Double motor block LGB locos battery power draw ?

DickyC

DickyC

(BZB Mountain Railway)
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~~Not sure if this has been asked before , please reference me a link if it has~~

Question for the Electric/Battery gurus out there. I have secured a nice LGB RhB Railcar via an auction, Im looking to convert it along with my other fleet to battery, this is a nice powerful bit of kit as it has two motor blocks. Any idea what kind of power will this be drawing in total? 24V ? As each motor block is picking up from the track normally im assuming it will be taking double the power . I have converted single block locos upto now and run from a 12v battery pack with good results, so was thinking this might need double battary packs or a big battery ?

PS, think this logo is perfect for conversion given all the space it has
PPS, be wary that is you buy from SAS acutions they take "FOREVER" to dispatch the items but they are well packed.

thanks in advanced Richard
 
You are confusing power, measured in Watts, with Voltage, measured in Volts and current draw, measured in Amps.

Firstly, the easiest one to understand is the voltage, in so much as the higher it is, up to 24V or 12V on the smaller scales, then the faster your loco speed.

Think of voltage as a tap to get a faster flow of water.

Battery packs from R/C cars tend to be 7.2 V, and some G scalers use a pair of these to give 14.4 V, more than adequate for most locos. But there are other options.

So let's talk about the current. Think of this as a tank of water which you drain off, As it empties you get less flow. This is your current. a tank is like a battery. The bigger the tank, the longer it will power your loco (or even your car whether it is fossil fuelled or electric). In battery terms this is the Amp/Hour.

(My Massoth DCC system is set to 18 V rather than 24 V and 12 A, for a slower top speed but with several locos on the track.)

Power next. If you haul a heavy train, you will need more power, but this will drain your battery quicker. When I tow my caravan, my MPG drops and I can't accelerate as quickly. Using the water analogy, less pressure, so turn up the stop-cock.

Others with more experience of battery control will advise the ways you can do this. You don't mention if you are considering radio control, but I would have thought something with a pair of R/C batteries wired in series to give 14.4 V would be enough to drive the electronics and the motors at a realistic speed....
 
Team_Kona said:
I have converted single block locos upto now and run from a 12v battery pack with good results, so was thinking this might need double battary packs or a big battery ?


thanks in advanced Richard
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Not deriding what Gizzy Gizzy has said, in some respects you are correct, but double up in parallel to give more current, than in series to give more voltage.
 
JimmyB said:
Not deriding what Gizzy Gizzy has said, in some respects you are correct, but double up in parallel to give more current, than in series to give more voltage.
Click to expand...
Thanks JimmyB, Had not considered the Parrellel v Series wire up, should have done so as just put solar panels on my cabin roof and explored that, back out with the dusty calc then to increase the current.
Gizzy said:
You are confusing power, measured in Watts, with Voltage, measured in Volts and current draw, measured in Amps.

Firstly, the easiest one to understand is the voltage, in so much as the higher it is, up to 24V or 12V on the smaller scales, then the faster your loco speed.

Think of voltage as a tap to get a faster flow of water.

Battery packs from R/C cars tend to be 7.2 V, and some G scalers use a pair of these to give 14.4 V, more than adequate for most locos. But there are other options.

So let's talk about the current. Think of this as a tank of water which you drain off, As it empties you get less flow. This is your current. a tank is like a battery. The bigger the tank, the longer it will power your loco (or even your car whether it is fossil fuelled or electric). In battery terms this is the Amp/Hour.

(My Massoth DCC system is set to 18 V rather than 24 V and 12 A, for a slower top speed but with several locos on the track.)

Power next. If you haul a heavy train, you will need more power, but this will drain your battery quicker. When I tow my caravan, my MPG drops and I can't accelerate as quickly. Using the water analogy, less pressure, so turn up the stop-cock.

Others with more experience of battery control will advise the ways you can do this. You don't mention if you are considering radio control, but I would have thought something with a pair of R/C batteries wired in series to give 14.4 V would be enough to drive the electronics and the motors at a realistic speed....
Click to expand...
Thanks Gizzy, this is a good explaination, but i was finding it hard to move the cogs in my brain about pulling my caravan with a 4x4, but one with a two hybrid motors connected to each axel rather than a drive shaft conexted to one motor ! do i need more water for this ?? hee hee (runs and hides from Gizzy). yes it will be an RC conversion.
 
