I have been thinking a little more regarding this and the position of the fuse between the battery and the Motor.

I think to a certain extent, where in circuit the fuse goes when you are dealing with a pure Linear ESC (ie. one that simply reduces the output voltage in proportion to the Throttle setting) the fuse here could go anywhere between the two!.. In a Switch mode, PWM or Brushless ESC and because of the nature of the 'pulsing' or 'chopping' of the output voltage (going repeatedly from 0v to full battery volts) of these devices, the preferred position for the fuse may well be in line with the Battery and BEFORE the ESC.

Anyone have other thoughts??

DG

Greg, what mfr?? The ones I see on Amazon hav a reset button (requiring a mechanical push to reset)

Your other option, so as to not leave you stranded out in the water, is tobuse Automotive type small circuit breaker, which will re-set after they do trip, usually in20 to 30 seconds.

Had challenges with the fuse installation on my Brave Borderer. The blog describes them in detail.
Essentially, the cylindrical glass style fail quickly and, as the max size is around 25a, with brushless motors this is quickly achieved. Was recommended to try Automotive blade type fuses as they are “slow blow”.
This solved my problem. Now use a 20a fuse on each motor circuit and have not had a fuse fail for months.

For my 650kv brushless on a 12v SLA the battery has a 20A fuse & then the motor has 20A fuse

Thanks so much Colin.

It is a very precise and clear indication.

Could you give me an example or even just tell me the value of one of your fuse?

Hi Colin. I wonder if you could explain to me your recent post regarding your phrases "the stall load of the motor" and "just below total load that will blow the esc". Im only a novice with electrical terminology and have only worked with wood, metal and plastic for the last 55 years.where do i find the values to work out these answers.
Thanks Roger.

Alessandro, I find a fuse of 5amps less than the stall load of the motor, this has never failed me when getting stuck in weeds.
The fuse to the battery should be just below the total load that will blow the esc.
Cheers Colin.

Great tip DGoss999.

I will look at this data to find the right threshold.

Meanwhile, would you have a number for me?
Do you think 20 amps is too little? Could I go up a little more?

Good evening to all modelers.

I have to thank Roger for opening this discussion, because it is very interesting and brings me back to a doubt I had. A doubt that I would like to remove.

I went to look at the photos (because I didn't remember and I did it before unscrewing the covers) to see what threshold I chose for the fuse.

As you can see in the photo I put a 20 amp fuse (connected to the fastons).
It has never jumped until now but I'm afraid it's too low a threshold.
I would like your opinion and advice.

I did some tests to test the current intensity and chose a value double that at which the motor runs in water, almost at maximum power, without impediments.
The engine is a Graupner Speed ​​600, the battery is AGM lead, 6 volts 4.5 Ah.

Whatever you decide - resettable Auto fuses may be the way to go..

The selected supplier below is just an illustration of what is available... Choose a value under the Max Current Capacity of your ESC and on or just over the Max Stall Current of your motor should be a good starting point!!

https://uk.rs-online.com/web/p/thermal-breakers/0409902?cm_mmc=UK-PLA-DS3A-_-google-_-CSS_UK_EN_PMAX_Catch+All-_--_-409902&matchtype=&gclsrc=ds

Thanks for your input. Fuses are very cheap,I will start low and go up to the next size. My other boat blew a fuse when opening up on all three motors so I upped the fuse 5amp and it’s been ok

Great decision Roger.

The expense is probably even less but you are certainly well protected.

Do not choose too low values ​​for the fuses. Now I am not able to tell you a precise value, but you could do some tests, in which some fuse could blow (but for a good cause).

Hi Fred , thanks for that link.ive had a quick look and i will have to study the pages, it looks interesting, they will make great bedtime reading.these days if i put new info into my little grey cells something has to fall out the back to be lost forever!. Well thats my excuse these days.

Wow!!! thanks for all your in depth explanations regarding the fitting and uses of in line fuses.
I have come to the conclusion that for the cost of 3 fuse fittings and abit of soldering i am fitting 1 between the battery and one each between the esc and motor. Then if anything shorts or jams up i will hopefully be covered. All the hours spent constructing and the cash spent would be a shame for the sake of £10s worth of components not to safegaurd the model.
Thankyou once again for everyones input it is very much appreciated.

