Hi! My first post here! Hope someone help me with this problem I got.
I made my own stay alive capacitor circuits for my LaisDCC KungFu decoders I got, but I got some problems. I used some small 5.5 volt, 0.1f super capacitors, like these:
I used three of them in series and wired them up like this diagram here:
(I edited this from an existing diagram I found that had different capacitors)
But it does not seem to work as good as it should, cus when I have the engine running and lift it of the track, it stops immediately, the motor gives of a faint buzzing sound tho for a few seconds, but it does not spin. If the engine have the LED light turned on while being lifted off the track, it stays on for a while, so seems to work quite okay for the LED, but yeah, not for the motor. So I wonder why it does not work right? I tought these capacitors would work fine, but mabye I am missing something?
I tested and wired this stay alive circuit up to 3 small tank engines I got and all three got the same problem. I have wired up some normal bigger electrolytic capacitors rated at 16v and 6800uf/10000uf on some bigger engines I got that has more room inside, and those work fine and makes the wheels spin for like 2 seconds or something, so I wonder what I'm doing wrong here with these, cus these 3x 5.5v, 0,1f capacitors should have like 33333uf I think, so much more than the 6800uf and 10000uf ones.
I use the Hornby Elite controller if that makes any difference.
So hope someone can tell what's wrong, or if I maybe should try some other small capacitors instead or something.
Thanks in advance!
Regards Dennis
Stay alive super capacitor problem
Re: Stay alive super capacitor problem
Although I don't understand the specifics of the diodes and resistor, I think your problem is that capacitors in series have an overall less capacitance than each of the individuals. If you want to add capacitances you have to connect them in parallel, which means that they all have to be rated for your supply voltage.
- Ironduke
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Re: Stay alive super capacitor problem
What are you using for the "negative" on the decoder. Can you post a good quality photo of the decoder with the stay alive circuit connected?
Do you have a part number or data sheet for the capacitors?
Do you have a part number or data sheet for the capacitors?
Regards
Rob
Rob
- Bufferstop
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Re: Stay alive super capacitor problem
Adding capacitors in series reduces the overall capacitance. The effect is the same as increasing the distance between the plates of a single capacitor. Putting them in parallel is the same as increasing the area of the plates which raises the stored charge.
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Re: Stay alive super capacitor problem
Hi denfin,
You are correct having the capacitors in series, if you put them in parallel then you would only be able to apply 5.5v at the most, in series you can have up to 15v depending on how many capacitors you have in series, the voltage is the critical thing here as you will still get your .1f out. Here is a link to youtube to show you exactly how to do things.
https://www.youtube.com/watch?v=EOE0BCV ... b_imp_woyt
You are correct having the capacitors in series, if you put them in parallel then you would only be able to apply 5.5v at the most, in series you can have up to 15v depending on how many capacitors you have in series, the voltage is the critical thing here as you will still get your .1f out. Here is a link to youtube to show you exactly how to do things.
https://www.youtube.com/watch?v=EOE0BCV ... b_imp_woyt
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Re: Stay alive super capacitor problem
Wait, how much uf does three 0.1f (which is 100000uf if I'm not mistaken?) capacitors in series generate? Maybe I calculated this totally wrong? XD I know the total is smaller than 0.1f at least, but maybe it's much smaller than I thought?
And I just use the two wires that are made for soldering a stay alive package to:
I have also added an on/off switch, which I heard is good to have when so you can turn the stay alive off when programming.
And here is a link to the capacitors I bought:
https://www.ebay.com/itm/2-10-50Pcs-ELN ... 2749.l2649
The part number is DXN-5R5V104U It seems.
And yes peroni, it's that scematic and video I watched to make this, but I guess the capacitance still will drop tho when adding them in series.
And I just use the two wires that are made for soldering a stay alive package to:
I have also added an on/off switch, which I heard is good to have when so you can turn the stay alive off when programming.
And here is a link to the capacitors I bought:
https://www.ebay.com/itm/2-10-50Pcs-ELN ... 2749.l2649
The part number is DXN-5R5V104U It seems.
And yes peroni, it's that scematic and video I watched to make this, but I guess the capacitance still will drop tho when adding them in series.
Re: Stay alive super capacitor problem
You're using 3 X 1F caps at 5.5v each so will be safe up to 16.5 volts less a bit of headroom, so call it 15v. Divide 1F by three and you get the answer you showed, roughly 333,000 uf. The Lais Kung Fu capacitor packs pack a good punch for the price and they have the charging circuit integrated, so no need for a separate circuit. They also come with a choice of layout. I gave up making my own when these came about.
Pete.
- Ironduke
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Re: Stay alive super capacitor problem
They are 0.1F caps so that's 33,000uF in total.Peterm wrote:You're using 3 X 1F caps
even so that's a lot. I can't see much in the picture but it looks ok, assuming all the caps are the right way around. How long do you think they take to charge up?
Regards
Rob
Rob
- Bufferstop
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Re: Stay alive super capacitor problem
Yep 3 x 1F in series gives you .33F at three times the voltage. five will give you .2F at five times the voltage. When testing the loco will have to be run long enough for the capacitors to charge up. My understanding is that supercapacitors have to be charged up more slowly.
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Re: Stay alive super capacitor problem
Denfin,
Sorry, not paying attention properly and thought you had 3x1F caps. As Bufferstop says, with three of those you'll get 330,000 uf, but as I said it's hardly worth it as you get plenty of storage with the Lais packages (others are available) and you don't have to worry about charging or balancing circuits as it's all done for you. They are also physically smaller than we could hope to make them.
Sorry, not paying attention properly and thought you had 3x1F caps. As Bufferstop says, with three of those you'll get 330,000 uf, but as I said it's hardly worth it as you get plenty of storage with the Lais packages (others are available) and you don't have to worry about charging or balancing circuits as it's all done for you. They are also physically smaller than we could hope to make them.
Pete.