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As I prepare to make the switch to battery (no pun intended), I have been thinking about an idea that may be stupid, impossible, or previously thought of and acted upon.  Can you have a battery car with 2 or 3 batteries on board, and have it rigged so that when one battery runs low on power a second one takes over, and then a third, etc. I can get 3 18V batteries in my 50' box cars so it has me wondering.  If possible, this would increase your run time three fold and not require battery switching as frequently.  Granted it would add additional weight and perhaps this is the trade-off or the idea killer.  Anyway, I assume that there's some kind of electrical regulator that could be used that would switch a switch and activate the next battery in the sequence if the power dropped below a certain point.  Anyone doing this?  Is such a thing possible.  Is it worth the effort or is it easier to just change the batteries?/DesktopModules/NTForums/themes/mls/emoticons/unsure.gif

Ed
 

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Having two battery packs is a snip.
Simply put a DPDT switch in between both packs.
When one runs down switch to the other one.
Three or more packs can be done but then it starts to get complicated.
 
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Actually, what I'm looking for is something that does it automatically so I don't have to switch.  I want to wire three batteries and have the car know when to switch so it can run for hours (like track power) without me having to baby it all day.

Ed
 

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Ed - You could use diodes, but this will drop your operating voltage by 1-2 volts. The battery with the highest voltage will supply the current. But overall, all 3 batteries would still discharge together, so all would require charging at the same time. The diodes will just complicate your charging scheme.

Many folks just swap batteries out, as needed (lots of drill battery users out there). Easier than multiple batteries, and like you said, much less weight.

If you charge batteries in place, in the loco, then your loco is out of service until recharged. But surely you have more than one to run?

What is your goal? There seems to be a great misconception that running battery power means you can't run as long as you want to. How long do you want to run between charges? 4 hours is usually obtainable. And if you have more than one locomotive, you can run for 8 hours on battery power at an open house. I run battery power daily in the summer time. Anywhere from 2-4 hours per session. I never run out of power. I just recharge at the end of each session.
 

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My Evans power car uses two Aristo-Craft lithium-ion battery packs in parallel to improve the run times for big diesels or multiple lash-ups.
 

 
While building it Doug, Ralph and I joked about building a Super Power Car using four lithium-ion battery packs.
 
http://ovgrs.editme.com/files/EvansPC/SuperCar.jpg

 
The switch is four pole double throw, center-off toggle from Al Electronics. Throwing the toggle either way brings two of the battery packs on line in parallel. The batteries can be charged by using the center-off position on the switch.
 
Of course you have to order the appropriate decals from Stan Cedarleaf for the sides of the car. We were thinking about the Superman logo with crossed lightning bolts underneath and “Super Power” lettering arced over the logo shield.
 

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Ed, I believe you're asking for quite an electronic task.  I think you'd need some quite sophisticated curcuits to handle that and could be quite costly.  

You could put some VERY heavy duty batteries in a battery car.  Like 10 amp hour or larger.  They do make these batteries in NiCad, NiMH and Li-ion that would run the train for long runs.  Jim Agnew has put some monsters in a couple of his units and gets very good run times.

What locomotives are you thinking of running with this setup?

Just a note that I run my LGB ALCO with 2 12 volt Gel Cells at 24 volts through a 10 amp Train Engineer pulling 20 cars and get 5-7 hours of run time depending on outside temerature.  Warmer weather, longer runs.  When the batteries discharge, I change them out for fresh ones and continue running.

The disclaimer here is that I don't have a great deal of electronic knowledge, just the experience of what's been working for me for 7 years.  /DesktopModules/NTForums/themes/mls/emoticons/hehe.gif:D;)

A couple of monster packs...
14.4 Volt 10 amp hour pack...
www.batteryspace.com/index.asp

14.4 Volt 13 amp hour Pack
www.batteryspace.com/index.asp
 

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I am using   Chicago Electric Cordelss Drill batteries.    I get about  3 hours or more  depending on  how many cars I am pulling.    I made a clip for the battery  and changing them is a snap.

