Newbie: what batteries for my locos?

[Beddhist]

Hi folks,

I have been reading through this forum and a lot of other stuff besides, but need a little more info. Here is the background:

Recently I bought a Bachmann Davenport and Railtruck. Track laying should begin soon. Yesterday I received my Airwire TX and Rx (Convertr) and 2 Zimo decoders. The plan is to remove all electrics and install batteries and the above in each loco.

It seems that people have used everything from AA batteries to LiPo packs in these small locos. What I don't know is what voltage do I need and what min. capacity. Some seem to run the Davenport on as little as 7.x V. According to manuals the Convrtr needs min. 8V and the Zimo 10V. I guess the Convrtr will cause a voltage drop, so is 12V the minimum then? What V do I need to get reasonable speed and pulling power? There will be steep grades on my line.

Thanks,
Peter.

 

[spoz]

Well, I'm no expert, and I know absolutely nothing about Airwire but I can give you some experience of modifying Bachmann products.

In my case, the most difficult modification was to a 2-6-0 Industrial Mogul, known as an Indy. There was so little room in that I ended up with space to fit 8 NiMH AAA batteries only (which in theory is 9.6V although I actually get a bit more than that from when fully charged). My line has a ruling grade of 1 in 30, and that is now about 80 feet long. I used Cliff Barker's r/c system for the Indy and get a reasonable speed out of the we beastie with fairly light loads, typically 16 axles behind the tender. A more detailed description is here: http://www.gscalecentral.net/battery-power/bachmann-indy-2-6-0-conversion-to-battery-rc/msg237169/#msg237169.

Starting voltage on B'mann products appear to average 3-4 volts to the motor in "on track" condition while Cliff's stuff seems to work with an input voltage as low as about 7v. I've also used Tony Walsham's stuff and have powered that as low as 8 volts although in the one installation I currently have it in permanently I'm using 14.2V.

The locos you are talking about are fairly small. I would think that NiMH AAs would be fine from a current point of view, and I have found that in general for Bachmann products any battery over 2000 maH gives at least two hours running between charge so I am therefore discharging at less than 0.5C which is important for battery life; as noted in the post on the Indy converion I am getting a < 0.5C discharge from 900maH AAAs. That would certainly be true for the railtruck I would think, and is likely to be for the Davenport although I've never actually played with one. If you are worried about that, though, try going for sub Cs which you can get with well over 3000 maH capacities.

I've never used the lithium chemistry batteries although plenty have used LiPos with great success. They do need special chargers but you get much more battery capacity for the same physical size; OTH they are considerably more expensive. It's really an individual thing; Tony for example swears by NiCds which hold their charge longer in storage than standard NiMHs but which can have "memory" problems. The NiMHs I use are a hybrid type with reduced storage discharge, they are usually sold under names beginining "Ene" something because the originals were brand name Eneloop, from Sony if I remember correctly. They are certainly better from that aspect than the conventional NiMHs, but then again they are more expensive although not as bad as LiPos. My early batteries were standard NiMH, and some of them have been installed for more than 5 years. The decision about which type is really a personal choice issue, but a bit of study of the internet (followed by the application of common sense because it is data from the internet!) will soon give you a fair understanding of the pros and cons of each type. Indeed, searching through the back threads of this forum will also provide quite an education in all things battery!

Hope this waffle helps,

Steve

 

[gregh]

Have a look at my explanation here - see reply number 5
http://www.gscalecentral.net/battery-power/alco-lgb-motor-loadingruntime-question/

 

[Beddhist]

Thanks for the pointers, Steve. You are right, this forum is a treasure trove of information (and opinions, of course) and I have trolled far through the battery section.

I read here a lot about the blue Chinese batteries that come with a simple charger. OTH, Mr Positive here in NZ on his site says that you should absolutely use a balanced charger. Then again, he does sell them...

I have just made a discovery in my shed: a relatively new AEG battery drill with two 12V Li-ion packs and what looks like an intelligent charger. I'm going to hook that up to the rail truck as an experiment and see how it goes. Of course, to do more than run forth and back 4m I will have to get some rail joiners and start laying track, even if it's only in the grass.

But first, I will attack that gear box...

Regards,
Peter.

 

[JRinTawa]

Hi Peter, my Bachmann Railtruck is equipped with an Aristocraft Revolution system and is powered but 12xAA on board in the back under a canopy I build for it. Granted your using a different system but power wise I expect they re similar. I'm using 2400mAh NiHM and they give me several hours run time when fully charged. There are a few local battery suppliers that might be a bit cheaper than say Jaycar. A key thing is getting a good quality smart charger and charge batteries at low rate. I've found if I charge at 0.6amps I get a better charge than at say 1.0amps. All said with the proviso that I am not electronic wiz, my charger for example was sort for me by a local guru, but there are now more around than when I got mine...chargers not gurus!

 

[Beddhist]

Thanks Greg, very clear and concise. Without track and power I won't be able to measure much, but George Shreyer has already published some measurements, so I can take it from there.

 

[Beddhist]

John, that is cool. 12x1.2V=14.4V, so that sounds plenty. Of course, there is a lot of room in the back there. In the Davenport it will be a lot more cramped, so I think it will end up being a Li of some sort. I already have a smart charger for NiMH, etc., but it only charges 4 at a time. The key here will be to get good quality batteries.

I wonder what's inside that AEG battery pack...?

Is there much slack in your gear box and did you fix it? Mine does at least a full turn of the wheels.

 

[JRinTawa]

The "smart" charger I use perhaps is better described as programable, you can set it to charge different packs f batteries with different amp hour rating and as I say adjust the charge rate. You can also do charge/discharge/charge cycles, very handy if you forget to turn off a receiver and over discharge a battery pack. I really recommend spending money on a good charger, if nothing else it could well prolong the life of the batteries you do use.

As for my one's gearbox, yes there is a bit of overrun downhill but so far, after several years running it's still going fine with no attention to the gearbox....touch wood :

 

[Beddhist]

I'm going to pull mine apart, seeing I am already working on it. Sounds like they all suffer this problem and I don't want my box to fall apart.

 

[maxi-model]

Looks like you are getting a lot of reasons to get some track down and start playing Peter Go to it.
With regards to battery power, it's a dark art to me. I was told just one thing - just don't forget to fit that safety fuse between all those expensive cicuit boards and your batteries before doing anything.

I have one battery loco, a GRS L&B Manning Wardle. It uses 2 x 6 AA's x 1.2v NiMH Strikalite made parrallel wired packs controlled by a Mac5. R/C control supplied by Spectum DX 6 TX and matching Spectrum RX. I have a stiff ruling grade and loco and its trains are heavy so it must pull a bit of juice. It runs for 2hrs plus before re-charges. Fun bit, I can double head and control a piston valved live steamer on the same TX at the same time.
Max

 

[Beddhist]

Yes, as soon as my rail joiners turn up I can start. Meanwhile, I have 'found' that my drill uses 12V Li-ion packs and I can tap into these. That should give me a good idea of how well that works and what I will need. Meanwhile, there is all this electronics work to do...

 

[PhilP]

I second Ross's comment..

Wiring should be:
Battery, fuse, everything else. - Even when testing things, make up a bodge-lead with a fuse-holder in it, and use it EVERY time.

 

[Beddhist]

Thanks. I have a flying fuse in my collection and will use that. Tomorrow. Now my eyes are falling shut. It was a trying day with 2 breakdowns. Not me, the mowers.

Good night.
Peter.