how to make a cheap cap bank.....

[ReddyWatts]

The issue is that with a high amp setup (big prop, heavy boat, etc.) when the throttle is chopped the boat's momentum drives the prop as a generator, and the back voltage going to the caps can exceed the nominal pack voltage a bunch. This is one reason that many have recommended for years not to run any ESC at its top rated voltage, the makers used small caps and the back voltage can blow them. Once the caps go the rest is soon to follow. That's why I put 63 volt caps on a controller I plan on using with 8S. As stated above the only downside is the caps are bigger.



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Can someone post their data log showing the voltage increase higher than batt voltage on the caps when the throttle is chopped?

[montymike]

So if u were using4-5s would u use 2000uf total (2) 1000uf
Or 4 500uf caps35 a the latter being the more desirable.
Per space.?

[montymike]

So if u were using4-5s would u use 2000uf total (2) 1000uf
Or 4 500uf caps35 a the latter being the more desirable.
Per space.? Ya picked up blank board from radioshack what wire size for
Ur connections did you use 10or 12 gauge?

[rickwess]

From reading Dr Wayne's thread, my take-away was that a combination of series and parallel caps would give you better charge/discharge rates.

You already have most of what you need to build it. You just need smaller caps.....say 470uf ZLH. These two are what I built for my boats.

IMG_20140604_205347.jpg IMG_20140605_113247.jpg
DSC_0039.jpg DSC_0041.jpg

[montymike]

So yours are 8 470uf in parallel= 3760uf 63v or 50v? Nice like the zip ties
Hold um in place did u use liquid electrical tape
To spray the bottom

[rickwess]

They are configured as:

(-)---[470uf]---[470uf]---(+)
(-)---[470uf]---[470uf]---(+)
(-)---[470uf]---[470uf]---(+)
(-)---[470uf]---[470uf]---(+)

The effective capacitance of the above is 470/2* 4 = 940uf. This was for a 4s set-up. You can add 470uf pairs for high voltage set-ups.

The plasti-dip is just to insulate everything. I used heat shrink to hold it all together. If you're really concerned about movement of the caps you can use CA glue to bond then to the peg board.

IMG_20140605_114140.jpg

[rickwess]

This is the key post to read:

http://forums.offshoreelectrics.com/...127#post448127

[montymike]

So soldered+ to- to make series parallel?

[rickwess]

So soldered+ to- to make series parallel?

(-)---[470uf]---[470uf]---(+) are in series (+ to -), then join multiples of these in parallel.

[montymike]

Looks like i got some cap banks to build tired of replacing escs first ones going on my new
120a seaking nice esc 1 cap going to fix that! Thanks for sharing

[gsbuickman]

you guys might find this interesting. this guy has a pretty good idea using compacitors from disposable cameras that you can get for free from drug stores and photo shops anywhere :) ...

http://m.youtube.com/watch?v=4Vao-xNSUUM