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Hello . I have a 2005 v6 3.0 and decided to update my entire surround in my car, but I noticed the following incident that the battery charge is 15 volts for the first 3 minutes and then drops to 13.2. I want to correct this and keep it at 14+ 15 volts as the standard for powering my other battery. What should I do?
Hello . I have a 2005 v6 3.0 and decided to update my entire surround in my car, but I noticed the following incident that the battery charge is 15 volts for the first 3 minutes and then drops to 13.2. I want to correct this and keep it at 14+ 15 volts as the standard for powering my other battery. What should I do? https://www.youtube.com/watch?v=djED...adimirstoyanov
Nothing. That’s exactly how the system works and can’t be changed.
keep it at 14+ 15 volts as the standard for powering my other battery.
As the others have said, you are seeing normal behavior for the charging system on 2003+ cars.
If you could somehow trick the system to maintain such a high level, I'm pretty sure it would damage your batteries. At minimum, it would probably boil out the electrolyte. At worst, the plates may warp and short out some cells.
There’s a whole chapter in the workshop manual concerning how critical the battery voltage and the charging process is. I recall that over 14 V isn’t good for a long period of time so I would let it do it’s thing I know that higher voltages can damage stuff
for 100 amps and these large motors it is normal to charge at 14.2 -14.4 V .
How much amperage does your sound system draw?
Is your system already installed and you're experiencing a problem? Or is it still in the design phase?
The reason I ask is I'm wondering just how well the stock Jaguar alternator would do. For example, I run dual batteries in my '84 pickup with its stone-age charging system. One battery is the normal start battery. The second is a large deep cycle that only powers the camper. When the ignition is off, the batteries are isolated via a big relay. While camped in the boonies, I often run the camper power for several days from the deep-cycle, and it is run down quite a bit when I start the engine again. In addition, the camper fridge automatically switches over to a 12v source, and I usually run the AC, too. In other words, the poor stock alternator works HARD. Max output is usually around 13.75v and it works just fine. Never had a problem.
I guess I'm curious where you've been told you need 14.2v+. Also, I wonder what the actual alternator output would be under a heavy load. It may settle down around the 13v you're seeing when the alternator senses the battery is well charged. If you're simultaneously drawing a heavy load, the controller may step up the output to match. Hence I asked if your sound system is already installed and you're seeing a problem, or if this is all just theoretical.
Това е моята система. SOUNDSTREAM 2000 RMS тласнат 200amps и си отиват 180-200 ампера! normal to start is 15.1 and hit the base go to 13.3 13.4 after 3 minutes it go normal cycle t 13.3 and hit the base go to 11.9 11.8 . Full the total power of the amplifier is measured at 14.4 volts and must support so much. What's going on right now. I do not charge the battery and do not use the amplifier as needed.
Wow, that is some sound system! I like the speakers built into the back seat. That is impressive.
Some more annoying questions, trying to get a handle on how power to the audio system is interfaced with the car's charging system. Just thinking out loud, but I'm starting to wonder if this is a power distribution problem (say an overloaded stock cable between the alternator and battery) as opposed to inadequate output from the alternator.
1) Is power to the audio system connected at (or close to) the battery?
2) Where are you reading voltage? On the dash display only, or with a voltmeter at the battery?
3) Are you experiencing any other electrical problems besides the low indicated voltage? For example: slow starter speed, dim headlights, parking brake fault, poor output from the audio system, etc.?
4) Did you check and clean where the battery's ground cable attaches to the body? This is a known problem area because the bolt passes through into the wheelwell, and moisture can collect there.
5) What is the total amperage draw of the sound system? Not the output wattage, but the input amperage at a nominal 12 volts. You may have already answered this one, so apologies if I missed it.
6) Do you know of anybody else who has installed a comparable audio system in a car of the same era? Most likely the charging system is of similar capability, so I'm wondering how others have fared.
I have a friend that has a mid 2000s bmw...i am sure it has a smart charge system like jaguar....he has a high power audio system, 2 batteries, same giant connector like yours....he had a good alternator shop build him a custom high amp alternator...like 160 or 175 amp....left voltage alone....the regulator is in the ecm and does volts not amps...he also added a protection device....i think you might need the same..high volts kills electronics....high amps just needs big enough cables as to not super heat and loose its power capabilities
1) in order to have a maximum peak and minimum losses, the installation must be as short as possible. 80 cm is the installation of the battery
2)the dashboard is 100% the same like a voltmeter
3)only weak headlights. but enters standard mode at 13.2 volts and is normal. listening to the rhythm, I fall below 124)yes
5) 2000rms 4000peak power 150a-200a
6) Not for a jaguar7) in this case there is no point in a second battery, as I can't even charge the first one as standard, but I need one
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Been thinking some more. No charge, and worth every penny. I've got a couple of ideas.
