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I read one of your posts a while ago about how to wire these supercaps to the PS leads, but now I can't find it.  The supercap's red positive wire goes to the locomotive's positive wire?  So if I'm attaching a 9v connector to the supercap, I want to wire the red positive supercap lead to the 9v connector's positive terminal?  Or is this reversed?

Also, just to clarify, I'm trying to replace the 8.4v battery in a PS1 loco with a 5.4v 1.5 F supercap.  Is this appropriate?  I swear when I ordered these caps I was going on info on this forum saying that would work, but now I'm seeing other threads saying that two of these caps need to be wired together with an additional diode.

Well, don't wire it that way!  Remember, you're creating a battery, not attaching to a battery!  Given that fact, the black lead will go to the positive side of the two series caps, the red lead goes to the negative side. On a battery, the small contact is positive, that's connected to the negative lead on a battery lead as it's intended to connect to the large (negative) lead on a battery.  Best to use an ohmmeter to check your work.

Think about it.

I'm not sure what manufacturer you're talking to, but that's not really true, and I'd be a bit suspect of a manufacturer that tells you that.  There is a grain of truth in it, but they mark the polarity for a reason.

On of many manufacturer's statement on the topic.  Remember, when you get them, they have already been charged in the testing process, so read on.

Eaton supercapacitors are designed with symmetrical electrodes, meaning they are similar in composition. When a supercapacitor is
first assembled, either electrode can be designated positive or negative. Once the supercapacitor is charged for the first time during
the 100% QA testing operation, the electrodes become polarized.  Every supercapacitor either has a negative stripe or sign denoting polarity.

Another manufacturer with a similar story.

For manufacturing and consistency purposes the terminals are marked with polarity. It is recommended practice to maintain the polarity although catastrophic failure will not occur if the ultracapacitor is reversed charged for some reason. If the ultracapacitor has been conditioned for charge in a certain direction and then is changed, the life can be reduced due to this conditioning. For the PC5, PC10 and PC55 products the case is comprised of stainless steel. Due to the corrosion potential it is required to maintain the polarity indicated on the products, and reverse polarity will cause accelerated life reduction.

Someone will have to explain to me why some people want to complicate a simple issue.  Use them with the marked polarity and they'll work fine and have their longest MTBF.  Isn't that what we all looking for?

Last edited by gunrunnerjohn

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