classic army mp5, 12v car battery

[ClockWork]

hey all,

i've got a classic army mp5, i forget what the srings compression rate is but it is a mid level gun firing between 250 and 300 fps.

it uses a 8.4v mini or a 9.6v mini in the foregrip, but it goes through batteries like water.

i connected a car battery and it fired well for about 10x200 rds, but then it drained the battery.

what i want to do is come up with a method so i can just sit in my back yard and target shoot, i tried connecting a car battery to a low amp charger (6/2 amp) it worked for a while but the charger cant replace the juice as fast as the mp5 drains it off.

i also tried just wiring my 12v battery charger that came with my gun directly to my mp5 but it didnt have the amps needed to fire the weapon, it only had 200mah

so what i really need to know is how to sustain enough power to fire all day without mutiple battery packs.

i dont need to be mobile, so weight or wires is not a problem but i do want it to be just electrical, i dont want to include an engine and alternator to replenish the battery i would rather run a battery charger to a 12v battery and then from the 12v battery to my gun, but i just cant figure out how to keep the juice flowing smoothly.

any help is appreaciated.

[m102404]

Wow...

How about just running an extension cord to a DC converter....(I'm kidding around...I know slightly more than nothing about electricity)

***edit***
On the non-kidding side of things...check out airsoftmechanics.com....I think Gandalf uses a bench top power supply for his testing...
*********

McGuyver (guy on this forum) is pretty handy with electricity...PM him. Please post his response?

[ujiro]

Benchtop power supply would be really the only feasible way to do it.
DC chargers only charge at max a few amps. Upgraded airsoft guns sometimes use big current, so most DC adapters wouldn't be able to do it.

[demco11]

120v wall electrical outlet.

Or 240v stove outlet....

(I wonder what would happen...? lol)

[ujiro]

LOL. The huge outlets for stoves/driers. That wouldn't even be funny, assuming they are high voltage and high current (I know the drier one is 30amp).

[coach]

find the smallest 12v car battery you can find and get like a .5 farad capacitor and run the gun straight from the capacitor. lol

or strap on a car battery booster on your back and shoot with that directly to the gun.

[ClockWork]

wow those are some ... uh interesting answers

thanks for the wiked fast replies, the bench top power supply might work best, does anyone have any suggestion on what brand or more importantly what the output would need to be set at?

and for the 120v wall outlet or 240v stove outlet, you better have thick wires thats all i can say :P

[Crunchmeister]

Wall outlets are AC power. Airsoft guns run on DC. Not even sure that would work without instantly frying the motor.

[ujiro]

It would just blow up if you put AC current through it.. lol. Guaranteed.

[lemegacool]

you'll need a very high amperage bench top power supply if you want to run the gun off it, i have a 7 amp adjustable one and the overload led lights as soon as i press the trigger... id say minimum 15 amps, and wtf it must be a very old car battery to be drained like that by a airsoft gun! i know car batteries arent made for deep discharge purpose but still...

and for hooking it up to the wall just buy 4 big diodes make a bridge with them (to obtain dc) and watch you gun firing it's last round with an incredible trigger response

[ClockWork]

yea even using a rectifier i still dont think its a good idea to hook up straight to the wall eeek! my hands are tingly

but yea the battery came out of a junker, good call !!

so you say it would require a mininmum of 15 amps, thank you for the info, if i ever come up with a good homemade solution i'll come back and post it, thanks for all the help.

[ClockWork]

and for the record its not the ac current that would melt it, its the voltage that would burn things out, but the ac would be the cause of your stripped gears because ac would spin the motor back and forth until the gearbox fell apart,

i do know a lil somethin'

[ledor473]

You can use a power supply unit for a computer. Some power supply have 3 different circuit that can pull something like 18watt each (my Antec have it). I think only 1 circuit can generate enough power to use with a AEG.
Also, you probably can find a way to use the AEG on the 3 circuit, but i'm not sure...

Some PSU cost like 45$+shipping and pull up to 18amps on the 12v (Like the Silverstone ST350)

[ujiro]

Originally Posted by ClockWork

and for the record its not the ac current that would melt it, its the voltage that would burn things out, but the ac would be the cause of your stripped gears because ac would spin the motor back and forth until the gearbox fell apart,

i do know a lil somethin'

AC wouldn't spin it back and forth, it switches too quickly. Basically what would happen is, instead of 90% of your P=IV power going to the load of pushing the gears, and 10% to heat, it would all go to heat. So your motor wouldn't even move, or would just buzz, but would basically melt.

[SHÖCK]

Save yourself the money and troubles just buy a high discharge rate (for consistently turning the motor), high mah Lipo battery.