Electrical playing radio with engine off

JD1964 · Sep 27, 2021

Consider you have a fully charged standard group 58 battery in your car and a sound system with 200 watt head unit and a 250 watt sub woofer. Roughly how long could you run this sound system at high output level without the engine running before depleting the battery enough that the car wouldn't start?

manicmechanic007 · Sep 27, 2021

IMHO 12 minutes and the car will not start

JD1964 · Sep 27, 2021

manicmechanic007 said:
IMHO 12 minutes and the car will not start

Wow! That quick?

General karthief · Sep 27, 2021

Can the power used to play the stereo be converted to cranking amps?

foxbodybill89 · Sep 27, 2021

How to calculate battery run-time when design equipment using batteries; Battery Technical Resources for Design Engineers from PowerStream

How long will a battery last calculator,AH to Watts and watt-hours, battery capacity, how to calculate battery life, run-time calculation Resources for designing equipment using battery packs from PowerStream

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manicmechanic007 · Sep 28, 2021

John Dirks Jr said:
Consider you have a fully charged standard group 58 battery in your car and a sound system with 200 watt head unit and a 250 watt sub woofer. Roughly how long could you run this sound system at high output level without the engine running before depleting the battery enough that the car wouldn't start?

I am currently almost done installing a cranker system in my van (94 E150)
JVC Marine deck with four 5volt pre outs
50w times 4 that I am not using
3 amps all real RMS watts
One Fosgate punch 400, one Fosgate Prime 400 and one Fosgate 1000 sub amp
I suppose I will only be able to run it for a few seconds with the engine off
I have some supercaps going in (a bit afraid of fire)

manicmechanic007 · Sep 28, 2021

John Dirks Jr said:
Consider you have a fully charged standard group 58 battery in your car and a sound system with 200 watt head unit and a 250 watt sub woofer. Roughly how long could you run this sound system at high output level without the engine running before depleting the battery enough that the car wouldn't start?

RMS watts right?

JD1964 · Sep 28, 2021

manicmechanic007 said:
RMS watts right?

Sub amp 250 RMS, head unit is MOSFET 50W x4. Not sure if the head unit spec is RMS or not

90sickfox · Sep 28, 2021

In my old fox I ran a battery isolator for the battery the system ran off of. The other battery was for the starter. The alternator charged both batteries but I could play music until the system battery died and still start the car off the other battery.

I also had a 2.0 farrad capacitor and a 500w power inverter for the SEGA that played on a couple LCD screens.

Potomus Pete · Sep 28, 2021

My car won't start after ten minutes
]

General karthief · Sep 29, 2021

My car won't start at all, guess I should put it back together first

Dan02gt · Oct 5, 2021

What's the reserve capacity of your battery? It's measured minutes that the battery can deliver 25Amps before the voltage would drop below 10.5V (dead).
For instance I have 2 group 24 batteries in my boat rated at 130RC. I can run the stereo system that consists of a single Pioneer 5 channel amp that produces 650w RMS @ 4 ohms for hours at moderate volume at the sand bar off on 1 battery, and then start the boat without switching to the 2nd battery.

The issue with running calculations on this kind of stuff is the fact that music is transient in nature and the current draw varies greatly greatly depending on what you are listening too.

dgollem · Oct 5, 2021

To do the math you need the watts or milliamp hours consumed by the head unit and any associated amplifiers not the max output to the speakers. With those numbers and the reserve capacity of the battery you could calculate the approximate run time. (remember temperature , charge and age of the battery will all have an effect on its capacity. Another option might be to keep a charged up jump pack in the car in case you go to long. Or you could use one of these as a fail safe, they pop like a circuit breaker before the battery gets to low.

Amazon product ASIN B0030A10V0View: https://www.amazon.com/PriorityStart-12-Volt-Pro-SP-Automatic-Battery-Protector/dp/B0030A10V0/ref=asc_df_B0030A10V0/?tag=hyprod-20&linkCode=df0&hvadid=312462950315&hvpos=&hvnetw=g&hvrand=15503664242817337688&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007652&hvtargid=pla-570905062796&psc=1&tag=&ref=&adgrpid=70635887228&hvpone=&hvptwo=&hvadid=312462950315&hvpos=&hvnetw=g&hvrand=15503664242817337688&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9007652&hvtargid=pla-570905062796

Electrical playing radio with engine off

JD1964

there is enough sticking out to grab on to

manicmechanic007

JD1964

there is enough sticking out to grab on to

General karthief

wonder how much it would cost to ship you a pair

foxbodybill89

Active Member

How to calculate battery run-time when design equipment using batteries; Battery Technical Resources for Design Engineers from PowerStream

manicmechanic007

manicmechanic007

JD1964

there is enough sticking out to grab on to

90sickfox

Wasn't a pretty sight...and I've got big hands

Potomus Pete

I'm still waiting for the fully nude shots

General karthief

wonder how much it would cost to ship you a pair

Dan02gt

mazing how much gas smell came from that tiny hole

dgollem

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Electrical playing radio with engine off

there is enough sticking out to grab on to

there is enough sticking out to grab on to

wonder how much it would cost to ship you a pair

Active Member

there is enough sticking out to grab on to

Wasn't a pretty sight...and I've got big hands

I'm still waiting for the fully nude shots

wonder how much it would cost to ship you a pair

mazing how much gas smell came from that tiny hole

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