Roger / Rogal118

Have a look at Component Shop go down to Action as there are a few fuse boards that may do the job.
https://www.componentshop.co.uk/action-electronics/power.html

As previously mentioned a fuse will protect any fault down stream a short circuit usually blows the fuse instantaneously but it will carry more than its rating for some time depending on its characteristics. If you mount a suitably rated fuse close to the battery it should protect the wiring to the esc and the esc and blow before the cables are damaged. A fuse fitted between the esc and the motor should be rated to safely carry its full load current continuously and short term inrush current due to acceleration or momentary overloads, not the current rating of the esc which may be substantially higher.

I put a fuse in the motor feed cable to protect the esc, and also one in the battery positive wireto help protect the battery.
I had a model once that I had given to me, it had no fuses and on its first outing fouled the prop while in the middle of a large deep lake first sign of trouble was the blue smoke coming from the model.
Cost me a new motor, esc and reciever.
Never again now all positive feed lines fused.
Cheers Colin.

I do this since the first boat I made59 years ago and has never caused any trouble

My opinion, is to protect the ESC.
I always put the fuse between the positive motor lead and the ESC, since it is usually the motor which is the source of the amperage overload.

Hi Rogal.

I'll give you my opinion but please listen carefully to any criticisms of my presentation and other comments before deciding and acting.
I warn you that I am a novice in the RC field, so I try to apply old electrotechnical and electronic knowledge.
However, I will always try to justify my statements and my choices.

In the meantime, I would summarize three main questions.
Do fuses need to be installed?
Where should they be placed?
What type and what value should they have if they are to be placed?


To the first question I always answer yes, even if many modelers think the opposite.
I tell you that it is always better to put a fuse, because the risk of a fire is worse than the risk of leaving the model still in the middle of the lake.
Furthermore, as ARL58 tells you, if you have two engines and only one fuse blows you can also return to shore.
Fire is always the worst thing that can happen to a model in the water.
The people who said the fuse is useless explained to me that modern ESCs are protected from overcurrent, short circuits and reverse polarity. They are probably right, but not being able to verify these statements with certainty, I decided to put the fuse.
The fuse will not do any damage but be careful, a fuse with a value that is too low can leave you in the middle of the lake for no real reason.

The second question (which is the one you ask) is where to put it.
I know that to intervene on a short circuit (which is the worst case of overcurrent with real fire risks) it must be placed upstream of the user who can generate the overcurrent.
Upstream of the fuse you are not protected, downstream of the fuse you are protected.
So, if we assume that the electric motor is the possible cause of an overcurrent, perhaps because the propeller blocks (which is not such a remote case), a fuse between the motor and ESC saves the motor. As long as the fuse is correctly calibrated.
However, if the short circuit occurs upstream of the fuse (which you placed between the motor and ESC) you are not protected.
So, for example, if a short circuit occurs in the ESC, the fuse placed between the motor and the ESC does not intervene because the overcurrent is the one that circulates between the battery and the ESC, i.e. upstream of that fuse.
Ergo a fuse between battery and ESC should protect both the ESC and the motor.
I don't think a fuse between the battery and ESC (for the same reasons mentioned above) can protect the battery from a possible short circuit that occurs between the cells of the battery itself. Lithium batteries should have protections by law, though.
So ARL58's advice to put the fuse between the battery and ESC is correct in my opinion.
There is another aspect to consider: The operating time of the fuse.
I used car fuses.
With the fuse placed between the battery and the ESC, in the event of a short circuit on the motor, the harmful current will also circulate in the ESC although for a short time. I don't know the electronics of the ESC well so I can't tell you if this could cause damage to it.
I wonder if putting a fuse between the ESC batteries and one between the ESC and the motor is not the best solution, even if it is redundant.

For the third question, I'm curious to know what type of fuse you want to put and what value (in amperes) you want to choose.

I hope that what I have written is of some use and is an acceptable translation.

P.S.
If you don't have a magnetoremic switch in your electrical panel at home, and failures never occur, you can say that you've never had any problems in your home.
Not because you are protected but because short circuits have never occurred.
The day the serious fault occurs without a circuit breaker you could report the fire.
Positive experiences in the absence of negative events are not statistics.

I'd fit 2x fuses, one between Bat+ and each ESC. This way:
1.- Battery will be protected if one ESC decides to "go away" (inserting it between ESC and motor will not cater for this type of fault).
2.- If one fuse blows, you will still have one motor left to try to go back port.

Hi Rogal118
Me I do not add a fuse at all, but some say if you do put one in then it should go between the battery and ESC so that the ESC is protected, then some say it should go between the ESC and motor then the motor is protected.
I use the 10/60 Hobbywing ESC on all my boats I have never had any problems.
Fred