Freeing my 2000XJ from the external regulator life

robsjeepxj said:

The issue with voltage when it comes to car audio is every time the bass hits it drains the battery a little bit at a time. I have a digital voltage meter that plugs into the cigarette lighter to monitor voltage level so the higher I can get it to begin with(within reason) the longer I can play it at competition level before I have to stop and let the batteries recover so every little bit helps, you know what I'm saying? Even if it is just 5%.

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Yes, I know what you're saying. I used to install high-end stereo systems in cars.

You need to learn more about this stuff before you go spending money on it. Seriously.

techno1154 said:

The battery temperature sensor at 80* (80 degrees) ambient temperature should read between 9 and 11 OHMs. I am yet to find one that is better than 9 OHM. Bear in mind the cooler the temperature the higher the OHM reading should be which in turn would cause the voltage to be higher.

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I must be missing something here.

Please explain how the battery temperature sensor has anything whatsoever to do with voltage output from the alternator?

I don't believe you folks understand how these systems work.....

Anak said:

I bet that is what was going on here:

The P.O. seemed to think a stereo was top priority. I have gotten rid of all that dead weight.

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I'd say PO was a moron. Demonstrably, and literally.

8Mud said:

The only reason to use more volts is to push more amps.

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Well, no.

A given electrical device is rated in Watts required to run it.

This is why I referred to Ohm's Law earlier.

At higher voltage, LESS amperage is required to meet the energy demands of the device. So your statement is exactly incorrect.

That said, it's not that simple- components are rated for voltage . The compnents may well not be rated for the higher voltage.

So still, it is a fact that pushing a higher voltage than 14.8 volts (nominal alternator/charge voltage for a car) is a very bad idea.... unless you enjoy replacing ECUs, TCUs, etc.

I've seen a lot of this sort of stuff over the years. Some folks just need to back away from the wire cutters. I've seen vehicles literally burn to the ground due to this sort of thing- in fact a white F150 yesterday, in traffic. It's not looking good for my friend, either- he let his insurance lapse.

burntkat said:

Well, no.

A given electrical device is rated in Watts required to run it.

This is why I referred to Ohm's Law earlier.

At higher voltage, LESS amperage is required to meet the energy demands of the device. So your statement is exactly incorrect.

That said, it's not that simple- components are rated for voltage . The compnents may well not be rated for the higher voltage.

So still, it is a fact that pushing a higher voltage than 14.8 volts (nominal alternator/charge voltage for a car) is a very bad idea.... unless you enjoy replacing ECUs, TCUs, etc.

I've seen a lot of this sort of stuff over the years. Some folks just need to back away from the wire cutters. I've seen vehicles literally burn to the ground due to this sort of thing- in fact a white F150 yesterday, in traffic. It's not looking good for my friend, either- he let his insurance lapse.

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I've looked at many amp meters and never noticed the amps going down as the voltage increases?

Not many machines designed to limit input or output, the watt rating is basically the work the machine does and/or heat it produces within design parameters.

To say the same thing in different (basic) terms the higher the voltage the more electron flow, electron flow is measured in amps. Sure there are limits, melt down being the big one.

Running any system to near the limits can cause failure, inductance changes with the temperature, the load fluctuates and the regulator doesn't react instantaneously.

But we are in agreement that leaving some margin for error is prudent.

My terminology is old school and the terminology has evolved over the years. But cause and effect hasn't.

burntkat said:

I must be missing something here.

Please explain how the battery temperature sensor has anything whatsoever to do with voltage output from the alternator?

I don't believe you folks understand how these systems work.....

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My friend, I regret to inform you regarding the magnitude of the error you demonstrated in your post. Battery temperature sensors are manufactured to do one thing and one thing only.

It is widely known that an overheating/heated battery will live a very short life. Ask anyone who live in Arizona and other hot places in the US. This is something I have know since the 1980's installing remote communications equipment in the Caribbean which consists of batteries, PV (photo voltaic) controllers also known as charge controllers and an array of solar panels.

Here is the simple explanation of how this works.

The sensor is placed on, as on the battery negative terminal, or in the battery compartment/box and in the case of Chrysler in the battery bracket in such a way that it contacts the battery case. This sensor communicates with the charge controller,...in the case of our XJ, the PCM. Depends on what the PCM sees, it regulates the voltage in an attempt to keep the battery temperature at an acceptable level.

The level that I gave, 9 to 11 OHM at 80* is taken from the 1996 XJ workshop manual section 8C page 6.

I hope this help you and others whose XJ voltage is below the level they prefer.

LJRockstar said:

Good to know... I'll happily try an 11ohm resister in place of the batt temp sender for $6 before blowing $65 on the regulator.

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Anak said:

I bet that is what was going on here:

I do not think that will work. Why? the PCM is looking for resistance changes over time If it do not see chances, it will go in a tizzy. Any way, I have not tried to bypass the sensor with just a resistor. Try it and let us know how it work.

The P.O. seemed to think a stereo was top priority. I have gotten rid of all that dead weight.

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That idea is the one I have given thought to but put it on the back burner since the battery is maintained at an acceptable lever even though I never see more than 13.8 volts at first startup in the morning. As I said in a previous post, after about an hour drive in 90+ degree temperature the voltage drops sometimes as low as 13.3 even though there is no other electrical draw on the system.

OH! on the rear winter mornings here in North Florida when the temperature in the mid to low 40's I see as much as 14.1 volts on first startup.

much of your issue will be resolved with a automotive audio capacitor or 2.

Actually capacitors are fairly useless and to be honest a pretty outdated solution compared to adding a second or third battery esp the new AGM units designed esp for high wattage car stereo applications. Yes in theory they do work but their small size and available capacity is no match to todays high amp, fast discharge, deep cycle AGM and the new lithium batteries available today. Technology has definitely caught up with the times and large battery banks are the go to solution when it comes to car audio today.

OK I have to ask this question-

Exactly how many watts total RMS are you running in your system?

robsjeepxj said:

Actually capacitors are fairly useless and to be honest a pretty outdated solution compared to adding a second or third battery esp the new AGM units designed esp for high wattage car stereo applications. Yes in theory they do work but their small size and available capacity is no match to todays high amp, fast discharge, deep cycle AGM and the new lithium batteries available today. Technology has definitely caught up with the times and large battery banks are the go to solution when it comes to car audio today.

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Except, no.

Batteries aren't designed for large energy drains in very short periods of times.

Capacitors, on the other hand, are.

Unless basic electronic theory has changed in the last 20 years, this remains the case.

(Hint: electronic theory hasn't changed)

Plus you can buy a 30 farad cap pretty cheap now! If you install one for each amp plus diodes..........

I keep envisioning this.........
BTW, the electrics in this one are excellently installed!
https://www.youtube.com/watch?v=hWv8RQZl0Eg

RCP Phx said:

I keep envisioning this.........
BTW, the electrics in this one are excellently installed!
https://www.youtube.com/watch?v=hWv8RQZl0Eg

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One word comes to mind.... "chengada"

RCP Phx said:

I keep envisioning this.........
BTW, the electrics in this one are excellently installed!
https://www.youtube.com/watch?v=hWv8RQZl0Eg

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I see a virtual Jeep ride here. Sync it up with a 360-degree camera, put the goggles on and go trail riding, out in the garage.
Wonder what it uses for a power supply? A big stack of lithiums?

Approx 3k at full volume although I haven't turned it past 3/4 volume. At that point the noise from the body panels vibrating sounds like total shit so I keep it to 25 out of 35 on the volume knob max, usually around 20 most often with the sub turned to 10 out of 15 on the head unit as far as bass boost.

What's the THD and at what frequency?