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Discussion Starter #1
Attempting BIG 3 upgrade in my 2015 Subaru Legacy 2.5i.
However, there is a device on the battery negative terminal that I don't know how to incorporate into the wiring.

Online search says it's a "SENSOR-BATTERY (ALTERNATOR. CURRENT SENSOR.)"
My guess is that this "Battery Sensor" might be a shunt to measure battery charging current. Then some computer uses that measurement to regulate the alternator somehow. But that is just a guess.
I don't think it could support the full current flow through it, So...Can I just bypass it with the new ground wires? (Will that affect the alternator output?)
Or maybe I should leave it there and run new grounds in parallel? (Would less current flow in this path signal a higher or lower alternator output?)

PS: I have new upgraded battery lugs to handle the upgrade. Also, I'm installing two amplifiers, a LOC and a 50 Farad Cap, using 4/0 power wire to the trunk. Everything together could draw up to 360 Amps. Depending upon real world power consumption, I may upgrade the battery and alternator - but waiting to test this first.

PICS:


 

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I somewhat doubt it's a regulates anything. More so just a sensor. I imagine there's some display in your car that shows it's readout. Or it monitors it to throw an engine code if something is wrong. I have no first hand experience with Subies, so I can't say for sure. Though my Nissan has sensors on the positive and negative that I have to deal with.

Modern smart cars can be finicky when something isn't right. I'd keep it connected in some way. Leaving the existing ground intact in a Big 3 isn't uncommon. It's ok leave some hard to deal with stuff, but double up that connection with your big gauge wire.

For a terminal solution, you could go with Knu's Bassik terminal, and a top post adapter. In this method, you can just hook up that existing connection to the Knu terminals Top post, and have room for other connections. Basically relocating the battery post, allowing more connection options, and looks decent.




Or Knu's Ultimate Terminals + Top Post.

 

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Discussion Starter #3
I wanted to follow up:

I'm using 4/0Ga wire and wanted the best connection I could get. Running through that Shunt just made things messy.

As a test, I ran the car for a week with the shunt sense wires disconnected and there were no issues or differences that I could notice.
So, now I put good solid terminals right to the battery and everything is working great.

Thanks for your reply.
 

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If it's anything like the ELD circuit in Hondas, welcome to modern cars. I would very much keep that sensor in place, otherwise it's possible that the alternator won't ramp up output to keep up with the stereo.
 

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Discussion Starter #5
@cobb2819 Thanks for the heads up!

From my research it was used to reduce the engine idle speed when the battery was full and the power draw was low. Thus removing it should only increase my idle speed at times. But from my testing so far, after the engine warms up the idle goes back to previous speeds and the reading at the battery maintains normal charging levels.
Since I've already implemented it, I will keep a close eye on it and put the shunt back in the circuit if needed.

Also, My amp can pull up to 309Amps (max reading at peak) and I suspect it may consume more power than my stock alternator can supply, so I've been researching after-market alternators and it seems they mostly eliminate the control circuit anyways. I found one that will fit my car and if things get bad then I will get it. But I want to test it using stock system first to see if it's really needed for my actual usage.

Either way, I've implemented a DROK for Ammeter, Voltmeter and Battery level to keep an eye on everything. Link: http://a.co/8j4q8g2

I'll reply back with an update later after some real life use.
 

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@cobb2819 Thanks for the heads up!

From my research it was used to reduce the engine idle speed when the battery was full and the power draw was low. Thus removing it should only increase my idle speed at times. But from my testing so far, after the engine warms up the idle goes back to previous speeds and the reading at the battery maintains normal charging levels.
Since I've already implemented it, I will keep a close eye on it and put the shunt back in the circuit if needed.

Also, My amp can pull up to 309Amps (max reading at peak) and I suspect it may consume more power than my stock alternator can supply, so I've been researching after-market alternators and it seems they mostly eliminate the control circuit anyways. I found one that will fit my car and if things get bad then I will get it. But I want to test it using stock system first to see if it's really needed for my actual usage.

Either way, I've implemented a DROK for Ammeter, Voltmeter and Battery level to keep an eye on everything. Link: http://a.co/8j4q8g2

I'll reply back with an update later after some real life use.
Those DROK components are very interesting. I didn't realize something like that existed, but now I'm going to build one of these into my system next to some VU meters.

Thanks for posting.
 

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I wanted to follow up:

I'm using 4/0Ga wire and wanted the best connection I could get. Running through that Shunt just made things messy.

As a test, I ran the car for a week with the shunt sense wires disconnected and there were no issues or differences that I could notice.
So, now I put good solid terminals right to the battery and everything is working great.

