LR4 Battery Charging Profile... Measured with IID... really this bad?

[ColoDisco]

Thanks for the heads up on the switch.

 

[unseenone]

taking lwg's comments into consideration, I've been testing a new alternator. The original had over 163k on it. No drives yet, but the 250amp alternator was putting out 13.8 at an idle at first start. Thanks are looking better. I initially noticed when I connected to the trailer with my battery connector, I was struggling to get those batteries up. When I plugged in, there was no change to the output voltage at idle. This leads me to believe I also had a weak alternator, moderately masked by my solar charger... I'll post up an update if anyone is interested. The previously linked graph will show the differences as time goes on.

Most notably, I noticed, previous to changing the alternator when accessories where running on the 2nd battery, I would see a voltage drop of about 1v. At initial glance, there is less than a 0.3 v drop when similarly loaded. No voltage drop, when plugging into the trailer batteries.

The alternator, which I have high hopes on, puts out a higher amperage at a lower RPM, via a smaller pulley and different diodes I believe. They suggested a 1" shorter belt may be necessary, if you hear any belt squeal. I'm hoping it will be fine with the existing belt, and at first glance there appears to be plenty of engagement on the tension device.

 

[LR Max]

Not to be that guy but the voltage shouldn't jump up, it should maintain under load or stay very close to the same. The amperage output should increase however. Technically if your only putting out 13.2v under no load your not likely to see it shoot up to 13.7 when under load. However a small drop in voltage is acceptable. That being said the 13.2v I referenced would be of concern in my vehicle.

With minor load changes, yes. But under significant load, the voltage would change. Hence why I recommended adding on a huge load.

Either way, sounds like he needed a new alternator. So either way, problem solved.

 

[perkj]

taking lwg's comments into consideration, I've been testing a new alternator. The original had over 163k on it. No drives yet, but the 250amp alternator was putting out 13.8 at an idle at first start. Thanks are looking better. I initially noticed when I connected to the trailer with my battery connector, I was struggling to get those batteries up. When I plugged in, there was no change to the output voltage at idle. This leads me to believe I also had a weak alternator, moderately masked by my solar charger... I'll post up an update if anyone is interested. The previously linked graph will show the differences as time goes on.

Most notably, I noticed, previous to changing the alternator when accessories where running on the 2nd battery, I would see a voltage drop of about 1v. At initial glance, there is less than a 0.3 v drop when similarly loaded. No voltage drop, when plugging into the trailer batteries.

The alternator, which I have high hopes on, puts out a higher amperage at a lower RPM, via a smaller pulley and different diodes I believe. They suggested a 1" shorter belt may be necessary, if you hear any belt squeal. I'm hoping it will be fine with the existing belt, and at first glance there appears to be plenty of engagement on the tension device.

What brand higher output alternator did you go with?

 

[proper4wd]

Just want to add this note for posterity - any comments not specifically relating to the LR4 platform and it's advanced alternator management strategy are irrelevant. This is not a D1 or D2 with a basic voltage regulator.

 

[unseenone]

Correct proper4wd

jperk I went with a powermax usa at least that's the brand they are selling them as on fleabay, I'll send you some links and information. Seems like great quality, it was done nicely.

 

[iowalr4]

I am seeing some similar issues with my 2013 LR4. I have a traxide kit and IID tool.

I jump started someone and since then I noticed my voltage (I have a national luna battery monitor in the cab) was low.. 12.2v when engine running. I ended up replacing my alternator, but I see the same issue.

Old and new alternator, i do see 14.3v on engine start for 30 seconds or so, then it goes to 13.2v or so. Then.... sometimes it stays there and goes to 14.3+v when throttle is applied, but sometimes it goes to battery level voltage.

Today for example it was going to 12.2v and letting my batteries drain.

Yesterday it acted fine. 14v all day on throttle, today not at all.

I have a new battery coming monday, but both my batteries are about a year old, good AGM's and I tend to keep them on a CTEK charger.

Is this the BMS? I will do a BMS reset on monday with the new battery, but I dont know what is going on.

@Pophamrt1 what did you end up doing here?

 

[DaveInDenver]

Just want to add this note for posterity - any comments not specifically relating to the LR4 platform and it's advanced alternator management strategy are irrelevant. This is not a D1 or D2 with a basic voltage regulator.

Yup. Sounds like the LR4 has a smart alternator and it should drop to about 12.8V, give or take (a nominal float voltage), when it decides the battery is charged and the load is light. It's an emissions, mileage, whatever feature that vehicles are starting to use. Throttling back the alternator reduces the load on the engine slightly, thereby increasing efficiency. Or so goes the theory. It should jump to 14.7V or so to charge, be that through regen braking, the alternator being told by the ECU to throttle up after starting discharge, turning on headlights/seat warmers/your 1000W boom stereo. Why the OP's truck is acting up is hard to know since there's a lot more players with their fingers in the punch bowl now than the old way with a dumb alternator and voltage regulator. But I would have thought the ECU would just say be in either low power or high power, so the 12.3V level sounds like a bad alternator.

 

[iowalr4]

What is strange though is that on starup it does get to 14.7v for a while, then definitely to 13.2v or so... then it decides to back off to 12.2 or battery voltage. That makes it seem like it is the PWM control deciding to turn it off.

I have also had it work perfectly during two different runs on the new alternator. I don't think the alternator is bad. It seems more like the computer is just turning it off. Computer thinks it has 83% state of charge no matter what the voltage. Is it possible to fry a BMS?

 

[DaveInDenver]

I can't think of any reason why the controller would want 12.2V with the engine running, but I'm far from familiar with various smart charging systems. That sounds like a large load is on the battery and there's no charging going on at all. It would seem that's an error, like it knows at 83% it shouldn't be in float but doesn't go to full charge. Like a logic issue. Where that is, definitely need Rover expertise.

 

[iowalr4]

More data.

Engine off, ignition on. Startup, high idle, then you see engine revs come down.. then I rev the engine twice. It doesn't look to even get to 14.7v... so could the new alternator just be bad also?

 

[iowalr4]

So, that graph.
1. startup sees only 14v.. not 14.7v.
2. amps get to 20... so alternator did something.
3. amps dips after rpm goes down but then comes back up.. so alternator still putting out something? but compared to my last graph a lot lower amps.
4. today throttle blips don't impact amps really at all.

 

[DaveInDenver]

Is this measuring voltage and current at the battery or the alternator? What is the open circuit voltage of the battery, particularly after you've charged it and let it rest?

 

[iowalr4]

So, my traxide kit is completely disconnected, everything stock as possible. (has been for the other graphs also).

But I just did a test... disconnected main battery, let the computer reset. And now it seems to work perfectly! So im screwing something up after a reset and then the computer never recovers. No codes either.

But i just did that and now I get this...

Engine startup, idle comes down, two throttle blips. 14.6v! 11-30amps (alternator isn't burnt out).

So, i need to scrutinize my traxide setup a bit more or something.. im going to leave it unplugged and just run this way. See if i still end up in the same situation.

@drivesafe have any thoughts on this?

 

[iowalr4]

Is this measuring voltage and current at the battery or the alternator? What is the open circuit voltage of the battery, particularly after you've charged it and let it rest?

Couple days ago I did a CTEK charge on the terminals with everything unplugged. Held 13.4v no problem. These should be pretty healthy AGM batteries. I did order a new one on friday anyway just because im going nuts, but at this point I think the battery is fine. It holds 12.6 fine after a bunch of engine starts.