Rules for adding second battery

[dbeez 5,000+ posts]

Yeah sure by all means, buy a $900 amp then only spend $100 on your electrical, what do I know, I'm only an electrical engineer...

oh god one of those dont go there i deal with those kind of pricks all day it works on the computer get in the real word and test man.$100 dont mean **** ever heard of a good deal i am trying to help people out selling $250 batts for 100 plus shipping they get good deals and are very satisfied ask many who have bought them they run 2k plus on them all day.

 

[audiolife 5,000+ posts]

There is a difference between running a "x" thousand watt amp and getting "x" watts out of it. A lot of variables in this that go under and over audible differences.

 

[reclessantics 10+ year member]

would it be best to just try and find a way to fit a d3100 xs power under the hood and call it a day? or should i really think about the d34 xs under hood, -> battery isolator -> second d34 in the back.?

 

[solidcrowd 10+ year member]

To the electrical engineer...I have 105 amp alt in my malibu. I have a 50 X 2 @4ohm eclipse amp for frontstage and 4 gauge KNU power wiring.

Whats the most watts I can run to my subwoofer @ 2ohm, class D...theoretically speaking.

 

[bubbagumper6 5,000+ posts]

To the electrical engineer...I have 105 amp alt in my malibu. I have a 50 X 2 @4ohm eclipse amp for frontstage and 4 gauge KNU power wiring.
Whats the most watts I can run to my subwoofer @ 2ohm, class D...theoretically speaking.

It depends on a lot of things man. There's not just a set threshold that if you cross it your system will instantly fail. It's all about headroom. Sure you could probably burp a couple thousand watts on that system if you did it instantaneously, but any length of time and your going to get horrible voltage drops. Batteries can help with voltage drops but only to a point, you'll still drop to whatever their resting voltage is and possibly lower if they can't handle the load. The more batteries you add the larger the load you put on the alternator. You could seemingly get away with thousands of watts if you have the appropriate battery bank however the load put on your alternator will almost certainly shorten it's life, if not kill it very shortly. I'm more about headroom than saving a buck, I'd rather have the capability to run 4kw and only actually run 3kw, and not be running my electrical system at 100% of it's capability all the time.

Anyway, that being said, a 105A alt is about average, if you threw a good batt in there you could probably get away with 1000w, go with two batts and you could probably approach 2kw. But like I said all of this puts a large load on your alt. I wouldn't cross 1200w without upgrading my alt but that's just me. I've seen burnt alts and blown amps (due to low voltage) so I don't take risks anymore.

And dbeez I really don't give a **** if you disagree.

 

[reclessantics 10+ year member]

how are h/o alts? im worried with 1 year warranty that it will still burn up just as fast. im looking into a mechman 270a alt for my truck. pushing absolute max 2500 watts. i want to throw 2 d3400 (xspower batts) 1 under hood and 1 in back. thats not going to be too big of a load would it?

 

[bubbagumper6 5,000+ posts]

how are h/o alts? im worried with 1 year warranty that it will still burn up just as fast. im looking into a mechman 270a alt for my truck. pushing absolute max 2500 watts. i want to throw 2 d3400 (xspower batts) 1 under hood and 1 in back. thats not going to be too big of a load would it?

No man, a 270A alt would be plenty for 2.5kw. You gotta look at this way, your stock alt is like a little honda crx, and the load your system represents, is a big 30ft camper. Imagine that crx trying to pull that camper, it might be able to, but it's going to burn the engine up pretty quick. Upgrading your alt, is like buying a nice big diesel 4x4 truck to pull that load, lol. Nice analogy right?

270A is plenty big for 2.5kw, you don't even have to go that big if you don't want to, but hey, the bigger the better...besides, you'll want to upgrade again soon enough.

 

[reclessantics 10+ year member]

i mean its 400$, and its basically the only one i could find. if i go that big, could i just go with one big ass battery? the biggest i can fit under the hood?

(yes i do like that analogy lol)

 

[bubbagumper6 5,000+ posts]

i mean its 400$, and its basically the only one i could find. if i go that big, could i just go with one big ass battery? the biggest i can fit under the hood?
(yes i do like that analogy lol)

What companies did you check with? I would be surprised if DC couldn't build one for you...what car is it again?

EDIT: Also the batts & alt work together, I wouldn't run 2kw with anything less than two decent batts, even with a powerful alt.

 

[reclessantics 10+ year member]

yeah ill have to go back and check some of the companies - i was on the phone and emailed ohio gen, dc power, mechman, and maybe one other. this was back in dec when my first stock alt died. was strapped for cash then and just got another stock that had a lifetime warranty. im just worried about how long they will last. (the h/o alts)

i drive a 2000 chevy silverado 1500 ext cab v6. its just, old lol so im iffy on buying equipment i can't change to another car or sell easy you know?

 

[Maxipads 10+ year member]

Im ordering the Mechman 270a Alt for my 01 Chevy Silverado 5.3 vortec v8.. its 400. DC is to much for me and every where else doesn't seem to let me order from the site.

 

[solidcrowd 10+ year member]

I'm not looking to upgrade my alt. and am only running one battery. It's new and is rated at 630 cranking amps and 525 cold amps. I'm just seeing what wattage I should run so I can be on the safe side and not put strain on my alt. or blow it. I'm putting 0 gauge from Battery (-) to Chassis (only left over wire I have right now lol). I was going to get the RSD1200.1 for $244 shipped and set the gains with test tone and DMM so it only puts 1000watts to the sub.

Or and amp that only puts out a true 950rms at 2ohms, but It's hard to find a better deal than the RSD.

 

[reclessantics 10+ year member]

yeah i liked mechman's stuff. also heard great things from them. excessive amperage was the last co btw. but i think mechman is what ill go with.

Still just trying to figureout what im going to go with for batts lol im not pos what i can fit under the hood. but ideally @ bubbagumper6 does it matter if both batteries are the same? cause i wont try to squeeze a 2700 where a 3400 fits snug. id rather just keep it stock size under hood, then grab a d3100 for the back later.

 

[reclessantics 10+ year member]

Im ordering the Mechman 270a Alt for my 01 Chevy Silverado 5.3 vortec v8.. its 400. DC is to much for me and every where else doesn't seem to let me order from the site.

i like your style. lol id be interested in seeing some of your stuff, just your setup in general. get some new ideas from another ride like mine. did you take out your back seat?

 

[bubbagumper6 5,000+ posts]

yeah i liked mechman's stuff. also heard great things from them. excessive amperage was the last co btw. but i think mechman is what ill go with.
Still just trying to figureout what im going to go with for batts lol im not pos what i can fit under the hood. but ideally @ bubbagumper6 does it matter if both batteries are the same? cause i wont try to squeeze a 2700 where a 3400 fits snug. id rather just keep it stock size under hood, then grab a d3100 for the back later.

That's kind of a dividing point for the forum. A lot of people swear they have to be the exact same batteries, other say it doesn't matter, and others say you have to use an isolator. Personally I've never had a problem running different batteries together with no isolator. It's been said that doing this will shorten the life of the batteries because they will have different resting voltages and will always be trying to equalize the system and drain each other. If your talking about buying new batts, and just getting two different physical sizes but the same style battery I think you'll be fine.