Double Bass Portable Power for busking w/ Mesa Walkabout

[sumeursault]

Hello,

I'm wondering if some of the more technically minded folks could help me out with something. I've got a music group that would like to try out the busking scene, but I'd like to have a little bit of low-end reinforcement. My Mesa Walkabout is rated at 300W@4ohm, and the back panel reads 120V~, 60hz, 6A. Would something like this work for supplying power for say an hour or so at relatively low volumes. It says 1200 peak amps and 200 watts continuous 120V AC power. Anyone care to take a stab at this?

Challah!

 

[Phil Smith]

Depending on the local laws you may need a permit for the amplification.

 

[Vince Waldon]

120 volts at 6 amps is 120x6 or 720 watts peak draw.

Your 200 watt battery booster unit would be able to supply power at low volumes for a while, but the listing doesn't seem to mention the capacity rating (the units would be amp-hours or Ah) that tells us how long it would last. We can postulate, however.

Lets assume it weights 50 pounds because it contains a typical car battery (it won't...and will likely have less capacity, but the math is helpful).

A car battery's capacity is in the range of 60 Ah. The inverter will be drawing 720 watts / 12 volts or 60 amps, if the inverter were perfectly efficient...so theoretically an hour of use.

In the real world:

- the inverter is somewhere between 85-95% efficient
- the 60 Ah battery only delivers that capacity at a much lower current draw (IIRC the test is done at 8 amps or thereabouts and is not linear) so at 60 amp draw much lower capacity
- it probably doesn't have a whole car battery inside it. If it did the cranking capacity would be closer to 500 amps

All of this means you'll likely get much much less than an hour of use....I'd randomly guess in the 15 to 30 minute range maybe, depending on how hard you crank it up.

Having said all of the above...those battery boosters are a safe convenient way to lug power around and are really popular right now...maybe you have a friend who already bought one or got it as a gift and could lend it to you for a real-world test?

 

[cultrvultr]

Did you see this? http://www.talkbass.com/forum/showthread.php?t=956563