hooking car amp for home system

[Hydrastas 10+ year member]

If i were to take a car battery and hook it up to a car battery charger that can charge the battery at 6 amps would it be ok to power an amplifier that runs around 14 amps? Or would it eventually drain the battery, then i'd have to wait for the charger to recharge it before i could continue listening to it?

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[Hydrastas 10+ year member]

ok, i've found another car battery charger in my garage 6 amp, plus a motorcycle battery charger 1 amp. So if i were to hook up all 3 chargers together would that make 13 amps total? That would be close enough to 14 amps that the little amplifier needs right? Would i even need to use a car battery then, could i just hook the three chargers up to the amp? It would be 13 amps at 12.6 volts... I've also just recalled that my stereo system has no rca outlets, so could i use a speaker wire to rca converter? If i did that what should i set the gain to? I'm not sure how much different the voltage is on this stereo system then it would be for a standard HU in a car. And for the remote wire of the amp would it be ok to just run a wire from the power input on the amp with a toggle switch?

 

[knukonceptz 10+ year member]

I do not think you can connect multiple chargers to one battery and have them charge at the same time. If you really want this to work, use two batteries on the 6 amp charger, with the two batteries you'll have good play time and be sure to run the charger before and after playing to keep the batteries charged. Be sure not to over charge (ie cook) the batteries - also non sealed batteries have a toxic vapor, in small spaces you can get sick.....

 

[Hydrastas 10+ year member]

If i only plan on listening to it for a couple songs at a time, should one battery be fine? What would be a good way of knowing when the battery is charged up good before it overcharges? The charger has a meter that says how many amperes its charging with, should i keep an eye on that and if it drops below 6 or something?

 

[Hydrastas 10+ year member]

Oh yeah, and is it ok to use the amp while the charger is charging the battery?

 

[jrz126 10+ year member]

You might get a pretty nasty 60Hz hum out of the speakers if you run it with the charger connected.

As for knowing when the battery is done charging, I'd say if the current drops below 3 amps or so. It depends on the battery though. All batteries will have a steady current draw when fully charged. The amount of current depends on the battery condition/age, charging voltage, and water temp.

If you hear the battery boiling, then it's fully charged

 

[headless 10+ year member]

Just go to radio shack and buy a 20amp 12vdc power supply. I've got an industrial PS that provides up to 70a @ 13.8v...cost me ~80$. Radioshack's look nicer and cost more.

 

[Hydrastas 10+ year member]

yeah im already getting a hum out of the sub, this thing from radio shack sounds a lot better than having to put up with fumes from a battery and such, is it just a simple converter that steps down the ac to 13 volts and then into direct current? How much would the 20 amp one cost?

 

[Hydrastas 10+ year member]

ok I went to radioshack.com and all i could find is dc to ac converters, would those work if i used them the other way?

 

[Hydrastas 10+ year member]

ok i found some ac to dc converters at http://www.voltage-converter-transformers.com/heavy-duty-voltage-converter.html

however i've noticed that they only have a dc output of 10 amps... thats not very heavy duty, wtf?

 

[headless 10+ year member]

http://www.radioshack.com/product/index.jsp?productId=2103960&cp=&origkw=power+supply&kw=power+supply&parentPage=search

http://www.radioshack.com/product/index.jsp?productId=2103961&cp=&origkw=power+supply&kw=power+supply&parentPage=search

You can also use PC power supplies (my pc's power supply cost ~100$ and provides 35a on the 12v rail, but only when loaded moderately on the 5v and 3v which required resistors inline)

 

[Hydrastas 10+ year member]

alright, next time im in town ima get one of those from radio shack, but for now, i was wondering how long i could play an amp that draws 34 amperes if the battery i have is 580 cranking amps before it would go dead? Is there a formula for that?

 

[headless 10+ year member]

alright, next time im in town ima get one of those from radio shack, but for now, i was wondering how long i could play an amp that draws 34 amperes if the battery i have is 580 cranking amps before it would go dead? Is there a formula for that?

cranking amps is not how you measure capacity. You need to know the capacity of the battery.

For example, a 1AH (AMP HOUR) battery can have a 1amp draw placed on it for one hour (thus one amp hour) before it is drained. Thus, a 34AH (34 amp hour) battery can provide 34amps for 1 hour before it is drained, or conversely, 1 amp for 34 hours before drained. A 90AH battery would be able to provide 30amps for 3 hours before it is drained, or 1 amp for 90 hours. 90 amps for 1 hour. Etc. Keep in mind these are CONTINUOUS draws -- music is not a continuous draw for many reasons, and has major hills/valleys in draw. My stereo pulls over (45+a at over 13v) 550w in spikes sometimes, but continuous average is under 20a almost the entire time. LOUD playing results in dynamic numbers between 5a and 30a, mostly under 15a.

 

[Hydrastas 10+ year member]

With just that one battery i listened to the radio for about 10 minutes having 2 15" subs going at 360 wrms, and afterwards i hooked up the charger to the battery and it is stable at 4 amperes, im not sure what this means but i'll let it charge for 20 minutes and if it hasn't gone up to 6 amps or if it goes down, then im guessing it is done charging, however it would be nice to know how long it would take to drain the battery with 580 cranking amps if its running a 34 ampere amplifier.

 

[Hydrastas 10+ year member]

weird, you posted as i was typing my last post, ok i'll look up the ah then, thanks a bunch