Running time on one battery charge, and reliability

[009 micro modeller]

I’m thinking of doing a shunting layout in 009 (with fairly large locos, so in theory not a problem to fit radio control to), for which battery powered radio control is a possible option (for various reasons conventional 2-rail DC isn’t possible in this case). I know radio control has been done successfully in 009 (by several people, including in some relatively small locos) but perhaps my question is more of an operational one; when I exhibit my existing small layouts, which run with only one loco at a time, I usually have two locos, swapping them every hour during the course of the exhibition (I sometimes have a third loco as a spare, but don’t usually need to actually use this - in many cases one could probably run all day on its own).

 

Based on likely running time on a battery charge and time needed to recharge, is the same sort of operation (with only two locos, or three at a pinch) likely to work with radio control? And on a related note, how reliable are the batteries themselves? My very limited experience with full-size narrow gauge battery traction has made me aware of some of the potential problems with batteries (overheating, charging issues etc.) and I understand there can be similar issues in model form, but how much of a problem is this likely to be, really?

[Corbs]

In my experience....

 

You can get more power out of a 3.7v battery by using a voltage step-up but at the expense of run-time. Some RTR 12v motors run fine on 3.7v but it varies. You're essentially running the motor at quarter speed so power and speed will be affected.

For a lot of my shunting locos I leave it at that because they don't need to move above a crawl, but for the mainline stuff I tend to use a 6v or 9v step-up.

Tender engines can fit bigger batteries in them.

 

I test my setups by charging the battery to full, then running the loco on full power on the rolling road (or upside down) until it stops. By timing this I get a good idea of my shortest run time, so I know roughly when I'll have to take it back to the shed to refuel (providing I remember to set the timer).

[009 micro modeller]

8 hours ago, Corbs said:

In my experience....

 

You can get more power out of a 3.7v battery by using a voltage step-up but at the expense of run-time. Some RTR 12v motors run fine on 3.7v but it varies. You're essentially running the motor at quarter speed so power and speed will be affected.

For a lot of my shunting locos I leave it at that because they don't need to move above a crawl, but for the mainline stuff I tend to use a 6v or 9v step-up.

Tender engines can fit bigger batteries in them.

 

I test my setups by charging the battery to full, then running the loco on full power on the rolling road (or upside down) until it stops. By timing this I get a good idea of my shortest run time, so I know roughly when I'll have to take it back to the shed to refuel (providing I remember to set the timer).

I would definitely be looking to increase the range/running time, at the expense of speed/power if necessary (it’s a shunting layout so it’s not like it has to be very fast). If I went down the radio control route I would probably use some sort of 3D printed tank loco on a Kato 4-wheel chassis - this seems to be a fairly common and well-proven option for radio control-fitted locos in 009 as you get a lot of space inside the body, though I know someone who fits radio control to much smaller locos as well. I don’t know how easy it would be to fit to older whitemetal kits as potentially the parts are thicker with less space inside the body.

 

How long do you find that it takes to charge a loco, relative to the time it can run for on that charge? I’m just thinking that my exhibition scenario as described above potentially relies on being able to get one hour of running time from only one hour of charging, which seems a bit unlikely.

[wasdavetheroad]

4 hours ago, 009 micro modeller said:

I would definitely be looking to increase the range/running time, at the expense of speed/power if necessary (it’s a shunting layout so it’s not like it has to be very fast). If I went down the radio control route I would probably use some sort of 3D printed tank loco on a Kato 4-wheel chassis - this seems to be a fairly common and well-proven option for radio control-fitted locos in 009 as you get a lot of space inside the body, though I know someone who fits radio control to much smaller locos as well. I don’t know how easy it would be to fit to older whitemetal kits as potentially the parts are thicker with less space inside the body.

 

How long do you find that it takes to charge a loco, relative to the time it can run for on that charge? I’m just thinking that my exhibition scenario as described above potentially relies on being able to get one hour of running time from only one hour of charging, which seems a bit unlikely.

Most my OO scale locos are modified to allow for a speedy battery change. The tenders lift off the chassis and the Diesels, mostly Lima have bodies that lift off. You need to find out the power draw of the loco by fitting a battery of say 100mAh and timing how long it will run. If your loco needs 200mA for an hour the battery should be larger capacity. The recharging is easy, have  pre charged spare batteries and just swop. It will only take a couple of minutes.

 

009 might have problems with finding room for the batteries

[009 micro modeller]

2 hours ago, wasdavetheroad said:

009 might have problems with finding room for the batteries

No, I’ve seen it done before (with surprisingly small locos as well, though obviously not quite down to Nigel Lawton Simplex size). The issue might be fitting the batteries in a way that allows them to be changed quickly, if that is what’s needed - most 009 locos I’ve seen have been 3D printed with the battery and receiver hidden in the tanks.

 

The layout this would be used on cannot be operated with normal 2-rail, for quite specific reasons. The alternative option is overhead wire, which has its own set of advantages and disadvantages.

[otherplanet]

I am intrigued by the reason for not being able to run on normal 2 rail power, all the options I can think of suggest it will be an interesting project. 

If you are unable to remove the batteries and therefore must recharge.

The best you should expect to achieve is about 1hr recharge time.

But there are 2 considerations.

Firstly, maximum charge rate of the battery. You should avoid charging at a rate of more than the capacity per hour.

E.g. if it's a 250mAh battery, do not exceed 250mA charge rate.