Thanks for your reply.
First off why are you using 4/0? That is ungodly huge wire and that is absolutely and totally overkill and a waste of time even for ground wires. And second your alt is only going to put out what ever it's rated at, bigger wire won't make it put out more amperage. The factory sizes the wire for the alternators output. Lastly my amps on full tilt between the two 1600w pull 21-26amps combine that's it. Changing the grounds will make a way bigger impact on your electrical system.
 

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Discussion Starter #10
Well, it's installed and running good so far without the shunt.

I only have a pair of my old 12's wired for 2 ohms in right now, plus the front amp running 4 speakers. At full tilt it will draw up around 110 Amps measured on both a clamp and also a DROK I installed. Thankfully with the 50F CAP I have in place the car seems to handle it. (Although I have not run it full tilt for longer than an hour straight)

I'm now shopping for a pair of 15's or 18's as so I can replace the back seat and wire them for 1 ohm - that's where I am worried and the reason for the 4/0 wire.
If the new speakers pull more than my system can handle, then I will upgrade the ALT and battery. (I've already got quotes)

Either way, I am happy the battery still charges fine without the shunt.

Here's some pics of the setup so far:



 

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Well, it's installed and running good so far without the shunt.



I only have a pair of my old 12's wired for 2 ohms in right now, plus the front amp running 4 speakers. At full tilt it will draw up around 110 Amps measured on both a clamp and also a DROK I installed. Thankfully with the 50F CAP I have in place the car seems to handle it. (Although I have not run it full tilt for longer than an hour straight)



I'm now shopping for a pair of 15's or 18's as so I can replace the back seat and wire them for 1 ohm - that's where I am worried and the reason for the 4/0 wire.

If the new speakers pull more than my system can handle, then I will upgrade the ALT and battery. (I've already got quotes)



Either way, I am happy the battery still charges fine without the shunt.



Here's some pics of the setup so far:









Where are you measuring 110amp draw? And your flirting with a fire not having a fuse on your alternator charge wire. It's useless anyway your alt isn't going to put out more than it's rated for but still still not smart


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Discussion Starter #12
@Redliner99,
It was measured on the + power cable running between the battery and the new equipment only.
I only wanted to measure the draw from my new equipment and not the rest of the car nor the batt charging load, etc..

Regarding the fuse on the cable running from the batt to the alt, you are correct, it is a concern. I already had a second fuse holder ordered, I'm just waiting for it to come in. But I wanted to get everything tested in the meantime, so I thought I would take the risk until then.
Also, I took several extra precautions regarding my power lines.
First, it's 4/0 WELDING cable and the insulator is extremely high temp resistant. Secondly I've added multiple layers of additional insulation to include High temp PET sleeve, High temp Heat Shrink tube and also for added vibration protection I have cut to fit pieces of 1" Poly Pipe around it all.

Also, I took several Thermal images after running the car for a long trip to verify it was not resting against anything overly hot to make it melt:

 

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@Redliner99,

It was measured on the + power cable running between the battery and the new equipment only.

I only wanted to measure the draw from my new equipment and not the rest of the car nor the batt charging load, etc..



Regarding the fuse on the cable running from the batt to the alt, you are correct, it is a concern. I already had a second fuse holder ordered, I'm just waiting for it to come in. But I wanted to get everything tested in the meantime, so I thought I would take the risk until then.

Also, I took several extra precautions regarding my power lines.

First, it's 4/0 WELDING cable and the insulator is extremely high temp resistant. Secondly I've added multiple layers of additional insulation to include High temp PET sleeve, High temp Heat Shrink tube and also for added vibration protection I have cut to fit pieces of 1" Poly Pipe around it all.



Also, I took several Thermal images after running the car for a long trip to verify it was not resting against anything overly hot to make it melt:





110amps sounds super high. I'm running a 1000w class d,a 600w class d, my head unit, and my dsp and I measured 28amp draw PEAK! I mean that was uncomfortable to listen to at that volume it's was closer to 23-25amps at listening levels and that was on a heavy bass song with that really partying.


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Discussion Starter #14
110amps sounds super high.
I knew it was going to be high when I started this project.

My Sub Amp is the SoundQubed S1-2250 which has over 2300+Watt output, however it is supposedly very inefficient on power usage.
According to a dyno run {below} @2ohms it could pull 181A Peak and @1Ohm up to 309Amps!

Now I realize that is max peak, but I wanted to build the power system to handle it and the front speakers amp and also several other pieces of equipment.
That's why I chose 4/0 cable and it was only $3.58/foot for 2071 strand oxygen free copper wire.
 

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I knew it was going to be high when I started this project.



My Sub Amp is the SoundQubed S1-2250 which has over 2300+Watt output, however it is supposedly very inefficient on power usage.

According to a dyno run {below} @2ohms it could pull 181A Peak and @1Ohm up to 309Amps!



Now I realize that is max peak, but I wanted to build the power system to handle it and the front speakers amp and also several other pieces of equipment.