But first, some boring theoretical stuff:
I'm not following exactly why a second battery is fitted, but this seems to be a standard feature for power-hungry audio systems. Please bear with me for a second. I'm not doubting the need for a second battery, but it doesn't seem to make any sense to me. A second battery is usually fitted in a vehicle that has a brief need for extra electrical power. Think of an electrical winch on a truck, or an electrically-driven hydraulic pump for a snow plow, for example. In both of those cases, the extra electrical demand is only for a short period, several minutes at most. Those extra loads draw more than the alternator can supply, so the extra capacity of a second battery is needed.
More boring stuff, still on the same subject:
Think of a battery as a very heavy duty balloon. To charge it, you pressurize it. Discharge it, and the pressure drops. Discharge it too much, and there's no pressure left to do any work, a dead battery in other words. As long as the alternator pressurizes the "balloon" faster than air is being draw out (by the car's combined electrical loads), the battery stays charged. But if you draw out more electrical pressure (air in the balloon) than the alternator can supply, the battery goes dead (deflated balloon).
The tow truck or snow plow with the occasional brief demand for lots of electrical power, more than the alternator can supply? The second battery is like making the balloon bigger, so there's a bigger reserve capacity. This massive electrical load is only intermittent, so the batteries don't go dead and they get recharged when the heavy extra load is switched off. (This is where I bring the conversation back around to your car, wait for it...)
But the situation is very different with a constant heavy electrical load, such as your sound system. In post #14, you said your sound system draws 150-200 amps. That's yuge! Looking at Rock Auto, the stock alternator is either 120 or 130 amps. If that is the maximum you can get from the alternator, and figure maybe 20ish+ amps to run normal electrical loads (fuel pump, fuel injectors, radiator fan, etc.), at best you've got 100 amps reserve charging capacity. But if the draw of your sound system routinely exceeds that, I don't understand the logic of adding a second battery. No matter how big the "balloon" is, the problem is you're drawing more than the charging system can supply. Increasing the battery capacity won't really change the equation. The balloon is still going to get deflated. The main variable is how fast. Quickly if only one battery. More slowly if two batteries. Theoretically, you could fit a dozen extra batteries, and even if you began with all of them fully charged, they will still slowly run down. The fix is you have to increase charging capability to more than the demand, not increase battery capacity.
Thus, I'm thoroughly confused why it's a standard feature to increase the battery capacity with a power-hungry sound system. I must be overlooking some part of the equation, as people smarter than me (yes, it's possible...) have been doing this for a long time. I'll just have to go on the premise that I've skipped some important detail so it all makes sense.
With that boring preface out of the way, there's only so much assistance I can offer, but my troubleshooting ideas should be quick to walk through. My general thoughts are to make sure the charging system is performing at maximum capacity, and the connecting circuits (positive and negative) are in top condition. My hopes are if we can verify these factors and correct as necessary, I won't necessarily have to understand why and can give my poor brain a rest. Interested?
If interested, let's make sure the connecting circuits can properly deliver the alternator output all the way back to the battery. (I was thinking along these lines when I asked if you cleaned the connection where the battery's ground cable bolts to the body.) This is a very simple electrical test, although access at the alternator may be difficult.
Make sure both batteries are fully charged. This is a very basic prerequisite for any electrical troubleshooting, so PLEASE don't skip this step. Partially discharged batteries can skew the test results. If you don't have a charger handy, remove the batteries and take them to a place than can do it for you. A trickle charger won't cut it. You'll need something with at least a 10 amp output, preferably automatic.
Next, you will need to rig up a simple test jumper, long enough to reach the length of the car. 14 or 16 gauge wire will be plenty, as it does not need to be very heavy. Fit alligator clips to both ends.
You will need to access the battery while operating the sound system. If you have to disconnect any part of the sound system to get under the trunk floor (looks like it), you will need to rig up a shorter second test lead that can reach from outside to the battery. Once again, light wire is fine, especially since it will need to flex around the edges of the custom enclosures in the trunk. For these tests, you will need to have the sound system fully functional and drawing max power, so it can't be partially disconnected.
