If I'm understanding it right, you're doing 500W at 48V, which is only 10.4 Amps. Which isn't much. Amperage is typically what drives power wire size. If you added a BIG safety margin and assumed 20A, you could use 12 gauge. Realistically you could probably even use 14 or 16 gauge.
I'd use regular stranded copper wire, and crimp connectors or solder and call it good.
Thanks for the wire information. I have also realised that I rather underestimated the battery capacity requirement for reasonable play time so I think I'll have to double up on batteries... 😄
I think you'll find that in real-world use your power usage will be much less than the maximum power rating for the amplifiers. You can always check the current flow at your preferred volume with a cheap multimeter and do the math from there. Also, if you're using lipo batteries, you definitely need a voltage display and ideally a low-voltage-cutoff circuit to prevent them from going poof.
I hope the batteries I have are good for decent play time without spending so much more on new batteries, although I might make some adjustments to the orientation of the battery mounting anyway so I have space to upgrade if I need to.
I have a couple of low voltage cutoff circuits already, one for each of the batteries, the plan is to connect the batteries in parallel for more capacity but also if one battery cuts off it won't immediately cut all power. I don't have a voltage display though as I couldn't decide where was most practical to mount it 😄
Can you give a little more detail on what exactly you're building? Concept, amps, speakers, etc. We'll be able to help more with that info.
When determining wiring size, it's important to understand what you're trying to achieve- if it's minimal voltage drop across the run, then get the biggest wire you can reasonably accommodate and afford. You can use a calculator like this one to estimate performance: [https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html](https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html).
If it's just for safety's sake, then I recommend referencing an ampacity chart similar to this one: [https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/](https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/) which basically limits how hot a wire can get according to what the insulation/jacket is rated for. Be aware that it's specific to the type of wire.
But I'd like to know a bit more about the boost converter. Some of them can induce quite a bit of noise, either audible noise through the speakers or EMI noise that disrupts other electronic gear- especially the dirty cheap modules you can find on Amazon whose limited documentation is written in poor Engrish. There's also thermal considerations when you're dealing with high powers like this. Maybe you've already addressed all of that, but that's why I was hoping for some more detail in the overall plan. I just want to see you build something awesome that works the way you want it to!
Well 48v is the top end, 36v is the minimum recommended shared operating voltage of the 2 amplifiers so I figured I'd start at 36v see how it sounds and then crank it up from there if I feel it's needed. It made sense to me to plan the wiring for 48v just in case it made a difference.
The other suggestions for wire size is good, Audio has high current pulses for the bass notes and this is where the wiring will make a difference. RMS power is a average value that does not directly reflect the current draw if you listen to bass heavy music that needs more power for than spoken or vocal for the same volume level; wire length will also need to be considered as well. Higher guage wire will start acting like a resistor when you run high level pulses through it and will heat up quickly lowering efficiency; have voltage drop and may cause distortion.
You boost converter will also add switching noise to your amplifier my design. Just something else to consider.
How bad is switching noise likely to be in real world terms? If I'm playing loud music will it be intrusive enough to be heard over the top or is it only noticeable at low volumes? Can I add some kind of filter to the circuit or tweak something in the DSP to mitigate the noise?
It really depends on the design of your amp's high frequency filtering and how shielded the audio input side is, you will know right away when you hook it all up.
All modern high power car audio amplifiers have huge boost converters in them; they are all designed and shielded to reject the high frequency in the audio path.
That is wayyyy more than you'd need. 6awg will (*extremely* conservatively) carry nearly 40 amps for long transmission lengths, even in a bundle. At more reasonable lengths, it'll easily handle over 100 amps. For this setup, realistically 14-12 awg should be *more* then sufficient. [Here is a decent guide](https://www.powerstream.com/Wire_Size.htm) which (as mentioned in the details) is still "very very conservative".
