I have a 24 volt DC amp (2x50watts) and a 12v DC Blue tooth board I would like to use in a portable boom box. I will be using two 12v batteries to get the 24volts. I found a way online to wire the two components so they each get their appropriate volts. However, I obviously need a on/off switch for the boom box. Would my wiring diagram be ok?
On a separate note, would a push button 12v switch that is rated for 10A be ok to use in this application? Or do I need a 24v on/off switch?
First at all ... always in a circuit the power switch cut the positve lead and you need a double pole single throw switch ...
Paint power FTW !
Paint power FTW !
Don't do it that way...Your amp will get 36V...and other bad things.
The magic smoke will probably leak out and it will not work without keeping the magic smoke in.
Use a double pole switch...one for each battery/device set in the positive connection.
Connect the negatives together at one point.
The magic smoke will probably leak out and it will not work without keeping the magic smoke in.
Use a double pole switch...one for each battery/device set in the positive connection.
Connect the negatives together at one point.
Attachments
Last edited:
Yeah but I would do it like this since there will be other cables that use common ground. You don't want to lift the main ground and have the potential for feedback and the amp using the signal cable for ground. It will smoke up.
As for the switch, the 12 will probably work but may eventually fail. You can just use one rated for 120 volts. Use a wall switch, good for 15 amps @ 120v.
Attachments
This would require two types of batteries and two types of chargers. The other method would use a common battery and a single 24v charger.
The way I have it pictured it would not have 36 volts or blue smoke. Besides, you can't get 36 volts out of two 12v batteries. This is common for wiring stuff in a 12/24v environment such as a tractor trailer where this amp was probably designed for use.
Thanks everyone!
Brian/lexar, where would I connect my charger leads to? I am planing on using this PSU wired to the batteries:
24 VDC 1880mA Switching Power Supply US and EU | 120-054
Would I just wire the female 2.5mm x 5.5mm plug directly to the batteries? One of the wires to the positive side of Battery 1 and the other wire to the negative side of Battery 2?
BTW: This is the amp and the bluetooth i am going to use:
Bluetooth Audio Receiver Board v2.1+EDR 12 VDC | 320-351
2x50W TDA7492 Class-D Amplifier Board | 320-301
Brian/lexar, where would I connect my charger leads to? I am planing on using this PSU wired to the batteries:
24 VDC 1880mA Switching Power Supply US and EU | 120-054
Would I just wire the female 2.5mm x 5.5mm plug directly to the batteries? One of the wires to the positive side of Battery 1 and the other wire to the negative side of Battery 2?
BTW: This is the amp and the bluetooth i am going to use:
Bluetooth Audio Receiver Board v2.1+EDR 12 VDC | 320-351
2x50W TDA7492 Class-D Amplifier Board | 320-301
Yes, I agree with this using the double pole switch.
Even if they were two 12V batteries there is still the problem with having the two negatives of your BT and AMP at different potentials.
Attachments
The drawing by DUG is the only correct one so far. Brian's drawing will probably smoke the bluetooth module.
The correct way is to either have 3 batteries. 2 in series for the amp and 1 for the bluetooth module (and possibly a mobile phone/mp3 player recharger). Or to have any number of identical 12V in parallel and use a dc-dc converter to get the 24V rail.
In the latter case you should notice that the bluetooth module and the amplifier must share ground so you do not connect the ground output of the dc-dc converter to anything but instead connect ground of the amp to the ground input of the dc-dc converter (or better still directly to the battery minus point).
In this set up you can also add a switch to shift to a 12V rail when you don't need maximum power output capacity. The amp uses about 5-6 times less power on 12V than on 24V when conversion loss in the dc-dc converter in considered.
In the latter case you should notice that the bluetooth module and the amplifier must share ground so you do not connect the ground output of the dc-dc converter to anything but instead connect ground of the amp to the ground input of the dc-dc converter (or better still directly to the battery minus point).
In this set up you can also add a switch to shift to a 12V rail when you don't need maximum power output capacity. The amp uses about 5-6 times less power on 12V than on 24V when conversion loss in the dc-dc converter in considered.
Attachments
Last edited:
No it would not. Voltage would not pass backward through the amp. It would be fine. The double pole switch is not a bad idea but it would not smoke either component.
Just looked at the amp listing. You do not need two batteries. The amp will run on 12v. It has a regulated input to accept a range. Don't over complicate this and just use a single 12v battery and be done with it.
Obviously your charging circuit will be 12v too. Will then give you the option to charge from a car too.
Obviously your charging circuit will be 12v too. Will then give you the option to charge from a car too.
Last edited:
Yes, it is because you will have different drain on the two batteries therefore the center connection is no longer the absolute reference ground.
Peak power output equals supply voltage squared divided with impedance. So no, if he wants the maximum possible output supply voltage must be higher than 12V.
Should I run 1 large 12v battery with a dc-dc 24v converter for the amp, or 2 smaller 12v batteries in series for 24 volts and dc-dc step down converter to 12 volts for the bluetooth (and phone charger)?
Basically, what would use less energy, a step up converter or a step down converter?
If a step down would use less energy (and give me longer radio playing time), is there any draw backs to using a step down converter?
I only want to use 1 charger for the boom box, so three batteries (2 for amp, and 1 for 12v rail) is out.
Basically, what would use less energy, a step up converter or a step down converter?
If a step down would use less energy (and give me longer radio playing time), is there any draw backs to using a step down converter?
I only want to use 1 charger for the boom box, so three batteries (2 for amp, and 1 for 12v rail) is out.
Last edited:
Where is your connection between the BT module and the AMP?
Please include that in your drawing and let us see how that would work.
A Bluetooth adapter is not going to be any significant load on the battery. If it was another amp then yeah, I see your point but not in this application.
- Status
- Not open for further replies.