Dealing with voltage drop on heavy hits better?

[gamehawk55 10+ year member]

The 2/0 Royal welding wire doesn't even support 300A of current running through it though. My T2500 amp's fuse is rated at 300A

 

[shizzzon 10+ year member]

First, what does your alternator run at constantly when vehicle is warm and stereo isnt playing? That would be your highest voltage point..

Next, measure voltage directly on alternator when load is high to see what voltage the alt is putting out.

I'm sure that alt can handle that amp fine, you just have tremendous voltage drop in the rear because you didn't upgrade wiring.

For that alt, i'd recommend 2 runs of power, minimum of 3/0 per run and 1 run of ground, minimum of 3/0.

In the rear, ground all battery(ies) to frame as many runs as possible(2 minimum of 1/0 minimum).

www.wireandsupply.com is cheapest source for 3-4/0 cable all year round.

If you need orders in bulk, use ACDCELECTRICPARTS on ebay for free shipping and extra off 50ft or more. Same store.

You want high voltage, you must pay to play.

Although, personally, i would have went with an amp that is engineered to put out it's power at 12.6v and much more efficient than the BDCP line. That way you wouldnt need to spend all this money in wiring, etc..

 

[undone1 10+ year member]

I wanna go with XS power one of these days but I'm not sure if they have a battery the proper size for under my hood or not. Do you think a different battery will make much difference? Upgrading from the AC Delco to the Yellow top under the hood didn't make much difference. It wasn't until I stuck the AC back in and put the yellow in the back that I finally saw a huge difference in my draw...My voltage meter no longer even dips into the yellow, and on some low hits before it could dip into the yellow and even RED (low voltage) before the second battery.
This is how bad it was before (voltage meter on the right) https://www.dropbox.com/s/oq163tpbi8ymenh/Voltage%20Drop.mp4

don't get to caught up on the xs and the price for them as you have plenty of other agm's to choose from for a WAY cheaper price....

you will kill the stock battery sooner then you expect...plates are too thin for repeated deep discharges...

the main difference you saw with the the two batteries..is well.. two batteries vs one.. more capacity..

 

[gamehawk55 10+ year member]

First, what does your alternator run at constantly when vehicle is warm and stereo isnt playing? That would be your highest voltage point..
Next, measure voltage directly on alternator when load is high to see what voltage the alt is putting out.

I'm sure that alt can handle that amp fine, you just have tremendous voltage drop in the rear because you didn't upgrade wiring.

For that alt, i'd recommend 2 runs of power, minimum of 3/0 per run and 1 run of ground, minimum of 3/0.

In the rear, ground all battery(ies) to frame as many runs as possible(2 minimum of 1/0 minimum).

www.wireandsupply.com is cheapest source for 3-4/0 cable all year round.

If you need orders in bulk, use ACDCELECTRICPARTS on ebay for free shipping and extra off 50ft or more. Same store.

You want high voltage, you must pay to play.

Although, personally, i would have went with an amp that is engineered to put out it's power at 12.6v and much more efficient than the BDCP line. That way you wouldnt need to spend all this money in wiring, etc..

Yeah I know...The amp is bada**. But I'm just now learning the downfalls of having this amp, that it needs SUPER TIGHT voltage for it to play smoothly. Maybe I might switch it out one day. I love having the accurate voltage meter on it though and the output meter to know when I'm near clipping. So if I ever swapped it out I would probably need to buy an SMD-VM1 to accompany the other amp to at least get the accurate voltage reading back.

Next amp will probably be a Sundown or Crescendo perhaps. Whichever runs cooler under heavy load. Cuz this T2500 COOKS when you pound it...The amp is practically engineered to be one big heatsink lol.

 

[brian84corvette 10+ year member]

it gets hot because its suffering from terrible negative electrical flow.

your chassi is probably uni body - and for negative flow to reach from your ground on amp back up to the alternator

it has to travel thru at least 15 diffrent pieces of sheet metal that have small spot welds holding them together.

now

imagine a single fat piece of copper wire spaning that same distance for the negative electrical to flow... im shure you can see how bad you need more wiring.

also as a side note.

a good agm battery lets say deka 9a31 - will have a resting charge a bunch higher than a normal wet cell car battery.

my agm rear batterys will sit at 13.1 volts with the truck off. wich means

if im playing harder than my alternator can produce - my amp starts eating battery at 13.1 volts vs a wet cell normal car battery will sit at 12.8 if your lucky.

.3 volts doesnt seem like much ? in dc electrical 12 volt systems it is.

i hated my optima yellow top so much. it would not hold a charge / was constantly discharged - and eventually i needed to install a manual cut off switch on it because even the slightest draw with the car turned off it would just **** that battery dead ( dead is less than 12.5 volts ) anything less than 12.4 volts is battery destruction terratory = the battery starts eating it self / and sulfates the lead plates and almost never comes back to full streingth after a huge discharge for a slight period of time.

i dont kno why i typed that last part. lol sorry

 

[gamehawk55 10+ year member]

it gets hot because its suffering from terrible negative electrical flow.your chassi is probably uni body - and for negative flow to reach from your ground on amp back up to the alternator

it has to travel thru at least 15 diffrent pieces of sheet metal that have small spot welds holding them together.

now

imagine a single fat piece of copper wire spaning that same distance for the negative electrical to flow... im shure you can see how bad you need more wiring.

also as a side note.

a good agm battery lets say deka 9a31 - will have a resting charge a bunch higher than a normal wet cell car battery.

my agm rear batterys will sit at 13.1 volts with the truck off. wich means

if im playing harder than my alternator can produce - my amp starts eating battery at 13.1 volts vs a wet cell normal car battery will sit at 12.8 if your lucky.