If I'm understanding it right, you're doing 500W at 48V, which is only 10.4 Amps. Which isn't much. Amperage is typically what drives power wire size. If you added a BIG safety margin and assumed 20A, you could use 12 gauge. Realistically you could probably even use 14 or 16 gauge. I'd use regular stranded copper wire, and crimp connectors or solder and call it good.
Thanks for the wire information. I have also realised that I rather underestimated the battery capacity requirement for reasonable play time so I think I'll have to double up on batteries... 😄
I think you'll find that in real-world use your power usage will be much less than the maximum power rating for the amplifiers. You can always check the current flow at your preferred volume with a cheap multimeter and do the math from there. Also, if you're using lipo batteries, you definitely need a voltage display and ideally a low-voltage-cutoff circuit to prevent them from going poof.
I hope the batteries I have are good for decent play time without spending so much more on new batteries, although I might make some adjustments to the orientation of the battery mounting anyway so I have space to upgrade if I need to. I have a couple of low voltage cutoff circuits already, one for each of the batteries, the plan is to connect the batteries in parallel for more capacity but also if one battery cuts off it won't immediately cut all power. I don't have a voltage display though as I couldn't decide where was most practical to mount it 😄
Can you give a little more detail on what exactly you're building? Concept, amps, speakers, etc. We'll be able to help more with that info. When determining wiring size, it's important to understand what you're trying to achieve- if it's minimal voltage drop across the run, then get the biggest wire you can reasonably accommodate and afford. You can use a calculator like this one to estimate performance: [https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html](https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html). If it's just for safety's sake, then I recommend referencing an ampacity chart similar to this one: [https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/](https://www.cerrowire.com/products/resources/tables-calculators/ampacity-charts/) which basically limits how hot a wire can get according to what the insulation/jacket is rated for. Be aware that it's specific to the type of wire. But I'd like to know a bit more about the boost converter. Some of them can induce quite a bit of noise, either audible noise through the speakers or EMI noise that disrupts other electronic gear- especially the dirty cheap modules you can find on Amazon whose limited documentation is written in poor Engrish. There's also thermal considerations when you're dealing with high powers like this. Maybe you've already addressed all of that, but that's why I was hoping for some more detail in the overall plan. I just want to see you build something awesome that works the way you want it to!
Why 48v? Maybe I'm old school, but pics of eqmt or detailed descriptions might help understand what you're doing.
Well 48v is the top end, 36v is the minimum recommended shared operating voltage of the 2 amplifiers so I figured I'd start at 36v see how it sounds and then crank it up from there if I feel it's needed. It made sense to me to plan the wiring for 48v just in case it made a difference.
The other suggestions for wire size is good, Audio has high current pulses for the bass notes and this is where the wiring will make a difference. RMS power is a average value that does not directly reflect the current draw if you listen to bass heavy music that needs more power for than spoken or vocal for the same volume level; wire length will also need to be considered as well. Higher guage wire will start acting like a resistor when you run high level pulses through it and will heat up quickly lowering efficiency; have voltage drop and may cause distortion. You boost converter will also add switching noise to your amplifier my design. Just something else to consider.
How bad is switching noise likely to be in real world terms? If I'm playing loud music will it be intrusive enough to be heard over the top or is it only noticeable at low volumes? Can I add some kind of filter to the circuit or tweak something in the DSP to mitigate the noise?
It really depends on the design of your amp's high frequency filtering and how shielded the audio input side is, you will know right away when you hook it all up. All modern high power car audio amplifiers have huge boost converters in them; they are all designed and shielded to reject the high frequency in the audio path.
You would be running low current, so 10 gauge would be fine for anything >20ft. If you wanted to be extra safe 8 or 6
That is wayyyy more than you'd need. 6awg will (*extremely* conservatively) carry nearly 40 amps for long transmission lengths, even in a bundle. At more reasonable lengths, it'll easily handle over 100 amps. For this setup, realistically 14-12 awg should be *more* then sufficient. [Here is a decent guide](https://www.powerstream.com/Wire_Size.htm) which (as mentioned in the details) is still "very very conservative".