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Lipo switching using a Mosfet


Basil
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Hi, just to be sure I am not an expert in electronics!!!!!!!!!!!

Some time ago there was some postings from a number of experts about the title subject. There were also some circuit diagrams, albeit fussy ones , this mean not all of the print was readable.

I have obtained a 100 amp mosfet (360amps,!XFN360N10T)and would like to use this in the fashion descibed. Can anyone supply a cicuit diagram for the Zener/resistor and condensor that is required. Can anyone advise me if the mosfet can be used without further cicuitry.

Basically HELP.

I would much appreciate some  advise as to the use of such a device which  means far easier Lipo switching using the Lipo itself as a power source, and a low volt simple on/off switch ,without bulky relays or what ever.

Thanks in advance.

Bas

Edited by Basil
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Sorry Bas, have read through the previous lipo switching posts, and this is to save taking off an elasticated wing, or building a hatch.

Quite rightly, the lipo is buried in the inaccessible model, and is a problem.

But, an Arming Plug is so much simpler. Arming Plugs are available online or easily constructed.

Is your ESC 100AMPS ?

That is a lot of potential power for an elastically positioned wing.

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Apologies Lads, missing words make my previous post appear nonsense.

I read back over Bas's problem of switching, and realised, as always, there are many solutions.

Mosfet switching, to me, just adds another layer of complexity and cables, and has a place in scale models, to hide the switch away.

100AMPS appeared in the frame and seemed excessive.

Did you know that most of your house operates between 13A and 30A, and by law, you must call in a Qualified Electrician to rectify faults.

Here we are discussing 100AMPS ! ! !

 

 

 

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Dennis, I have a couple of electric models that pull more than 70amps under load, so any switch has to be rated above this.

 

But getting back on topic, if the continuous current is less than 35 amps, Multiplex do their Antiflash unit to which you can add an arming switch. It used to be that brushless speed controllers were fitted with an arming switch, I've got a couple, but you don't see these around anymore.

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The point I failed to make clear was as we learn and develop in the hobby, and we don't quite understand some of the implications,

Then go for simpler solutions, as stated above by others. Electronics is no way a " trial and error " activity. High amps are common these days and like any plan, you must stick to known outcomes with your gear.

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I'll try and cover some of the comments made so far;

I did make a typo, its capable of handling 100volt, 360amp( I am only a beginer but large lipo's go over 100+ amps, if I am correct.I could have selected a slightly lower volt & amps but this was on offer. (Being as its a leap into the unknown for me I whent for its higher handling capabilities).

Early bird, thats the one.

Dennis, just have a look at a few heavy duty ESC's, high amps!!!!! even if its for a short time.

It weighs 37gr, is 38mm x 24mm x17mm including the terminal screws, I dont call this big,after all it was meant for large models.

At the moment I am using Exterior mounted arming plugs, but these are ugly( Talking scale here) and not easy to manipulate. Easy to hide away a low volt switch.( Underneath perhaps.)

Personally I think this idea is worth persueing it hardly hitech/weighty etc it does not require a high wiring content as suggested, just a cut in the main lipo lead and a very small number of additional components that have almost no additional weight .

I am trying to get those who first put this subject on the forum and showed the circuits to come forth and let me know the details of the simple circuits they originally discussed. No names mentioned.I dont know enough about electronics to be sure I have the correct info, even though I have a strong interest in the subject.

So to those who first discussed this, please can you give me some more details.

I thanks those in advance;

Bas

 

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Basil,

You may need a heatsink on that device if you are going to push it any where near it's full spec. Be aware the heat in watts can be calculated by the formula P+I^2R meaning the current in amps squared multiplied by the on resistance of the MOSFET .0026 Ohms. Its specified to be able to dissipate as much as 830 Watts but only on a large heatsink otherwise it would overheat and burn out.

What is the maximum current you want it to pass, a lot depends on this.

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5 hours ago, Denis Watkins said:

<snip>

Did you know that most of your house operates between 13A and 30A, and by law, you must call in a Qualified Electrician to rectify faults.

Here we are discussing 100AMPS ! ! !

++

Agreed but that is at a different voltage.

Rough figures... 100 amp at 12 volts is 1200 Watts, at 230 volts it is 23000 Watts.

5 hours ago, Denis Watkins said:

 

 

 

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4 hours ago, Basil said:

I am trying to get those who first put this subject on the forum and showed the circuits to come forth and let me know the details of the simple circuits they originally discussed. No names mentioned.I dont know enough about electronics to be sure I have the correct info, even though I have a strong interest in the subject.

So to those who first discussed this, please can you give me some more details.

 

If you only want answers from those people specifically then go to the original thread and PM them direct - this will avoid wasting peoples time in this thread. Alternatively just tag them here using the "@" symbol i.e. @Basil and they will be notified of this thread (assuming they are still actively using the forum). 

 

PS - If it is this thread you are talking about it's very old, not sure you are going to get a response...

 

Edited by MattyB
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Matt, I am asking anybody to volunter info.So far there has only been excuses about not using a mosfet.

Andy, I am aware of that. Looking at a 5/6s , over a 6s I would need a bit more than a basic cicuit because  I am told possible voltage surge!.

Bas

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8 minutes ago, Basil said:

Matt, I am asking anybody to volunter info.

 

In a post above you stated "I am trying to get those who first put this subject on the forum and showed the circuits to come forth and let me know the details of the simple circuits they originally discussed. No names mentioned.", so I posted two ways you can do that. I was just trying to help you achieve your goal.

 

8 minutes ago, Basil said:

So far there has only been excuses about not using a mosfet.

 

I don't see any excuses, just well reasoned responses stating the requirement for a heatsink and pointing out a MOSFET represents additional complexity and components to go wrong in your powertrain. For someone who stated at the outset "just to be sure I am not an expert in electronics!!!!!!!!!!!" and "I dont know enough about electronics to be sure I have the correct info" you seem quick to dismiss the views of those who are more knowledgeable... ?

 

Over and out.

 

 

 

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I am not out to dismiss other views/knowledge at all . If you look at most of the replies they seem not to be giving info about the mosfet subject but talking about why it should not be considered. If no one persues these subjects then they will never be discussed. I was not negating the statement about heat sinks I stated that I was aware of it.

Dick, yes they seem a similar/same animal, dose not give a price as far as I can see.

 

Bas

Edited by Basil
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22 minutes ago, Basil said:

...................................

Dick, yes they seem a similar/same animal, dose not give a price as far as I can see.

 

Bas

Have a look down this page. These ones provide telemetry and offer remote switching when integrated with the Jeti system, so other brands may be cheaper.

 

Dick

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Some years ago I built a device to give me 200amps at low volts for testing current sensors. It was a simple setup using 10 NiMh cells in parallel, each switched by a MOSFET. I don't know if this circuit will be any help to you, but have attached it anyway.

 

Dick

Current generator.jpg

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17 minutes ago, Nigel R said:

 

 

Perhaps there may be a reason for that.

 

 

 

 

 

Not sure why they are available commercially, Hacker also do a range

 

They are also nice as they incorporate the antiflash, whereas an arming plug, unless it has the built in resistor connect first, doesn't, so a high voltage system e.g. 4s and above the spark will damage the plug overtime.

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Andy, thanks. This forum is one of those that I have been looking at.There was some past discussion about the circuits by persons who had knowledge regarding the subject. They also made suggestions.The copies I have of the diagrams are not good, and the wording can be understood in more than 1 way, thats why I am trying to get some fresh veiws about the subject. I was rather hoping that a knowledgable contributor would offer some advise so that the subject could be refined/explored a little. There is time yet.

Thanks again Andy

Bas

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