2nd battery to fight voltage spikes help!

[bigpoppahump]

So I installed a new 270 amp alt and I'm getting 17.8v spikes at the battery and 17.5 at the amps. I'm being told that the g35 bosch plat agm under the hood is not cutting it. It's my only battery and I was not planning to add any others because I don't play the system hard with the engine off.

Could I get away with using one of those cheesy caps? Do I need a large battery or can I keep this in my budget which is, right now, 180 but I can put 60-100 more into it in a week or so.

I've searched and not found much info on what I think they called "backfeed".

2004 sub forester

orion 2500.1dz (@ 2ohms till i get a 2nd sub)

sony xm-zr1252mids/highs amp

One run of 1/0 knu ofc for the orion amp

One run of 4ga CCA for the sony amp (left in from my original install that I thought I would be happy with)

Big 3/4 with excessive grounds all 1/0 knu ofc and sky high lugs

I'm starting to hate the fact that I spent more on my alt than most of my system and now have to put more money into power to make it work properly but I wanted overkill and now I'm all in //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Any recommendations you guys can give are greatly appreciated.

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[wew lad 5,000+ posts]

So I installed a new 270 amp alt and I'm getting 17.8v spikes at the battery and 17.5 at the amps. I'm being told that the g35 bosch plat agm under the hood is not cutting it. It's my only battery and I was not planning to add any others because I don't play the system hard with the engine off.
Could I get away with using one of those cheesy caps? Do I need a large battery or can I keep this in my budget which is, right now, 180 but I can put 60-100 more into it in a week or so.

I've searched and not found much info on what I think they called "backfeed".

2004 sub forester

orion 2500.1dz (@ 2ohms till i get a 2nd sub)

sony xm-zr1252mids/highs amp

One run of 1/0 knu ofc for the orion amp

One run of 4ga CCA for the sony amp (left in from my original install that I thought I would be happy with)

Big 3/4 with excessive grounds all 1/0 knu ofc and sky high lugs

I'm starting to hate the fact that I spent more on my alt than most of my system and now have to put more money into power to make it work properly but I wanted overkill and now I'm all in //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

Any recommendations you guys can give are greatly appreciated.

who the **** told you the battery is the cause of the spikes? your alternator probably has a bad voltage regulator or rectifier

never waste your time on those **** caps less than 10 farads. you need 300+ farads to notice any difference at all and that means banks of maxwell or XS ultracaps

 

[Hertz Mafia]

My alt will spike like high 15s on a big bass note and then when the bass stops the voltage will spike for a second. Never seen 17+ but not a big deal imo if nothing is shutting off

 

[Mayhem]

Adding a second battery isn't just for playing your system while it's off.

Your alt is spiking your voltage. What brand is your alt? What voltmeter are you using?

This hobbie is expensive. Most of us have thousands in our systems and 30% of that is just on electrical.

 

[bigpoppahump]

who the **** told you the battery is the cause of the spikes?

DC Power and not really the battery itself, more that the battery is just too small for a 270amp alt and I don't see many examples of people running a 270a alt with a single group 35 battery so I couldn't argue. He just thought that a larger capacity of storage might smooth out the spikes.

A lot has changed since my punch 200's on kicker solo rounds were the **** so I am defiantly a noob these days and learning a lot more as I try to get louder.

 

[bigpoppahump]

not a big deal imo if nothing is shutting off

The Sony amp has been going into protect randomly when heavy bass hits, since upgrading the alt and wiring, and comes right back on within a few seconds.

 

[bigpoppahump]

Adding a second battery isn't just for playing your system while it's off.
Your alt is spiking your voltage. What brand is your alt? What voltmeter are you using?

DC Power and I'm using a Fluke12 meter set to record min/max. I also use torque app and it shows a max over 17v as well.

I'm also getting a minimum of 10.5v at the fused distribution block in the back with the fluke and 11.7v min in torque. This is at highway speeds 65+.

