G
The Voice of Reason
Joined: 02 Feb 2002
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 Posted: 10:33 - 17 May 2015  Post subject: Calculating ultracapcitor 'starting amps' - what farad cap's |
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On from my lithium battery thread, which turned out to be a moot question as a boat would have been more useful than a bike that day...
The ideal would be an ultracapcitor starter for the track bike, I reckon.
A bit lighter than a battery and won't be damaged by being left in various states of charge for months/years on end.
Should probably cost a bit less than a 'good'-make battery, but more than a cheap one.
Some ultra-caps list a maximum amps, but generally not suggest that shouldn't really be used, at least not for any significant period.
Does anyone know if I can use this figure as a basis for calculations?
Also, I know capacitance in farads is reduced when they are added together in series, but I'm presuming amps are not?
The battery listed for the bike is rated between 85CCA and 120CCA, depending on which company etc - the 85A end is probably a little too low, at least when if the battery is starting to get a bit tired and losing power from that.
Engine is stock, so doesn't have to worry about extra strain from high compression etc.
I'd need six in series. |
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BillyJ
Nearly there...
Joined: 07 Jan 2013
Karma :  
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| Posted: 12:59 - 17 May 2015 Post subject: Re: Calculating ultracapcitor 'starting amps' - what farad c |
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| G wrote: | On from my lithium battery thread, which turned out to be a moot question as a boat would have been more useful than a bike that day...
The ideal would be an ultracapcitor starter for the track bike, I reckon.
A bit lighter than a battery and won't be damaged by being left in various states of charge for months/years on end.
Should probably cost a bit less than a 'good'-make battery, but more than a cheap one.
Some ultra-caps list a maximum amps, but generally not suggest that shouldn't really be used, at least not for any significant period.
Does anyone know if I can use this figure as a basis for calculations?
Also, I know capacitance in farads is reduced when they are added together in series, but I'm presuming amps are not?
The battery listed for the bike is rated between 85CCA and 120CCA, depending on which company etc - the 85A end is probably a little too low, at least when if the battery is starting to get a bit tired and losing power from that.
Engine is stock, so doesn't have to worry about extra strain from high compression etc.
I'd need six in series. |
The current capability will be equal to the lowest one in the set if they are in series.
I.e. 6 caps, 5 can deliver 100A and one can deliver 10A, you would only want to draw 10A from it but if they are all capable of delivering 100A then you can still draw 100A from the set as a whole.
If you want more CCA then add some capacitors in parallel, if you have 2 capacitors capable of delivering 100A each, put them in parallel and you can theoretically draw 200A
In regards to capacitance,
Capacitors in parallel: Ctotal = C1 + C2 + ... + Cn
Capacitors in series: 1/Ctotal = 1/C1 + 1/C2 + ... + 1/Cn
It's basically the opposite of resistors.
I forgot to add:
I'm guessing you need 6 to get to a usable voltage, just remember when charging them to treat each cap as a separate cell and balance them properly, just like Lithium batteries. Charging and discharging them can get pretty bad pretty quickly if they aren't balanced well.
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Had: '06 CBR125R + '01 GSF600 + '07 SPRINT ST 1050 + '80 CB250 RSA + '93 Ducati 900SS
Have: '13 GSXR-1000 + '01 CB500S
"The aryan confuser" |
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