Under the hood, connect one end of the long test lead to the big insulated stud on the alternator. This is the terminal all by itself, with one heavy cable attached. This is the alternator output, feeding into the heavy cable running back to the battery. Put the alligator clip directly on the stud, not the crimped terminal on the end of the cable. Be careful, because this test lead is now energized, so don't let the other end touch ground. Be careful to route the test lead away from any moving parts or the exhaust.
At the back of the car, connect the other end of the long test lead to the red lead of a voltmeter (meter off). Connect the black lead to the positive battery post. That's not a typo, black meter lead to the (+) post. Use the shorter test lead as an extension for the black meter lead, if needed. Be careful, as this short test lead is also hot, so don't let the ends touch ground.
Turn on the meter and select a range that will cover 15VDC. Ignore any voltage reading you get with the engine off. It doesn't mean anything. We will be checking the ability of the fat cable to deliver the alternator output all the way back to the battery. Start the engine, and let it idle for a few minutes so the alternator output drops down. (Watch this on the dash, not the voltmeter as it isn't connected to read alternator output.) Notice I haven't asked for the reading of the voltmeter back at the battery, as we aren't to that point yet.
Once the dash display drops down to the 11ish you've been seeing, crank your sound system to max. Maybe some Carpenters. Record it and post to Youtube under your normal user name. No particular reason for the music choice, other than this inspiration:
Hold the engine RPM around 2000 to make sure the alternator is cranking out full power. (You may need a helper unless you can prop up the meter to see it from the driver's seat.) NOW you can look at the voltmeter back at the battery. If the heavy cable run from the alternator to the battery was in absolutely perfect condition, you would see 0.000 VDC. This is a voltage drop test, and it quickly verifies the current-carrying capability of any conductor. But 0.000 VDC is not theoretically possible, as it is normal to see some voltage drop. All circuits have some voltage drop. You can't avoid it. A practical limit is 0.5 VDC (half a volt), but the closer to 0.000 the better. If needed, manually select a lower range on your meter for an accurate reading on such a small value.
The higher the reading, the more of an unwanted restriction you've got between the two test points. It could be a high resistance connection in the cable run. It could be an overheated crimp that has corroded. It could even be an undersized conductor that just can't handle the massive current flow and is acting like a giant resistor. Even if you don't understand the concept of a voltage drop test, it is the cat's meow for finding unwanted restrictions, especially in a high current circuit. Remember, this voltage reading is only meaningful with the circuit under load. Please post the value seen on the meter with a maximum load on the electrical system.
That only tests the positive side of the circuit between the alternator and battery. Let's move on to the negative side, which is equally important. Turn off the meter, and fully disconnect the meter leads and extensions. At the alternator, connect the long test lead extension to the alternator case. You can usually get a good grip at the slots for cooling air, or wherever you can get a good connection. Back at the battery, connect the other end of the long extension to the black meter lead. Connect the red meter lead to the battery's negative post. Once again, that's not a typo. Red lead to the (-) post. Turn on the meter and repeat the basic test as above. Let the voltage drop down around 11ish again, as seen as the dash display. Crank some music to load the electrical system, and hold the engine RPM around 2000. As above, if all was perfect (not possible), you'd see 0.000 VDC. Realistically, you should see no more than 0.5 VDC. A value higher than that means an unwanted restriction in the negative leg of the charging circuit. Please post this value, too.
I hope this test doesn't sound too complicated. It's actually very simple, just two meter hook-ups, and it will tell me LOTS. The only difficult part is the logistics of accessing the alternator and battery. Like I said, you don't have to understand it. Just post the numbers from the two tests and we can go from there.
Is your brain full yet? Mine is. I've got some more ideas, but the test above should be a good starting point for troubleshooting. My other ideas will have to wait until my brain swelling goes down.
Been thinking some more. No charge, and worth every penny. I've got a couple of ideas.
But first, some boring theoretical stuff:
I'm not following exactly why a second battery is fitted, but this seems to be a standard feature for power-hungry audio systems. Please bear with me for a second. I'm not doubting the need for a second battery, but it doesn't seem to make any sense to me. A second battery is usually fitted in a vehicle that has a brief need for extra electrical power. Think of an electrical winch on a truck, or an electrically-driven hydraulic pump for a snow plow, for example. In both of those cases, the extra electrical demand is only for a short period, several minutes at most. Those extra loads draw more than the alternator can supply, so the extra capacity of a second battery is needed.
More boring stuff, still on the same subject:
Think of a battery as a very heavy duty balloon. To charge it, you pressurize it. Discharge it, and the pressure drops. Discharge it too much, and there's no pressure left to do any work, a dead battery in other words. As long as the alternator pressurizes the "balloon" faster than air is being draw out (by the car's combined electrical loads), the battery stays charged. But if you draw out more electrical pressure (air in the balloon) than the alternator can supply, the battery goes dead (deflated balloon).