 

[wew lad 5,000+ posts]

DC Power and not really the battery itself, more that the battery is just too small for a 270amp alt and I don't see many examples of people running a 270a alt with a single group 35 battery so I couldn't argue. He just thought that a larger capacity of storage might smooth out the spikes.
A lot has changed since my punch 200's on kicker solo rounds were the **** so I am defiantly a noob these days and learning a lot more as I try to get louder.

DC power has some intelligent individuals but that sounds like complete bs to me

Voltage regulators limit the voltage in most alternators but if your car is ECM controlled I dunno what to say. It's a 2004 so i doubt it

You have serious issues if you're at 10.5v at the back at any time

 

[BOOMINGRANDPA 5,000+ posts]

don't know that 2nd batt will fix that but if u want to replace stating batt gp car audio has pretty good sale on northstar batts.. Best Car Audio AGM Battery

 

[shizzzon 10+ year member]

The context they are telling you this is in this context-

If you have a single starting battery and a single alternator (doesn't matter it's size, stock or larger..), having the battery with loose connections or POOR performance DUE to age of battery will increase resistance at the battery.

Since everything is connected to the battery, the battery must be in good condition and connected tight. Having one or both of these conditions go sour forces the alternator to ramp the voltage up to "bleed" through the resistance so the battery finally sees the voltage it suppose to see.

The downside to this is since everything is connected to the battery, electrical will flow through all the wires in use past the battery at the maximum output voltage the alternator is set to at that time.

Meaning.. if you are reading 17v somewhere else, then that means the regulator is outputting that high of voltage just to overcome some issue at the battery.

This is pretty serious.

This isn't a voltage spike you should keep allowing.

Adding a new battery of course will help eliminate the spikes.. But without attempting to re-secure your connections at the starting battery OR replacing it altogether, adding additional batteries will only temporarily solve the issue until the new battery(ies) bleed into the starting battery for whatever reason eventually damaging either the alternator from overworking it or never fully charging the newly added batteries.

The notion your starting battery is too small isn't the correct answer but it's CAPACITY that is available may not be enough BECAUSE of other factors or it could be very well too small altogether because the car is requesting simply too much capacity from it during a cycle before recharge therefore concluding it's capacity is too small.

 

[poolman966554]

your amp will pull 270A @ 2 ohm if your trying to push 2400 watts.. Seems like a power hungry amp but its cheap tho.



Box rise will keep you far from your 2 ohm load.

That said, id look into the regulator/rectifier. What brand Alt?? Is it internal? or external?? either way, it should never let a 17v spike though the system if set properly.

 

[bigpoppahump]

The context they are telling you this is in this context

Thank you, I'll check my terminals. I did just replace some kicker terminals I was using temporarily with knu konfused positive and negative terminals last week but never double checked them after clamping them down the first time. The battery is a year old and is always above 12.8v and as high as 13.2 after resting for a night. All grounds are new, knu kol 1/0 ofc with sky high lugs crimped with a 16 ton crimper within the last week.

The one thing I need to change for sure is the sub amp and alt are connected to the isolated (fused) side of the positive terminal which makes my amp wire live at all times, without the fuses installed in the terminal, thanks to the factory wire still connected to the alt and battery on the non isolated side. An oversight for sure and will be the first thing I do tomorrow.

 

[bigpoppahump]

your amp will pull 270A @ 2 ohm if your trying to push 2400 watts.. Seems like a power hungry amp but its cheap tho.

I'm fused with 160a at the block in the back on the sub amp and 60a on the 4ga CCA thats connected to mids/highs amp so I know I'm not pulling a ton of amperage yet or I think I would be blowing fuses. I am curious as to what it is pulling currently and will be picking up a clamp meter to see.

I know my box rise is pretty high. I was able to run a ppi phantom 1k at .5ohms for about a year before upgrading. I just set the gain a bit lower than where it went into protect and the distortion light on my dd-1 never lit even to protection. Before you debunk that, I am an idiot so take that with a grain of salt.

It's a dc power 270xp. Support did have me cut the blue wire that sends the alt battery voltage, and connect it directly to the battery but it made no difference.

Thanks everyone for all the help so far.

 

[Jcsaudio]

With 17 volts you could reduce your wire size //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif