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Jun 25, 2001, 11:01 AM
Registered User
Paul's Avatar

High current fuses/fuse holders

I am ready to install the motor/ESC in my new LT-25 and trying to find a suitable fuse. I cannot seem to find the automotive blade or tube shaped fuses in anything higher than 30A. How high do these types go? I am running an AF15G with CC Pegasus 35 ESC on 11 cells with a 12x8 or larger prop. This could draw above 30A so I should use about a 35A-40A fuse right? What do you use for fuses and fuse holders for such a setup? Or do you not use one?

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Jun 25, 2001, 11:38 AM
Registered User
Personally speaking, I used a fuse once in my very first electric plane, a glider, because the intructions said to do it. I got so fed up with it that I got rid of it and never looked back.
With today's elecronic ESCs with "arming" functions, better radios and equipment, fuses have dissappeared from e-flight. I am sure you could find someone here or there that uses them, but I bet if you did a poll, at least 9 out of 10 do NOT use them. I can't tell you what to do, and I do not want to be responsible for any damage if you do not use a fuse, so use your best judgement.
But the reality is that most flyers do not use them.

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Jun 25, 2001, 11:43 AM
Registered User
Most auto parts stores carry a single blade fuse holder attached to wire leads. I've seen the balde fuses available from 10A to 30A in 5A increments. I've never used them, but I believe blade type fuses are available to 40A and possibly beyond.

Jun 25, 2001, 03:05 PM
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Andy W's Avatar
Don't use a fuse. Most of us have at some point, and quit.
Jun 25, 2001, 03:37 PM
jrb's Avatar

Think fuses have their place, I use them when my ESC doesn’t have an arming switch, and have to connect the batteries before putting on the wing.

Contrary to “conventional wisdom”, I’ve used a Sermos fuse holder between my battery and ESC w/my BEC’d BL plane; it was easier than adding a switch between the RX and ESC.

I like the added level of safety when carrying my plane to the flight line at a busy RC club.

I know its been discussed before, but I like arming switches, then I don’t use a fuse.
Jun 25, 2001, 03:46 PM
Registered User
The original post asked if most people jsut don't use them, and the answer is "no, they don't ".

But if you want to use them, Radio Sahck carries the upper range fuses in the blade style.
I knew a guy that mounted the fuse holder through the fuselage side for easy access.
To "arm" the plane, he would just plug the fuse into the fuse holder and fly.
The problem with mounting them inline between the battery and and ESC with a BEC is that if the fuse blows, NOTHING has power.
Sad to see a $500 plane go down due to a poorly manufactured $1 fuse.
That is why the aforementioned gentleman stopped using fuses after a 400 foot death spiral.

Jun 25, 2001, 04:21 PM
jrb's Avatar
$500 plane or leg, foot, arm???

Not long ago, one of our fellow E-Zoners told us he had to leave the hobby because of the injury he sustained.

18 cells, 600 watts, 13x10 APC"E"; w/o an arming switch I think fuse!
Jun 25, 2001, 04:37 PM
Registered User
No, I wouldn't give my leg, foot, arm for $500.
But my point was that given the choice between the fuse and a proper arming ESC, with a $2 micro switch if needed, I would take the ESC with switch.

Jun 25, 2001, 05:49 PM
Electric Airplane Junkie
bhchan's Avatar
You guys con"fused" me. The switch and fuse are two different things. The fuse blown when something got in the way of prop when landing(crashing). The switch is a on/off swithc to pass/cutoff current in the circuit. It will still cut the heck out of your arm, leg...even you have a fuse. The ESC with a switch is even worst, it only cutoff power to the rx(bec), the power connection to the motor is still alive(hot). The switch give a false sense of security. The best way is to arm the plane just before flying. AND stay away from the prop ONCE IT IS ARMED.

Brian, an EAJ.
Jun 25, 2001, 06:24 PM
Registered User
Andy W's Avatar
I put a LOT of power into my F5B models (propped for 90A or so static, on 8 and 12 cells so far). My models have no fuses. When I carry them to the flight line, I hold them securely, and keep the dangerous end away from people (including myself). When I land, I retrieve the model and take it back to my station and dissasemble and disarm it right away.
Jun 25, 2001, 09:25 PM
Eat, Sleep, Fly!
realglow's Avatar
I flew my LT-40 with an AF40G and AF217D for the first time yesterday. I use a 30A fuze to arm the motor since I do not have a BEC. It works fine so far. Even if I lose the motor battery because of a fuze blown, I still have RX power via the RX battery pack.

It is convenient to be able to play with the controls at pre-flight or in the workshop without worrying about the possibility of the motor being activated. I use a blown red fuze (25A ?) with a big tag that says, "NOT ARMED", until I am ready to replace it with the arming fuze. Works for me. Fact is, I am scared of that old AF40G firing up with the 12x9 prop! You could lose a finger, an eye, a friend...... !!!
James (aka RealGlow)
Jun 26, 2001, 12:03 AM
Hairy E-Pilot
All__talk's Avatar
Hello friends

I'm not a fan of using fuses in e-flight but if you feel the need look into the ones designed for high end auto sound, very high currents, very low resistance, most are gold plated.

Jun 26, 2001, 12:09 AM
Registered User
I use a 40 amp blade type fuse in my LT-25 with an Astro 05G FAI on 10 cells and a 12 x 8 prop. Static is around 50 amps. I get the fuse from a Marine Dealer (boats and motors - full size). I usually fly it with a MEC Turbo Ten Plus which draws up to 40 amps with a 12 x 8. With a 11 x 7 it draws 32.4 amps so the 30 amp fuse was marginal.
Jun 26, 2001, 08:02 AM
Registered User
Fuses gives one false security. Rather know your plane is armed and handle it as such - Safely !!!!!