The tow truck or snow plow with the occasional brief demand for lots of electrical power, more than the alternator can supply? The second battery is like making the balloon bigger, so there's a bigger reserve capacity. This massive electrical load is only intermittent, so the batteries don't go dead and they get recharged when the heavy extra load is switched off. (This is where I bring the conversation back around to your car, wait for it...)
But the situation is very different with a constant heavy electrical load, such as your sound system. In post #14, you said your sound system draws 150-200 amps. That's yuge! Looking at Rock Auto, the stock alternator is either 120 or 130 amps. If that is the maximum you can get from the alternator, and figure maybe 20ish+ amps to run normal electrical loads (fuel pump, fuel injectors, radiator fan, etc.), at best you've got 100 amps reserve charging capacity. But if the draw of your sound system routinely exceeds that, I don't understand the logic of adding a second battery. No matter how big the "balloon" is, the problem is you're drawing more than the charging system can supply. Increasing the battery capacity won't really change the equation. The balloon is still going to get deflated. The main variable is how fast. Quickly if only one battery. More slowly if two batteries. Theoretically, you could fit a dozen extra batteries, and even if you began with all of them fully charged, they will still slowly run down. The fix is you have to increase charging capability to more than the demand, not increase battery capacity.
With that boring preface out of the way, there's only so much assistance I can offer, but my troubleshooting ideas should be quick to walk through. My general thoughts are to make sure the charging system is performing at maximum capacity, and the connecting circuits (positive and negative) are in top condition. My hopes are if we can verify these factors and correct as necessary, I won't necessarily have to understand why and can give my poor brain a rest. Interested?
If interested, let's make sure the connecting circuits can properly deliver the alternator output all the way back to the battery. (I was thinking along these lines when I asked if you cleaned the connection where the battery's ground cable bolts to the body.) This is a very simple electrical test, although access at the alternator may be difficult.
Make sure both batteries are fully charged. This is a very basic prerequisite for any electrical troubleshooting, so PLEASE don't skip this step. Partially discharged batteries can skew the test results. If you don't have a charger handy, remove the batteries and take them to a place than can do it for you. A trickle charger won't cut it. You'll need something with at least a 10 amp output, preferably automatic.
Next, you will need to rig up a simple test jumper, long enough to reach the length of the car. 14 or 16 gauge wire will be plenty, as it does not need to be very heavy. Fit alligator clips to both ends.
You will need to access the battery while operating the sound system. If you have to disconnect any part of the sound system to get under the trunk floor (looks like it), you will need to rig up a shorter second test lead that can reach from outside to the battery. Once again, light wire is fine, especially since it will need to flex around the edges of the custom enclosures in the trunk. For these tests, you will need to have the sound system fully functional and drawing max power, so it can't be partially disconnected.
Under the hood, connect one end of the long test lead to the big insulated stud on the alternator. This is the terminal all by itself, with one heavy cable attached. This is the alternator output, feeding into the heavy cable running back to the battery. Put the alligator clip directly on the stud, not the crimped terminal on the end of the cable. Be careful, because this test lead is now energized, so don't let the other end touch ground. Be careful to route the test lead away from any moving parts or the exhaust.
At the back of the car, connect the other end of the long test lead to the red lead of a voltmeter (meter off). Connect the black lead to the positive battery post. That's not a typo, black meter lead to the (+) post. Use the shorter test lead as an extension for the black meter lead, if needed. Be careful, as this short test lead is also hot, so don't let the ends touch ground.
Turn on the meter and select a range that will cover 15VDC. Ignore any voltage reading you get with the engine off. It doesn't mean anything. We will be checking the ability of the fat cable to deliver the alternator output all the way back to the battery. Start the engine, and let it idle for a few minutes so the alternator output drops down. (Watch this on the dash, not the voltmeter as it isn't connected to read alternator output.) Notice I haven't asked for the reading of the voltmeter back at the battery, as we aren't to that point yet.
