Portable speakers hooked to car battery?

[johans.m]

Hi people.

I own a "Logitech Pure-Fi Anywhere 2" (http://www.ctfootscray.com.au/store/...984-000065.jpg).
The festival I'm planning on going to this year lasts for roughly one week. Thus I expect the battery of my stereo to run out long before that.

My thouhts are if it's possible to directly hook up a 12V car battery to my little baby. When she's pugged in with the regular charger she receives 12.9V at 1.39 amperes. Which corresponds to rouhly 17-18 watts if I'm not mistaken.

My questions are these:

1. Would it really work like that?
2. Should I build a protective system of some kind?
3. Some years temeprature in the shade reaches 30 degrees celsius. Issue?
4. Can I do rough calcuations on how long a car battery would last? I honestly don't know how many miliamperes the speaker battery is


In advance I'd like to thank anyone who could shed light on this issue.

[J M Fahey]

Short answer based on posted data:

if it's possible to directly hook up a 12V car battery to my little baby. When she's pugged in with the regular charger she receives 12.9V ........... 1. Would it really work like that? .

Should work: 12.9 V (nominal) sounds very close to 12.6V (car battery) to me.
beware of connector polarity to avoid smoke/sparks/fire.

2. Should I build a protective system of some kind?

A 2A fuse should do.

3. Some years temeprature in the shade reaches 30 degrees celsius. Issue?

No.

4. Can I do rough calcuations on how long a car battery would last? .... at 1.39 amperes ......

Considering a 55AH car battery: 55AH/1.3A=39.6 Hours uninterrupted sound.
That considering it does never get recharged and the amplifier is run full power continuously .
If that battery is in a car which is used daily, no problem, although I'd unplug the amp when doing so, not only because of the 14.4 V present when the engine runs, but because of the 28V to 40V spikes that appear often, which would kill any equipment not specially designed for car use.
If you are at the festival some hours every day, but sleep or whatever (your choice) at a hotel/hostel/trailer park/ashram/temple/etc. where you can plug a charger, probably you can use a much lighter 12V 7A Gel type battery (like those in alarms) which should last all day in practical use. (that meaning you are not the Festival DJ/non stop Music provider)
Have fun and don't forget: Love and Peace Brother !!!! Woodstock was such fun !!!!!

[johans.m]

J M Fahey, that sure was useful. The festival I'm attending is outdoors so I'm not gonna be able to recharge the battery. But it should last long enough though.

Does any of that make a difference?

[Brad1]

????

You're gonna haul that thing and a car battery around at an outdoor festival? Seems like a lot of trouble to listen to cheap, underpowered speakers in the middle of a bunch of noisy people?

Just wondering.

Brad1

[J M Fahey]

That will certainly be fun, yet I still have a couple doubts:
1) You will be outdoors for 7 days running, non stop, (nothing against that, quite the contrary) or you will sleep at or visit sometimes some mains powered place ? or *somebody* else has a car? Those are all recharging possibilities.
2) If you are "green" you might carry a light solar panel to recharge a smaller battery, such as the Gel type I suggested. Very much in the spirit of any outdoors festival.
3) If it's a Rock/Trance/etc. festival, *they* will provide free, loud music all the time, maybe a couple Ipods can provide some to stand the few minutes of silence, if any.
4) Make it short, forget electronics, play whatever you play with you: acoustic guitar, violin, brass, woods, ocarina, or at least some percussion and make your own music, joining others.
It will be *much* more fun, not forgetting the girl magnet it becomes.
5) Which Festival is it? Got curious about it.
6) I backpack sometimes to really desert places such as Valle de la Luna – Ischigualasto Provincial Park <--click and see
A small stash of AAA batteries powers MP3 players and Palms for ages.
2 extra cellphone batteries keep me connected for a week.
Forget about notebooks here.