Just got this Christmas Train Set - battery powered. Runs on four C cell batteries. When I opened the battery compartment the batteries that were in them were ALL OF THEM Leaked. They have been in there for many years. Possibly a decade or longer. Consequently the corrosion is extensive. Any suggestions on how to clean the terminals? Can the battery terminals be cleaned sufficiently to make contact with new batteries? Or should I scrap the whole thing. Maybe modify it to hold two 18650's? Would have to include BMS to prevent over discharging and to control charging at proper rates? Ideally would like to put four 18650 in the coal tender but I don't think there would be enough space. Wonder if there's a flat pack Li-Ion battery that can be fitted into the tender. Looks like the best I can do would be two 18650's.

 

It's hard to tell just how bad it is, but it looks like there's a fair chance to save it the existing contacts. Use cotton-tipped swabs and white vinegar to gently scrub the contacts. A tooth pick can help chip off the residue and corroded flakes. When finished, some fine sandpaper can expose good metal so that you can get a good electrical contact. Unless you're going to be running this thing a lot, I wouldn't mess with trying to fit in a rechargeable battery pack. Plus, doing so would serious reduce any vintage toy value it might have.

 

It's hard to tell just how bad it is, but it looks like there's a fair chance to save it the existing contacts. Use cotton-tipped swabs and white vinegar to gently scrub the contacts. A tooth pick can help chip off the residue and corroded flakes. When finished, some fine sandpaper can expose good metal so that you can get a good electrical contact. Unless you're going to be running this thing a lot, I wouldn't mess with trying to fit in a rechargeable battery pack. Plus, doing so would serious reduce any vintage toy value it might have.

Thank you. As for it being "Vintage" I'm not so sure it has much value in that arena. It's all plastic. Now, if you want Vintage? I wish I had the train I once had when I was a child. All metal construction with a siren consisting of a fluted fan and cage covered by a louver that slowly opened and closed to mimic the train whistle - wwwWWWWWwwwwwWWWWWwwwwwWW - WWWWWwwwww. They don't make them like that anymore. Nowadays they have electronic sounds that are cheesy at best.

Back to this train: Thanks for the vinegar tip. I have some industrial vinegar out in the garage. I wouldn't use it in the house, the fumes are killer strong. I'll give it a shot tomorrow sometime.
I actually got two train sets, both battery powered. The other one hasn't had batteries in it yet - I don't think. It's clean and slightly bigger than the one I'd like to refurbish. Tracks are not the same size so I can't mix / match them together. "(

 

It's hard to tell just how bad it is.

Really bad. I've never seen such bad corrosion before.


This is why I wonder if it's better off getting something else in there with near the same Ah rating. I've seen This and they're small enough to put two of them in the battery compartment wired in parallel. BUT - I don't know what kind of BMS would be required.
"Li-Mn02". Totally unfamiliar with that battery.

Never mind. Says "DO NOT RECHARGE".

 

What if I disassemble them and soak them in CLR? (Calcium Lime Rust) remover.

 

Still salvageable.
Firstly, clean with water and a toothbrush. Scrape away any solid deposits. Use a metal file and clean all surfaces that will contact the battery. Rinse with IPA (isopropyl alcohol). Blow dry.

Don’t substitute the batteries with 18650. Use the required C cells.

 

A bronze brush like this one will make cleaning those contacts an order of magnitude easier

​

 

A bronze brush

I think I have one. Thanks.

 

I suggest scrubbing with a mix of baking soda and water, followed by a good rinsing. THAT should remove most or all of the corrosion and battery juice. If the first time does not work, do it again.

 

The blue residue is indicative of an alkaline corrosive, so a mild acid, such as white vinegar, is better. Baking soda is alkaline itself, which is better for acid-based chemistries.

 

I suggest scrubbing with a mix of baking soda and water, followed by a good rinsing. THAT should remove most or all of the corrosion and battery juice. If the first time does not work, do it again.

Nope the best thing to use is vinegar the weak acid neutralizes the stronger acid far better than Baking soda with a nice wire brush with fine bristles and that will clean the corrosion off and then fine sandpaper to get to some bare metal. I have cleaned many of these contacts in old toys and that has always worked a treat for me.

 

After the terminal is cleaned, and copper is visible, Tinning it with a bit of solder will make it less likely to corrode again. BUTCAUTION is needed when melting solder on the terminal because the plastic enclosure does tend to melt. So you will need flux-core solder and you do need to work rapidly!