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Running an amp on battery power?

Discussion in 'Amps and Cabs [BG]' started by IvanMike, Dec 28, 2004.

  1. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    Hey there. a quick qestion for all you electrician types. I love the idae of the PJB briefcase amp. I've always wanted to have something i could take to use with acoustic guitars when a power source wasn't available. However, my bank account's a little small at the moment. I was wondering if there's a way i could supply the correct power to my small 150 watt head (swr electric blue) from some sort of battery setup? The 12 volt battery used with the PBJ would be cool just from the standpoint of weight, although i understand that even is phil's amp the power only lasts for about an hour. Soooooo. What kind of devices are available to transform the power of a battery to the 120 v required by my amp?
  2. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    I wouldn't be sure it would be possible using an already exsisting head that has been designed to be used with a standard AC voltage.

    To get an amplifier to run from a battery would need a different circuitery and even at that I couldn't image there would be much in the way of huge power for a long period of time.

    What sort of battery are you considering? Car battery or smaller?
  3. Mike Money

    Mike Money Banned

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    Some marching bands with pits buy these battery packs from sears... i dont have any info on them, but it is what my school will be using as of 2nd semester...


    I used that carvin.. doesn't sound too bad. runs for hours.
  4. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i'm really not sure about what kind of battery im thinking of. Obviously i don't want to modify the head, just see if there is a device that can take the juice from a battery and transform it into current that the amp can use. I'm not sure how the PBJ amp makes the switch from running on ac power to running on the 12 volt battery, although they state that you can use a car battery as well. The internal 12 volt battery (kind of looks liek one of those huge flashlight batteries and you have to buy one seperately from a 34rd party) gets recharged whenever the PBJ breifcase is plugged into the wall. I'm assuming that the PBJ doesn't take the current directly from the battery, but has a transformer to enable it to run on battery power when not plugged int oan AC outlet, but i dunno.
  5. You can hook a power inverter up to a car battery and it'll work. A bunch of a electricians around here will tell you its a bad idea because it creates some sort of fake sine wave thing, but I've used it a number of times with no negative effects on my amp or my cab.
  6. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    There is one device which i have seen used at Car boot sale (good ol' English Sunday Car Boot) which they clip to the car battery and use to power radios and stereos. Its called an Inverter, it creates an AC wave form but whether it would be any good or not to power a bass guitar amplifier rated at 150watts drawing quite a bit of current I wouldn't know.

    EDIT: - Didin't see the reply above before posting!
  7. They do inded make power inverters that will create a synthetic 120 VAC power from 12 VDC. Granted, it's a lousy looking sine wave, but it'll power non-sensitive devices such as a guitar amp. You need to make sure the one you buy will handle the power your amp will draw (NOT the power going to the speakers). For example, on the back of the amp it'll say something like 120VAC, 500 Watts, 50/60 hZ or something like that. So you would buy a power inverter rated 500 watts or more.

    I have indeed powered an amp with such a device, from my car battery in the middle of the woods. In less than an hour my car battery was completely dead and I was stuck in the middle of nowhere. :eek:
  8. Joe P

    Joe P

    Jul 15, 2004
    Milwaukee, WI
    There ARE inverters for delicate equipment - Ham Radio operators and the like would use them - but a regular one would probably work fine. The worst you would get is a little hum-noise.

    As for required wattage; don't go with the rated output power, but use the other wattage number off the back of the amp - it should be a higher value than the rated output. Either way: even an 800W or 1200W inverter is cheap.

    Check it out - you can get them in all sorts of places. I'd probably check 'Farm & Fleet' around here.

    No problem. You've got it handled.

  9. NJL


    Apr 12, 2002
    San Antonio

    yeah but well worth it, imho! ;)
  10. Warwick player

    Warwick player

    Dec 31, 2002
    Bucks, UK
    Us hams prefer to connect directly to the battery, as most ham equipment is designed to run from 12Vdc! :D

    Just thought you might like to know!
  11. CamMcIntyre


    Jun 6, 2000
    Before our marching band decided to use my DCM2k as the center of our electronics setup [me, a synth, and a few mics]. We ran my Bassman 200 off of a series of a car batteries that went to an inverter. The catch-that thing only did 1k watts out and my Bassman took 540, so when the idea of using my DCM came around....we called the comps we were going to and made sure we would have a power outlet to plug into. :) There are ways-i think Pep Boys sells inverters. That's all
  12. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    i remember that story of yours - :p
  13. Passinwind

    Passinwind I Know Nothing Supporting Member

    I once helped a harp player design one with a car stereo power amp and a small battery powered preamp. I don't know if he ever got it happening though, he had a few other battery powered amps that he used every time I saw him playing on the street. An active bass into a smallish car stereo amp, plus a very sensitive speaker, would be easy to try out, at least.

    Personally, I'd look into a solar powered solution, but I can promise that won't be cheap! :cool:
  14. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    ya know, that sounds good, but somehow a solar powered amp being used to accompany acoutsic guitars at a campfire doesnt seem too effective. :p
  15. Passinwind

    Passinwind I Know Nothing Supporting Member

    It does if it keeps a fresh stash of charged batteries ready to go, no? :eyebrow:

    How about a big ol' hamster wheel with a generator attached to it then? :ninja:
  16. dude, just buy a Pignose HOG30!
    simple, effective, ugly and light!
    They are cheap and the battery last quite a long time. It does not have the power or tone of a bigger amp, but that irrelevant if you are playing acoustic sets. I take mine to a bud's cottage and we jam there!
  17. I bought a pretty powerful inverter from Radio Shack. It was in the neigboorhood of 500 watts. I made some lighter and battery clip connetors. The thing was almost $130.

    We can run a power stip with a few small combo amps to allow jam sessions virtually anywhere. I have learned a few things about using this devices:

    1. It sucks but you have to turn on the your car. The battery will drain quickly if not and as nashvillebill found out you will get stranded. I run an extension cord to get some distance from the car.

    2. Use heavy gauge extension cords. I have had trouble with light gauge extension cords, they seemed to short out. They must restrict the power to much.

    All in all these things can be pretty fun.
  18. pierce

    pierce freethinker

    May 25, 2000
    San Francisco, Ca
    i have been looking at the pignose hog 30, and it seems pretty cool for the price. could it keep up with an acoustic guitar, and a cocktail set for street corner gorilla gigs? what about 2 of them?