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Calculating Battery Life for 370W Speaker & Amplifier: Ampere-Hour for 3-4 Hours Playtime

tuniolx 40569 35
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Treść została przetłumaczona polish » english Zobacz oryginalną wersję tematu
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  • #1 11848897
    tuniolx
    Level 14  
    Hello,
    I have a speaker and an amplifier that together are 370 watts MAX (not rms)
    How many ampere-hour batteries should I buy so that it can play with 3-4 hours?
    from my calculations, a 12v 100ah battery will play ~ 3h, so I'm definitely doing something wrong
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  • #2 11848915
    kizek
    Level 35  
    370W ÷ 12V = 30.8A
    30.8Ax4h = 123.3Ah
    Yes, in short.
  • #3 11848931
    tuniolx
    Level 14  
    that is, to power a stupid portable speaker you need a car battery ??
  • #4 11848934
    vodiczka
    Level 43  
    The maximum music power does not (read: very differently) translate to RMS and how long it will play depends on the efficiency of the amplifier, what volume you set and what music you will listen to.
    You can play (I shoot :D ) from 4 to 8 hours. Connect any charged battery (it may be borrowed) with known capacity and check experimentally.

    Added after 2 [minutes]:

    kizek wrote:
    Yes, in short.

    In a very telegraph, because the 370 W is not RMS, which the author clearly indicated :D
  • #5 11848956
    tuniolx
    Level 14  
    I see
    I will not put in such a capacious battery for monetary reasons, so the last question
    there is a lot of difference between a 7ah da 12 ah battery ??
    the price difference is 50 PLN, it is better to add the money and have a longer one or leave the 7ah
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  • #6 11848975
    Rzuuf
    Level 43  
    Hello!
    Of course you are counting wrong:
    - if the amplifier is to deliver 370W to the loudspeaker, its consumption will be higher (the efficiency is about 65%), so 370 / 0.65 = 570W will be taken from the battery, which corresponds to a current of 570W / 12V = 47.5A.
    A 100Ah battery loaded with 47.5A current (so almost "2-hour") will have a much smaller capacity than with the "10-hour" current for which its nominal capacity is given, so it should be sufficient for 1 - 1.5 hours of such play. The power of 570W is almost the power of a starter!
    If you play half-heartedly, the electricity will be enough for twice as long.
    Ordinary car batteries "do not like" deep discharge with high currents, special traction batteries have been developed for such conditions.
  • #7 11849006
    tuniolx
    Level 14  
    no no no
    maybe I'll start differently.
    Amplifier
    SONY
    -2 canals (I need 1)
    -30w RMS x2 or 70w RMS x1 (bridge)
    - 60w x2 or 160 x1 peak power (PEAK power)

    loudspeaker
    JBL
    70 W / 210 W continuous / peak power

    that is 370wat total, not 570
  • #8 11849020
    vodiczka
    Level 43  
    Rzuuf wrote:
    - if the amplifier is to deliver 370W to the loudspeaker,

    Why do you assume that it should give non-stop for 1-1.5 hours?
    If they give 370 W MAX, the RMS power can be 30-60 W depending on the fantasy of the amplifier manufacturer in determining the maximum power.
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  • #9 11849029
    tuniolx
    Level 14  
    then I have to count the maximum power or the one in rms
    if in rms it comes out 90
    and if max is 370
  • #10 11849032
    vodiczka
    Level 43  
    Did you add the peak power of your amplifier to the maximum power of the loudspeaker? :D
    Where did you get the 370 from?
  • #11 11849039
    tuniolx
    Level 14  
    Yes
    it is 370 watts
    and in rms 90wat total (speaker + amplifier)
  • #12 11849050
    vodiczka
    Level 43  
    Count for RMS and adopt 65% efficiency as proposed Rzuuf.
  • #13 11849059
    tuniolx
    Level 14  
    loudspeaker
    210w / rms peak power 70
    amplifier
    peak power 160w / rms 70x1,30 x2
  • #14 11849062
    Rzuuf
    Level 43  
    tuniolx wrote:
    that is 370 watts in total
    Ooooh, boy ...
    I let myself be "done" - for the first time I see the TOTALIZATION of the power of the loudspeaker and the amplifier!
    I mean - if the amplifier has ZERO (because it is not working or it is not there), the speaker can give, for example, 100W?
    I like it! For greater effect, I would add the shoe number and date of birth!
  • #15 11849066
    tuniolx
    Level 14  
    such a request you could calculate it because I don't think that's it
  • #16 11849073
    Anonymous
    Anonymous  
  • #17 11849079
    vodiczka
    Level 43  
    tuniolx wrote:
    Yes

