MTH battery terminals???

It's an Molex product, but I don't know the Digikey name.

Here it is: http://www.digikey.com/product...25/WM18886-ND/403301

Thanks, John.  The battery site didn't include that Molex.  I found them, 2/3AA NiMH, 800 mah on another site, from China, for $3 each in lots of 8, with wire leads.  I'll solder the old connectors to these wires. 

My 2.4-volt PS2 batteries are 6-10 years old, so it's probably time to change.  I have about 18 of these locos, so alternatives to a battery is not economically feasible.

I note that the 2/3 AA are 700-800 mah, depending on source, which is the same rating the the full-size NiCad AA's MTH used to use. 

You can install a Super-Cap with that connector and it'll be the last battery you need. 

2.5F 5V SuperCAP, $4.60/ea for 10 or more, $4.29/ea for 25 or more.  Add that cheap connector and you're done.  For less than $5/ea you can solve the issue permanently.

I used this 1.5F cap and it worked fine, so I'm sure the 2.5F one would be more than sufficient.

If the cap is dead and the track is powered up, can the equivalent of a short that lasts a few microseconds damage the PS2 charging circuit.'  What digikey number is the cheap connector you added?

The shell is: S9498-ND, and the contacts you'll need are S9475CT-ND.  These are the connectors that directly plug into the 3V board battery connection.  You no longer need the charging jack, as it's surplus.  Of course, you can just use the previously posted Molex connectors and just plug them in in place of the battery.  No reason to rip anything out.

Since you don't have the crimp tool, you'll have to hand crimp them, and I solder them as well after crimping.  A bit labor intensive, but I don't have $400 for the tool.

Those are tiny!  If you surplus the charging port, it might be easier to remove the port-to-board lead and connect that to the supercap.

I did chop some of them off old batteries.  Also, the same Molex connector is used elsewhere in both MTH and other brands at times.

To answer the other question, I know of no issues with the supercap killing the charging circuit, the BCR that is widely used is just a supercap.

I notice J&W says it has other components, e.g., a zener diode, in its packs.  If your circuit is acceptable, and I don't say it is deficient, why does J&W add components?

Beats me.  However, I think J&W has two separate supercaps in their 2.4V model, so they are using the Zener diodes to balance them.  The two capacitors in the package are obviously balanced as they have created a single capacitor in packaging.

I have no idea what they'd use the Zener for with this package.

Gunner,

"Back in the day" when you built these things from scratch, do I remember you saying that you connected the leads of the SuperCaps that you created externally with the positive side (+) of the SuperCap soldered to the black wire and the negative (-) side to the red wire?

Does the same external wiring configuration hold true for these "pre-built" SuperCaps from DigiKey; in other words the positive side of the cap to the black wire and negative side to the red?

Thanks,

Dave

9V has zeners because it is 4 caps.  2.4V not required and I don't think BCRs have the either. G

The only reason you connected the 9V model in what looks like reverse polarity was because you were using a battery clip as the battery connection, that reverses the polarity.  When the smoke settles, you want the positive lead connected to the positive connection to the boards.

GRJ, if you used 1.5 F and it worked fine, why do you recommend 2.5?  COuld the added capacity overtax the charging system?

He did not recommend it just said it would be more than sufficient.  The 2.5F holds more charge.  So if you have an engine with a more demanding shut down sequence you have the capacity to play it through. 

For a few nickels more I use the 2.5F. 

The charging system controls how fast it charges, not the capacitor.  It does take longer to charge the first time, but after that it charges rather quickly. Even the one on my bench that may sit for a few days.   G

Thanks, GGG.  I was concerned that the capacitor being dead, could more current flow during the initial charge than the charging circuit can handle? 

I remember car parts suppliers cautioning that trying to charge a dead car battery could damage an alternator.

What does happen if one hits startup before a supercap has had a chance to charge up?

I see George answered it, that's exactly why.  I saw the larger ones, and they were almost the same price.  The 1.5F ones have worked in about half a dozen engines with no issues.  I made up six of them, and I don't have any left.  When I went to reorder, I found the 2.5F capacitors, so I now use them.

OK, thanks, George & John.  I think I'll get a few for a few locos that I don't use too often & and see what happens.

For the benefit of forumites who want to learn a bit more about capacitors and supercapacitors, here's a link:

http://batteryuniversity.com/l...the_supercapacitor/1

If your in conventional and you hit direction before charged, the board shuts down and starts up again.  No issue.  In DCS it would not matter unless you turned off track power immediately.  No harm to PS-2.

