Probably a "How long is a piece of string" question!

[rab]

My grandson was given a Hornby starter set a couple of years ago,but has not been able to use it much due to lack of space indoors. His Dad is now thinking about setting it up in the garage. The only problem is there is no electricity in the garage and as it doesn't adjoin the house or garden it would be difficult to run power to it other than with a long extension lead.

I just wondered if it would be possible to run from a car battery and this is where the piece of string comes in, how much running time could he expect to get per charge.

I'm sure it's not as simple as this but if it were say a 25 amp hour battery and he's drawing say one amp he should expect to get at least 20 hrs between charges.

I know current drawn is variable but tbe one amp is based on tbe fact its a simple roundly track plan with a couple of sidings, short trains and no gradients.

Are there alternatives to a car battery?

His Dad has suggested a solar panel on the roof but he'd still need some sort of storage means (ie battery) otherwise he could only run when the solar panel is giving an output.

If using a battery is possible would some form of control\protection (ie fuse or similar) be needed between the battery and the locos?

[PatB]

Your Amp hour reckoning seems reasonable. If I were doing this, I'd have a battery (doesn't have to be a new one as running a model railway is a fairly undemanding application), kept charged with one of those el-cheapo solar batery maintainers. Dunno what they cost in the UK but out here they're $20-30 a pop and seem to last about 10 years before the sun eats the plastic casing. Even in the UK, I would expect such a panel to be able to keep up with the fairly low, intermittent demands on the battery.

 

For safety I'd have the battery in a plastic (or wooden) box (caravan or boat supplies possibly) to minimise the possibility of shorts across the terminals, and have an inline fuse of maybe 3A between battery and controller. I'd expect the controller to have its own thermal cutout to protect itself and the locos.

[BG John]

A leisure battery would be better than a car battery, as it's more like the job they're designed for. I was building my Small, Broad and Totally Pointless layout to run off the one in my van when I was travelling, but didn't get that far with it. One of my concerns was with running a controller off 12v dc, as they mostly have 16v ac inputs. I think I asked about this here a long time ago, and it seemed that it would be OK, but I can't remember what was said now.

 

Don't forget that these batteries put out a lot of power if things are poked into them by small hands, so safety is vital.

[DCB]

Car batteries are designed for brief periods of high power 100 plus amps and the simple linear equation that 40 amp hour s provides 1 amp for 40 hours is not necessarily true.

I would head for the local scrap yard and get a second hand car battery with Ford type terminals for bolt on lugs and get a car type fuse holder and a handfull of fuses while you are at it, I would use a 3 amp fuse and put it right by the positive terminal. Car batteries need respect, they deliver a lot more amps than mains and are arguably more dangerous than mains, as there is a real risk of fires from  shorts, feed wire insulation will melt and catch fire as the wire glows red hot, I have seen it many timed in almost 40 years in the motor trade so do use fuses, an do use plastic covers over both terminals.  I would use a big battery and charge it with a car battery charger though a solar charger might be ok if you can aim it to the south. 

Don't use a rectifier controller as the rectifier will drop the voltage a couple of volts.

I don't know.which sort of controller to suggest, the old Playcraft controller was very good as it relied on diodes rather than a variable resistor but lacks a decent cut out.  Most current controllers use feedback or pulse power which are not available with smooth DC.  Normal mains derived 12 volt power is a wave form averaging 12 of 16 volts with very much higher peaks and troughs.

Track will need to be kept clean as arcing will be much worse.with all those amps, but you should be surprised how smoothly locos run and the points will bang over very nicely with no need of a CDU, and in many ways it will be better than mains, just don't short it out, or drop the battery, nasty stuff battery acid.

[kit basher]

All it takes is a loose track pin to be picked up by a loco and BANG!!

ok, a fuse would blow, but it wouldn't blow quick enough to stop the short damaging the loco and possibly the controller.

What I would do, is use an inverter on a leisure battery, the inverter will power any 240v controller safely, so long as the wattage isn't exceeded.

Also use a solar battery charger, you may have to give the battery a top up charge every now and again.

[Crosland]

If you use a car battery, just be careful not to discharge it too much. Leisure batteries are much more suitable.

 

Any controller should have its own internal overload protection, so no worries there. It is still good practice to fit some form of fuse or breaker very close to the battery to protect against faults in the wiring from the battey to the controller.

 

A short on the layout will not damage a loco unless it was a faulty loco that caused the short in the first place.

 

A modern OO loco will take neare 1/4A than 1A, especially the smaller locos in some of the starter sets. You could get a good few hours of play from a battery pack made from D size MiMH (for best results check the capacity and make sure thay are true D cells and not AA or C in a larger wrapper. Easy to carry indoors for charging.

 

Andrew

[RailWest]

Two comments:-

 

1. If it is going to be in a garage, then why not run it from the car itself - long lead with cigarette-lighter type connector on the end? Save all the battery handling, fusing, charging issues etc. Or will the car be out of the garage too often?

 

2. If having a layout in garage, what about environmental conditions - eg will it get too cold, damp, rusty etc, especially if there is no electricity for heating etc?

[peter220950]

Installing an expensive solar panel to power the layout in the garage/shed seems a waste of money to me: having the mains extended is probably cheaper Doing the preparation work yourself will save even further on costs, plus it'll increase the value of the property.

I think the original post pointed to the fact that the garage doesn't adjoin the house or garden, by impication a power supply would be crossing someone else's land?

[rab]

Thanks for all the responses.

Looks like a leisure battery with an inverter is the best and safest option.

As they,re into camping they might make use of it for that as well.

 

With reference to the garage being damp,

we had thought of that but it's the only real option.

I've suggested the locos,controller etc be kept in doors

and we're hoping that the nickel silver track will counteract to some extent, the corrosion problem.

 

Thanks again.

[SHMD]

Put a few (empty) cardboard boxes in the garage along with a couple of old books (you don't want anymore) and leave them.

Then monitor how they deteriorate over as many weeks as you can allow.

 

This will give some indication as to how you could expect a model railway to behave.

 

 

Kev.

[Joseph_Pestell]

There was a club in SW France that used a 12v battery to run its layout at exhibitions. A boon to exhibition managers as the layout, a roundy-roundy, could be placed anywhere in the hall without worrying about cables trailing across the floor. A full charge was ample to keep the layout, which was quite large, going all day. Only snag came at one venue where they plugged in the battery charger into a nearby socket to charge overnight on Saturday evening. Caretaker turned all electricity off at the main distribution board as a fire precaution so no trains operated for the first couple of hours on the Sunday.

 

Agree with other posters. Battery needs to be protected in a ventilated box so that terminals will not be touched. Then an inverter to produce 220v into a conventional transformer controller set-up so that any shorts do not draw the full amps available from the battery.

[shortliner]

Tried running it with a long piece of string - didn't work very well - think the lectrickery is having trouble getting squeezed together at the knots. A short piece of string, attached to the front coupler, does work a bit however, but you have to keep walking round the layout pulling it behind you, and the wheels make scraping noises along the track!

[kevinlms]

Tried running it with a long piece of string - didn't work very well - think the lectrickery is having trouble getting squeezed together at the knots. A short piece of string, attached to the front coupler, does work a bit however, but you have to keep walking round the layout pulling it behind you, and the wheels make scraping noises along the etrack!

Its actually hard work, pulling trains around a roundy all day & the various operators get tangled up when passing trains. Works best with flyovers for the operators.