To LUGNET HomepageTo LUGNET News HomepageTo LUGNET Guide Homepage
 Help on Searching
 
Post new message to lugnet.trainsOpen lugnet.trains in your NNTP NewsreaderTo LUGNET News Traffic PageSign In (Members)
 Trains / 30153
30152  |  30154
Subject: 
Re: New Press Release about Power Function Trains
Newsgroups: 
lugnet.trains
Date: 
Fri, 28 Mar 2008 02:37:15 GMT
Viewed: 
10513 times
  
In lugnet.trains, Doug Eaton wrote:
In lugnet.trains, Eric Kingsley wrote:
In lugnet.trains, Steven Barile wrote:
BTW the batt box is 4 bricks high, not studs.
I found the real news in this release was the battery box.  What I am waiting to
hear is some real tests in terms of battery life before a charge is needed and
how long it takes to charge.  (How many batteries are we going to need to do a
show without having a long period waiting on batteries).

Ideally I want a battery that can pull a standard 6 wide train with 10 average
cars for at least an hour and a recharge time of less than an hour**.  If we get
that minimum standard or more I will make the switch.  If not I may be stuck
nursing my old 9v stuff for the foreseeable future.

Here are some rough calculations to estimate the longevity of the announced
battery.

Li-poly technology offers 300Wh per litre[1]. The battery box will be 4x8x5 lu
(4 bricks high=5 studs) = 32*64*40mm3 Assuming 2mm thick walls, that leaves
28*60*36 =  60ml for the cells so we get about 18Wh to use. Capacity would be
23Wh with 0.5mm thick walls. Of course, leave room for the power jack and any
recharge/protection circuitry that may be inside the housing as well.

I found no info on the power draw of the RC train motor but the 9V motor draws
up to 950mA[2] (stall current, 9W) when pulling a long, heavy load. Shorter,
lighter trains such as the retail RC trains would probably draw closer to 3W.

Given the above assumptions, this battery box should run a typical retail sized
train about 6 hours non-stop and an AFOL train about 2 hours (the kind where
having a second motor helps but is not required.) I am likely off on both power
available and required, have neglected efficiency and maximum drain level but
this should still last at least one hour under worst case conditions.

Recharge time could be about an hour if an external charger is used. All bets
are off if the recharge circuitry is embedded in the battery box. For reference,
the NXT Lithium Ion battery has embedded recharge circuitry and takes about 4
hours to recharge although this is slightly different technology.  The standard
LEGO 9V transformer supplies 7W@12V so we are probably looking at a 4 hour
recharge time here as well.

Doug

[1]http://en.wikipedia.org/wiki/Lithium-polymer
[2]http://www.philohome.com/motors/motorcomp.htm

Given the size of the battery box 6 wide hood units will be a thing of the
past, would it be possible to have a 4 stud wide footprint on the bottom and the
have the rest of the side recessed similar to the headlight brick
configuration.This will give the ability to build 6 wide hood units by providing
a 4 x 8 plate sized studded surface on the battery box side, the ability to use
plates, mod plates,tiles and mod tiles, gives great potential to model doors,
grills, handrails etc. The majority of AFOL train builders use SNOT techniques
as basic construction, having this feature would serve as a great selling point
and a more adaptable model to the AFOL market.
The biggest problem with the IR chassis was the lack of adaptability SLTC
members such as David Parkin and EmpireofLego were able to make some nice MOC's
based on IR such as SRA 48 Class Alco (27 wagons pulled using 2 motors), SD 70
and an adaption of James Mathis Alco RS-1 but it was very limited in what could
be done prototype wise.
The new system needs to have some good features to sway people such as myself
who have invested heavily into 9 Volt Trains, I only bought 2 copies of 7898 for
the parts, I did build the wagons for my rolling stock collection but the
locomotive parts were used on MOC'S, I will not be wasting money on a set that
does not match 9 volt for adaptabilty, power and modelling potential.



Message has 1 Reply:
  Re: New Press Release about Power Function Trains
 
(...) Excellent idea, even if it means extending the battery by another two+ studs lengthwise. Another permutation to consider would be instead of recessing a half plate on each side, to make it a full plate thinner on both sides so that any surface (...) (16 years ago, 28-Mar-08, to lugnet.trains)

Message is in Reply To:
  Re: New Press Release about Power Function Trains
 
(...) Here are some rough calculations to estimate the longevity of the announced battery. Li-poly technology offers 300Wh per litre[1]. The battery box will be 4x8x5 lu (4 bricks high=5 studs) = 32*64*40mm3 Assuming 2mm thick walls, that leaves (...) (16 years ago, 26-Mar-08, to lugnet.trains)

37 Messages in This Thread:



















Entire Thread on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact

This Message and its Replies on One Page:
Nested:  All | Brief | Compact | Dots
Linear:  All | Brief | Compact
    

Custom Search

©2005 LUGNET. All rights reserved. - hosted by steinbruch.info GbR