One of the reasons I was reluctant to change to  Battery power was  all theones a  saw were  permanant  installtion on a car and you had to  change the whole car.     Then I went to Marty's  and saw how he did it with  cordless drill batteries.    Then I saw Stan C with a  removable top to a box car.   I was hooked.
 

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I am using a 12v 12 amp gel cell on a USA drop-center car, fitted with bearings. The battery is sized to fit the depressed center floor section and I made a wooden cover to simulate a freight load. When I am storing it I keep in on a wooden stand I made to keep the weight off the trucks, just in case it would eventually bow the car's structure.  I haven't logged my run times per se, but I do keep a sticker on the battery where I update the recharging dates and it appears to be a monthly (at most) recharge.  This is being used with LocoLinc on GP30 and/or GP38-2 (known power hogs).  I fiddled with the combinations and switches using 6 volt batteries in series, switched as a parallel so as to give me 12 volts and approx 4 amps per, in a trailing box car and found it was forever running out of juice behind the arbovitae, in the bridge, or some other place hard to reach.  Admittedly, the 8# seems like a lot, but with the 6 amp receivers and 12 ~ 15 cars, it handles itself with ease. I expect the same good results once I complete my change-over to AirWire later this spring. 

***updated 7/4/08**** The change to QSI/AirWire is now complete. I have settled on a 12v 10000 mAh NiMH which is 2 amph less but is serving the purpose quite well. I am running the controls and this battery in a boxcar with a removeable top. However, the battery has an extra pigtail for connecting to the charger, so simply slide one of the boxcar doors open and hook up (after turning off the feed to the controls of course). My locomotive(s) and the battery car (read as control car now) are brought inside when not in use. The NiMH downside is that it doesn't seem to retain it's charge as long as the SLA type. Recharge time is less than two hours, even on the slow rate, so just a bit of planning and I am good to go.
 

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Ed Harvey
 As I prepare to make the switch to battery (no pun intended), I have been thinking about an idea that may be stupid, impossible, or previously thought of and acted upon.  Can you have a battery car with 2 or 3 batteries on board, and have it rigged so that when one battery runs low on power a second one takes over, and then a third, etc. I can get 3 18V batteries in my 50' box cars so it has me wondering.  If possible, this would increase your run time three fold and not require battery switching as frequently.  Granted it would add additional weight and perhaps this is the trade-off or the idea killer.  Anyway, I assume that there's some kind of electrical regulator that could be used that would switch a switch and activate the next battery in the sequence if the power dropped below a certain point.  Anyone doing this?  Is such a thing possible.  Is it worth the effort or is it easier to just change the batteries?


Ed


Like Stan Cedarleaf said. You can put very heavy duty batt's. in your car but don't forget the extra wt. you have to pull.. So the more wt the more power to pull it. theres no off set. So if your train is long then you need more power and more power takes more batt. power and so on. He is getting 5 to 7 hr's. out of one charge that's fantastic for what he is pulling. So guess we need more information on just how long you plan to run your Eng or Eng's' plus loads plus the time you need to run auto change over to Batt.power.????


Sounds like a interesting idea.      So I'll try to give you some ideas and you can go from there and I'm sure others have more ideas to.. 


One .... You can do like they do for indicating low batt's on Forklifts or Cameras for instance . It's a Voltage sensor circuit that can tell when a certain fixed voltage is past a set point. Like you want 18 volts DC and maybe a set point of 16 Volts DC to indicate a low batt. change.


Like a Camera has a batt. that is say 9 volts DC. and when it uses the flash a lot of times will sense the batt low point and will flash a low batt light. This kind of a circuit can be used in your case to relax a small relay cir. like to switch from "A" Batt. to "B" Batt. When switching to "B" Batt then the low voltage cir. is no longer in use. That cir. can be working off of the"A" Batt. and drops out.. .. This kind of a package/circuit can be made to keep dropping out to the next Batt. ("C' Batt.) low voltage cir. and so on.


Almost like a Train track Sig Cir'. Keep changing Track target Sig's.on down the lines..



Yep.... confusing ..yet it can be done. I did a lot of the different kind of circuits on my Ho layout.. and ya they do work..



