AAA Battery Box (88000) vs. Rechargeable Battery Box (8878)

[Toastie]

I'm wondering if there is a low-discharge prevention circuit on the li-Poly pack. I also fly RC model planes, and if you over-discharge Li-poly cells, they are permanently damaged - won't re-charge, or give duration which it had before. I am thinking of making a 2s pack up and using my Li-poly charger to recharge, balance the cells as it charges)

(2s= 2cell @ 3.7v nom x2, giving 7.4v nom, in series).

Beware, though, short-circuiting can cause fire, which is nasty!

Hi Brickimaid,

there is virtually "everything" in TLC's LiPo: Input charging voltage may vary between 9V (charging is slow then though) and 18 V (super fast charging) - 12 V is your best bet because matching wall warts are dead cheap. TLC's LiPo simply stops working when approaching low voltage levels. It turns off by default (timer functions) after about 2 hours of permanent operation - when you continue to operate that thing under heavy load it simply turns off when getting close to melt down. The only thing you can then do is charging. And: TLC's LiPo comes with a separate voltage controlled output (on the PF terminal); here you have permantent LiPo power (9V/0V lines) or dial controlled output power (C1/C2 lines). Not too(!) bad for the amount they are charging.

And yes: LiPo's are cool explosive devices: You can generate almost the equivalent of the stored electrical energy as net - well - destructive energy.

All the best,

Thorsten

[hoeij]

...

It turns off by default (timer functions) after about 2 hours of permanent operation

...

That's very helpful information. I used it for the E.N. in a small layout at a local event here, and the train stopped after about 2 hours. I assumed that the 8878 was empty by then, and replaced it with a AAA battery box. But in retrospect, the 8878 was probably not empty (it is supposed to run the EN for 3 hours, and I have done that in the past).

For technic lego, I can use AA rechargeable batteries or the 8878, but my AA rechargeable batteries are always empty when I want to use them for something, and the 8878 never seems to be empty (only exception is at the train show when the train has run for hours in a row). So it's convenient to have.

[Toastie]

Hi Hoeij

I used it for the E.N. in a small layout at a local event here, and the train stopped after about 2 hours. I assumed that the 8878 was empty by then, and replaced it with a AAA battery box. But in retrospect, the 8878 was probably not empty (it is supposed to run the EN for 3 hours, and I have done that in the past).

That makes absolutely sense. I came about the same data (see article in RailBricks #7). When the train is not pulling 50+ cars, it runs for 2 hours and stops. Turned it on again and it ran additional 1 1/2 hours and then it turned off and wouldn't turn on again until the force came back by charging.

For technic lego, I can use AA rechargeable batteries or the 8878, but my AA rechargeable batteries are always empty when I want to use them for something, and the 8878 never seems to be empty (only exception is at the train show when the train has run for hours in a row). So it's convenient to have.

I completely agree. My separate NiMH rechargeables do behave the same - the LiPo once charged - seems to stay charged for very long times.

All the best,

Thorsten

Edited February 23, 2011 by Toastie

[Brickthus]

The 8878 LiPo battery has the advantage of a re-starting circuit, which gets a heavy train to the top of the hill by retrying if it stalls.

I think the auto-off time of a 6AAA battery box is shorter - not helpful if you have a tunnel on your layout!

With really heavy trains, best to have a battery in each loco. I would like to have a larger capacity LiPo battery in one loco and run a cable to the "B" loco, using a single IR receiver to make sure both locos' motors got exactly the same command and power all the time. If not, there is the possibility of one loco pushing the other off the rails. I would have to make a slave H-bridge motor driver and run a few of them from a single IR receiver command in order to power all the motors - a single IR receiver can power only two train motors at once. The motor driver chip recommends 400mA per channel and 800mA total but a single motor can pull more than 200mA with a heavy train.

Nevertheless, the 8878 LiPo is a really good product for light or average weight trains.

Mark

[Toastie]

Nevertheless, the 8878 LiPo is a really good product for light or average weight trains.

Mark, agreed,

and TLC's LiPo is an 100% all-nerd (like me), hard-core, as-close-as-possible LEGO-only-solution - with all the bells and whistles: I like it

But, you are absolutely right: If you want to really take it to what-is-possible: Your approach is simply beautiful: I like that as well

That is the beauty of LEGO: Make your choice and go nuts. Thanks for sharing!!! I'll try it.

All the best,

Thorsten

[Brickimad]

Hi Hoeij

That makes absolutely sense. I came about the same data (see article in RailBricks #7). When the train is not pulling 50+ cars, it runs for 2 hours and stops. Turned it on again and it ran additional 1 1/2 hours and then it turned off and wouldn't turn on again until the force came back by charging.

I completely agree. My separate NiMH rechargeables do behave the same - the LiPo once charged - seems to stay charged for very long times.

All the best,

Thorsten

NiMH Cells have a tendancy to self discharge over time. ABout 10% every fortnight-depending on the condition on the cells. Obviously this is annoying, if you have a camera you want to use and the cells are dead. I fly Rc model Aircraft, as well, and if you have a flat battery-especially in the air, than it's worse, a pile of expensive rc model, destroyed.

We are using these cells. They are NimH, but keep their charge much longer. They say 95% after 6 months, whereas a normal NIMH would be empty. They are called "Enloop" or Vapextech. Both are available on the web, and do AA and AAA sizes. Very handy...

