TMCC Battery Replacment with Charger

Do you really need 1.25 F? Reason I ask, there are some smaller supercaps, like the Eaton PB-5R0V105-R, that are rectangular and a pair of them would probably fit in a 9 V battery outline with room to spare (for the electronics.) But, a pair of them would give only .5 F.

Thats way over my head. I just wait for you to manufacture an item then I buy it.

Rof Miller

hello guys and gals.......

Maybe make a BCR-3 for it ?

Tiffany

PLCProf posted:

Do you really need 1.25 F? Reason I ask, there are some smaller supercaps, like the Eaton PB-5R0V105-R, that are rectangular and a pair of them would probably fit in a 9 V battery outline with room to spare (for the electronics.) But, a pair of them would give only .5 F.

That's a good question, I don't know at this point how much would be required.  The ones I specified are not all that much larger than those Eaton ones.  If I were going for size, maybe maybe I should just consider these on eBay, they're 5.5V 1.0F and would much more easily fit into the 9V form-factor.  They're $1.50 each and shipping for as many as you buy would be $2 total.  I actually have a bunch of this type of 1F capacitor in my parts box.

eBay: 162139053842

 5.5V 1F KAMCAP H Type Coin Electric Double Layer Farad Super Capacitor

Tiffany posted:

hello guys and gals.......

Maybe make a BCR-3 for it ?

Tiffany

What's a BCR-3?

gunrunnerjohn posted:

Tiffany posted:

hello guys and gals.......

Maybe make a BCR-3 for it ?

Tiffany

What's a BCR-3?

Maybe it's a BCR-2 which is 3 volts...and thus the 3.

Chuck, why would I make a 3V replacement, I'm targeting the TMCC/Legacy 9V battery replacement.  The only 3V requirement for a BCR clone is PS/2, which already has charging capability.

gunrunnerjohn posted:

Chuck, why would I make a 3V replacement, I'm targeting the TMCC/Legacy 9V battery replacement.  The only 3V requirement for a BCR clone is PS/2, which already has charging capability.

I don't know why, just got interested in researching what a BCR-3 might be

I presume this is for those who run in conventional mode, yes?

The reason I ask is I've yet to install a battery in a TMCC/Legacy loco as I have never seen the need when operating in command mode.  Have I overlooked some reason for installing a battery in a command operated TMCC/Legacy loco? 

I like this idea though, a 9 volt "battery" that won't go flat or leak. I have one engine that drops out the sound if there is no battery in it on some layouts...

We see dropouts of some locomotives in command mode, both TMCC and Legacy in certain conditions, so I see a need for a battery in command or conventional mode.  If I use a battery, I want one that I never have to change and doesn't leak.

Obviously, if you perceive you have no issue, this topic probably isn't of interest to you.

I'm going to try the two 1F caps in series and see how long they'll hold up the RailSounds board, they may be all that's required.

Do you know the resistance of that cap?  Most coin-style supercaps have resistances measured in the 10's of ohms.  For example, eBay (182260239593) with similar pricing shows 15 ohms:

So two stacked caps would be 30 ohms.  So let's say you need 1 Watt of power to drive the audio during track power interruptions.  The 9V battery would need to deliver over 100 mA so that would be a drop of 3V thru the caps' internal resistance and you'd only have 6V available to the electronics.  Additionally, a 1/2 Farad cap discharging 100 mA drops 0.2V per sec; I don't know how long the TMCC sounds run but this would be another consideration.

The Eaton supercap mentioned earlier has an internal resistance of less than 1 ohm due to different technology.  This is the type used in the BCR devices and in the MTH PS3 engines.  The coin-style caps are typically used in low discharge current applications and of course are much less expensive.   

I did note that Stan,I figured I'd try them and see what happens.  I have a few so I can give them a test and see how they do on a RailSounds board.  If they don't work, well, I haven't invested anything. 

Well... you're right, I was hoping that wouldn't be too much internal resistance.  I guess I'll keep looking...

I'd like to find a lower cost alternative to the $5 capacitors, that bumps the price up quite a bit.  I'd like to be able to get all the parts for something like this for $10 or less, including the circuit board.  I'd also like it to be as small as possible.

I'd buy them for all my TMCC/Legacy locomotives that take batteries, as it'd save me from having to make my own.  Now, the next question is, you have looked into adding this to a locomotive that doesn't have a battery, like the VLBB and the B6sb?

sinclair posted:

Now, the next question is, you have looked into adding this to a locomotive that doesn't have a battery, like the VLBB and the B6sb?

No way to do that for those that don't have a battery.  If the circuit on the sound board isn't there, that's all she wrote.

I have a couple thoughts, but not sure about any of them.  

The first is to perhaps use 3 of the inexpensive Caps, to allow maybe a 12-15v charge level.  This would require input and output regulators, so adds a step of complexity, but it may be less expensive that way.  

Second idea is to use just 1 good quality super cap, and a boost module to raise it's 5v to 9v.  Here, I'm unsure if a booster would provide enough current. 

The last is more of a question, while a 9v battery is used for the sound system, is the railsounds board actually running at 5v?  if so, would it be possible to add the supercap to the board in a way that bypasses the step down from 9v to 5v?  It would make for a more complex install, obviously, but may make for much fewer parts as you pretty much only need to limit in-rush current to the cap.  

JGL

John, I looked at both of those options, but I think just using two of the proven 5V supercaps is the way to go.  Trying to add multiple regulators seems like way more complicated than this project should be, and boosting it requires either using one of the cheap eBay switcher modules, or laying out a boost regulator.  Neither of these are attractive options, at least to me.

No way I want to screw around tapping into the RailSounds board, that is messy beyond belief!  Besides, this will be a project that the great unwashed masses might want to use, and there are very few people that would be able to hack into the boards to attach this, and even fewer that would want to.

gunrunnerjohn posted:

sinclair posted:

Now, the next question is, you have looked into adding this to a locomotive that doesn't have a battery, like the VLBB and the B6sb?

No way to do that for those that don't have a battery.  If the circuit on the sound board isn't there, that's all she wrote.

Do we know the circuit isn't on the board, or is it there, but unpopulated, or is it there and populated but just doesn't have a battery connector?  I was under the impression the boards were mostly modular, they just changed the sound chips.  If they spun custom boards for these locomotives, then I understand that's all there is to it.

Well, you're certainly welcome to research it.   I don't see how 99% of the populace here would be interested in hacking into their $100+ VL-BB sound board in the hopes of adding a battery!