Cap banks - the pre-emptive answer

[Fella1340]

Great reading, I could have continued on for ages. Glad to see its still current as I have a couple stupid questions of my own to add soon:smile

[drwayne]

They're only stupid questions if you present them after something went wrong .................

[Fella1340]

Hello Doc, I am wanting to know how much is to much. I am building a 50" semi scale mono of the P1 Fountain. It's been heavily reinforced with multiple layers on cf and kevlar from stern to bow and top and bottom. A heavy boat. I will be running a TP 5660, 820kv, 6wye motor and swordfish 300 amp pro plus esc. Batteries will 10s2p 10000mah 30c minimum. Long before reading this I purchased 2 cap capacitor banks from rc boat bitz. This is where you smile because you know exactly what I have but will add it now for the record. The capacitors are 50volt, 1200uf each and a total of 10 each for 12000uf. I have purchased two of these and at the time was digging how they would look in my setup. Having them in hand they are much longer than I would like. In this case after reading and gaining an understanding of the importance of having them I will choose function over form. They are well made with 8 ga wires coming off the board. I also bought the sword fish parallel /anti-spark board. The idea being to series a 6s and 4s together for each side and them make the parallel connection on the board. My original thoughts were to connect the cap bank one on each side of the four battery leads before it got to the board but if I understand a little better now I would be best making the connection are the parallel antispark board. My basic understanding is vastly improved, especially the relevance part to our hobby. What would you recommend I do? I would prefer to run 2 separate banks to help these fit into the build as a lot of time is going into making this look as nice as hopefully it will perform. What I would prefer and the reality of how this is has to be done may be at odds to one another. Both sets totalling 24000uf. Back to the original question. How much is to much? Cutting and changing the number of caps is no problem. I hope you can help me out doc as that part if the project is only a couple weeks away. I also have another one to tackle after this one. The use of a power regulator (2s power) and a cap bank in a single engine fast electric running 3-4 hv servos. One under heavy load. Fun project! Thanks Doc, look forward to hearing from you. Jeff

[drwayne]

5660?.. why not 5850 ??...

One of the RCBB 12000uf cap banks will be most adequate your needs.

Be warned .. when you connect 10S2P to the cap bank it will throw a spark intense enough to cause bowel motions ....

The addition of a resistor to soft charge the caps will offer no degradation of performance .. but will likely save a repetitive cleaning bill !
Also saves the plugs from damage.

Hook batteries together as 10S2P. press and hold down the little switch for 10 seconds.. this will slow charge the caps.. so when you then make that final connection to the ESC there is no blinding flash ( or mess in your trousers )

fella1340.jpg

[Fella1340]

Thanks Doc,
I really appreciate the help. I am not sure I understand what you mean by using the spark resistor. The parallel board has the anti spark resistor post built in , would it not charge the caps on board it as well as the cap bank I am going to install? I really like the momentary push switch charge idea, much better than having a dangling lead! That's the best way to discharge the caps after running, won't just pulling the wire leave a potential for quite a bite from the stored energy? Now I need to find a home for this extra-long bank. If I was making my own what would you recommend? is there a better solution more personalized to my setup you can recommend? Just because have the "one sixes fits all version" doesn't mean I have to use it. I would prefer the best solution over the easiest any day of the week
Why not the 5859? I am already modifying the motor mount to accept the larger motor. Seeing your comment is leading me to just order the dam thing. It was recommended awhile back and I bought it. A 5850 just may be in there before this hits the water! Thanks again. Jeff

[drwayne]

Hi
The parallel board from HIFEI is intended to make wiring the SF300 simpler task.
The 2 black and 2 red 6AWG input wires are a pain in the arse!! . and the board makes that connection a bit easier.
All that said, I do not like the diminutive size of it, and the lack of separation between rails (power sides ).
On your best day there is still a chance a drop of H2O may strike that board .. instant roasted karma .

Thus my suggestion of push button spark eliminator removes need for the board.

When the 'LOOP' as detailed above is disconnected end of a run .. application of throttle (the 'FINGER') will drain whatever residual power is stored within the cap bank to a safer level.
The datalog will show a sudden spike of amp draw during it's last few seconds of life.. be aware this is due the voltage drop off and power loss from it's supply..panic not !
^^ keeping Tx/Rx active during this time would be of paramount importance !

'Loop' does not need to be a physical loop of wire for removal.. it could well be the single last link between parallel batteries and the capbank/esc interface..
In some countries ( like mine ) an external mains power disconnection safety loop is mandatory .. so my diags tend to cater those users

If you're ordering a new (medium budget) motor to suit your beasty .. I do thoroughly recommend the Castle 2028 for 10S...
I openly admit I was stunned in admiration of it's performance when abused by my 'Go Finger' !.
Steve here at OSE supplies a decent 5" rail mount for this motor at ~$60USD..

regs W

[Fella1340]

Thanks for taking the time to tell it like it is. I really disliked they parallel board but it grew on me as time passed because it was a good solution for those god awful wires. Looks like I will ne joining them up, adding the 6ga cap bank wires and the push putty system in. All on 3" of wire. Not happy with the reality of that let me tell you! There's nothing worse though than being told what you want to hear though, thanks for providing me with the solution. I have come to very much dislike the entire sf300 layout altogether. I know what I have to do now, your help here is saving people a lot of time, frustration and many. Hold that, the sf is still going to frustrating. If it was just a race setup it would be of little concern but I am attempting a clean build and will have ti rethink the whole thing.
I stopped receiving email notifications by email over a week ago and cannot fix the problem so forgive my slow response time, thanks again. I will be back to chat about the rx power system, gryphon power regulator and hv servos and a cap bank for ít once I have things organized.