That's why I chose 4/0 cable and it was only $3.58/foot for 2071 strand oxygen free copper wire.



That is outrageously inefficient. What is the rms at 2ohms peak is just for sales. Also what amperage is your alt rated to?


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Discussion Starter #16 (Edited)
That is outrageously inefficient. What is the rms at 2ohms peak is just for sales. Also what amperage is your alt rated to?
Did you even read my post or watch the video?
That's NOT the sales numbers, that's the actual measured RMS Dyno numbers by an independant third party.
This one is 62% efficient at worst case @1ohm Peak Dynamic.
Compare that with other amps that put out this much power at this price range and it's NOT terribly abnormal.

My stock alt is only rated at 140Amps.
Now, given the nature of music, my system will NOT constantly draw that much power.
I'm hoping the Batt and CAP will compensate until they are recharged.
But if not, that's why I have quotes for aftermarket Alts and batteries just in case.
 

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having driven a car with the same charging handicap I would say your better off doing the following:


1) ditch the system entirely for a much more efficient amp


2) purchase comps and subs that best suit the mentioned amp



3) ditch the cap as they do noting for your benefit and do infact add more load


4) get a more efficient,stronger battery such as Varta (if you guys have them in the U.S) or Optima etc AGM



went from DLS RA20 + RA30 which isnt a great big deal to begin with in terms of load to a moderatly more efficient Alpine PDX 2gen (alpine pdx v9) and added switched from a 72ah EFB battery to a Varta AGM 70ah and things immediately changed for the better.



now my charging system has no difficulty powering my sistem even at very high listening levels and with A/C ,headlights etc on.


before that my lights used to dim and the sub did miss a beat from time to time
 

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Discussion Starter #18
@audiocholic

I do not have ANY issues with lights dimming nor battery not charging.
I tested removing the CAP and then the lights do dim when the bass hits.
Therefore the CAP will remain as it is doing exactly what it needs to by providing the extra power during those key moments.

Also, I will keep my current equipment as I'm not rich and cannot "Ditch" equipment so carelessly. Except for the Speaker upgrade which I mentioned earlier. If I were rich, then I would have taken an entirely different approach to this project. For now though the system is working great and fits in my budget. However, if you would be willing to provide the equipment, then I would be happy to throw it all out. Please let me know.

Until your willing to help, then my plan is to stick to my limited budget and get those new 15's put in, if I have issues then I will upgrade the Battery to a SHURiKEN SK-BT100 that has a 100AH rating and is the largest I found that would fit in the Batt area and has a reasonable price.
And if I still have issues, then I will save up for the upgraded Alternator which I have Quoted from Singer. But only if really needed.

I'm really excited to hear what equipment you will be sending.
Let me know, thanks!
 

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dear friend,




my advise to you is to look into what this sensor does really in the real world conditions in your car. if its anything like the sensors in honda's,european cars such as Renault than this is trouble.


1) with a DMM check battery voltage with the car running and nothing on
2) recheck with only A/C on
3) rechech with only headlights on
4) recheck with only the head unit on and at moderate listening levels
5) recheck with all of the above on

if you find that the voltage swings from 12.6v to 14.4v with any of these actions than your pretty much screwed as I'am with my renault.

no battery from optima or eslewhere in world is going to help nor will any cap.these will only increase capacity and do nada for this voltage swing.


if this turns out the case for you I would like to say look into JL Audios amps that have R.I.P.S technology which allows for a stable output voltage/rms no matter the input voltage meaning it produces the same RMS value at 12.6v as does at 14.4v.

I'am trying to give you sincere advise that I find valuable which I wish someone esle had given me on my first steps , to take it with respect or to make funny jokes about it and ignore is upto you.

regarding the rich rich rich money statement you kept making I would say relax alittle mate.this is what I do and never have lost any money I mean not even a penny in the past 7 years.


1) buy a valuable product that is somewhat new tech or if older one that is very well respected that is in awesome condition yet used and is far off from its initial new price.

for example which do you see a bigger loss?

a) buying a flea market amp or some so so amp for a few hundred brand new than while trying to sell it a few years later finding no one cares for it so it stays in the garage or gets sold for 1/5th the price?
or
b) buying say a JL HD600/4 or perhaps a euro Audison 5.1K used for half price and selling for exactly the same of even more later on?


2) always try not to strain the system, this means clean amp power with plenty of headroom and gains low, more efficient subs that do the same job with far less strain on the battery or most importantly the alternator etc you get the idea.

theres a famous saying, I'am not rich enough to buy cheap which I do find correct to an important extent.

If you can find quality products in your local area used that you can physically check before buying then yeah maybe its too risky to purchase these valuable goods otherwise its pretty simple and I havent seen this idea fault me once on probably my 6 or 7th system all of which were hi end stuff.
 
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