Isolation loop and using a anti-spark battery lead

[1945dave]

This question is really two questions in one. Here in the USA the isolation loop is not required or very popular, yet I think they are very useful and worthy of being incorporated in my builds. The question though stems from my belief that the resistor anti-spark lead is also a good thing so how do we marry both together? If anyone has this loop in a Genesis could you shoot me a photo to see how you did it?

Dave

[viper1]

Hi Dave,




That photo I send you earlier came from a UK based site, here's the full article about making a loop:

http://www.fastelectrics.net/isolation_loop.php

It looks like it has been done on a rigger in that example.

Given that the ESC to battery wiring needs to be as short as possible, your options on the Genesis are limited when it comes to location of this 'loop' in my humble opinion, either left or right outside the hull close to the ESC.

To incorporate the anti-spark lead it could look something like this:



I run for fun only so won't even think about cutting holes in that nice hull (and paint job).

[1945dave]

Well Viper, I am with you on trying to not mess up my Genesis paint any worse than I already have, but I did have a close call that could have be helped if I could have unplugged that isolation loop. Still my issue now is seeing any installation of such a loop and with the anti-spark feature as well. I agree that your sketch would serve that purpose but the idea that you or someone in a retrieve boat can quickly and safely rip that loop from the sockets to kill the power may be complicated by having a more fraigle resistor lead as well. I am hoping some of our UK members can shed some light on this.

Let me compliment you on the neat short wire setup on your ESC/motor in the Genesis, it looks great. You did a great job.

Dave

[785boats]

Dave.
As you are probably aware, here in Australia We must use a safety loop to be able to race.
I did use a resistor in one setup, but I don't bother in any of my boats now. A healthy spark shows that the caps are all good.
I placed the resistor across the loop terminals inside the boat so that as soon as the batteries were connected the resistor was in circuit & charging up the caps. No need to plug & unplug the resistor separately that way. After taping up the main loop is connected to arm the system ready for running.
Here's a pic of the one with the resistor & one without.
Note: by passing one wire straight through the wooden block & hull, you eliminate one connection (less resistance) & most of all, you can't loose the loop.
Cheers.
Paul.

[viper1]

Thanks for the compliment Dave,

Just a thought to add on the subject;
Many ESC's now have a anti-spark circuit build in from manufacturer.
That would leave only the loop to design.

But yeah, that would require investment....

No need to plug & unplug the resistor separately that way.

Paul, good idea to feed wire through on one side but I think Dave wanted the loop also to double as a master switch (no un-taping of the hatch between runs)
and that way the resistor stays connected right? (As long as batts are connected inside the hull)

Regards,
GJ

[1945dave]

Dave.
As you are probably aware, here in Australia We must use a safety loop to be able to race.
I did use a resistor in one setup, but I don't bother in any of my boats now. A healthy spark shows that the caps are all good.
I placed the resistor across the loop terminals inside the boat so that as soon as the batteries were connected the resistor was in circuit & charging up the caps. No need to plug & unplug the resistor separately that way. After taping up the main loop is connected to arm the system ready for running.
Here's a pic of the one with the resistor & one without.
Note: by passing one wire straight through the wooden block & hull, you eliminate one connection (less resistance) & most of all, you can't loose the loop.
Cheers.
Paul.

Paul would your attached loop satisfy the UK requirement? Also with the resistor staying connected inside the boat does that really allow a full disconnect? or would the resistor then become a fuse?

Thanks,

Dave

[1945dave]

Many ESC's now have a anti-spark circuit build in from manufacturer.
But yeah, that would require investment....

GJ

Viper, I still do not know what the extra bank of 4 caps across the battery leads of my new T-180 do, but I don't think they are anti spark do you? To me the idea behind the resistor is to drop the voltage available to the ESC upon connecting the batteries so the voltage is brought up in steps thus reducing the spark shock. However connecting the dropping resistor across the two terminals may also do that but I agree that I want both the dropping resistor (think shunt) and the main feed disconnected between heats.

[drwayne]

Hi Dave, thanks for the PM.

Anti-spark slow charges the capacitors to avoid that nasty plug/esc melting ZAP on connect.
In Au and Eu a deck mounted safety loop is mandatory in race spec.
The diagrams below caters to both these considerations in the 'easy' way, and then the more robust but harder way.

antizap-easy.JPG-IMG_0175.jpg

antispark.JPG-IMG_0213.jpg-IMG_0221.jpg

[KartRacer]

Drwayne
What do you use for the disconnect as far as mounting the bullets in the hull?

[viper1]

Check the link in the 2nd post Dennis,
I think your answer is in there.

[drwayne]

Drwayne
What do you use for the disconnect as far as mounting the bullets in the hull?

Hi
I use a ~10mm nylon kitchen cutting board I cut into a large backing sheet .. biggest that fits is best for it staying in there .. , epoxied under the hull deck.. then I drill through for the plugs. Assemble the leads to female plugs.. insert from the inside of deck.. tape over the top.. hold hull upside down, and flood the plug.hole area with thick epoxy.. never comes out ( unless the dremel is handy )

W

[KartRacer]

Thanks Everyone, I agree I will be adding to my build.

[drwayne]

Here's what I have on my twin 54" MHZ
(sharing one loop to 2 independent battery/esc systems is the next lecture, boys )

Switch on L is swordfish on/off, central 2 plugs are main battery disconnect, button on R is the resistor shunt.

neat, clean and (almost) idiot proof

[drwayne]

Here's the sequence for those still challenged by safety...
1. 5 secs.. charges caps. .. keep down
2. insert main loop plug#1.
3. insert main loop plug#2 ... release charge button
4. in this sample the esc have on/off switch feature.. if your esc uses inbuilt bec, you need to pass the 'red' servo wire through this switch to disable arming until the sw is closed.

IMG_0324-1.JPG

[785boats]

Good ideas there drwayne.

Dave & Viper.
Although you've probably got all the info you need now, I just saw the questions your earlier posts & it would be rude of me not to answer.
With the resistor still connected the main isolation loop still disarmed the ESC. At least the one I used.
We would always untape after a race/run & disconnect the batteries ready for replacement before the next race/run.
I did, however, leave a depleted pack connected in a hull for 4 days before I remembered it. The cells were down to 2.4 V/ cell. Because they were drained under such a low load, no noticeable damage was done. I was able to bring them up to full charge again.
That's one of the reasons I don't use the antispark resistor in any of my boats. Mind you I only run up to 6s.
Cheers.
Paul.