[drwayne]

A friend has previously shown work using a Female 8mm plug,,the 8mm entry side, slightly crushed into an oval shape, makes for an ideal spot to insert 2 red esc 6AWG input cables to make a join.. and another plug similar hammered for black.. the other side the female plug is a pre-made solder point for 6AWG to lead towards whatever else is in circuit. !
I assemble and trim 1/2" off one of each color so the plug naturally lays off to side the esc when all done ..
Use double or super good heatshrink
:smiile:

2358 here atm.. time to go count sheeps.. :)

[Fella1340]

I will be making a couple oval connectors. The female plug thing is great. Thanks for helping again.

[rickwess]

Hey Jeff. Take a look at post #145 in this thread. IMO, a better way to connect the wires. I did a variation of that when I built my mono and needed to connect two batteries and a cap bank to the ESC. I used wire from a CAT6 cable to wrap the wires and 3:1 heat shrink with the adhesive liner to cover the joint.

DSC_0135.jpg DSC_0136.jpg DSC_0137.jpg

[Fella1340]

I was considering doing something like that as well, was going to use 6ga after the connection to the bullet to the battery. I will be paralleling (2x6s+4s in series)10s2p into it. Just thought it may be better. Running 10s 2p into the single set of 8mm bullets would be the bottleneck point then. I am not sure what the 8mm bulet's are rated for, I really would have liked to use the parallel board as it would have made things much nicer. I wonder if making a copper buss for each side would make things work better. Makes you wonder why they don't make the bullets out of copper, anyone know why. Hope the above makes sense.

[srislash]

I was considering doing something like that as well, was going to use 6ga after the connection to the bullet to the battery. I will be paralleling (2x6s+4s in series)10s2p into it. Just thought it may be better. Running 10s 2p into the single set of 8mm bullets would be the bottleneck point then. I am not sure what the 8mm bulet's are rated for, I really would have liked to use the parallel board as it would have made things much nicer. I wonder if making a copper buss for each side would make things work better. Makes you wonder why they don't make the bullets out of copper, anyone know why. Hope the above makes sense.

I have kinda wondered that myself. Copper is too costly and soft perhaps. Brass is a terrible conductor though.

[drwayne]

The Castle 8mm bullets have thin walls on the female compared the much thicker HK variety..but the metallurgy has visible differences too.
I see Castle claim 200A capability for theirs. which really means bugger all !
200A at 1V .. or 200A at 50V ??
I have pushed the HK thicker wall plugs beyond 400A on 50V without issue...
The less contact(cup size) and conduction density of the Castle plugs my only deterrent .... now using the HK as alternative ...

Copper rails from mains power electrical boards are cumbersome to translate to RC ..
Our Australian 240VAC 10A fused rails .. 2400W .. are well below the needs some our 44V setups here
eg 10S2P10000 where 40/80c translates to 35200W !!!!!!


regs
W

[Fella1340]

I am still trying to understand how gold plated brass is better. I am set up to do small item plating, would making copper bullets and gold plating them be a better solution? It's not something I would want to do all the time but for arguments sake if I went to the trouble to make a set or two for this specific application would conduct better and stay cooler? I am tempted to do an experiment between gold plated brass versus gold plated copper. I have telemetry and could use a temperature sensor on the final connection, before batteries.
What do you think Dr. Wayne? Get over it and just run the hk bullets or would copper bullets be worth a shot? It just doesn't seem proper to run a double set of battery leads down to a single connection where batteries are paralleling into them. I got everything plus the kitchen sink to make and plate something up. If you had a better idea for a fella like me with to much time on his hands to try out I would love to hear it. I don't know what being practical is like with this stuff and could use some perspective on this. How could the same thing in brass be better than copper other than expense? Slap some sense into me!

[drwayne]

your packs have either 10AWG or 8AWG.. the esc has 2x8AWG uptakes

"Theoretically" the best option is for zero reduction of intake cabling, and I accomplish this via battery and esc connections at the cap bank which fits between packs and esc.. not as a external bank as the ones you have from RCBB.
Attaching intake and out-take leads to the rcbb capbank would need a full run of cable across its base to furnish sufficient carry capacity across that board, as the printed circuit has no capacity the supply your esc will demand.
^^ modifying that RCBB/FC capbank is impractical as it would be most shyt when done... not to the standard this build seems to demand !

ergo

ESC==CAPBANK===BATTS


copper Vs composite alloy: conductivity improvements are inconsequential / minimal compared the benefits of premade alloy plug set configurations.
regs

W