Note, may still take more than an hour. It's more complex than filling a bucket from a hose 

Secondly, available charge rate from your battery. This sounds obvious, but at the smaller capacities you are likely to be using for OO9, it is harder to find fully adjustable chargers. so if you can only find a charger that runs at 200mAh and 600mAh, your 250mAh battery will obviously take longer. 

 

Your discharge rate / time has more variability depending on your motor choice and battery. You can buy batteries with higher discharge rates ("C" rating) but if you are making use of this, you will have run out before your recharge hour is up, assuming you are running continuously. Your receiver will also brown out before you get to completely flat (Batteries don't like that anyway)

 

Apply a healthy dose of safety margin.

My 70mAh battery trucks draw about 65mA but only last about 40 mins heavy running.

 

 

My first exhibition with these, I had 2 road vehicles, and only occasionally had to swap the batteries instead of recharging. But I had the safety net that they were secondary operating feature to the normal  railway. Things were not going to grind to a standstill if I couldn't keep  them running 

 

I am planning a small radio controlled exhibition layout and consider 3 locos to be the absolute bare minimum. 1 running, 1 charging, 1 spare. (And would rather have 4). And I have other moving stock on the layout which will run alternately with these locos, to spread the running time over a longer period. 

 

 

 

If you would normally have 2-3 I would recommend 3-4. And try them out for prolonged running sessions before your first show.

Oh. And remember, the batteries will deteriorate with use, which will eat into your safety margin.

 

Good luck and please share your progress.

[009 micro modeller]

2 hours ago, otherplanet said:

I am intrigued by the reason for not being able to run on normal 2 rail power, all the options I can think of suggest it will be an interesting project. 

I’ve vaguely mentioned this in a couple of other threads on RMWeb but it will hopefully be a layout with working transporter wagons (the kind where standard gauge wagons are transported along the narrow gauge lines, like on the Leek & Manifold or various Continental NG lines). One way that I’ve seen this done before, and which I’d like to do myself, is to motorise the standard gauge wagons individually and run them on and off the transporters so that it looks like they are rolling under gravity or being hand-shunted (this avoids having to fit them with working couplings and means they can’t roll off the end of the transporters).

 

To do this reliably I’ve decided to supply power to the SG rails on top of the transporter wagon via the transporter’s NG wheels, which will pick up from a short bit of track at the end of a loading siding, electrically separated from the rest of the NG track, but if I’m using the narrow gauge track to supply the transporters in this way then I can’t also use it to power the narrow gauge loco that shunts the transporters, so the rest of the NG track needs to be done either as dead rail (for radio control) or with both rails at the same polarity (for live overhead with return through both rails). As a bonus, both options have the secondary advantage that the 3 way point I hope to use would no longer be difficult to wire (it would instead either be completely dead or all live, no frog switching etc.).

 

I think with DCC it might actually be possible to avoid the issue entirely and operate in a relatively conventional way, but that would mean chipping 8 standard gauge motorised wagons (plus possible spares) and 2 narrow gauge locos; it gets a bit expensive and it’s just not an option that I’m hugely interested in. Similarly you could do it the other way round, have radio control for the motorised wagons and the narrow gauge could be normal 2-rail, but the only real advantage to this (compared to having the NG locos radio controlled) is to avoid problems with the transporters picking up power, something I was worried about before but which now seems to be coming together quite well. It’s a very slow project though and I’m still quite far from the point where I need to make a decision on radio control vs overhead wire.

 

5 hours ago, otherplanet said:

If you are unable to remove the batteries and therefore must recharge.

The best you should expect to achieve is about 1hr recharge time.

But there are 2 considerations.

Firstly, maximum charge rate of the battery. You should avoid charging at a rate of more than the capacity per hour.

E.g. if it's a 250mAh battery, do not exceed 250mA charge rate.

Note, may still take more than an hour. It's more complex than filling a bucket from a hose 

Secondly, available charge rate from your battery. This sounds obvious, but at the smaller capacities you are likely to be using for OO9, it is harder to find fully adjustable chargers. so if you can only find a charger that runs at 200mAh and 600mAh, your 250mAh battery will obviously take longer. 

 

Your discharge rate / time has more variability depending on your motor choice and battery. You can buy batteries with higher discharge rates ("C" rating) but if you are making use of this, you will have run out before your recharge hour is up, assuming you are running continuously. Your receiver will also brown out before you get to completely flat (Batteries don't like that anyway)

 

Apply a healthy dose of safety margin.

My 70mAh battery trucks draw about 65mA but only last about 40 mins heavy running.

 

 

My first exhibition with these, I had 2 road vehicles, and only occasionally had to swap the batteries instead of recharging. But I had the safety net that they were secondary operating feature to the normal  railway. Things were not going to grind to a standstill if I couldn't keep  them running 

 

I am planning a small radio controlled exhibition layout and consider 3 locos to be the absolute bare minimum. 1 running, 1 charging, 1 spare. (And would rather have 4). And I have other moving stock on the layout which will run alternately with these locos, to spread the running time over a longer period. 

 

 

 

If you would normally have 2-3 I would recommend 3-4. And try them out for prolonged running sessions before your first show.

Oh. And remember, the batteries will deteriorate with use, which will eat into your safety margin.

 

Good luck and please share your progress.

This is all really helpful to know, thank you. The battery life and deterioration is something I was worried about. Is overheating (of the battery itself, as opposed to the motor) likely to be a concern? I know it can be for some battery powered vehicles but in model form?

 

It would be better to be able to swap the batteries, I’m just not sure how easy this would be in 009. A further thought that occurs to me regarding power requirements is that, while speeds would be low, the wagons being hauled might end up being quite heavy by normal 009 standards.