Once the dash display drops down to the 11ish you've been seeing, crank your sound system to max. Maybe some Carpenters. Record it and post to Youtube under your normal user name. No particular reason for the music choice, other than this inspiration:
Hold the engine RPM around 2000 to make sure the alternator is cranking out full power. (You may need a helper unless you can prop up the meter to see it from the driver's seat.) NOW you can look at the voltmeter back at the battery. If the heavy cable run from the alternator to the battery was in absolutely perfect condition, you would see 0.000 VDC. This is a voltage drop test, and it quickly verifies the current-carrying capability of any conductor. But 0.000 VDC is not theoretically possible, as it is normal to see some voltage drop. All circuits have some voltage drop. You can't avoid it. A practical limit is 0.5 VDC (half a volt), but the closer to 0.000 the better. If needed, manually select a lower range on your meter for an accurate reading on such a small value.
The higher the reading, the more of an unwanted restriction you've got between the two test points. It could be a high resistance connection in the cable run. It could be an overheated crimp that has corroded. It could even be an undersized conductor that just can't handle the massive current flow and is acting like a giant resistor. Even if you don't understand the concept of a voltage drop test, it is the cat's meow for finding unwanted restrictions, especially in a high current circuit. Remember, this voltage reading is only meaningful with the circuit under load. Please post the value seen on the meter with a maximum load on the electrical system.
That only tests the positive side of the circuit between the alternator and battery. Let's move on to the negative side, which is equally important. Turn off the meter, and fully disconnect the meter leads and extensions. At the alternator, connect the long test lead extension to the alternator case. You can usually get a good grip at the slots for cooling air, or wherever you can get a good connection. Back at the battery, connect the other end of the long extension to the black meter lead. Connect the red meter lead to the battery's negative post. Once again, that's not a typo. Red lead to the (-) post. Turn on the meter and repeat the basic test as above. Let the voltage drop down around 11ish again, as seen as the dash display. Crank some music to load the electrical system, and hold the engine RPM around 2000. As above, if all was perfect (not possible), you'd see 0.000 VDC. Realistically, you should see no more than 0.5 VDC. A value higher than that means an unwanted restriction in the negative leg of the charging circuit. Please post this value, too.
I hope this test doesn't sound too complicated. It's actually very simple, just two meter hook-ups, and it will tell me LOTS. The only difficult part is the logistics of accessing the alternator and battery. Like I said, you don't have to understand it. Just post the numbers from the two tests and we can go from there.
Is your brain full yet? Mine is. I've got some more ideas, but the test above should be a good starting point for troubleshooting. My other ideas will have to wait until my brain swelling goes down.
I answer your question about the battery in the simplest way. You have an amplifier that is 2000 total rms system wattage . to power it you need Cranking Amps - 2000CA. two batteries of 100ah and CA1000 = 2000CA. hat is, in the equation we are always looking for CA (CRANKING AMPS) . More battery more Cranking more ping . colleague focuses on what I need and how to make it hold 15.3 max and control it. the topic is too big. Focus only if you can help me right now with a commodity stock alternator
colleague focuses on what I need and how to make it hold 15.3 max and control it.
Hope I didn't scare you away, lol. Please let us know what your friend discovers.
My TheoryDuJour™ is the alternator itself is working fine and meeting its output specs. I say this because you are initially seeing around 15 volts for the first several minutes. But for reasons still unknown, the charging control system thinks all is good and is reducing the alternator output. I think this is related to the location where the control system is sampling voltage. Wherever this sample point is located, the controller sees proper voltage and thinks all is good everywhere, even though voltage is low elsewhere in the system. If indeed such a split is present, it would be because huge amounts of power are being drawn from an unusual location (i.e. close to the battery) and the controller is not capable of realizing this.
I've been researching where the controller actually samples system voltage, but I've found conflicting info. One training guide says the sample is taken from the front power distribution box. Per the wiring diagrams, it looks more like the primary junction box, inside the cabin. Hoping to find more conclusive info.
Meanwhile, please don't totally poo-poo my suggestion to do the voltage drop test between the alternator and battery. You're drawing a lot of power from a spot that normally doesn't see much current draw (other than cranking the starter), so even just a fraction of an ohm of extra resistance can cause all sorts of grief. The problem could even be as simple as a missing ground strap between the engine and chassis, or something similar. The voltage drop test will cover all of that in a matter of minutes, and help guide your next steps.
Where I work we design most electrical parts for 16v max. So... IMO what your seeing is well within normal automotive specs
I was a reliability engineer for 21 years for various satellite components and was required to determine component stress of various circuits we made. And its not recommended to operate at the high end of the range. And it actually hurts parts to run them st their absolute max voltage rating. So just because a part has an absolute maximum operating voltage of 16v, if you run it at its max voltage, its life degrades much faster than when you operate it at recommended voltage. It does stress parts and degrade their life. I used to have the formula memorized but no more
10-23-2020, 02:43 AM
low battery charge
