Argument thread: Low specc batteries don't kill ESC's. Or do they?

[T-birdJunkie]

Originally Posted by PBO

It's too basic an analogy

You could always adapt an RC to run on pressurised water...then the analogy is perfect. Electricity is far more complex than water & can't be simplified into hydraulic pressure - sorry just doesn't work

Electricity is not that complex. It's electrons flowing one way through a system. hydraulic flow is really no different than electrical flow. If you really wanted to, you could build a 3 phase hydraulic stator motor and a system to properly feed it.

If you don't understand the analogy because you don't understand fluid dynamics, that's fine. Don't pretend electricity is more complex than fluid flow, though.

The point is, if the battery can't supply the amperage, then the battery can't supply the amperage. People post a LOT about "ripple current" and simply accept it as fact without understanding it (kind of like how people assume fluid dynamics and electrical flow are different), yet nobody has offered a proper explanation.

From how ThunderbirdJunkie understands it, ripple current is from a battery not being able to supply the drawn current, then suddenly supplies it, and stops, and continues that cycle.

Is this accurate?

[lincpimp]

Originally Posted by T-birdJunkie

Electricity is not that complex. It's electrons flowing one way through a system. hydraulic flow is really no different than electrical flow. If you really wanted to, you could build a 3 phase hydraulic stator motor and a system to properly feed it.

Hmm, water is quite a bit different than electricity. I have felt electricity and it is not wet. I can't wash my hair in electricity, and my water faucet works quite a bit different from my MMM.

All kidding aside, you have to factor amp spikes, in both directions. Heat and its effect on materials that conduct electricity is very important. Kinda like friction. If you do not factor friction into physics equations they are very simple, however we do not live in a friction-less enviorment so it is kinda important.

The battery has to be able to output a stable voltage at high current levels while also having low internal resistance to keep from getting hot, and also accepting a charge back from the regen brakes. The esc has the task of controlling the motor and ducting the electrons to and from the battery.

I am by no means in full understanding of how this stuff really works, but I do know that the battery is the single most important part of these brushless systems. I have experiemented with alot of different batteries and there is a difference.

[lincpimp]

Originally Posted by T-birdJunkie

From how ThunderbirdJunkie understands it, ripple current is from a battery not being able to supply the drawn current, then suddenly supplies it, and stops, and continues that cycle.

Is this accurate?

Dude, not to be a "freezebyte" but the 3rd person diatribe is not necessary. If you say "I" or "me" we will understand. Not the traxxas or savvy forum...

[PBO]

Originally Posted by T-birdJunkie

If you don't understand the analogy because you don't understand fluid dynamics, that's fine. Don't pretend electricity is more complex than fluid flow, though.

This annoys me, firstly I do have specialised knowledge of fluid dynamics. My knowledge isn't in hydraulic's as such but in airflow, aerofoil, hullforms etc

Secondly while I was using an small (hydraulic) excavator today I realised my dismissal of the analogy was hasty & wrong, it is actually a reasonable analogy...especially when considering 'ripple current' and 'fluid hammer' for example

I thought of an excellent analogy between supercavitation & C ratings in cells if you want to keep playing with analogies