Another idea is....... I have tried on my Ho layout using a Reeds installed between the rails to a counter to count off 10 times a train has past by an certain point. Then it operates a Track switch to bring in a train to the yard off of the main line.


So this idea can be used to in your Batt, car to count how many times you want your train to go around your layout and then switch the small relay (positive side)of your "A" Batt. to "B" Batt. . Yep it can get complicated and more stuff to install in you Batt. car..
Like Tony Walsham said. Just put in a simple DBL.Switch for one Batt. to another or install a Gang Switch for two or more batt's. Just move the switch to next batt. in line. This idea can also be used to switch from one charging cir.to another..


There are many ways to get deep into electronics..


Tony helped me out a few years ago on my Darn Aristo TM's relays. that I kept getting locking relays.. Found out how they worked. One relay was relaxed while the other one pulled in.( This is kind of how you can switch from one Batt to another by letting relay relax for 2 nd batt.) This was a way for DBL pole Switching was not able to have a polarity short at any given time. So Tony sent sample relays that I used to double up there poles to gain form 5amp relay to a 10 amp relays.. Well.. my problem was we were switching with heavy loads on the relays and burning the contacts.. This happens when you have new people in our Train group not knowing how to operate the TM's and by not stopping first before switching to other direction. So long story short was to be able to change Tonys relays out by making them as a plug in relay and stop having to send TM's back to Aristo for repairs.


Now you can see how involved these cir's. got with my problems..


But those same kind of relays can be use in your Batt. switching cir. real easy.


Look what John J. did with drill motors  batts.. He gets  a lot of power and time from them..


I know it sure is easy to just set back for hrs. with company get-togethers and let her run idea and do nothing to it.until you smell smoke. laf..


I don't think I would run a train unattended for any length of time. So many things can happen. De-rails, something gets on the tracks, or gets knocked off.. Maybe get a short somewhere and not know it.. .


I've had a few things happen here, being not attended and got pic's to show how wheels melt down before the breaker kicked in and didn't know about it. or ya see by my LOGO, my Rio feather saying... how an Eng. gets dump in the water not paying attn. to it.


Boy didn't mean to make this so long but when it comes to electronics Gismo and an old Radio Ham ( K6WGZ) from the 50ths, I can't help getting my two six bits worth in.. /DesktopModules/NTForums/themes/mls/emoticons/crazy.gifNoel
 

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One thing to keep in mind is that generally the higher the discharge rate, the lower the time that rate is available.

So, for a 2AH (amp - hour) battery, you might get 2 hours at 1 amp, but only 3/4 hours at 2 amps.

If our engine draws 2 amps

With 2 batteries, you get a 2 hour run time
With 2 batteries, but only one at a time, you get 1-1/2 hours run time. Additionally, there is also the loss in powering the electronic changeover mechanism.
 

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all-battery.com has a special on 3800mAh NiMH packs. Look under "RC Cars, 9.6v" I put 2 of these together to make 19.2v. The charger is $26.

(Don't forget the -. It's a different place from allbattery.com.)
 

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Ed,
Just out of curiosity,  how long are your average operating sessions and what does your average train consist of?  This may have more of a bearing on what you need for batteries.
 

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In my battery/control cars I can run 1 to 4 batteries in parallel (4 x Aristo Li-Ion 21 volt 2 amp) to supply the type of engine setup I have. They just plug into the terminal strip; I have up to 4 connectors, one for each battery. The battery/control cars are all 40 foot box cars, using roller bearing wheels and KD #1 body mount couplers.
These will run an ABBA setup with 8 motors with no issue; however that will draw the amps down faster.
Remember, when you put batteries in parallel, they keep the same voltage, but add the amps together, so I my case using the Aristo li-ion batteries in parallel ,the voltage stays at 21 but the amps add for each battery at 2 amps each, so with 4 batteries I have 21 volts at 8 amps. Usually, the more amps, the longer the run time depending on amp draw.


This setup will also allow me, in the same space, run two sets of AA battery packs at 18 bolts, which is 32  - AA batteries. However the amp output is only about 4 with the AA setup.
see my battery car page @
http://kcndrr.com/battery_car_kcndrw.htm


KC


 
 
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