Cap banks - the pre-emptive answer

[drwayne]

:) Please illuminate me with your thoughts.

[Fella1340]

Thanks again, i had to laugh at myself when I opened the box up and realized the actual size of the fc cap bank. That was quite awhile ago before i had found any sound reading on the subject. Perhaps they'll get cut down and used one day after i get through the the fifty 63 volt and fifty 35 volt bags of capacitors i have here! Keep us posted with any new updates on hv cap bank arrangements that will stand up to serious abuse, enjoy the warm weather. Snow is just around the corner here:-(

[3-UP]

Quick answer.... 4....

Thanks for helping out, would it be OK to solder the bigger caps into the factory t180 aux cap bank board?

[olwarbirds]

:) Please illuminate me with your thoughts.

It might darken them It has been a long time since my military electronic days, I will try. I know that in modern hitech setups charging and using multiple lithium ion and polymer batteries. They are using various single stage PFC converters. In these setups their using caps along with BV inductors to control ripple voltage and to keep the DC voltage at a more constant level IE: no voltage drop until the preset cutoff.

Our lipos start out 4.20v-4.25v per cell and drop in voltage rapidly. For me if I could keep the voltage constant on a "SAW" setup then I would have more consistent timed runs IE: one up one down the course, so its feasible. In heat racing I dont think there is enough stored amperage to support this with the current max battery mah rules.

How to use these BV inductors in my "SAW" setup is where I'm rather unsure about the placement. Can I add them in the capbank or would this have to be something actually added to the board on the ESC ? ... DJ

[drwayne]

Thanks for helping out, would it be OK to solder the bigger caps into the factory t180 aux cap bank board?

physically impossible.. std caps have 3/16→1/4 leg gap .. the little tackers much less .. dont bend pins to suit the boards .. start again new board and space correctly.

[drwayne]

It might darken them It has been a long time since my military electronic days, I will try. I know that in modern hitech setups charging and using multiple lithium ion and polymer batteries. They are using various single stage PFC converters. In these setups their using caps along with BV inductors to control ripple voltage and to keep the DC voltage at a more constant level IE: no voltage drop until the preset cutoff.

Our lipos start out 4.20v-4.25v per cell and drop in voltage rapidly. For me if I could keep the voltage constant on a "SAW" setup then I would have more consistent timed runs IE: one up one down the course, so its feasible. In heat racing I dont think there is enough stored amperage to support this with the current max battery mah rules.

How to use these BV inductors in my "SAW" setup is where I'm rather unsure about the placement. Can I add them in the capbank or would this have to be something actually added to the board on the ESC ? ... DJ

most inductors I placed into circuits were to limit (power) rail ripple ..they are made/wound to target specific harmonics.... dont truly offer a wide frequency coverage ..more a 'choke' effect on the circuit for the frequency they are wound.
eg in DC/AC inverters they could hold the input voltage stable for conversion to 120VAC60Hz through switching.
in rc ESC, also DC/AC inverters, where we have variable output frequency..the inductance would need rate change to benefit the circuit .... here we look into toroids with movable primary/secondary coils ..which is already in the too hard basket for this miniature work with such high draw.

[olwarbirds]

Wayne, ok now I do understand why we dont do this. It was a thought anyways. Yes the setups I was referring to are alot bigger than our rc units... I dont care what they say about you Aussies being upside down all the time, it must help blood flow through the brain. again tks for explaining why it wouldnt work and how it does work... DJ

[drwayne]

Wayne, ok now I do understand why we dont do this. It was a thought anyways. Yes the setups I was referring to are alot bigger than our rc units... I dont care what they say about you Aussies being upside down all the time, it must help blood flow through the brain. again tks for explaining why it wouldnt work and how it does work... J

It's all a matter of perspective, mate .. we are not upside down, you lot are.
You are not on top of the world, we are.
Contrary to popular belief the earth rotates west to east, orbits the sun in direct conflict of path as first determined by Galileo.
The Catholics were right to question his results.
The sooner you Northerners all accept that reality, the better we will all be.
regards
W


btw, if we were upside down, the backflush from our backsides would fill our heads with....

