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When I first fitted my K28 with radio control, the limited space in the cab lead me to use a clip with four NiMH AAA cells. This seemed to work OK initially; but, when I gave it its first real run at ECLSTS, the R/C quit after about 25 minutes. I'm not sure whether the batteries got too hot from being right next to the boiler or whether the small cells just didn't have the capacity. I decided that I would move the batteries to the tender and use larger capacity cells. Below, is an account of how I did it.

First, I made up a four-cell pack of sub-C cells which I had bought from Digi-Key. They have a 3000 mah capacity and they have soldering tabs for connecting the cells. I realize that 3000 mah is a huge capacity for the task at hand; but I should be able to steam all day without ever recharging. Getting into the space behind the water reservoir in the tender appears to be a major chore, so I elected to put my battery pack in the doghouse. The doghouse is held in place be four very small hex head bolts and is easy to remove.



The tender deck extends over the water reservoir, so it was a simple matter to drill a hole in the doghouse floor for the wires to pass through. I taped the four batteries together and taped a square of 1/16” thick styrene to the bottom so that the soldering tabs could not chafe through and short against the brass tender. Before reinstalling the doghouse, I put tape over the tops of the batteries to further forestall any short circuits.



I drilled a hole high in the forward bulkhead and put in a coaxial battery connector from Radio Shack. I also put in a fuse since an unhappy experience with one of my sparkie models clearly pointed out the need. I also further protected the wires from chafing by putting on heat shrink tubing.



All-in-all, it was an easy installation and provides me with batteries of ample capacity located well away from the boiler.

Llyn
 

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Nice install, Lyn!:)
When I RC'd my 3-cylinder Shay, space was DEFINETLY limited /DesktopModules/NTForums/themes/mls/emoticons/ermm.gif for battery install.
- So I made up a WATERPROOFED /DesktopModules/NTForums/themes/mls/emoticons/blink.gif pack of 600 maH Sanyo cells, & installed them RIGHT IN the tender water tank!/DesktopModules/NTForums/themes/mls/emoticons/hehe.gif


-They've been sitting immersed in the water for over 3 years now, without any problems!/DesktopModules/NTForums/themes/mls/emoticons/laugh.gif
/DesktopModules/NTForums/themes/mls/emoticons/wow.gif Tom
 

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Hi Tom,

Your installation makes perfect sense. I had contemplated doing something like that; but, discoverd that there was room in the doghouse. We all seem to learn ingenuity playing with our live steamers.

Llyn
 

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Hi Llyn,
As a precaution I noticed you do not have the ends of the nicads covered, is that hut hiding them metal, if it is your asking for a disaster/DesktopModules/NTForums/themes/mls/emoticons/w00t.gif I have seen packs short /DesktopModules/NTForums/themes/mls/emoticons/sick.gif"
Tony
 

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Hi Tony,

The doghouse most certainly is all metal. As I said in my original post, I covered the tops of the batteries with tape to insulate them before I put the doghouse back in place. A battery pack of that capacity really can do unhappy things if it shorts out!

Llyn
 

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Tony,Llyn
Small, square shaped, wrapped and already protected 4.8v NiMH rechargeable battery packs are available from Hobbico or RC Hobbies and others.
http://www.hobbico.com/radioaccys/hcam6300.html
or
http://www.rchobbies.org
Several square versions including the HCAM 6314 (1650 mAh) and the HCAM 6330 (2000 mAh) or the smaller HCAM 6322 (2000 mAh) packs fit in a dog house. (Like the battery on the middle right in the picture.)



I use the flat version (lower right) for my K-27, which powers my receiver for several sessions between charging. I use a big 9.6v, 2500 mAh square version (similar to the one in the upper right) for my DX6 transmitter. I use a purple Super Brain to charge the batteries because the SB is plug and play, figuring out the correct charging rate for each battery.
http://h1071118.hobbyshopnow.com/products/description.asp?prod=MRCRB960

If anyone wants information on specific batteries, chargers, plug adapters and where to get the stuff, let me know and I will be glad to send it to you.
 

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Carl,

You are the battery expert. Thanks for your help at/after ECLSTS.

As far as submerging batteries, I always wondered if you can dip a battery pack in the black plasti-dip type stuff a few times (except the connector) and water proof it that way..... it would blend right it.
 

