High Power Class-D powered from Lion battery project.

[Sma1033]

hello everyone, I'm building my own portable PA system for street busking.

From my busking experience, the power I need for enough volume is in the range between 1.5KW~2kW.

I tried TAS5630 module before, however, It's far from powerful for me to drive 4 Ohm speaker under any circumstance. (TAS5630 module)
(even I boost the rail voltage to 56V.) 🙁

Due to space limitation, I can only carry a pair or 4 Ohm, 10-inch PA speacker in my 1600cc car.

I did some calculations for my amp.

the desired amp output voltage should be 55V RMS(750W @ 4 Ohm Load) in low THD(lower than 1%)

Therefore, I will need a amplifier work with 55V*1.414 + 10V (Head room) = 88V rail voltage in BTL mode. (single supply.)

To maximize portability, It seems the only light-weight power source solution is lion battery.

I plan to use 28S4P Li-on battery package to feed my Amp directly without any DC-DC converter.
(hard to find DC-DC converter for Li-on battery that can output 90V, 20A with efficiency above 95%)

without any DC-DC converter, the amp should run smoothly in the entire battery operate range (89.6V~117.6V)

I searched over internet, the best available module I can found so far is Sure Electronics : AA-AB32413

Anyony have tried this integrated high power module ?

Is it good product for loud, clear sound ? 😕

Any suggestion for amp module or system design is welcome as well.

 

[JonSnell Electronic]

1.5 - 2kW ... for busking ...?
That sort of power is dangerous for passing peoples ears!

 

[Sma1033]

1.5 kw is the minimum power you need to give a clean sound for 100 people event on street without lossing too much sound quality (especilly bass part in the music)

 

[Kjeldsen]

No 10" PA speaker can take that sort of power.

If you really want that kind of power, then look into car audio class D amplifier. The proper DC-DC converter is already build in.

or something like this

HP 8 car amplifier booster board 12v switching power supply 1200w with protection DC DC inverter power supply finished board-in Amplifier from Consumer Electronics on Aliexpress.com | Alibaba Group

 

[Sma1033]

i already tried some of those dc-dc 12v input module, however, those china module actually run efficiency under 80%, which means lot energy loss and bulky with heatsink.

thats why i want to power my amp dirctly with battery.

still thanks for your advice.

 

[Sma1033]

I know there's some pa speaker can handle more than 500W peak power in short time without permanent damage. (for example. Yamaha CBR-10)

I have a pair of modified CBR-10 with 4 ohm woofer actully. 🙄

Howevery, to drive PA speaker with this huge amount power, It’s important to limit the high power output period in short time.

But even in short period, I don't want my amp output distorted sound. That's why i need huge power more than 1 kw. 😛

 

[29285]

In that case I would go for the Li-Ion solution.
The seeed-studio power modules, operating in mono full bridge, would be the parts to be considered.
Nevertheless - big bass in open air is always a problem.
No real busker does need them, except for DJs who prefer techno etc.

 

[Sma1033]

Having LOUD, CLEAR PA system with maximum portability is pure fun for DIYer.

with or without busking, I will still try my best to build the high power system. 😀

 

[Sma1033]

BTW, I have Rockford Rockford Fosgate T1000-4AD in bridged mode (2 x 500W )for busking now.

From my experience, the power output is somehow just above the lower boundary for giving LOUD CLEAR sound.

(street busking with more than 100 people)

Although the power T1000-4AD provide is acceptable, the whole system is too bulky to carry.

I need 3 x 12V car battery in parallel or 3S64P 18650 lion battery with DC-DC converter + Super CAP to drive the system.

That's why I want to build a new high efficiency PA system. 😉

 

[Khron]

Sounds to me (no pun intended) like Hoffman's Iron Law applies here as well, just as it does for subwoofers: "Loud, low, small - pick any two".

Loud and low, won't be small.
Loud and small, won't go too low (in frequency).
Low and small, won't be loud.

 

[29285]

Considering the distance people keep to you there is no need to increase output power.

 

[Sma1033]

Sounds to me (no pun intended) like Hoffman's Iron Law applies here as well, just as it does for subwoofers: "Loud, low, small - pick any two".

Loud and low, won't be small.
Loud and small, won't go too low (in frequency).
Low and small, won't be loud.

there's always trade-off between "Loud, low, and small". Especially for speakers, physical limitation is obvious.

But. I want to push my amplifier into it's limit.

In the acceptable power output range, I want it as small as possible.

With Class-D topology, I think it's possible to have a handy amplifier output more than 1 KW.

 

[Sma1033]

Considering the distance people keep to you there is no need to increase output power.

I will say 1 KW(500W x 2) is acceptable. 🙂

However, I still need an amplifier to run with 44V RMS x 1.414 + 10V Headroom = 73V in BTW mode.

no easy to find such an integrate amplifier module under single rail except Sure Electronics's product.

any suggestion ?

 

[Khron]

There's no doubt in my mind the amps can be made really small nowadays.

The power supplies for them, on the other hand... 😉

 

[Sma1033]

There's no doubt in my mind the amps can be made really small nowadays.

The power supplies for them, on the other hand... 😉

A single rail, wide input range amplifier can work easily with lion batteries from my point of view.

For example, A single Panasonic NCR18650B can handle 6A dischare current safely.

This is also the plan I am going to use in my project.