Hi all, as far as fuses go I do not use them as I have small boats with about 15 - 20 Watts power and the esc can deal with a stall current. It has never been a problem with my models.
Roy

Hi StephenT, I answered your second question but I don't know if you read it or not, check your private messages if you want.

P.S. I still hear noise (maybe white noise) from people who don't understand that original photos and videos (of detailed construction phases, tests, etc.) cannot be the result of artificial intelligence. Its big bluff was called out long ago, but envy remains a nasty beast.
Out of politeness, I follow this rule: I provide my opinions, supporting them with facts, I answer questions on the public forum or privately (if asked), I describe my working methods and production phases, I ask questions, but I never criticize other people's comments and opinions. Nor do I allow myself to send insults privately.

Hi Roy,
Thanks for sharing your method for measuring the operating current of a brushed motor.
It's very informative, and I completely agree with it. We've already discussed this in connection with brushed motors with permanent magnets, if you remember.
One question: after finding the stalled current and operating current, what size would you choose for a fuse? Would a value between 20% and 25% of the stall current be appropriate, or would another value be appropriate?

Not everyone copies from the internet, especially lengthy posts filled with data nobody cares about. Just a few (maybe one?) that try to emulate AI. The vast majority on this site are wonderful, talented, and give great advice. They are the real "model boaters". Get a life!

Lew

Hi Black shoe. With unkown motors I use a rule of thumb approach. Assuming you have a volt meter capable of reading 20 amps I connect the meter in series with the drive battery and motor.

Using a pair of pliers I grip the drive shaft and measure the stall current. Do this for the shortest time as it can effect the permanent magnet.
The most efficient running of the motor will be with a load (prop) at 20% of the stalled current. You would be OK for running at 25% but this does work where performance data is not known.

If the numbers come out rather low then it is likely the motor was designed to run at a higher voltage than you are using.

Roy

Hi GregHiltz, thanks for sharing your method. I read your procedure with great interest.
At least you have a working method and you're not just talking nonsense, like someone who boasts of his experience but has little real substance and a knowledge base that's too limited to boast every chance he gets.
I understand you're in favor of using fuses and you've given excellent advice on choosing their size.
I also (after studying the factory data) perform tests directly on the model and take measurements in various conditions (both dry and wet) as I mentioned in the previous message (in fact, I wasn't just talking about theory, but always performing targeted tests).

Hi BlackShoe, I also really appreciate your approach and the measurements you take. Thank you for sharing it.
You're right, many engines don't have data for various reasons.
I have many whose specifications I don't know, but some of my technical knowledge and targeted testing help me conduct targeted checks.
I also made videos of the electrical measurement tests I've performed on ship models.

P.S. Anyone who thinks everyone just copies from the internet is doing it themselves and can't realize and accept that some people have real technical knowledge. Envy is a nasty beast.

Mr. Shoe, I agree with everything you said, right down to the paint. Advice from those who have real experience is valuable. Useless banter copied from the internet is just an annoying and has no real value.
Lew

Greg and Lew, I agree completely. The motors I use are mutts bought off the 'net with no pedigree, label, brand, or spec sheet, so manufacturer tech is non-existent. When I have a new build and after I've proven the watertightness, I put the boat in my small pond, put the bow against the edge and run the boat (single or twin screw) at full throttle with an ammeter hooked up in series with the motor(s) for an extended period of time. Monitoring the amp draw and feeling the motors for temperature occasionally I can garner enough information in real time without a lot of theory behind the build. (Theory is good, but someone telling you the stove is hot, is not the same as drawing close to it and discovering for yourself indeed, it's hot.)
Once I know the loaded amp value of the system, I simply install a breaker around double the running amp load and call it good. (I am an advocate of the "KISS" principle. I also don't use any artificially over priced marine bottom paint, but that's another subject.😊)

This is after all a hobby and as such should be enjoyed rather than getting bogged down with a myriad of principles and over-the-top confusing data unless of course that's the part of the hobby someone thrives on.

In my 50 years of gearing up and running R/C boats, I have always been cognitive of fusing my systems , as at sailings I have seen boats blow fuses out in the water, seen some burn up their motors, and others fry their ESCs.
If I am using a known motor with established Amperage draw , I won't test the motor operation for max draw, but will install a fuse slightly above the stall /max amperage. If it is a motor without specs , i will bench test with an Amperage Meter at free spin( no-load), then run the motor while pressing the shaft on the edge of my workbench (under working load), and I will then lock a Vise-Grip pliers onto the shaft and hold the motor against the workbench then hit the throttle/ connect the power briefly to get a maximum amperage draw for few seconds. With this info, I will size my fuse to be just under that max. Amp draw. This would represent the boat getting caught in the weeds or perhaps winding fishing twine around the Prop and causing a near-stall.
I would rather pop a fuse than ruin a good ESC or smoke my motor and possibly burn up my model.
Cheers