Dear all,

I'm a bit confused about the capacitor to use on my recent 6S build. The frame is a SL5 V2.1 and the ESC is a iflight Succex 50A and, when I bought it, it came with a 470uf 50V capacitor (size D.10 x L.20mm). Unfortunately i cannot use it anymore because it got damaged on the previous build it was mounted on; in addition it doesn't fit in the typical slot that iflight frames have for housing the capacitor. 

Actually that ESC comes with a 220uF 35V capacitor BUT, the following statement has been added:

Include one pc 35V 220uf Capacitor. Don't need use adtional one within 5S Lipo. If use for 6S, MUST add above 50V Capacitor


By reading this statement i assume that a 220uF 50V should be ok (and it's about 6 mm shorter!). Like this:

https://www.amazon.it/gp/product/B08LSBJ...CKNV&psc=1

Now, I know that the only difference I may have changing the capacitance is a slower response in dampening the spikes but... does it really matter? 

Please support me choosing the capacitor, thank you!  

So you can use one cap on the lipo pigtail or 4 smaller caps for each ESC. Most find it easier and cleaner just to use one cap on pigtail.

As for voltage, if you are using 6S (25.2V) lipos, then in theory 35V rated cap is enough. But in engineering terms, you want to always double the voltage rating for what you are using. Hence the 50V recommendation. I personally use 35V without issue. There is a higher chance the 35v cap can short more easily compared to 50V.

As for the capacity of the capacitor, 470uF is a little small. 1000uF is recommended for 5" quad.

The most important thing is your capacitor has to be a Low ESR type capacitor. The one you link will not work. Panasonic is the brand of choice.

https://www.amazon.com/dp/B076TZGGHS/ref...G4CSJT16EP

(08-Apr-2021, 08:59 AM)voodoo614 Wrote: So you can use one cap on the lipo pigtail or 4 smaller caps for each ESC. Most find it easier and cleaner just to use one cap on pigtail.

As for voltage, if you are using 6S (25.2V) lipos, then in theory 35V rated cap is enough. But in engineering terms, you want to always double the voltage rating for what you are using. Hence the 50V recommendation. I personally use 35V without issue. There is a higher chance the 35v cap can short more easily compared to 50V.

As for the capacity of the capacitor, 470uF is a little small. 1000uF is recommended for 5" quad.

The most important thing is your capacitor has to be a Low ESR type capacitor. The one you link will not work. Panasonic is the brand of choice.

https://www.amazon.com/dp/B076TZGGHS/ref...G4CSJT16EP

Thank you for your help.

By saying on the pigtail you mean at the ESC-to-pigtail solderings or it may be also placed at the XT-60 plug ?

1000uf 50V is veeeeeery big!! Why manufactureres keep using 220 or 470 ?

Panasonic are not available on Amazon Italy. What about this one ? It should fit in the space available:

https://www.amazon.it/gp/product/B01N4NS...G0TA&psc=1

Pigtail is referring to the XT60. You would solder onto the same pads you solder the XT60. Have a read regarding caps in FPV.

https://oscarliang.com/capacitors-mini-quad/

Why manufacturers use 220 or 470 uF? I don't know. I usually just toss them aside and put on a proper size cap. Yes, the 50V is Hugh. That is why I use 35V.

The brand you linked, I am not familiar with. In Oscar blog, he listed good brands.

I bought some 1000uF 50V caps for my 6S build but when I saw what monsters they were which clearly weren't going fit anywhere inside the frame I was left with the option of either a 470uF 50V cap or a 1000uF 35V cap (both of those are the same size). I've opted to use the 1000uF 35V cap. I think you would have to be quite unlucky to blow a 35V cap using 6S voltage and the only time a high voltage spike will occur is at initial plug-in of the LiPo.