    Sorry, I laughed to tears. Where did you come up with the idea to add the power of the amplifier to the power of the loudspeaker?
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  • #18 11849106
    tuniolx
    Level 14  
    vodiczka
    I have to count the power of the loudspeaker without an amplifier ??
    or vice versa
  • #19 11849134
    vodiczka
    Level 43  
    The amplifier amplifies the electrical signal and feeds it to the loudspeaker. A loudspeaker is a receiver that converts an electrical signal into an acoustic one.
    If the 10 W amplifier works with a 60 W speaker, it will give it 10 W, not 60.
    The only thing that matters is the power of the amplifier and its efficiency.

    Assuming that the power supply works in a bridge and gives 70 W RMS, with an efficiency of approx. 65%, it takes about 110 W. from the battery.
  • #20 11849149
    tuniolx
    Level 14  
    aaa that explains a lot :D
    and when I use one of the two channels (I do not want to bridge) it gets the power ino of that one channel or both ??
  • #21 11849157
    Anonymous
    Anonymous  
  • #22 11849179
    tuniolx
    Level 14  
    or 65% of 30 watts
    how do you count it ??
  • #23 11849188
    vodiczka
    Level 43  
    And when you do not have a speaker connected to the second channel, what should it download? Exactly - even an unloaded amplifier, if connected to the power supply, consumes current, the value of which depends on the class of the amplifier's work. In your case, it will not be much.
  • #24 11849199
    Anonymous
    Anonymous  
  • #25 11849200
    tuniolx
    Level 14  
    that's cool :D
    last request :P
    how many hours will the music play as if I were playing about 75% of the possibilities on the 7ah battery and how many on 12ah
  • #26 11849201
    vodiczka
    Level 43  
    tuniolx wrote:
    or 65% of 30 watts
    how do you count it ??

    Not 65% of 30, only 30 divided by 0.65.

    Added after 2 [minutes]:

    No matter how you play at 12Ah, you will play 70% longer
    At 7 Ah you will play 1- 1.5 hours
  • #27 11849219
    tuniolx
    Level 14  
    but I mean how many hours on this 7ah battery
  • #28 11849224
    vodiczka
    Level 43  
    In addition to the previous post, I gave it a bit longer on the new one, up to 2 hours, but take into account that the capacity of the battery decreases over time.
  • #29 11849244
    tuniolx
    Level 14  
    sorki i didn't notice
  • #30 11849256
    Anonymous
    Anonymous  
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Topic summary

The discussion revolves around calculating the appropriate ampere-hour (Ah) battery capacity needed to power a 370W speaker and amplifier setup for 3-4 hours. Initial calculations suggested a 12V 100Ah battery would suffice, but further analysis revealed that the actual power consumption is higher due to amplifier efficiency (approximately 65%). This leads to a requirement of around 570W from the battery, translating to a current draw of 47.5A, which would deplete a 100Ah battery in about 1-1.5 hours under heavy use. Participants debated the importance of RMS versus peak power ratings, concluding that only the amplifier's RMS power should be considered for battery calculations. Recommendations included testing with a borrowed battery to measure actual performance and using an ammeter to monitor current draw.
Summary generated by the language model.
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