Battery low voltage warning
#1
11-18-2022, 05:41 PM
Battery low voltage warning
I've been getting the dreaded low voltage warning anytime I open the vehicle door, and I've got a service appointment in a week or so. In the meantime, I've had to use a Noco trickle charger overnight which makes the warning go away for about 3 days.
Anyway my question.. when I measure the battery voltage with a voltmeter it shows 12.39v.. some quick research shows that this is the normal range for vehicle batteries. Why in the world is the vehicle acting this way if the voltage is sufficient?
Has anyone else had this issue.. and if so did it require a software fix or battery swap?
Anyway my question.. when I measure the battery voltage with a voltmeter it shows 12.39v.. some quick research shows that this is the normal range for vehicle batteries. Why in the world is the vehicle acting this way if the voltage is sufficient?
Has anyone else had this issue.. and if so did it require a software fix or battery swap?
#2
11-19-2022, 10:18 AM
There's a lot more to batteries than just voltage, but let's back up a bit before we get to that.
P300, 400, V8? Are you getting app notifications also? Has the vehicle every failed to start? Are you checking vintage with the vehicle completely asleep (locked for at least ten minutes), key on, or somewhere in between?
The vehicle monitors the 12v battery via voltage, internal resistance, and charge cycle history. Battery testers use internal resistance mostly, and a then voltage. Voltage doesn't mean much because you can have a surface charge that disappears as soon as any real load is put on the system. Also, if your vehicle has any type of hybrid system (either P400 48v, or real plug-in) the HV system can support the 12v system, even with the key off under the right circumstances.
A better indicator of battery health using just a voltmeter would be too see how low voltage drops while starting the engine. On a non-hybrid, depending on a ton of factors that aren't with going into, you generally don't want voltage to drop below approximately 10-10.5v. Some vehicles are more or less sensitive, adding 0.5v on either end of that range. I suspect the defender is on the more sensitive side. Also, hybrids, and engines with direct fuel injection, can take huge loads off of the 12v starter motor (if equipped, not all hybrids use a 12v starter, and IIRC the P400 is like that). Obviously is there is no 12v starter on your vehicle, starter voltage drop test won't work.
It's entirely possible that your battery is fine and just needs a really good charge. The reason it needs a charge could be that it has a quiescent draw, or maybe you frequently use functions like lights and radio or a fridge/freezer for extended periods with the engine off. I suspect that something is bringing the battery down since you said the warning goes away for a few days after charging.
Mind you, I'm not a LR mechanic, so I could be a little off with some of this, but I am a Mercedes mechanic, so I'm probably not super far off. Hope this all helps.
P300, 400, V8? Are you getting app notifications also? Has the vehicle every failed to start? Are you checking vintage with the vehicle completely asleep (locked for at least ten minutes), key on, or somewhere in between?
The vehicle monitors the 12v battery via voltage, internal resistance, and charge cycle history. Battery testers use internal resistance mostly, and a then voltage. Voltage doesn't mean much because you can have a surface charge that disappears as soon as any real load is put on the system. Also, if your vehicle has any type of hybrid system (either P400 48v, or real plug-in) the HV system can support the 12v system, even with the key off under the right circumstances.
A better indicator of battery health using just a voltmeter would be too see how low voltage drops while starting the engine. On a non-hybrid, depending on a ton of factors that aren't with going into, you generally don't want voltage to drop below approximately 10-10.5v. Some vehicles are more or less sensitive, adding 0.5v on either end of that range. I suspect the defender is on the more sensitive side. Also, hybrids, and engines with direct fuel injection, can take huge loads off of the 12v starter motor (if equipped, not all hybrids use a 12v starter, and IIRC the P400 is like that). Obviously is there is no 12v starter on your vehicle, starter voltage drop test won't work.
It's entirely possible that your battery is fine and just needs a really good charge. The reason it needs a charge could be that it has a quiescent draw, or maybe you frequently use functions like lights and radio or a fridge/freezer for extended periods with the engine off. I suspect that something is bringing the battery down since you said the warning goes away for a few days after charging.
Mind you, I'm not a LR mechanic, so I could be a little off with some of this, but I am a Mercedes mechanic, so I'm probably not super far off. Hope this all helps.
The following 2 users liked this post by this_account_is_mt:
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#3
11-19-2022, 11:05 AM
hi,
anomalous absorption problem has occurred on several defenders, try watching this video.
the best thing in this case would be to measure the current absorption directly on the positive cable of the battery with an current clamp.
car locked, wait 5 minutes, everything should be silent.
https://www.google.it/url?sa=t&rct=j...8YJJaRrLAO0Ihu
marco
anomalous absorption problem has occurred on several defenders, try watching this video.
the best thing in this case would be to measure the current absorption directly on the positive cable of the battery with an current clamp.
car locked, wait 5 minutes, everything should be silent.
https://www.google.it/url?sa=t&rct=j...8YJJaRrLAO0Ihu
marco
#4
11-19-2022, 12:44 PM
Mine has been in twice since birth to get a new battery after weeks of low voltage start engine warnings. I have even tracked it with a recording voltmeter I use on aircraft. I did get the CTEK (Land Rover endorsed) charger and have a permanent jack to hook the vehicle up to to keep it topped up. So what might be the problem that is causing this. First off, waaaaay toooo much tech. Every time you open the door, it draws 10 amps for about 10 minutes. This is apparently due to the car booting all the computers up to be quick at responding by the time you settle in the car and start it up. If you go in and out of your car a bunch, opening and closing the door, 10 amps 10 minutes, 10 amps 10 minutes and so on, it will progressively drain your battery down. Using ECO mode; I love ECO mode, makes the car rather economical, I say rather, not a Prius, but better than a RAM 1500. It does this by doing several things to economize and reduce load. Like toning down or even turning off many environmental functions. It also, apparently does not charge as aggressively while running, so even on a 20 minute drive it may not top the battery up, especially if you're letting the car auto stop start the engine. Sum all this up, it is actually not a healthy lifestyle for the poor battery. It has caused the death of two since I received the vehicle back in May. Even my trying to help the poor thing out by hooking up the CTEK charger has not saved it. I may be heading for a third new battery soon, as I got a low battery voltage warning yet again last week.
