2 alt, 3 batts, and still dropping like crazy...

[boostNbeer]

The optima rests @ 12.5, the rears @ 12.6. With all amps off ( I have a switch to give them remote power) my car idles @ 14.6

The voltage doesnt start to drop until like 11 or 12 volume, but once you get to 15ish and above, it just drops like crazy.

I heard the V4000xd was a power hog.... but cmon... this bad?

About diconnecting my factory alt, would that work? Would my car even still run?

 

[satchel50207 10+ year member]

man i have a 105A stock alt one deca intimidator in the rear and all 4 gauge wire ran. and i only drop to 12V with teh car on. im running 3k rms at 1 ohm. i would check everything and troubleshoot the problem till i found it

 

[boostNbeer]

i would check everything and troubleshoot the problem till i found it

Would you like to tell me wat to check lol, wires are tight, overkill on size, everything is new...

 

[k_schutte 10+ year member]

your car will still run with the factory alt disconnected. If you don't want to disconnect the factory alt you can simply disconnect the wire from you factory battery to you second alt. So disconnect the wire from you factory battery to you second alt, then start it up and see what you rear batteries have for voltage.

Basicaly what I think the case might be is that your new alt isn't putting out any power and the cable from you factory alternator to you second alt might be the only reason your rear batteries are at 14v+ when the vehicle is running. As in, your factory alt is the only thing powering the system which is why it would drop so bad... Make Sense?

 

[kodak314 10+ year member]

are both the runs to the back positive? if so ill change it to have 1 positive and 1 negative run front to back

 

[gtbike900 10+ year member]

try unplugging one alt see if your charging then vice versa unplugg with car off pull the clip

 

[davey2020 10+ year member]

That is what i think the problem is. The second alternator isn't working.

 

[kodak314 10+ year member]

man i have a 105A stock alt one deca intimidator in the rear and all 4 gauge wire ran. and i only drop to 12V with teh car on. im running 3k rms at 1 ohm. i would check everything and troubleshoot the problem till i found it

//content.invisioncic.com/y282845/emoticons/uhoh.gif.c07307dd22ee7e63e22fc8e9c614d1fd.gif

 

[DammitJames 10+ year member]

you should try and do voltage drops on the wires with a dmm and see if your loosing any power in your connections

 

[DBBOOM 10+ year member]

you should try and do voltage drops on the wires with a dmm and see if your loosing any power in your connections

Take resistance readings across all connections with a DMM.

 

[LoudCav]

your car will still run with the factory alt disconnected. If you don't want to disconnect the factory alt you can simply disconnect the wire from you factory battery to you second alt. So disconnect the wire from you factory battery to you second alt, then start it up and see what you rear batteries have for voltage.
Basicaly what I think the case might be is that your new alt isn't putting out any power and the cable from you factory alternator to you second alt might be the only reason your rear batteries are at 14v+ when the vehicle is running. As in, your factory alt is the only thing powering the system which is why it would drop so bad... Make Sense?

^^ this. Plus there's no real reason to connect the 2nd alt to the stock batt if your system isn't draining from it.

Do this. Ground your amps straight to the batts in the back and get rid of the grounds for them to the frame. Ditch the ground from the 2nd alt to the body/frame and run a ground from the 2nd alt to the batts in the back (just do a temp run) and see if you still have the issues. Unhook the pos run from the stock alt to the rear batts, too. This will completely isolate the secondary system from the primary. Then start testing stuff if you still have problems. Make sense?

Or you can just go to autozone and get the alt and batts tested for free first, then check all your grounds.

 

[stevew007 10+ year member]

I would isolate each alt and test with dmm to make sure they are charging. and yes the xd is power hungry and if you dont be carefull with low voltage you might smioke the amp. if both alts are charging pull the amp and swap it to see if you still get the mad drop.it might just be the amp

 

[njaykaplan 10+ year member]

I don't think you can completely isolate the alternators. The only way i could think of, is having it externally regulated. The alternator has to know the battery voltage so it doesnt overcharge, my buddy had a second alternator and forgot to connect it together, and it charged at 17-18v until it was connected.

 

[Notloud00 10+ year member]

those batts should easily stay in the low 12's just by themselves //content.invisioncic.com/y282845/emoticons/fyi.gif.9f1f679348da7204ce960cfc74bca8e0.gif

 

[plugitin 5,000+ posts]

how do you have the second alt hooked up? is it a one wire alt?