Cap banks - the pre-emptive answer

[Fella1340]

Hello there, an error on this page made it impossible to reply. Guess it's working again! I have no issue with scrapping the rc boat bitz cap bank. What is the best solution, I can custom make whatever you decide is best. I had planned on taking off the 8ga on the banks and tieing it inline like I saw with the etti banks. Not having them apart yet I didn't realize this wouldn't work properly. I must be a pain in the ass with all this but your stuck with me till I get this sorted out with the best option available to make the system work optimally. Help a lost Canadian find his way! Thanks for all your help, it's very much appreciated.
Jeff

[drwayne]

Hi
The SF300 are good for ~400A peaks...
The photo below was mid build the cap bank I use for 12S1P SF300 to Castle 2028
The board is a shelf item .. without copper dots or rails.. doubled up to offer more rigidity.
Each capacitor is 63V1000uf low esr .. and this board has 16 of them.
2 joined in series is a series pair..there are 8 series pairs joined in parallel.
The picture should explain what that means

Hope this helps



20140308_182034_resized.jpg

8x2capbank.jpg

[Fella1340]

That's quite the creature you are building. I am going to order some capacitors/ boards up and make something up. Thanks Doc.

[Fella1340]

I finally stripped the heat shrink off the rcboatbitz cap bank. Very surprised to find out its a fightercat board! Strange. These were the same boards I was going to buy earlier and put my own caps on. Does this mean all those hv cats runing around with these are wasting there time?
what am I going to build that will work so much better? I don't know if I am ready to step up to the level you are going doc but want something that works. We have an awful version of radio shack here In Canada. The boards they had there were similar to the fighter cat version. I need a little hand holding here. The wheels are turning but nothing is clicking into place. Help me understand what I need to do. I very much enjoy photos! The bottom of the board is copper full width for each side if that matters. Better than I could have got at the store. Somewhere online to buy what I need? Help!!

[Fella1340]

Perhaps a more compact way of doing it. What is castle or etti doing so different than what I have?
Running a 6"-8" long set of series/parallel. Would be hard to make work. This is a sport boat and much effort is going into appearance as well. I'm missing something here bigtime!
Jeff

[drwayne]

Filtering out voltage spikes / drops or buffering the power supply so there is a constant high voltage available to esc ?
The standard parallel cap banks do both reasonably well.
The circuit I use does same but with 8x the speed of release and recharge.
End of day your power requirements will profile what extras you need.

[Fella1340]

Thanks, I am going to map out what space I have and see what I can fit.

[mekzoid]

Hi again,
I have looked through all the pages and couldn't find my answer.
I am adding the cap bank onto a swordfish 300 running 2x 4s lipos
Could someone please do a diagram on how to solder this up.
Do both negatives and positives coming from the esc need to go through the cap bank?

Thanks guys, New to all this hv stuff

[drwayne]

2x 4S is not HV mate !

if 4S (16V ) is your max voltage, then the optimal bank will not be suitable higher voltages
give me a ring, Im in SAdelaide X414794022

Wayne

[mekzoid]

29.6v is max (2x4s) voltage, Unless you are meant to run a cap bank for each battery individually?

cant call mate, waiting for telstra to send me out my s5 haha

[drwayne]

all good.. you are running 2x4S as 8S
it read 4S2P to me . lol
what type of loading ?
motor, hull and prop ??
W

[Fella1340]

Good day Doctor,
Looks like I know to much now. I either should be shot or do this job correctly! If I run up to 12s and end up staying there will 50volt caps be enough. What should I a at for total uf? I would like to try the series/parallel arrangement. Space is a big factor, is good performance actually available in a smaller package? This has been the last thing I think of and the first thing when going to and getting up from bed! It plagues my dreams! So the correct approach is the only option. If you could advise on cap voltage and total uf for a series/parallel bank with attempting to keep it small I will be in your debt.Armed with these numbers I should be good to go. Yes, I keep coming back and will continue to till its done properly.
Thank-you,
Jeff

[drwayne]

Ok.
Boat usage.. you still have this overweight P1 replica on 10S2P sf300 ?

What was your final motor and Kv choice ???

Do you intend to run this hard at 100% .. or more a play thing ????

[Fella1340]

Sorry about disappearing, life gets busy. The boat will be run on 10s2p and 12s2p through a sf 300 tp5660 820kv, 6 wye. It's certainly not in race trim weight wise but it should par up with similar
Sized boats. I do intend to eventually run it hard. Initially I will spent the time setting it set up. I don't need to perform hard hole shots but I do Want to see how far It can go. 14s may even be an option.
Spending the time initially setting up and running the boat should give me an idea on amp draw and if it's worth pushing. It's an unknown how this hull react to speed. An upgrade in motor will likely happen this summer. You mentioned the castle 2028, I noticed it's only good on paper to 35000rpm. I am curious as to why you recommend it?. I just wanted to say thanks again for the past and to come spoon feeding session. I saw your friends fantasm running a shared cap bank. That had five caps in it, would something like a three behind, two infront arrangement work? I am just thawing out from a long Canadian winter so go easy on me, that and the bucket full of pain medication from back surgery makes decisions that can be very expensive not done correctly best left to others!:-) I should be ready in a week, two at tops and want to get things on order. Thanks again
Jeff

[mekzoid]

Sorry mate totally forgot about this.
will be running a cheetah, swordfish 300, tp5660, Prather 245 or 240. Will spike just above 320amps I think

Thanks for your help