Help with a diagnoses.

[youbsilent357]

Hey guys. Thanks for letting me join here. I have an issue and need suggestions. I have a 2015 pilot. Running 2 sets of C3 JL audio 6.5 components by an Alpine PDX 4.150. 2 Sundown X12’s in a ported enclosure by a sundown 1.13,500. I have an XS Power D7500 battery in the back. I have an issue with voltage jumping all around. 14.2-12.3. I took it to Honda to check the alternator and they said it was bad. I bought a new alternator. It’s a Jpower 250A I believe. Plenty strong I assume. Even with the swap(the old one was 250A as well) the voltage is still jumping around. Dipping to 12.3 even while driving. Especially while driving. Could it be a ground? I used the back row seating lug. 3/4 head bolt. Used a dremel tool to strip all the paint around it. What you guys think? Thank you guys for any help.

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[1aespinoza 10+ year member]

Thank you guys for any help.

Did you add what is known as "The Big 3"?

 

[youbsilent357]

Did you add what is known as "The Big 3"?

I have a fuse with holder that connects to front battery to rear battery. Then that power wire goes to the alternator. The accessory power is also wired to the terminal. I have the battery grounded good to the chassis. I think that’s big 3 right? If so then yes. My new charging wire is 0Gage. It runs front to back and to the alternator.

 

[1aespinoza 10+ year member]

I think that’s big 3 right?

There should also be one from the engine to the vehicle chassis.

 

[Jimi77 5,000+ posts]

Hondas and many modern cars regulate the alternator's voltage/output to maximize mileage. You may be fighting the Pilot's OEM charging system. Big 3 is the first step and can you clarify what you mean by "voltage is jumping around?"

 

[youbsilent357]

Hondas and many modern cars regulate the alternator's voltage/output to maximize mileage. You may be fighting the Pilot's OEM charging system. Big 3 is the first step and can you clarify what you mean by "voltage is jumping around?"

I have a little meter plugged into the cigarette lighter. It shows 14.2V mostly. But while listening to or even sometimes not listening to my music it’ll jump around from 12.3 to 14.2V. It did alarm out the charging system a while back and that led me to disconnect the audio system from the batteries. I also went and had the alternator tested. It was a 250A and Honda said it was bad. I bought a new alternator and have installed it. So far, the charging system hasn’t alarmed out, but the voltage is moving like it was before.

So I need a ground wire from the alternator to the chassis as well as a wire from the negative battery terminal to the chassis?

 

[youbsilent357]

There should also be one from the engine to the vehicle chassis.

Okay. No I did not install/upgrade this.

 

[Jimi77 5,000+ posts]

I have a little meter plugged into the cigarette lighter. It shows 14.2V mostly. But while listening to or even sometimes not listening to my music it’ll jump around from 12.3 to 14.2V. It did alarm out the charging system a while back and that led me to disconnect the audio system from the batteries. I also went and had the alternator tested. It was a 250A and Honda said it was bad. I bought a new alternator and have installed it. So far, the charging system hasn’t alarmed out, but the voltage is moving like it was before.

So I need a ground wire from the alternator to the chassis as well as a wire from the negative battery terminal to the chassis?

The alternator is well grounded to the block. There should be a engine block to chassis ground and that needs to be upgraded. Some people will ground directly to the alternator case since it's usually pretty easy.

 

[dragon.breath 10+ year member]

Wait, you are running a 13000 watt amplifier that will draw well in excess of 1000 amps of current with a 250 amp alternator and the voltage is only dropping to 12.3v? That is not a problem, it’s a miracle.

 

[audiobaun 5,000+ posts]

Wait, you are running a 13000 watt amplifier that will draw well in excess of 1000 amps of current with a 250 amp alternator and the voltage is only dropping to 12.3v? That is not a problem, it’s a miracle.

Yes. Deff a miracle and working better than most vehicles. LOL

 

[Firewalker]

That has to be a typo because those X12's are only 2,000 watts rms on the latest version which is iirc V3, the V2's are iirc 1,500 watts rms. A 13,500 watt Sundown amp would blow them apart in a heartbeat. Has to be a Sundown SFB 3,500 or a SIA 3.5K.

 

[youbsilent357]

Wait, you are running a 13000 watt amplifier that will draw well in excess of 1000 amps of current with a 250 amp alternator and the voltage is only dropping to 12.3v? That is not a problem, it’s a miracle.

It’s throttled way back. The Suns are rated 1500W Rms. I have that amp around 40%. I still clip and it’s a head scratcher.

 

[youbsilent357]

That has to be a typo because those X12's are only 2,000 watts rms on the latest version which is iirc V3, the V2's are iirc 1,500 watts rms. A 13,500 watt Sundown amp would blow them apart in a heartbeat. Has to be a Sundown SFB 3,500 or a SIA 3.5K.

No. It’s the 13,500. I ordered the 5000.1 but they sent me the wrong amp. I called them trying to do the right thing and they gave me the option to return it for the correct amp or keep it. So I kept it and I have it throttled way back.

 

[HardofWhoring]

I have a fuse with holder that connects to front battery to rear battery. Then that power wire goes to the alternator. The accessory power is also wired to the terminal. I have the battery grounded good to the chassis. I think that’s big 3 right? If so then yes. My new charging wire is 0Gage. It runs front to back and to the alternator.

You have your power cable going from the main battery to the rear battery, then off the rear battery going to the alternator?

What accessory is wired to the terminal? An accessory wire is supposed to be a switch wire, that is only powered when accessory is turned on. If you wired it to the terminal, you wired it up as a 12v hot wire, and not a switched wire.

 

[youbsilent357]

You have your power cable going from the main battery to the rear battery, then off the rear battery going to the alternator?

What accessory is wired to the terminal? An accessory wire is supposed to be a switch wire, that is only powered when accessory is turned on. If you wired it to the terminal, you wired it up as a 12v hot wire, and not a switched wire.

I’ll start from the alternator. There’s an upgraded charging wire running from that to the front battery. The factory accessory wire is also ran to the front battery just like it would be normally. Then the power wire comes out of that multi source block and runs to the fuse holder up front right under my wipers mounted under the hood. From there the power wire runs to the rear battery where it goes into a big block on the terminal to support multiple power runs to both amps. Hope that helps