I tend to spend a lot of time during this season in the office awaiting returned phone calls. Really is a trend lately with nobody actually picking up when you call, but wait to call you back. This allows me to spend more than a healthy amount of time on the internet wasting time. In my poking about, I have found a few people that have had certain modules in the vehicle staying powered up and not sleeping. This only will go away when it is identified and its internal firmware updated. It also seems to be a task not too many technicians are really able to figure out, like programming my Activity Key (don't get me started on that epic struggle). To this end, after the holidays, I am scheduling an appointment for essentially a full body scan of all the modules and their consumption. Because if it is the third time, you can start to invoke the lemon law and give them the car back. I really don't want to do that, I like it too much. Besides what would I get? It took forever to get this one. Perhaps I should not have pushed the button for the all cool cleaver gizmo package, then it may be a lot simpler. Really, my wife refuses to drive it due to too much tech, it intimidates her. I suppose she fears somehow it will eject the driver seat out the roof or something. I know I hated ejection seats, all my buds who used them have ruined for life backs or dead from broken necks. I suppose being all dead is not so good. It is a rather irrational fear on her side, but she is a firm believer in ***** and physical buttons. Too many screens and braying warnings just bother her.
There is no one answer fits all on this Low Voltage Start Engine battery thing. Besides, the physical battery is not all that big in the first place. The Range Rover and even my old '97 Defender 90 ST (Where the stereo was the only high tech item) had bigger batteries.
I tend to spend a lot of time during this season in the office awaiting returned phone calls. Really is a trend lately with nobody actually picking up when you call, but wait to call you back. This allows me to spend more than a healthy amount of time on the internet wasting time. In my poking about, I have found a few people that have had certain modules in the vehicle staying powered up and not sleeping. This only will go away when it is identified and its internal firmware updated. It also seems to be a task not too many technicians are really able to figure out, like programming my Activity Key (don't get me started on that epic struggle). To this end, after the holidays, I am scheduling an appointment for essentially a full body scan of all the modules and their consumption. Because if it is the third time, you can start to invoke the lemon law and give them the car back. I really don't want to do that, I like it too much. Besides what would I get? It took forever to get this one. Perhaps I should not have pushed the button for the all cool cleaver gizmo package, then it may be a lot simpler. Really, my wife refuses to drive it due to too much tech, it intimidates her. I suppose she fears somehow it will eject the driver seat out the roof or something. I know I hated ejection seats, all my buds who used them have ruined for life backs or dead from broken necks. I suppose being all dead is not so good. It is a rather irrational fear on her side, but she is a firm believer in ***** and physical buttons. Too many screens and braying warnings just bother her.
There is no one answer fits all on this Low Voltage Start Engine battery thing. Besides, the physical battery is not all that big in the first place. The Range Rover and even my old '97 Defender 90 ST (Where the stereo was the only high tech item) had bigger batteries.
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#5
11-19-2022, 04:13 PM
#6
11-20-2022, 07:11 AM
Three Wheeling
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#7
11-20-2022, 11:06 AM
Thanks for all the helpful responses. I realized my initial post may have not contained much info.
- This is a P400 X
- I've got no accessories directly connected to the battery (ie fridge)
- I haven't had an issue starting the vehicle, yet, mainly since I manually charge it when the issue occurs.
- I lock the vehicle every time I exit, and I leave the keys quite far away inside my home
- I've done long drives, and the problem resurfaces a couple days later
- Charging using a quality trickle charger to top it off, shows some issues. After a full 24 hours of charging, the charger shows full charge while the car is still locked. The moment I unlock the vehicle the charger shows low voltage and starts blinking red (Noco Genius 5).
- The problem triggered me to call for a service appointment after the vehicle has downloaded a new Pivi Pro update, but no matter what I am unable to apply this update because the vehicle keeps complaining that the voltage is too low to update, even after a long drive.
Not sure if it matters, but I've definitely noticed that the screen and electronics stay turned on much longer since the last Pivi update. I feel like this could easily be solved via a software update.. if LR reads these forums?
- This is a P400 X
- I've got no accessories directly connected to the battery (ie fridge)
- I haven't had an issue starting the vehicle, yet, mainly since I manually charge it when the issue occurs.
- I lock the vehicle every time I exit, and I leave the keys quite far away inside my home
- I've done long drives, and the problem resurfaces a couple days later
- Charging using a quality trickle charger to top it off, shows some issues. After a full 24 hours of charging, the charger shows full charge while the car is still locked. The moment I unlock the vehicle the charger shows low voltage and starts blinking red (Noco Genius 5).
- The problem triggered me to call for a service appointment after the vehicle has downloaded a new Pivi Pro update, but no matter what I am unable to apply this update because the vehicle keeps complaining that the voltage is too low to update, even after a long drive.
Not sure if it matters, but I've definitely noticed that the screen and electronics stay turned on much longer since the last Pivi update. I feel like this could easily be solved via a software update.. if LR reads these forums?
#8
11-20-2022, 01:23 PM
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ficklma1 (11-21-2022)
