Large Scale Central

Using Supercaps with a Sierra soundcard?

I have a NW2 with a Sierra sound board in it. I have been using a rechargeable 9volt battery to power it on my track powered RR but it does not always work. I thought about putting in a bank of super capacitors to give it constant power with no drops over sketchy track. I have a GP with a Phoenix that I bought used and it performs nicely. I don’t know what type of battery is in it but it recharges from the track.
I bought a super cap setup for the Sierra that is used by the Revolution system. Did I make a mistake here? The caps are rated for 25v 3300uF. The plug is the same on the super cap setup and fits the Sierra battery input plug but I think they are too powerful?

The bigger question is if not super caps then what type of battery for the Sierra board?
My understanding of electronics is amateur. I can install things but I can’t build boards and circuits etc…

Any ideas? Thanks.

Shouldn’t be a problem as long as you run at ~12 volt minimum. At lesser voltages, the board doesn’t put out enough to charge the caps.

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Will these be ok at 25 volt or do I need to get smaller ones? I will give it a try.

They are fed power from the Sierra board and it puts out ~7.5 volts.

The NW2 is still torn apart. The supercaps are not working. The Sierra board comes to life over 12v and I have connected the caps to the battery terminal on the board. My meter tells me that 7.5 v is present at that terminal. I have run the engine on my test rollers for several minutes but once I drop the throttle below 12v the sound cuts out.
What am I doing wrong here?

Does the meter say that you have 7.5 volts at the supercap terminals when the track voltage >12 volts?

Thanks for getting back Todd.
I saw your post and went back to check. At 12v the unit is sputtering. At 13+ it is working. With the engine humming along at 14 volts I checked at the terminals that go into the caps and it was sketchy but each cap read 6.8v ?
This is weird. I also noticed that one of the little squares on the Sierra board is melted. That can’t be good.

Nope, not good.

I’ve found that the caps work so long as the voltage stays above about 13+. When it starts dropping below (down around 12), the cap probably goes into a continual discharge/recharge and the board gets very hot and can and will burn out parts.

I’ve got one dieing such as yours is and I can see the parts smoke when I power up. I believe these are either the regulator chip, or onboard capacitors.

One of the guys, maybe on MyLargeScale, put together a circuit that I designed that let the Sierra run down to less than ~5 volts and has not smoked anything. It uses a boost circuit too raise the voltage, then a buck circuit to reduce it to the proper level.

UGH… So this board is on its way to becoming junk?

I thought the supercaps were an alternative to the older style batteries but it seems not.
I was hoping that by using them I would be able to keep the sound going over spotty track and at lower speeds and while switching cars.

Where can I get a battery that will allow this?

Good question.

My circuit, but he used separate buck and boost modules.

When I looked at your board, I noticed that there appeard to be an additional part. Looking at it, I figured that they had added an in-rush suppressor/current limiter to take care of this potential problem. I guess not.