20¢ Fuse Saves the Electrics Again - Your Thoughts?

[Marc780]

I took my Tiger 1 over to my father in laws to drive it on their lawn and sidewalk etc. It drives just fine on (mowed) grass which is more then my King tiger can do, for some reason it wallows a bit in the same conditions...anyways I was showing my father in law afterwards and telling him what it could do, and about the real thing etc. and all of a sudeen all goes dead (the tank not my father in law, fortunately). I pop the top and the Rx18 fan is still turning. Thinking the worst (and forgetting exactly how i did the wiring) i waited to get it home to fix.

After examining the connections i realized the Rx fan was not in the fused circuit - WHEW! Change the fuse (5 amp) and all is well again...I'd rather change a hundred fuses then a Rx anyday, of course. A similar thing happened a while ago, i was driving my King Tiger in grass and those chips they sometimes throw around trees for decoration. A wood chip jammed the idler, the fuse blew, again the fuse saved the Rx (or did it really?)

I have a rudimentary knowledge of electronics. Enough to recognize pos from neg and to fry things and otherwise get myself in expensive trouble. But not this time at least. Anyhow my discussion and question is, what am i really accomplishing by having a fuse in line with the power cable to the Rx? I use a 5a, i noticed some people use a 7.5 and some even use a 10 amp. Would one be better then the other, whats the science here, and is there something else i can add to protect the expensive RX18 ?(its the 2.4Ghz FWIW).

[MichaelC]

Marc,

The only time I ever fired a MFU (RX-18/Taigen 2.4 Mhz/Clark) is when I crossed the wire or a bare wire touching metals. I think there is some tolerance within the board itself, so even though your fuse blew it doesn't necessarily meant that it saved the MFU. Of course there is nothing wrong with an early warning system so if it is working for you, I think it is a good idea. Like you say, those fuses are dime and a dozen, where as the MFU not only cost more but you have to wait for them. That's why I always keep some spares around.........

MichaelC.

[ttt]

Hi Marc,
What was it that caused the fuse to blow and where do you have it located in the wiring.
I would have thought that if it was immediately downstream of the on/off switch the fan would have stopped when it blew.
Perhaps you have fitted a number of fuses to protect individual functions?

Anyhow my discussion and question is, what am i really accomplishing by having a fuse in line with the power cable to the Rx? I use a 5a, i noticed some people use a 7.5 and some even use a 10 amp. Would one be better then the other, whats the science here, and is there something else i can add to protect the expensive RX18 ?(its the 2.4Ghz FWIW).

I'm afraid I can't help you with this (I'm a complete novice) but am eagerly waiting to see what the experts recommend.
Tim

[jackalope]

When your King Tigers track jammed that would have caused a voltage spike when the load on the motor became more then the 5 amp fuse could handle. Not sure if the fuse not being there would have allowed the KT to get hurt from said spike or not but better safe then sorry. On my Tiger I gummed the tracks up with so much wet sand the thing threw its tracks off the drive sprockets and got hotter then HELL inside but thankfully nothing got cooked. I should probly do like you did and install an inline fuse as it is a good idea.

On your Tiger did it hit anything or jam its tracks? If not you may want to think about upping to a 7.5 amp fuse because if a 5 will just randomly blow that means its not a high enough amp fuse and you only want to step up to the next size.

[Marc780]

Jackalope it actually wasn't doing anything at the exact moment, but i had just driven it on carpet to show my FIL. And of course the factory says "do not drive the tank on carpet." I guess i could have connected the fan to the fused circuit but then that would increase the load and a 5 amp would blow even faster.
While we are on the subject of HL electronics, I'm so tired of buying Rx from this lousy seller and that one, if they send you one bad out of the box and you complain, they ignore you (ebay sellers). The TPA store on amazon is the place I buy these electrics! They stand behind their products. I have been Been burned by the chinese sellers on ali express and of course ebay scammers (if they wont stand behind their product they're not getting my business again-i keep an actual list of people NOt to buy from ever again and check it before i buy anything!)and i'd install darn near anything in line in the circuit to avoid that, we all know the Chinese electrics are delicate enough as is. Maybe the secret is if you keep them cool they will last a while?

[MichaelC]

Marc,

Are you on Taigen 2.4 Ghz or HL RX-18s ? Just curious as I have box full of RX-18s that I am trying to get rid off.

MichaelC.

[jackalope]

Marc, I have a Heng Long Tiger with Taigen lower hull and 4.1 upgraded transmissions and I've run my tank to the point where the tracks were gummed up with so much wet sand the track was thrown off the sprocket wheel and when I opened the tank up it was VERY VERY hot inside and mine has kept on running and acting perfectly fine after I cleaned all the sand out of it and fixed the one transmission so the electronics aren't THAT bad inside these things.

I have no fuse but it not a bad idea to add one I just need to figure out where it would go in the circuit. With yours I would step up to a 7.5 amp fuse over the 5 if it was just sitting there when it blew. It sounds like the running on the carpet may have been to much for the 5 amp fuse to handle but as to why it blew after the run I couldn't tell you. But from what I've done with mine and its still alive and well and I have no fuse stepping up to the next higher rated fuse shouldn't cause a problem.