I always use Panasonic FR series capacitors (or FM series if FR ones aren't available). You can get them on eBay. Always buy a reputable brand of capacitor. A list of the capacitor brands I recommend are in the post below:-

https://intofpv.com/t-capacitor-s-lifesp...0#pid50930

(08-Apr-2021, 11:48 AM)SnowLeopardFPV Wrote: I bought some 1000uF 50V caps for my 6S build but when I saw what monsters they were which clearly weren't going fit anywhere inside the frame I was left with the option of either a 470uF 50V cap or a 1000uF 35V cap (both of those are the same size). I've opted to use the 1000uF 35V cap. I think you would have to be quite unlucky to blow a 35V cap using 6S voltage and the only time a high voltage spike will occur is at initial plug-in of the LiPo.

I always use Panasonic FR series capacitors (or FM series if FR ones aren't available). You can get them on eBay. Always buy a reputable brand of capacitor. A list of the capacitor brands I recommend are in the post below:-

https://intofpv.com/t-capacitor-s-lifesp...0#pid50930

Thank you Snow!

Have you got a positive experience using 1000uF 35V ? Are you still using 35V capacitors for 6S ?

Which are the difference between FR and FM ?

(08-Apr-2021, 11:57 AM)Zanna83 Wrote: Have you got a positive experience using 1000uF 35V ? Are you still using 35V capacitors for 6S ?

1000uF 35V from Panasonic is 13mm diam x 25mm lenght

No, not yet. My 6S quad is still only half built, but looking at what others use on their 6S quads it seems like a fairly safe gamble to me. I would rather have a higher capacitance with a lower voltage ceiling than a lower capacitance with a higher voltage ceiling.

The Panasonic FR series 1000uF 35V capacitors are 12.5mm in diameter x 20mm in length. A datasheet on the FR series is at the link below...

https://b2b-api.panasonic.eu/file_stream...rsion/2846

You can see that the 470uF 50V capacitors are the same size as the 1000uF 35V capacitors, so take your pick. I'm going with the latter. If I was building a 7" or a 10" quad with loads of room inside the frame I would just fit one of the 1000uF 50V capacitors (16mm diameter x 25mm length), but I'm not so I have to make a compromise.

The FR series are the newest series of low ESR capacitors that Panasonic make and they have a lower ESR and longer lifetime than the older FM series.

(08-Apr-2021, 12:20 PM)SnowLeopardFPV Wrote: No, not yet. My 6S quad is still only half built, but looking at what others use on their 6S quads it seems like a fairly safe gamble to me. I would rather have a higher capacitance with a lower voltage ceiling than a lower capacitance with a higher voltage ceiling.

The Panasonic FR series 1000uF 35V capacitors are 12.5mm in diameter x 20mm in length. A datasheet on the FR series is at the link below...

https://b2b-api.panasonic.eu/file_stream...rsion/2846

You can see that the 470uF 50V capacitors are the same size as the 1000uF 35V capacitors, so take your pick. I'm going with the latter. If I was building a 7" or a 10" quad with loads of room inside the frame I would just fit one of the 1000uF 50V capacitors (16mm diameter x 25mm length), but I'm not so I have to make a compromise.

The FR series are the newest series of low ESR capacitors that Panasonic make and they have a lower ESR and longer lifetime than the older FM series.

Got the point, I just purchase from RS Italy 10x FR 1000uF 35V (for 6S) and 5x FR 1000uf 25V (for 4S) -> 24 EUR delivered... is it good ?

I was thinking about what you said about the size of 470uF 50V... probably, since the manufacturers are forced to choose safety against performance, they fit the biggest possible capacitance with that voltage.

I use a 1000uF 35v cap on my 4S 5" build as well. If you have the space, fit a capacitor with both the highest voltage and capacitor ceilings up to 1000uF and up to ~2x the LiPo voltage. Only when you are tight on space should you make a compromise on either capacitance or voltage, IMO.

In the UK Ebay is useful for Panasonic capacitors e.g. https://www.ebay.co.uk/itm/5-X-Panasonic...0456858600