Castle data logging data explanation

[Mattyd926]

Ok so I understand what all the values mean I just don’t know what is good or bad. This data is for a drag car. I am trying to understand what changes to what.

 

[vpr5793]

The main values I would be looking at are battery voltage, ripple voltage, and speed controller temperature.

I would look at battery voltage under acceleration. a rapid drop in voltage under acceleration could indicate a battery that is being pushed beyond its capabilities, or a poor connection somewhere between the battery and the speed control.

Ripple voltage indicates how hard the speed control is working to regulate the voltage on the main circuit. excessive ripple on the main battery circuit is typically caused by a battery that's being over stressed, a poor connection between the battery and the speed control, or being over-geared. There are a few different ways to solve these kinds of problems. You can add a capacitor pack onto the main battery leaves, reduce gearing, or put better connectors between the battery and the speed control

Speed controller temperature is pretty obvious. And what I see on that graph it's doing pretty well though. You want to keep the temperature as low as possible in order to make sure that the speed control isn't getting pushed too hard.

any of these problems if left unchecked could result in electronics failure.

Also if you don't have an infrared temperature gauge get one. Use it to measure the temperature of the motor at the end and raise or lower your gearing appropriately.

 

[Mattyd926]

That is what I wanted to hear “ doing pretty well”. If all those parameters look good I will now work on my launching

 

[jkflow]

Wanted to hear? Based on what you have shown it's absolutely meaningless as you have to zoom into the sections of interest. What you show is multiple runs that completed, which by all means you already knew

Check this video, datalogging starts around 1h25min into it.

 

[olds97_lss]

This was in response to a query I sent to castle about the logs from my MMX in my savage flux:

Inspect the capacitors on the ESC. I’m seeing a LOT of ripple in the system. It’s supposed to be below 10% of pack voltage at all times, but I’m seeing 3.4v on a 4S LiPo. Most you should ever see is 1.5v. Usually when the ripple is that high there is either a battery connection issue, or the capacitors are damaged so when you’re hitting the throttle the caps can’t keep the processor powered up and it reboots. Let me know what you find.

I wasn't asking about ripple, I was asking about something else on the graph and they mentioned that in the reply.

At 3.4V, your more than 10% on a 6S system, so might be something you want to look at. I built a cap pack for mine and the ripple dropped to <1V in the logs.

I used 6 of these in parallel:

To make this:

 

[BashingBrian]

This was in response to a query I sent to castle about the logs from my MMX in my savage flux:


I wasn't asking about ripple, I was asking about something else on the graph and they mentioned that in the reply.

At 3.4V, your more than 10% on a 6S system, so might be something you want to look at. I built a cap pack for mine and the ripple dropped to <1V in the logs.

I used 6 of these in parallel:

To make this:

I was looking to make my own cap packs, but how do you find out what caps to use..??
When I looked at my local electronics suppler they had so many I was just lost..?

 

[olds97_lss]

I was looking to make my own cap packs, but how do you find out what caps to use..??
When I looked at my local electronics suppler they had so many I was just lost..?

More V than you need, low ESR (speed at which it stores/releases), as much capacity as you want to fit.

These are 35V low ESR, so should work for up to 8S (33.6V fully charged), but may want to go with 50V for that. Plenty for 6S (25.2V fully charged) on down though.

 

[BashingBrian]

What is a low ESR value.??
My stockist has some 3300uF ones, what's the difference between those and your 1800uF ones..??

 

[olds97_lss]

What is a low ESR value.??
My stockist has some 3300uF ones, what's the difference between those and your 1800uF ones..??

From what I understood, ESR affects the rate at which it stores/releases. The lower, the better.

Guessing 3300uf ones will be pretty big physically. Kind of why I went with the 1800uf ones, a bit more compact.

 

[jkflow]

These are polarized and contain a LOT of smoke, if you want to release it just reverse polarity. Careful these can be worse than firecrackers (alu can might splinter) and they stink.

At any rate, you know when you have enough when you do not see a noticeable improvement in your log (ripple). Other threads mentioned that ~ 6000uF is the sweetspot for this combo.
Soldering them in parallel will increase capacity of the pack (simply adding values). Somewhat reverse logic with respect to resistors.
Doesn't really matter how you get to those values, sizes and personal preference matter, not really a technical issue.

I wonder if anyone ever tried a supercapacitior but they only come in low voltage versions thus far.

 

[vpr5793]

ESR is equivalent series resistance. Basically the measure of how resistant the capacitor is to receiving or delivering current. Lower ESR values mean that current can flow in and out of the capacitor a lot easier.