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

[kfxguy]

Well i think u voltager supposed to use 25% higher.
So 14.8x2=29.6vx25%=37v all caps are in parallel so thinking
U need 50v caps because u would b stressing the 35v
ones on 8s . Are they the low e.s.r.( Caps with the 109c rating im not a expert
There is way better folks here. Just trying to help mike

What uF you think I should use? So I can use 50v even tho I may run 6s? If so, I might as well get 50 v for now on. I can still use this cap bank for something else. Was a good first effort tho!

[kfxguy]

Yes they are high temp....105c

What's some good caps to order? I'm gonna order some 50v. I see other name brands, what should I stay away from?

[NativePaul]

Functionally that looks pretty much the same as mine now.

Higher voltage rating than you will use is no problem electrically, you could use 300v caps and they would only charge to the voltage of your battery pack, the down side is that the higher the voltage the bigger they are for the same capacitance.

In that thread I linked you DrWayne recommends leaving 25% headroom on voltage, I believe that is because when you come off the throttle the motor acts as an alternator and generates voltage in addition to the cell voltage. I used 35v caps too, but I only ever intend to use mine on 6s, I think 50v would be sensible to use if you want to run 8s, my 8s max Ice ESCs came with 50v caps stock and I doubt Castle would waste there money on bigger than was needed.

[kfxguy]

Functionally that looks pretty much the same as mine now.

Higher voltage rating than you will use is no problem electrically, you could use 300v caps and they would only charge to the voltage of your battery pack, the down side is that the higher the voltage the bigger they are for the same capacitance.

In that thread I linked you DrWayne recommends leaving 25% headroom on voltage, I believe that is because when you come off the throttle the motor acts as an alternator and generates voltage in addition to the cell voltage. I used 35v caps too, but I only ever intend to use mine on 6s, I think 50v would be sensible to use if you want to run 8s, my 8s max Ice ESCs came with 50v caps stock and I doubt Castle would waste there money on bigger than was needed.

I ordered some rubycon 50v, 1000uf, 105c caps for the next bank I'm making. I ordered 25 of them so I can make some extras. I can still use the cap bank on something.

[montymike]

Rubycon 50v 1000 uf if u look at ose thread listed above
Under tips and tricks(vary good read) escs there is a link to rubycon and
The caps u need good luck mike

[montymike]

I need 4 just like u built for 6s, am thinking 4 caps 500uf for my
4s setups.mike

[gsbuickman]

[QUOTE=kfxguy;590738]How about this....



Right on Travis :) . That's a creative approach to 1 piece buss terminal / power leads, that Macgyver would be proud of . that's definitely one I'll remember :) ...

[olwarbirds]

Travis, I'd make it so you could swap it out. One for 6S like ya got then make the next for 7S and up. I read someplace about not using the 50V for 6S or lower because of some type of a time delay. I've done lots of electical stuff but I cant remember theory. Hated theory in military electrical schools. I'm going to need some of these capbanks myself, tks for the ideas .... DJ

[Fluid]

Travis the 35v 1000uf caps are actually only rated to 6S supposedly, which to me does not make since since they are 35v caps.....

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.



.

[kfxguy]

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.



.

Thanks Jay. I'll order some higher voltage ones also. What microfarad should I go with? The castles I've been using are 220uf and 50v. They only use 4...I say it's been working fine....I have not run any logs but I've had no problems....

[darryl whitman]

Fluid , it won't hurt to use 63 volt caps 4s up to 6s will it?

[Fluid]

The smaller capacity caps will charge/discharge faster than larger ones, for normal use two 500s may work better than one 1000....but they do take up more space (twice as many). The total capacity should increase if you see spikes above 10 percent of pack voltage. For example, for 6S if ripple voltage is above 2.2 volts you are stressing the ESC. It may last fine, but lowering the ripple voltage will help extend ESC life and performance.

The only downside to using a higher voltage cap is the larger size of the caps. You can use 63 volt caps with 4S to 10S just fine.



.

[drwayne]

The smaller capacity caps will charge/discharge faster than larger ones, for normal use two 500s may work better than one 1000....but they do take up more space (twice as many). The total capacity should increase if you see spikes above 10 percent of pack voltage. For example, for 6S if ripple voltage is above 2.2 volts you are stressing the ESC. It may last fine, but lowering the ripple voltage will help extend ESC life and performance.

The only downside to using a higher voltage cap is the larger size of the caps. You can use 63 volt caps with 4S to 10S just fine.
.

If you're after voltage ripple reduction, larger capacity caps are great. (1000uf)
If you're after current flow consistency, lower capacity caps are great. (330uf → 470uf)
Higher voltage caps have larger legs, which is always a good thing.

A pair of 470uf will outperform a single 1000uf in all high demand apps.... unless your batteries are poop ....

An observation for kfxguy's cap bank .. remove the unused copper 'dots' between power rails .. they can/will track electrons between rails when moisture is around, similarly, space the caps apart by one hole <insert smoke icon here>
Nice build besides

[olwarbirds]

Ok now I understand more...tks guys....

[kfxguy]

If you're after voltage ripple reduction, larger capacity caps are great. (1000uf)
If you're after current flow consistency, lower capacity caps are great. (330uf → 470uf)
Higher voltage caps have larger legs, which is always a good thing.

A pair of 470uf will outperform a single 1000uf in all high demand apps.... unless your batteries are poop ....

An observation for kfxguy's cap bank .. remove the unused copper 'dots' between power rails .. they can/will track electrons between rails when moisture is around, similarly, space the caps apart by one hole <insert smoke icon here>
Nice build besides

Thanks for visiting my thread! Your info is always welcome. On the copper dots, good observation! It will be completely sealed from water tho. But for now on I'll use blank boards. Thanks!