Now, if you did it with PS-1 with BCR before the BCR charged it would look like a weak battery.  Some mid point voltage.  So it could cause a software scramble.   G

So, in DCS/PS2:

1. If the layout has been powered up with watchdog come and gonr, and I throw a toggle to power up the block on which loco is sitting, if power is cut before charged, nothing happens.

2. If tiny fingers have touched Grandpa's trains and left a derailment, or if Grandpa left layout with a derailment, and now I power up so loco gets the watchdog signal, power will come on briefly until breaker opens, and this could scramble settings in the loco (not the software)??????  Not permanent harm but a PITA to be unravelled.

I have a PS3 that on its own became locked in conventional reverse, and would take off full tilt upon any power up.  Took a conventrional reset to cure.  Wonder if #2 above was the cause????

I am lost and you are over thinking this; and nothing is grand kid proof!  Suffice to say they work and don't hurt anything a battery can't hurt.   G

You are not the first person to accuse me of that, and I won'tdeny it..

The shell is: S9498-ND, and the contacts you'll need are S9475CT-ND. 

They came in today, along with 5 of the supercaps.  I can only make one comment to you, GRJ:  You must have very good eyesight!!! They are tiny.

I recommended long ago to not mess with crimping your own wires but hey some guy are ok with wasting an hour of their time for $.25.  If it relaxes you it is worth it, if your blood pressure rises, what are you thinking

Both Lionel and MTH sell wire pre-crimped.  I believe even Lionel sells the same connector in some harnesses.  I have seen them in Lionel and K-line products.

Worst case is use your existing harness or order a battery harness from MTH.  $4.  G

GGG, well I'm only out a couple of bucks.  I have a large collection of wires and plugs left over from upgrades, and may just re-use the existing charging port links. 

I have now completed my first PS2 battery-to-supercap conversion, an early-1990's GG-1, going from an old 2.4-volt NiCad to one of the 2.5F 5-volt supercapacitors that GRJ recommended above.  Took about 5 minutes, apart from getting the shell off and back on.  I simply plugged the leads from the supercap into the socket on the charging port harness into which the batteries had been plugged.  I did put insulating sleeves on the supercap leads and some Super 88 tape to assure they stayed in place.  I picked the GG-1 because I don't run it often.

At about the same price as a replacement battery, or less, this is a viable alternative for consideration.  I did notice that until it fully charged up, about a minute, the sound volume was very low, which I understand is normal.

Does anyone out there in forumland know when MTH switched from NiCad to NiMH in the upgrade kits?  I'm trying to guess how old this battery is, which has given no problems whatsoever.

If you could get pre-crimped wires for 25 cents, that would be great.  MSRP for BC-1000008  is $3.00, and even at the price techs buy them for, I'll spend a minute or two to solder the wire onto a contact.  It really isn't that difficult.

What's the BC-1000008?

It's a crimped #22 wire with a contact from MTH.

John, I said save $.25 cents.  I told you years ago when you were making your own Lionel wire.  Lionel sells colored wire pre-crimped for $.40 MSRP.  In the various sizes we need, 2 and 2.5mm.

So you can buy the wire from Lionel and the connector from Digi-key.  By the time you buy wire & connectors and spend 2 minutes soldering them, (normally crimped).

I install a precrimped correctly colored wire from Lionel.  G

George, if it took me an hour to solder one wire, I'd agree with you.   However, it really doesn't.

I don't remember the last time I had to solder a Lionel contact, I have a junkbox full of old Lionel wiring, I just pick an appropriate wire with contact from the pile and use it.  What I'd really like to find is some MTH PS3 contacts wired.

I looked up supercaps on the E....y and noticed several ads for battery packs with Molex connectors.

Could these be used for the MTH type Molex connectors on PS2 engines since seem to be  hard to find?

Molex makes thousands of connector styles, so without specific information nobody can say if they'd work.

I gather this is a DIY substitute for the BCR-2 device?

I gather this is a DIY substitute for the BCR-2 device?

If you mean the supercap GRJ mentioned, yes.

GRJ:  I have just tried using those shells & connectors mentioned above.  John, my hat's off to you.  You must be a master at the art.

GGG & GRJ:  Are these wires and plugs, for plugging into the battery terminals on a PS2 board, available made up?

If you buy the 3V harness or a 5V harness for the hirose yes.  Lionel may have a  harness sold separate you just need to search their site.

The wires from lionel yes, or spare MTH wires.  The plastic connector yes.  Just push the crimped wire into the connector housing and done.  Just made one an hr ago.  G