There are plenty of car and electronics experts on this board so I figured I might as well ask someone who knows what they’re talking about... I’m doing a little spring tailgating at a ski resort here tomorrow and will want to listen to the empeg in my XTerra for much of the day.

My question is: How long can I leave the empeg playing on my car battery? How often should I start the car and how long should I let it run to keep the battery charged? It will be powering the empeg through a single amp with a single sub.

Thanks in advance

Bill

Working on one of my trucks while playing music with a single amp I averaged about 4-5 hrs before running down the battery. It all is a factor of how much current your amp draws. That amp has a single 30 amp fuse, but a 10 amp battery charger allows continuous play when the engine is off.

Also how big your battery is.

I plan on running two batteries just for when i'm out playing the stereo, so that i'll have a fresh one to start the vehicle. i just haven't gotten around to buying the necessary 120 amp battery isolator yet. The amp in my van will drop the voltage down within no time at all, so you got to be reasonable with the amp size and play level if you want a reasonable play time on battery.

I don't know how big the battery is. It's whatever is standard on a Nissan XTerra. My amp has two 25 amp fuses. Roughly how long do you think I could run the empeg? And how long should I run the engine to recharge the battery?

Roughly how long do you think I could run the empeg? And how long should I run the engine to recharge the battery?


There are just too many variables to give a definitive answer.

1) How many watts do your amplifier(s) draw?
2) How many amp-hour capacity is your battery?
3) How old and in how good condition is your battery?
4) How far do you want to discharge your battery? (deep-cycling a lead-acid battery is very hard on it)
5) How much current does your starter need to start your engine?
6) How many interior lights come on when you open your tailgate?
7) How fast will you run your engine during re-charging?
8) What is the output capacity of your alternator at that engine speed?

It's sort of like asking "How high is up?" About all I can suggest is you give it a dry run in your garage (with battery charger handy) -- see how long it takes before the battery is too discharged to restart the engine. Then you'll know. I can't think of any other practical method of finding out.

tanstaafl.

bring jumpers!

Or park facing down a long hill (if it's a stick-shift). Ever compression-started your car before?

Confucious say, he who try push start truck in snow park doesn't know the FAQ's.

Just to be incredibly mean and pernickety about a question a good friend has asked in a public place, let me re-state Q1):

1) How much Power does your amplifier consume (Wattage)?
1A) What is your battery Voltage (12V or 24V)?


Using P = VI (Power = Volts X Current) you should be able to work out:

2) What is the curent draw of your amplifier at peak driven watts (RMS)?

And don't confuse consumed power with music power, as there's that pesky efficiency factor inbetween them...

/Michael

If you run your amps at the verge of blowing the fuses (50A), they would drain an average battery (60-100 Ah) in half an hour. However, nothing is stoping you from turning the volume down (10dB quieter should be enough to make the battery last few hours). As for recharging, see your alternator data - nowadays they give at least 50A, more likely 100, but I have no idea at what RPM.

Dry run suggested by Doug is the only sure way of knowing, but lacking that, take a voltmeter (best a cheap analogue one - to avoid draining its battery) or simply crank the engine as soon as the battery icon appears on the empeg.

Have a nice time! (hm, I just realized that this reply is late by at least a day )