Its the battery, stupid.)

As @greiswig stated, the electrical charging system is dynamic. And inspired to provide more charging power should the current state of the battery be depleted. BUT, it is essential to think of the generator as a "maintainer" and not a "charger". This is a significant change from vehicles of the past where alternators were oversized/wasteful and worked against the efficiencies expected today.

This is well described in the workshop manual. Do you have it?

Moreover, as I have commented many times, a battery at rest for 6 hours must show a voltage of 12.6v +. If it only shows 12.4v, it is at less than 50% capacity. And must be replaced.

Cheers to All!

 

[Abram]

Overnight voltage was 12v but I’ll check again after driving and letting it rest 6 hours specifically.

Mind you this is a brand new battery, which is why I was wanting to make sure it’s behaving correctly.

 

[greiswig]

Moreover, as I have commented many times, a battery at rest for 6 hours must show a voltage of 12.6v +. If it only shows 12.4v, it is at less than 50% capacity. And must be replaced.

Cheers to All!

I would guess that this only applies to disconnected batteries, which by definition have zero load on them. Even asleep, these vehicles draw some current from the main battery. I don't think I've ever measured 12.6V on the connected battery under my hood, even when it was new. In the sun, with the solar panel charging, it reads 12.5V on the solar panel's meter, with a 3-year-old Interstate battery. Starts reliably, no voltage issues (knock on wood).