Try them, they are well worth it!

http://www.eneloop.info/home/the-new-improved-eneloop.html

http://www.vapextech.co.uk/

On the subject of Li-po, they have a very low self-discharge, but if they go below 2.9v(per cell, therefore 5.8v for 2S pack @nom 7.4v), they will not recharge, and if they do, will have reduced capacity, and may "balloon" up, probably splitting the lego battery box.

Edited February 27, 2011 by Brickimad

[KMO]

The question of which is better is looking increasingly moot.

I ordered an 8878 from the UK shop in January for my Emerald Night. It was backordered to March when I placed the order, a few weeks ago that slipped to May, and this morning I got an e-mail saying it was now due mid-August.

So that's out of production/stock for over six months. Wondering if I'm ever going to get it...

[Locutis]

The question of which is better is looking increasingly moot.

I ordered an 8878 from the UK shop in January for my Emerald Night. It was backordered to March when I placed the order, a few weeks ago that slipped to May, and this morning I got an e-mail saying it was now due mid-August.

So that's out of production/stock for over six months. Wondering if I'm ever going to get it...

Shop@Home in North America lists this as available, but UK says "Sold Out". Very interesting...

[RockeTeK]

Hey all, I would like your opinion on the following matter (sorry if this was posted before!)

I have rechargeable batteries (6 Duracell AAA) and the batterybox 88000, the 8878 costs around EUR50,-.

Should I buy the 8878 or not? Does it make my trains perform better compared to the 88000?

thanks,

RockeTeK

[hoeij]

Should I buy the 8878 or not? Does it make my trains perform better compared to the 88000?

thanks,

RockeTeK

I don't think it'll make any difference. It should work fine either way.

(PS. I have 8878 and also 88000, and have used them to run the EN. Either way it runs fine).

Edited March 31, 2011 by hoeij

[peterab]

Hey all, I would like your opinion on the following matter (sorry if this was posted before!)

I have rechargeable batteries (6 Duracell AAA) and the batterybox 88000, the 8878 costs around EUR50,-.

Should I buy the 8878 or not? Does it make my trains perform better compared to the 88000?

thanks,

RockeTeK

You will probably find the 8878 will allow your trains to run longer on a charge, other than that there should be little difference in performance. 8878 is reported to have very good charging circuitry which might mean it last longer than your AAAs depending on how much care you take of them.

[Cwetqo]

What about pulling power and constant output? Does it allow larger output current? I know its not so important on single motor setups, but if you have dual motors (train or even PF XL ones in technic setups) then maybe it would make some difference.

[KMO]

Can you even get the 8878? Ordered mine in January - backordered until August.

[hoeij]

What about pulling power and constant output? Does it allow larger output current? I know its not so important on single motor setups, but if you have dual motors (train or even PF XL ones in technic setups) then maybe it would make some difference.

Two train motors should be no problem at all. Whether you go with a 8878, or use the 88000 with 6 rechargeable batteries, either way you'll have plenty of current.

One XL motor can draw as much current as two train motors. The Emerald Night train runs with one XL motor. It has no problems pulling a 10 feet long train (I've tried it with 8878 and with 88000, either way it works fine).

I have used the 8878 for lego technic, running 3 M motors at the same time, and that worked well. Two XL motors would be the equivalent of 4 M motors, my guess that that'll be OK too but I have not tested it.

[Tearloch33]

I prefer the LiPo one based on convenience. If you don't run your trains at a show or for long periods of time, the time to charge is not an issue (with the AAA one, you can quickly swap batteries). My real like for the LiPo is that it can be charged in place. Some trains take a bit of demolition to get to the battery back if using AAA.

[gotoAndLego]

Sorry about the necro-post guys, this came up in a search and i didn't check the date.

Edited April 22, 2016 by gotoAndLego

[hawran]

I'd definitely prefer AAA battery box (88000).

Recently I asked myself the same questions...

Comparing pros and cons the "common" battery box wins, because if you buy low- or mid-priced AAA batteries (10-12 pcs for some 1.5 EUR - comparing to 50 EUR for rechargeable box) and encounter a "short" time to replace batteries it's clear...

And someone wrote this here - will the rechargeable box work after 20 years...?

[ShrikeArghast]

I'd get the AA battery box myself. You can always design removable covers for tenders without too much difficulty... and I've had rotten experiences with rechargeable batteries over the years.

[Railfan9]

I'd get the AA battery box myself. You can always design removable covers for tenders without too much difficulty... and I've had rotten experiences with rechargeable batteries over the years.

Exactly I bought a rechargeable battery box and I dont think they are better than the AA battery box.

[pirzyk]

I go the other way. I have 10 or 11 LiPo battery packs, the oldest from 2009 and they all are still working well. I can get upto 7 hours on a charge (depending on how long the train I am running) and takes about 2 hours to charge up. I converted the Engine Train Yard to my recharging station while I swap out the engine.

Ripping apart an engine to swap the batteries out is not an option, since I have shoved so much into my interiors and/or I have custom decals on the side of the battery box. I leave a small access plate to plug in the recharger, think the 4x4 plate on the Maersk.

[dr_spock]

I went the AAA battery route since my kids toys used AAA and AA batteries and I had a lot of NiMh rechargeables for them. My MOCs are designed with easy access to the battery box in mind. In a couple of minutes i can swap out batteries and have the train running again. I don't bother tightening the two screws on the bottom of the AAA battery box. In fact the bottom piece of the box stays in the engine during battery change.