The Boominator - another stab at the ultimate party machine

[axebay]

Originally Posted by Saturnus

You can make the middle compartment bigger, no problem. I think your major problem will be having enough power.

Peltier element are seriously ineffective. If I recall correctly the most effective peltiers have around 10% efficiency if ambient temperature is optimal and cooling is optimal. Let's just assume it's not, and go with 5% efficiency.

A cup of water of 100ml takes around 420Ws to heat or cool one degree. Let's just round that up to 1.2Wh per degree.

If ambient temperature is 25 degrees, then you need to cool it 20 degrees, and remember that 5% effieciency, that's times 20 again.

So all in all you need around 480Wh or 40Ah to cool one cup of water.

I may have made a mistake here as everything is from memory but at the end of the day, it's a really really bad idea.

But since you're at the beach already, why not water cooling. 15m of tubing, something weigh the end down so you get to the cold water at the bottom, and a water pump. That's about it, really.

Ouch, knew they weren't super efficient but that's really bad. A compressor seams the only way but will be to expensive and heavy...
Perhaps the best way would be a regular ice pack:P But I think I'll discharge this idea..

[ron1]

Sprayed today, Matt black with a silver flec, happy with it!
Now to wire the fecking thing!!




Getting primed-

[viktor89]

Wow, this one's gonna be a beauty! Can't wait to see the final results!

[whalebreath]

Hi guys, thanks so much to Saturnus for this design and everyone else for the tips. I'm starting a Boominator build and would love some advice re combining solar and mains battery charging. (I have read this entire thread and searched many phrases before posting!)

Can I mains charge, and run the amplifier at the same time?

Here's my workings-out.

I will have two 12v, 7Ah SLAs, fed by 2x10w amorphous panels, into a 10A solar controller. I will mostly run from solar, but want to use the Boominator at home sometimes too, preferably listening to music while trickle-charging from mains at the same time.

I will take danielwritesbac's advice of:

"Put TWO low voltage schottky diodes into the input + port of your charge controller.
The diode's stripe goes closest to the charge controller.
Connect the solar cell to one of the schottky.
Connect laptop charger (SMPS) to the Other schottky. "

From what I have read (Frequently Asked Questions – Exegon Battery Chargers), I think it is safe to have a laptop 12v supply charge my SLAs, and run the AMP6 load at the same time. As long as:

1) While charging the SLAs, the DC load current should be ≤ 20% of charger's current rating.
AMP6 max current draw is 350ma, so, laptop charger needs to be minimum 1.75A.

2) A charge regulator also needs to be present, so if there is a battery on charge voltage increase, this doesn't affect the AMP6. I assume a solar controller would take care of this?

3) Finally, I've read that the max amp rating of a charger should be ≤ the battery Ah rating / 5. So, for two 7Ah SLAs (14Ah), this would be a maximum charger rating of 2.8a/h.

4) It appears OK to have two separate inputs feeding into the solar regulator, via schottky diodes, and leave these constantly connected.

Does all of this sound right? Is there any specific type of wiring I should do? I'm assuming the 4th question means I'm parralel wiring the solar and mains chargers, which is the right thing to do (in case panels add charge while mains charging).


Thanks for any help. I'm compiling a list of found answers to my n00b questions, in a google doc, which I will post for others once boominator is completed.

[whalebreath]

I may just be a little too worried about this. Perhaps I'll just for out for a proper 2A smart charger, connect it to the solar controller input with diode and see what happens.

[bitSmasher]

Sorta relevant, to the Australian builders... Jaycar knocked $10 off their 7.2Ah SLA for December
7.2 Amp Hour 12V Sealed Lead Acid Battery - Jaycar Electronics

[fousifop]

Originally Posted by bitSmasher

Sorta relevant, to the Australian builders... Jaycar knocked $10 off their 7.2Ah SLA for December
7.2 Amp Hour 12V Sealed Lead Acid Battery - Jaycar Electronics

Also relevant to me in NZ, same discount over here, thanks for the tip.
7.2 Amp Hour 12V Sealed Lead Acid Battery - Jaycar Electronics

[fousifop]

I have looked through the thread but cant find an answer (or one that I can understand anyway). I am finally going to be building a Boominator (been waiting to be able to for a few years now!) , but in two halves, so you can unclip them and just use one, or get some separation between l/r channels. So each half will be mono with 2xHP10W+2xTweeter+Amp+battery. For the amps I have two TA2020's, I know you cant bridge the channels. Would it be better for me to use just one channel of the amp into both speakers (@ 4 ohm), or one channel per speaker( @ 8 ohm)? Hope that makes sense!

[Saturnus]

Build it like a halfinator with an extra passive part. Just wire the speakers as normal for the halfinator and use a switch to wire them as normal for a full Boominator when the extra part is connected. Remember to make it fool-proof so people can't accidentally switch while playing. For example by using a key switch. That way you only need amp.

Alternatively just build 2 halfinators and use splitter cables so you get mono in each when you want to use them in stereo.

[fousifop]

Thanks for the reply Saturnus. The halfinator is stereo tho yes? I assume this has drawbacks, eg two halfinators /= 1 boominator? I already have the two amps, maybe I should ask; what is the best way to wire up one mono halfinator, with a 2 channel amp. It seems the only way to get all the information (eg It seems hard to find simple info like 'Just wire the speakers as normal for the halfinator' is to read the entire 300+ page thread, so that's what I'm going to go do now