Super Capacitors

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dero said:
OK , it looks like it is a possibility .
Can any of the electrical gurus on the site offer any advice before I burn my bike to the ground .
2.7v 6F caps x 6 = 16.2v Is this high enough ?
Does it matter what kind of regulation I am using ? Zenner or SH775 etc .
Single or 3 phase alternator ? I have heard that 3 phase gives a bit more a bit earlier .
Any pitfalls I may encounter ?

Kommando...I presume the caps in your examples are the standard type 2MC or similar ?
Click to expand...
Bit bigger than the 2MC, if I use the decompressor on the B44 and kick it over a few times and then turn the ignition on the Voltage monitor LED stays on for 15 secs, 10 of which are 12V or higher. They were £1 ea off ebay.

Super Capacitors
 
dero said:
OK , it looks like it is a possibility .
Can any of the electrical gurus on the site offer any advice before I burn my bike to the ground .
2.7v 6F caps x 6 = 16.2v Is this high enough ?
Does it matter what kind of regulation I am using ? Zenner or SH775 etc .
Single or 3 phase alternator ? I have heard that 3 phase gives a bit more a bit earlier .
Any pitfalls I may encounter ?

Kommando...I presume the caps in your examples are the standard type 2MC or similar ?
Click to expand...
I think therein lies the problem. The low voltage of these caps means that using 6 in series as you suggest to increase voltage rating reduces the capacitance to 1/6. So to get a 6F cap at 16V you need 6 sets in parallel of 6 in series I.e. 36 super caps. Haven't done the calcs but I wonder how long a 6F cap will hold it's charge and how much space it needs.
Also when you wire several super caps in series some electronics is required to ensure each cap is balanced.
 
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OK , this could get well beyond me .
If points ignition only needs 47000uf , is there an advantage to electronic ig. by having the 1,000,000uf ? of the 6x6 bank ?
And is 16.2v a high enough safety margin ?
Looking at the balancing , ideas seem to range from simple resistors to quite complicated circuits , would resistors be enough ?
 
Depends on how much energy the alternator produces when kicking, if it's over 4700 then a bigger capacitor will store the extra. But if this is for a kickstart bike so more likely it's the alternator output is too low at kicking speeds which is where the bump start working comes in.

What exactly are you looking for, these high F capacitors only seem to work for daily riders with electric start. Leave the bike for a week and the starter will not work without giving the caps a charge.
 
kommando said:
Depends on how much energy the alternator produces when kicking, if it's over 4700 then a bigger capacitor will store the extra. But if this is for a kickstart bike so more likely it's the alternator output is too low at kicking speeds which is where the bump start working comes in.

What exactly are you looking for, these high F capacitors only seem to work for daily riders with electric start. Leave the bike for a week and the starter will not work without giving the caps a charge.
Click to expand...
Just looking into possibilities of a better system that might give enough extra oomph for the electronic ignition .
Maybe its not the answer .
 
Maybe for the first start of the day it could be charged with one of those mini power storage units with a quick connect.
 
Time Warp said:
Maybe for the first start of the day it could be charged with one of those mini power storage units with a quick connect.
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I was thinking along the same line , if it held its charge for a day or so or even if it charged up quick enough from the alternator on kicking , it could be good .
 
I remember a dude in Darwin with an older HD Sportster that had a solar panel on the back of it, maybe one could be installed on the garage roof with a drop down cord as another between rides option.
 
Charging in the shed is no problem as long as it can be made to start the bike readily .
 
As a (hopefully) humorous aside, you realise the rest of the world is (allegedly) heading towards stuffing every vehicle on the planet full of batteries, yet you want to go in the opposite direction?
 
Well & truly on the opposite path to most of the rest of the world anyway .
74 Norton & 97 Land rover . I figure if I own simple things I can usually get them going again when they stop .
 
I used to have a battery-less B44 as sole transport, though still with points. Never a problem starting or riding at night, but.... One winter night the gear lever fell off, stalled the bike attempting a U-turn, it all went very black so no chance of finding the errant part.
A bitch to bump start in third on a snow covered road :-(
 
dero said:
even if it charged up quick enough from the alternator on kicking
Click to expand...
That is not going to happen unless you have a exhaust valve decompressor as I have on my B44, then you can spin the engine over a few times before turning the ignition on and kicking very quickly. With a Norton Commando you either need stronger legs or live on a hill.
 
dynodave said:
If the caps are 3 or 6 Farad as they were saying, that is electrically huge. The regular blue cap is around 3600 MICRO farad or .0036 farad.
A regular 3 farad cap may be as big as a 55 gallon drum or a 275 gallon oil tank.
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Check the first video again - he says they're 350 FARADS the size of a D Cell. Super, indeed.

Large capacity low ESR caps have been around for years, seeing useage by the car audio crowd. Mounted at your sub woofer amp to keep the voltage from dipping during high power bass notes. Their effectiveness is highly debated, but they do exist...

https://www.crutchfield.com/p_1203DDC/T-Spec-Capacitor.html

Those are suppliments to a battery system though, and must be charged through a resistor before attaching to the battery wires.

A suitable replacement for the 2MC is a 10,000 uF 63 volt cap that fits in the same spring mount

1606054120034.png
 
Very roughly with points, bridge, and Zener, discharge times:

4,700 uF - .02 sec
10,000 uF = .04 sec
100,000 uF = .4 sec
1 farad = 4 sec
5 farad = 20 sec

So, pre-charging anything significantly smaller than a battery makes little sense. The original capacitor works because it is fed multiple pulses per revolution. I use a capacitor that is 10,000 uF, 63 volt and is the same size as the 2MC. I get them from Amazon:

Amazon product ASIN B011NATCBS
 
marshg246 said:
Very roughly with points, bridge, and Zener, discharge times:

4,700 uF - .02 sec
10,000 uF = .04 sec
100,000 uF = .4 sec
1 farad = 4 sec
5 farad = 20 sec
Click to expand...
Your numbers are good, assuming a 3 amp load and a 12 volt discharge.

i = C dv/dt
dt = C dv/i

Luckily the frequency of a 6 pole alternator at 500 rpm would be 50 Hz, doubled by the bridge rectifier, and a period of .01 seconds, so even 4700 uF seems to work..

It seems that these "super" caps don't follow the same physics, as I can't figure out how they supply e-start current for a few seconds. Capacitance reduces when in series, so those six 350 Farad caps combine to 58 F.
 
maylar said:
It seems that these "super" caps don't follow the same physics, as I can't figure out how they supply e-start current for a few seconds. Capacitance reduces when in series, so those six 350 Farad caps combine to 58 F.
Click to expand...
Yes, and the elephant in the room: a discharged capacitor connected directly to a supply is essentially a short circuit at the instant it is connected. Not a big deal with 10,000 uF and maybe ok at 1 farad. At 58 farad, smoke will happen if not connected through a resistor until charged. I don't remember the formulas for charge rate and time, but a 12 volt battery connected across a discharged capacitor will cause the wires to briefly carry however many amps the battery is capable of delivering - the higher the uF, the longer the effective short circuit exists.
 
1 time constant is just R*C, that brings it to 63%. Full charge is 5 time constants. The car audio guys say to put a tail light bulb in series with the cap and when it goes out, the cap is charged.
 
maylar said:
It seems that these "super" caps don't follow the same physics,
Click to expand...
This is where I'm headed also with both electrochemical battery with some capacitor characteristics.
Rating the small quick discharging battery as if it was a HUGE farad capacitor is the mumbo jumbo part. Old name assigned for a different new (60 year old) physics hybrid component just add SUPER to the name and $tart $elling it.
Still warrants more study!
 
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