Is it a good idea to use the polyswitch resettable fuse to replace the glass fuse in AEGs?

[ccyg8774]

Polyswitch such as this (http://www.ebay.com/itm/5pcs-New-Pol...item3a6b188df0), the current and voltage rating looks good for AEG using. Is it a good idea to use that to replace the glass fuse in AEGs?

I have no experience with Polyswitch before, but according to wikipedia, it seems able to save us from the trouble with the glass fuse and have the circuit protected. Is that true?

[ccyg8774]

I am still looking for its data sheet so I can tell the resistance.

[R.I.T.Z]

you'll notice that a vast majority of people rip out the fuse and dont use them in their guns.

[ccyg8774]

Originally Posted by R.I.T.Z

you'll notice that a vast majority of people rip out the fuse and dont use them in their guns.

I noticed that, and some of my guns even come without a fuse. But my wiring looks so complicated (not in the reliable way) with the home made MOSFET (http://www.airsoftcanada.com/showthread.php?t=89097) that I feel I need a fuse in case some shit happens and my gun get short circuit. As a complicated system is more tend to fail and the crane stock battery is just next to my face...

[HKGhost]

Don't use a polyfuse if you don't know what amp it can take. Most recommended amp to use is 25A-30A. Anything less is just pointless. If you're running a lipo or a Mosfet, it's recommended to use a fuse unless it has one built in.

[SuperHog]

A fuse blows for a reason. A polyfuse resets in a few minutes and you can fire your gun again. If you have a short, you could burn out the electrics completely once a polyfuse resets.

With a regular fuse, you fix the problem before replacing the fuse.

[ccyg8774]

Originally Posted by SuperHog

A fuse blows for a reason. A polyfuse resets in a few minutes and you can fire your gun again. If you have a short, you could burn out the electrics completely once a polyfuse resets.

With a regular fuse, you fix the problem before replacing the fuse.

(If I fused my gun with polyfuse), I will stop using the gun as I got the initial cut off from the polyfuse (and remove battery to start diagnosis). Not as good as glass fuse in this aspect since it needs precaution, but way better than no fuse.

[ccyg8774]

Originally Posted by HKGhost

Don't use a polyfuse if you don't know what amp it can take. Most recommended amp to use is 25A-30A. Anything less is just pointless. If you're running a lipo or a Mosfet, it's recommended to use a fuse unless it has one built in.

Good call, I need to estimate/calculate the current rating first...
Most of my batteries are just 7.2V lipo or small/crane type 8.4V NiMH, but the homemade MOSFET may make a difference in the current...

[ccyg8774]

http://www.ebay.com/itm/Narva-25-AMP...item27c9277293
Not really a polyswitch like the ones above, but this is probably better in Amp rating and for it is reset manually...

[ThunderCactus]

What's the max amperage of your mosfet?
what's the max amperage of your lipo?
whichever number is smaller, is what you need for a fuse

Most AEG's don't use more than 10A, so 20A is more than enough assuming your lipo can put out 20 or more

[HKGhost]

Originally Posted by ThunderCactus

What's the max amperage of your mosfet?
what's the max amperage of your lipo?
whichever number is smaller, is what you need for a fuse

Most AEG's don't use more than 10A, so 20A is more than enough assuming your lipo can put out 20 or more

True that most AEGs don't need more than 20A continuously, but the spike at the beginning is usually more, and that's the part that will trip the fuse. So a 20A+ fuse is better to prevent that. Try a 15A fuse in your gun and you'll see.

[Cobrajr122]

Don't 'estimate or calculate'... get a DMM and measure, you probably wont get the spike current on the meter (Unless you have a fancy one)

Unless the spike is RETERDED high (which would indicate a problem anyways) it wont blow a fuse right away. Even normal fuses take time to blow, still much faster then slow blow fuses though.

[ccyg8774]

Originally Posted by Cobrajr122

Don't 'estimate or calculate'... get a DMM and measure, you probably wont get the spike current on the meter (Unless you have a fancy one)

Unless the spike is RETERDED high (which would indicate a problem anyways) it wont blow a fuse right away. Even normal fuses take time to blow, still much faster then slow blow fuses though.

I thought the resopnce of DMM is too slow to measure the "normal working current" of an AEG, since the duration time is short (in a trigger pull). But As I just tried that, it turns out that the multimeter in the circuit provent the motor from getting enough power to cycle the gun, and the current became continous (rather than just the duration of a trigger pull). Good for making the measurement, but will overheat the MOSFET unit (http://www.airsoftcanada.com/showthread.php?t=89097) if not carefully done.

The measured current is about 12A.

[ThunderCactus]

You can run a stock marui with a 10A fuse, biggest factor in there is the motor
stock EG700 pulls maybe 3-4A
stock systema magnum pulls 12-15A
G&P motors anywhere from 3-12A

[Cobrajr122]

Originally Posted by ccyg8774

I thought the resopnce of DMM is too slow to measure the "normal working current" of an AEG, since the duration time is short (in a trigger pull). But As I just tried that, it turns out that the multimeter in the circuit provent the motor from getting enough power to cycle the gun, and the current became continous (rather than just the duration of a trigger pull). Good for making the measurement, but will overheat the MOSFET unit (http://www.airsoftcanada.com/showthread.php?t=89097) if not carefully done.

The measured current is about 12A.

That is odd as properly hooking up a DMM to measure current adds nearly 0 load to a circuit. If you have access to another DMM I would check the resistance of the first one, might be junk.