.3 volts doesnt seem like much ? in dc electrical 12 volt systems it is.

i hated my optima yellow top so much. it would not hold a charge / was constantly discharged - and eventually i needed to install a manual cut off switch on it because even the slightest draw with the car turned off it would just **** that battery dead ( dead is less than 12.5 volts ) anything less than 12.4 volts is battery destruction terratory = the battery starts eating it self / and sulfates the lead plates and almost never comes back to full streingth after a huge discharge for a slight period of time.

i dont kno why i typed that last part. lol sorry

I havent had any problems with my Optima yet. voltage with car off is like 13ish volts. and the batteries are never drained in the morning. My batteries are actually strongest in the morning it seems. I get slightly worse voltage drop as the day goes on. I run my system ALOT throughout the day as I drive my own car for work so it's pounding alot loll.

 

[gamehawk55 10+ year member]

And the amp is getting hot cuz the amp's body is practically one giant heatsink. There are no fans in the amp. The amp is the cooling system lol

 

[brian84corvette 10+ year member]

last question - is your alternator grounded "enough"

is there a direct run from your front battery negative to a mounting bolt on your alternator ? or are you grounded to somewhere else on the engine block ?

i only ask because

you have a bad *** alternator / same one im getting and it should be making tons of power for you.

i was quoted 200 to 220 amps capable at engine idle on a singer hairpin for my suburban and 320 amps at 2k rpm

i chose internaly regulated - im guessing you chose that also ?

 

[gamehawk55 10+ year member]

last question - is your alternator grounded "enough"is there a direct run from your front battery negative to a mounting bolt on your alternator ? or are you grounded to somewhere else on the engine block ?

i only ask because

you have a bad *** alternator / same one im getting and it should be making tons of power for you.

i was quoted 200 to 220 amps capable at engine idle on a singer hairpin for my suburban and 320 amps at 2k rpm

i chose internaly regulated - im guessing you chose that also ?

Yeah my alt is grounded "enough" I have the BIG 3 PLUS a 0 gauge ground going direct to the alternator mounting bolt under it from the battery.

 

[gamehawk55 10+ year member]

And yeah i chose internal reg. Usually runs about 14v in city driving and on the highway i'll rise to 14.4v

 

---------- Post added at 07:07 PM ---------- Previous post was at 07:06 PM ----------

 

In the morning I'll usually have a brief window where the alt runs at 14.6-14.9v but that goes away quickly unfortunately.

 

[shizzzon 10+ year member]

Sundown and Crescendo are worse than the amp you have now... Don't do that.

Plus, the SMD-VM1 is a cosmetic toy.

If you want a voltmeter thats actually useful, PM me and i'll show you some voltmeters we make that not only show you voltage but protect the entire car audio system from low voltage by shutting them down before something bad happens..

Did i mention they are programmable to each install? And they are cheaper than SMD simply because they do not manufacture enough products to compete with the market to keep cost down.

PM me for all kinds of info.. You'd be shocked at what you'd find from us.

 

[Haunz 10+ year member]

I read that when buying welding cable though you need twice the size to get the same substance in the cable. So a 2/0 welding cable is the same approx. to a 1/0 of good OFC cable from like KNU or something?

Whoever said that is an idiot..

See if there is a Princess Auto in your area.. that's where I usually buy my power wire.. (I'm also in Canada)

 

[gamehawk55 10+ year member]

Whoever said that is an idiot..
See if there is a Princess Auto in your area.. that's where I usually buy my power wire.. (I'm also in Canada)

I recently went to Princess Auto in my area. And yes they do sell the wire. But I was right in saying that the 2/0 gauge welding wire is the same size as 1/0 gauge CCA or OFC wire. The 2/0 gauge was $5/ft. Which after shipping is what 1/0 gauge OFC would be.

 

[csu87 10+ year member]

1/0 Welding cable is true 1/0

The issue is some companies try to make their 1/0 bigger to make up for poor materials.

Didnt read through much, but where is your ground for the rear battery/amp now currently? if its to the frame and your upfront ground is to the frame, then running a dedicated wire from front to back isnt going to help much.

What size yellowtop do you have? get a solid G31 battery and i bet your voltage issues get better. Since you already have the alternator, the next thing to do is to add quality batteries

 

[gamehawk55 10+ year member]

1/0 Welding cable is true 1/0
The issue is some companies try to make their 1/0 bigger to make up for poor materials.

Didnt read through much, but where is your ground for the rear battery/amp now currently? if its to the frame and your upfront ground is to the frame, then running a dedicated wire from front to back isnt going to help much.

What size yellowtop do you have? get a solid G31 battery and i bet your voltage issues get better. Since you already have the alternator, the next thing to do is to add quality batteries

The 2/0 gauge they had was rated for 300A, which is what quality 1/0 gauge OFC is rated for.

Also no my ground is not attached to my frame. It's just attached to the sanded off chassis of the trunk. Which I know is not ideal when dealing with 1500W+ systems, but it's getting my by for now. And my yellow top is a fair size. It's the D34. Like I said in the OP. My voltage drop with quick hits is much better but I still get larger than ideal dips with EDM and Rap music. I would say it dips to about 12.8-13.2, which with a 310A alternator and 2 batteries on 1500-2000W seems pretty unacceptable, even with a bit of clipping.