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Basically, if you have run a single motor Loco with 12V and you are happy with the performance, running a dual motor Loco will be 'the same' in regards to speed (discounting different gearbox ratios).

However, as you have two motors working together you will be using twice the current. If you used the same battery as a single motor Loco in a twin motor Loco, the battery would last for 1/2 as long.

As mentioned by Gizzy and Jimmy, you would need to add a second 12v battery (or one of higher amp hour capacity) to get the same running time as a single motor.


So yes - you need a bigger tank if you want to have the same run duration as a single motor.
 
Cobalt6700 said:
Basically, if you have run a single motor Loco with 12V and you are happy with the performance, running a dual motor Loco will be 'the same' in regards to speed (discounting different gearbox ratios).

However, as you have two motors working together you will be using twice the current. If you used the same battery as a single motor Loco in a twin motor Loco, the battery would last for 1/2 as long.

As mentioned by Gizzy and Jimmy, you would need to add a second 12v battery (or one of higher amp hour capacity) to get the same running time as a single motor.


So yes - you need a bigger tank if you want to have the same run duration as a single motor.
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Boom, total respect and respect to Gizzy and Jimmy for trying to teach the unwise bubblegum chewer but that explaination "hit it out of the park" thanks , I use the following battery which has 2AH, Maybe i need tow my carvan with one of those fancy 2wd that just convert to 4wd when required, heehee.

 
Glad you've got there :)

Stick two batteries in the Loco, wired in parallel (positive to positive, negative to negative), nice 'big tank', wire your motors in the same way, sorted.
 
Ok so I have a good amount of experience with battery power on double motored LGB Locomotives.
2x USA type 2-4-0 chassis 12AA 2100MaH MLS Sound
0-6-6-0 Mallett 15AA 2300 MaH DCC Sound
Wizzy Cranks 2100 MaH Brian Jines Sound Card
All Locomotives shown above and others (Train Line) with similar battery packs give me 2 days running my train timetable schedule that is around 4-5 hours each day. I am finding that the 0-6-6-0 appears these days to be around an hour short of running time on the second schedule but this could be a larger power draw on the 6 wheel chassis rather than being DCC fitted.

2 battery packs not needed (this appears to be 7.2 rc pack thinking), I get the size made up by Fosworks after test fitting using old AA batteries then send a picture of the requirement. I have a couple of Bogie Railcars using USA Chassis with similar sized battery packs, one being a long narrow pack mounted in the roof.

A look at some of my battery conversions will show how I have achieved some of the above.
 
dunnyrail said:
2 battery packs not needed (this appears to be 7.2 rc pack thinking), I get the size made up by Fosworks after test fitting using old AA batteries then send a picture of the requirement. I have a couple of Bogie Railcars using USA Chassis with similar sized battery packs, one being a long narrow pack mounted in the roof.
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I agree 2 pack and not NEEDED, but surely with twin motors the single packs power is drained twice as quick.
 
JimmyB said:
I agree 2 pack and not NEEDED, but surely with twin motors the single packs power is drained twice as quick.
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Who knows, but my my running time mentioned above is probably ok for most people. Single motor powered locomotives with slightly less Mah batteries appear to be pretty similar running times.
 
It is not as simple as 'two-motors', 'twice the power required'..

Two motors will share the load, but due to losses in the system, will each draw more than 'half' the current of a single motor.
For a given formation of stock, running a two-motor loco will not necessarily require 'twice' the current of a single motored loco.

For most users, a battery pack of 2100mAh cells will be adequate for around three hours of running.
This will not fully-drain (stress) the battery pack, so increasing it's ability to recover when charged.
Size the number of cells (voltage) for the top-speed you require, and perhaps add another cell or two, to give you a little more headroom.

For most LGB locomotives, 12-14.4V will be more than adequate for a reasonable (scale) speed.
A Stainz, or starter set diesel, can be run from 9.6V and when 'Little Johnny' runs it flat-out round an R1 curve, it won't fall off the track.

If you run an express, on your perfectly aligned largest-radius track, you may require a higher voltage, to represent main-line express speeds.

YMMV.

