AMPLIFIED  ·  Field Tool

Will Your Charging System Keep Up?

Answer honestly, we'll do the math. No guessing, no sales pitch, just what your setup actually needs and the cheapest real way to get there.

What's your total system RMS wattage?

Add up the RMS rating of every amplifier in the vehicle, subs and full-range both.

WATTS RMS

What's most of your amplification?

Amp class changes how much current it actually pulls to make that RMS rating.

Mostly Class DMonoblock sub amps, most efficient, least current draw per watt
Mixed systemClass D subs + Class AB/full-range amps
Mostly Class ABOld-school full-range build, least efficient, most current draw

How do you actually run the system?

Real music draws far less average current than a sustained test tone, but SPL tones don't get that break.

Normal driving, bass-heavy playlistsDynamic content, average draw is well under peak RMS
Mix of cruising and bass demosSome sustained passages mixed with normal music
SPL / dB competition tonesSustained sine tones, must handle full continuous draw

Where do you push it hardest?

A stock alternator can put out far less than its rated max at idle, exactly when most demos happen.

Parked, engine idlingLot demos, meets, competitions, worst case for alternator output
City driving, stop-and-goModerate, variable RPM
Highway cruisingHigher, sustained RPM, best case for alternator output

What's your current battery setup?

This changes what "upgrade" actually means for your build.

Stock flooded lead-acidWhatever came with the vehicle
Upgraded AGMAlready running a dedicated AGM battery
Lithium (LiFePO4)Already running a lithium battery bank

How many dedicated audio batteries?

Not counting your starting/cranking battery, just batteries added for the audio system.

0, just the starting battery
1
2
3 or more

How many alternators does the vehicle have?

Dual/triple alternator setups change what "upgrade" means at the high end.

1Whether stock or already upgraded, we'll ask its output next
2
3 or more

Do you know your alternator's actual output?

If you've had it load-tested or it's on the spec sheet, use the real numbers, otherwise we'll estimate from the rated amps and your usage pattern.

I only know the rated ampsWe'll estimate idle/driving output for you
I know the actual tested outputEnter idle and driving amps directly

How loaded is your factory electrical?

Headlights, HVAC, ECU, and any add-ons all eat into what's left for audio.

Stock accessories onlyNo aftermarket electrical add-ons
Some add-onsLED lighting, moderate accessories
Heavy add-onsHIDs/light bars, winch, air suspension, etc.

What wire are you running right now for main power?

Battery or alternator to your amp rack. Pick what's actually installed, not what you think it should be.

Not installed yet
8 AWG or smaller
6 AWG
4 AWG
2 AWG
1 AWG
1/0 AWG
2/0 AWG
4/0 AWG or bigger

How long is that run?

Battery to amp rack, one direction. Longer runs need thicker wire to carry the same current without losing voltage along the way.

FEET, ONE WAY

OFC or CCA wire?

Copper clad aluminum (CCA) is cheaper but carries less current per gauge size than pure copper (OFC). Check the packaging if you're not sure.

OFC (oxygen free copper)Pure copper, best conductor
CCA (copper clad aluminum)Common in budget kits
Not sureWe'll assume CCA to stay on the safe side

Is a high-output alternator even available for your vehicle?

High-output alternator makers only build for popular platforms, some vehicles have no aftermarket option at all.

YesI've found one, or my platform is commonly supported
Not sureHaven't checked yet
NoI've checked, nothing exists for my vehicle

Could your vehicle physically fit a second alternator?

Bracket kits for dual alternators only exist for a handful of platforms, mostly trucks and SUVs.

YesBracket kits exist, or there's engine bay room
Not sure
NoNo room, no kit available

Are you open to a lithium battery bank?

Lithium performs better here, but it costs meaningfully more than AGM. This is a real budget call, not just a technical one.

Yes, open to lithiumBest performance, higher cost
No strong preferenceRecommend whichever actually solves it
AGM/lead-acid onlyWant to avoid lithium's cost

Want a recovery-time estimate?

If you run repeated demos or passes, this estimates how long your system needs to recharge between them. Optional, skip if you don't do back-to-back sessions.

TYPICAL SESSION LENGTH (MIN)
REST TIME BETWEEN (MIN)
-
-

-

Battery
Alternator
Amp Rack
Available capacity- A
System demand- A
Required alternator
-
Recommended battery
-
Wire you need
-
Margin
-

Your Upgrade Path: Cheapest Fix First

Estimates current draw from RMS wattage, amp class efficiency, and rail voltage, then compares it against your alternator's real output, either your tested idle/driving numbers if you provided them, or your rated amps scaled by a typical RPM curve if not, minus a reserve for factory loads. Multiple alternators are treated as a combined total. Music-dynamics discount reflects the crest factor of real content vs. sustained test tones. Single-alternator recommendations are capped at ~400A, the realistic ceiling for mainstream and extreme custom automotive alternators, demand beyond that is shown as multiple units, and vehicles with no compatible high-output alternator or no room for a second unit get a demand-reduction/idle-up plan instead of an impossible number. Battery sizing reflects your stated lithium preference; AGM figures assume ~0.5C safe continuous discharge, lithium assumes your stated (or a conservative 1C) rating. The recovery estimate assumes recharging happens at idle and is capped by your battery chemistry's safe charge-acceptance rate (lithium ~1C, AGM ~0.3C, flooded ~0.2C). Upgrade order follows standard install practice: fix grounds/wiring before spending on batteries or alternators, a cheap Big 3 upgrade resolves a real share of "electrical" complaints on its own. Treat all of this as a planning guideline, not a substitute for a professional electrical audit.

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