[ray schrauwen]

Top of the world to ya Wayne! lol...

I thought there was no top of the world and if there was it would be the rotating surface of the equator area but, how would I know what angle and or direction our universe is traveling in?? lol... I'm stupid.

[Fluid]

Top of the World Hotel - 3060 Eben Hopson Street, Barrow, Alaska 99723 Barrow, Alaska

http://travel.rbth.com/travel/2013/02/12/the_antarctic_russians_make_themselves_at_home_at_the_south_pole_22777

[drwayne]

Top of the World Hotel - 3060 Eben Hopson Street, Barrow, Alaska 99723 Barrow, Alaska


http://travel.rbth.com/travel/2013/0...uth_pole_22777

Been Antartica for work. !
Douglas Mawson base.. all of 10 days turnaround before the ship returned for more vegetables and beer

There's a tourist mob here in Au who hire a 747 or 767 or something, and fly gawkers down and around the place for a ten hour total flight .. never touching down... easy way to spend $2k+ ....
A mate ( Jamie ) offered them full fare for a one way trip, intending to wing suit down to Mawsons.. but they seem uninterested his adventurous nature, or the media sensationalism it would bring topromote their flights.
lol

[kfxguy]

So......I'm wasting my time what what I've done? I have a t180, (3) 50v 1000uf caps on the esc (repacking the stock ones of 35v) and then 5 more additional ones of the same 50v 1000uf.... mainly hard saw passes but rolling into the throttle. Maybe ditch Two of the caps? (Setup is a neu 1524, 32" cat, 7s, 1860kv)

[drwayne]

So......I'm wasting my time what what I've done? I have a t180, (3) 50v 1000uf caps on the esc (repacking the stock ones of 35v) and then 5 more additional ones of the same 50v 1000uf.... mainly hard saw passes but rolling into the throttle. Maybe ditch Two of the caps? (Setup is a neu 1524, 32" cat, 7s, 1860kv)

The cap bank ADDS to the existing capacitance onboard an ESC.
Most ESC support around 1000uF total... +3 or 4x 1000uF caps =~ 5000uF ± 500uF

As you already have 3x1000uF onboard.. 3 more is a good total.
Capacitor and battery temps will identify if this is the sweet spot.
'5 second rule' ..if you can hold a finger on cap crest for 5 seconds without burn.. that's ok .. if burn !! .. need more.

[srislash]

Top of the season to you Doc, it has been a while. Just read the whole thread(for the most part) and now have a bit better understanding though now the brain is overloaded.LOL

So the current project is an AC R-42 with twin 1717's and FC 8s300 ESC's. Am planning on running 5-6s2p per side(Dinogy 3300mah all) and am now at the point to consider a good cap arrangement. This is to be the
Hull that rips 70 or so around the course just for fun(4-5 laps). So I am looking for a recommendation. Thank you for taking the time, Shawn

[drwayne]

Top of the season indeed !
Weatherman predicts something around 41'celcius for my new year's eve
Im getting a few in early to prevent dehydration

Why limit to 6600 a side when you can blow out to 10,000 ?..

1717/1580 are Y winds which demand more from a 100% launch than possible at 100% rpm .. so bottom end surge capability is what you should aim for.... with a little ripple coverage higher up.

Expect all those 8S300A can handle if you spin big wheels...

I advise 3000→5000uf as the vague magic number for capbanks ..but how that is determined depends on your application.

In your case of high demand on launch, and ripple clipping later on, use 8x 63V1000uf per esc as below

+.batt.-
+.......-
+o-+o-
+o-+o-
+o-+o-
+o-+o-
+......-
+.esc.-

zoom zoom

best of your wintry season to you, mate .. your welcome to the cold !!!