PhilP
 
dunnyrail said:
Ok so I have a good amount of experience with battery power on double motored LGB Locomotives.
2x USA type 2-4-0 chassis 12AA 2100MaH MLS Sound
0-6-6-0 Mallett 15AA 2300 MaH DCC Sound
Wizzy Cranks 2100 MaH Brian Jines Sound Card
All Locomotives shown above and others (Train Line) with similar battery packs give me 2 days running my train timetable schedule that is around 4-5 hours each day. I am finding that the 0-6-6-0 appears these days to be around an hour short of running time on the second schedule but this could be a larger power draw on the 6 wheel chassis rather than being DCC fitted.

2 battery packs not needed (this appears to be 7.2 rc pack thinking), I get the size made up by Fosworks after test fitting using old AA batteries then send a picture of the requirement. I have a couple of Bogie Railcars using USA Chassis with similar sized battery packs, one being a long narrow pack mounted in the roof.

A look at some of my battery conversions will show how I have achieved some of the above.
Click to expand...
Interesting, I thought the Mallett would be a good camparison, but instead of two battery packs you are using "larger" voltage packs, if im correct (0-6-6-0 Mallett 15AA 2300 MaH DCC Sound) 15AA = 18v @ 2300MaH. 18V did to my thinking sound about right.
 
A higher voltage pack stores more energy.

I recently converted a PIKO V20 to battery (single motor) which I use to pull my track cleaning rig. This draws around 400mA when running at the speed I clean track. I used a 2500mAh 6S li-ion, which is 22.2V nominal voltage. I don't need the higher voltage for the top speed, however it allows the motor to produce more torque and, as mentioned, gives me more energy storage.

Maybe overkill, however with all of my other Locos being track power I'm used to just being able to use them and not have to charge them, so wanted the longest run time I could fit into the space.
 
This is a very useful thread, and as this question is always being asked in various forms, is there anyway of keeping somewhere where it's easy to locate?
 
Paul M said:
This is a very useful thread, and as this question is always being asked in various forms, is there anyway of keeping somewhere where it's easy to locate?
Click to expand...
Yes i have found it really helpful from everyone, Im going to ask another question seperatly now that my printer not micro electrical engineer brain needs answering.
 
... looking into uploading file into Resources.

EDIT: Now sorted, compiled the info from the Topic, collated into a minor edited form, and converted to a PDF available to download.

www.gscalecentral.net

Double motor block LGB locos battery power draw

Double motor block LGB locos battery power draw, collected and edited from Topic on the Forum, and converted into a PDF
www.gscalecentral.net www.gscalecentral.net
 
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Gizzy said:
You are confusing power, measured in Watts, with Voltage, measured in Volts and current draw, measured in Amps.

Firstly, the easiest one to understand is the voltage, in so much as the higher it is, up to 24V or 12V on the smaller scales, then the faster your loco speed.

Think of voltage as a tap to get a faster flow of water.

Battery packs from R/C cars tend to be 7.2 V, and some G scalers use a pair of these to give 14.4 V, more than adequate for most locos. But there are other options.

So let's talk about the current. Think of this as a tank of water which you drain off, As it empties you get less flow. This is your current. a tank is like a battery. The bigger the tank, the longer it will power your loco (or even your car whether it is fossil fuelled or electric). In battery terms this is the Amp/Hour.

(My Massoth DCC system is set to 18 V rather than 24 V and 12 A, for a slower top speed but with several locos on the track.)

Power next. If you haul a heavy train, you will need more power, but this will drain your battery quicker. When I tow my caravan, my MPG drops and I can't accelerate as quickly. Using the water analogy, less pressure, so turn up the stop-cock.

Others with more experience of battery control will advise the ways you can do this. You don't mention if you are considering radio control, but I would have thought something with a pair of R/C batteries wired in series to give 14.4 V would be enough to drive the electronics and the motors at a realistic speed....
Click to expand...
I limit my decoder top speed via the decoder, I keep my system at the full power output. When I go to a club meeting or friends home my engine controls the top speed, not the system.
 
Note on motor power draw...2 motors are not double the current as the current drawn by the load is shared by both motors, each supplies 1/2 the current. Current will almost double if you double the amount of cars being pulled!!
 
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