Tachometer for BL motors?

[ScarabChris]

Does this exist without all the fancy complicated telemetry?

Something like they make for the gas engines like this?
http://bonzisports.com/images/parts/tiny.tach.jpg

I would just like to know what the top RPMs are.

[m4a1usr]

An Eagle Tree system will provide that. Also the data logger function available from many of the speedos now being sold. As well Medusa has a system. Or you can go super cheap and buy a KV checker. That will give you motor rpm. Are you looking for something like saved data or just a bench checker?

John

[ScarabChris]

I want to run the boat and see a readout of the peak RPMs after.

Something like that Tiny Tach but with a sensor on one of the wires without all the extras? I want to keep it simple. I was looking at the Eagle Tree stuff but it looks a little complicated.

If someone could simplify it I'm all ears......or on the internet all eyes.

[sailr]

You would have to be riding in the boat to read that thing. You have to have something to log the RPM's so you can read it after bringing the boat back in. There has to be some sort of memory and software involved.

Does this exist without all the fancy complicated telemetry?

Something like they make for the gas engines like this?
http://bonzisports.com/images/parts/tiny.tach.jpg

I would just like to know what the top RPMs are.

[befu]

Eagle tree

Chris, get an eagle tree data logger. The base unit is great, gives you real time volts and amps along with the power calculations you want. Then add the eagle tree gps unit and you get a graph of your speed. Throw in a cheap rpm meter with it. Two wires and I just pinch them in the motor bullets. Gives you real time rpm.

So you can look at your boat speed, know how fast your props are spinning and what the pack voltage and amperage does. You can tell the difference in the graphs of smooth water vs. waves!

With how much $$ you are spending on boats, motors and props, you really should be looking at this stuff.

I have put an eagle tree into a brushless crackerbox that I built RTR for the same amount as ONE of your props! The eagle tree was worth more than the boat, radio, battery and charger combined!

Brian

[ScarabChris]

You would have to be riding in the boat to read that thing. You have to have something to log the RPM's so you can read it after bringing the boat back in. There has to be some sort of memory and software involved.

Those record peak RPMs.

[NativePaul]

Those record peak RPMs.

I'm not sure how useful that would be as its unlikely that the prop would be in the water doing any work when it hits peak rpm, but if that's what you want how about pointing one of these at your coupler you would need a LED inside your boat to illuminate it but it should be able to get RPM from the grub screw passing it.

I think the eagletree datalogger with brushless RPM sensor is the answer you are looking for.