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

[T-birdJunkie]

So you're saying water pressure does not drop when something pulling said water through a pressurized system?

Sorry, but in this analogy:

Motor:pumper truck::ESC:hydrant::water supply for hydrant:battery

Electricity, for the most part, works like water, guys.

[PBO]

Originally Posted by T-birdJunkie

Electricity, for the most part, works like water, guys.

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

[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

[slimthelineman]

Originally Posted by T-birdJunkie

So you're saying water pressure does not drop when something pulling said water through a pressurized system?

Sorry, but in this analogy:

Motor:pumper truck::ESC:hydrant::water supply for hydrant:battery

Electricity, for the most part, works like water, guys.

enough with this water crap. it is not the same, nice try though. you might be an expert in that area, congrats. when have you ever worked with REAL electricity? not this measily sub 600 volt stuff either. show me water that will seek a path to ground at all costs. is it going to jump out of your cup? no. if you stand too close to a full pool will the water arc out and hit you because you are dry no. show me a pipe which water will flow through that has a resistance value. show me a capacitor for water that will correct power factor(voltage lagging behind current). water in no way behaves like electricity other than the fact that it flows. sure electrons do the same but they dont flow through a pipe or hydrant or any of that. electrons flow due to a difference in potential. fluid dynamics are fluid dynamics for a reason, it fluid. electricity is electricity, it behaves in one manner, it wants ground, and wont do anything for you until you give it that. water will do whatever you tell it to in the vessel you give it. there are a few excelent posts in this thread, all with the same underlying theme. if the power is not there to be taken other componets will fail trying to make up for this, being subpar has nothing to do with it. heat is a byproduct of current, and will destroy things in a hurry. most obvious is the fact that when the voltage sags under load the three giant caps on the mmm will compensate for the voltage lagging behind the current, when they cant keep up other componets take the brunt of the excess current and fail. dont claim to know it all but believe me when i say i am alive today because i know how electricity works.

[lincpimp]

Originally Posted by slimthelineman

enough with this water crap. it is not the same, nice try though. you might be an expert in that area, congrats. when have you ever worked with REAL electricity? not this measily sub 600 volt stuff either. show me water that will seek a path to ground at all costs. is it going to jump out of your cup? no. if you stand too close to a full pool will the water arc out and hit you because you are dry no. show me a pipe which water will flow through that has a resistance value. show me a capacitor for water that will correct power factor(voltage lagging behind current). water in no way behaves like electricity other than the fact that it flows. sure electrons do the same but they dont flow through a pipe or hydrant or any of that. electrons flow due to a difference in potential. fluid dynamics are fluid dynamics for a reason, it fluid. electricity is electricity, it behaves in one manner, it wants ground, and wont do anything for you until you give it that. water will do whatever you tell it to in the vessel you give it. there are a few excelent posts in this thread, all with the same underlying theme. if the power is not there to be taken other componets will fail trying to make up for this, being subpar has nothing to do with it. heat is a byproduct of current, and will destroy things in a hurry. most obvious is the fact that when the voltage sags under load the three giant caps on the mmm will compensate for the voltage lagging behind the current, when they cant keep up other componets take the brunt of the excess current and fail. dont claim to know it all but believe me when i say i am alive today because i know how electricity works.

Excellent, no getting around this info!!!