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I don't recommend putting any battery under water even if sealed. There are too many other solutions. One is the shallow tray I have in the top of my tender allowing for a safe water bath. It's a solution Jon Kling came up with. I like Llyn's dog house idea and will do that on my K-28 when I get it.
 

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Carl,

Good point. I used the dog house on my #453 K-27 and it works fine. If you do not have a dog house, then a custom coal load is an option.
 

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Carl, just a comment on how I "waterproofed" the batteries in my Shay; I first made up the pack (4 X 600 maH new Sanyo cells I salvaged from new UNUSED surplus computer battery packs I picked up at a local ham radio / computer flea market). These battery packs already had the cells tab-welded together in a 10-pack. After cutting a group of 4 cells loose, I soldered a standard Futaba RC battery lead to the positive & negative of the 2 end cells. After initial charging & testing, I coated the ends of the cells liberally with clear GE "Silicone II" rubber. IMMEDIATELY after coating the cells (while the RTV was still "wet"), I slipped the completed pack into a regular (not a "zip-lock" style) plastic sandwich bag. This bag was then inserted into a SECOND identical sandwich bag to give 2 full layers of plastic between the outside of the cells & the water. The open ends of the two bags were then tightly twisted around the battery lead & cable-tied ( the red cable ties are visible in the photo). The Futaba plug was slipped through the same hole in the front of the tender water space that the brass output line from the feed-water hand pump exits. With BOTH plastic bags now tightly conforming to the battery pack, the OUTER plastic sandwich bag was then "glued" inside the tender water compartment with a liberal amount of GE Silicone II rubber, which was allowed to set for a full 24 hours. Battery charging is accomplished through a standard RC airplane ON/OFF slide switch (which has an additional battery charge lead coming out); this charging lead just sits loose on the cab floor. When I said the battery pack sat IN the water, the cells THEMSELVES are NOT in direct contact with the water, but isolated by the 2 plastic bags (I used 2 as a "redundancy" measure);) JUST in case one developed a leak!/DesktopModules/NTForums/themes/mls/emoticons/wow.gif Tom
 

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Tom,
Good job on the waterproofing. I sure do think it's adaquate and would put my camera in there. Are you having any problem with heat disipation as these batteries warm up as they discharge? Now that I think of it, they might provide a 1 or 2 degree temp to help the water bath if your fuel tank is in there like mine is.
 

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I haven't had any real heat issues with the batteries so far, Carl. They're far enough removed from the boiler that it doesn't normally get particularly hot back there. I "hedged" a bit with the "normally":confused: because I DO recall a couple of instances where the boiler check valve wasn't seating properly & letting steam leak BACK INTO the tender water/DesktopModules/NTForums/themes/mls/emoticons/unsure.gif - I'd see an occasional bubble rising from the water pump intake /DesktopModules/NTForums/themes/mls/emoticons/blink.gif , & wisps of steam rising from the water surface; sticking a finger in the tank proved that the water was HOT!/DesktopModules/NTForums/themes/mls/emoticons/crazy.gif The worst case of this occurred when a tiny blade of grass somehow made it's way into the check valve seat (how that happened is a bit mysterious :confused: , since my entire railroad is elevated); removing the check valve from the boiler, & getting that tiny sliver of grass out of the valve seat cured that problem.:) When the check valve's working properly, the water temperature is cool to no more than lukewarm, largely dependent on the outdoor temperature. I typically hand-pump additional water in during a run each "lap" around the mainline, adding water at the top of my grade; since the added cold water pulls down the boiler pressure, adding it at the "summit" (marked with a dummy water crane) enables me to restart the Shay going DOWNGRADE with as little as 10 PSI boiler pressure./DesktopModules/NTForums/themes/mls/emoticons/blush.gif The (happily rare!/DesktopModules/NTForums/themes/mls/emoticons/wow.gif ) exposure to hot water appears to have had no adverse affect on the batteries. The electrical load on them isn't particularly great, as they are powering only the RC (75 Mhz. FM-mode) receiver, 1 mini-servo (which moves the reverse valve ONLY, doubling as both reverser & "throttle"), & 2 hi-intensity LED's for headlights. I slow-charge them after a day of running using a typical Futaba "wall-wart" charger.
:) Tom
 
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