NiMH or Li-ion or Li-pos for winter running

[beavercreek]

This is sort of related to my thread about the acquisition of a new quad charger.

I will be batterying up some diesels and one steamer/motorised-combine set up for winter running . I will be using the Aristo Revolution system as I have managed to obtain all the bits for a very goodly price.

My question is on the battery power needed for the locos.
My layout has some very steep inclines (15% in one place) and I tend to run double heading as a minimum with triple or quad for long trains. The steamer will have another three cars and caboose behind the motorised combine.
Each loco will have its own battery set-up and will have sound and lights...maybe not smoke but it would be good to have the option

I was thinking that if I went down the NiMH route for the diesels then two 8.4v 3300hr (or 3700... its those inclines) packs in series would be fine in each loco as there should be enough room to get them inside the hoods.
The steamer is another matter. I could use the combine reconfigured internally to take the packs or ...........
.......there is the option of putting a smaller but still powerful Lipo or Li-ion in the tender.

An esteemed and experienced member of the forum has warned me off Lipos as although they are very powerful (used in aero circles) but have inherent risks etc.
The quad charger has external balance boards etc for plugging in the Lipo or Li-ion packs (the packs come with two leads..one for power and the other to plug into the balance boards) so that the charger can monitor the cells whilst charging etc. It can also charge any type of other battery as well.....

Is the general concensus along the lines that, although Lipos are very powerful for their size and weight, it is better to leave them to the aero modelling and model car racing fraternity and use Li-ion (with its own safety concerns) instead?....or even just stick to NiMH unless there just isn't enough room for them..........
Is the use of inline fuses what ever battery a good idea to protect the Revo receiver/control boards

I need the power and capacity for the inclines, and in the steamer tender instance, the smallest high power solution...

Boys, I am a beginner in the full battery power world so any input will be gratefully received and go into the melting pot....

 

[beavercreek]

Hi Ross
Indeed, Peter is the esteemed member who has given me some good input on the LiPo situation. The reason for me even considering them was that the quad charger comes with the external balance boards for the associated LiPo packs.
Am I to take it that even with dedicated balance boards, ready made purpose built LiPo packs etc, LiPos are just too dangerous to use?
Do Li-Ions use the same balance boards in charging?
What concerns are there when using Li-ions?

 

[CoggesRailway]

I really am no expert but with a big american diesel where you have room and weight is good the nimh pack will do OK. Interestingly last week I tested my LGB alco. No sound, LED lights, No smoke, 10 bachman bogie wagons behind and I stopped at 2hours 30 and there was no discernable drop off. It slowed after a couple of laps, I picked up the speed a bit and it settled in for the period. It has 2x7.2v Tamyia style racing batteries in series of 4500mah. At Peters very hilly layout with a similar but slightly shorter train it ran for 80 odd minutes before dying.

I have also got a set up in my 2095 (i now consider over the top) which has the same as above times two discharging in paralell but diode protected so the packs charge seperately and cannot discharge into each other. This runs sound and lights and runs FOREVER even in Ruritiania you may wish to consider this for large US locos on gradients as a high performance alternative to lith.

I think if you follow advice of the likes of Whatlep with lith you need not be scared! I had a helicopted lipo go off- it was only tiny but still was like a welders torch, thnak God on a concrete floor. However this was a very different animal to those used by peter, mel etc.

 

[beavercreek]

Thanks Ross and Ian
Ross, the quad charger has outputs for Li-ion and is fully automatic so it should be fine for any Li-ion pack. I was not sure if the balance boards were for Li-ion as well as Li-po,s so thanks for clearing that one up for me

Ian, you mentioned that the twin pack Li-ions had a diode between them to stop discharging into each other etc. How is that configured or should I ask Peter
If using NiMh twin packs it is just a case of connecting them in series and charging them as if one pack? How would a twin Li-ion pack be set up?
The 2 x 7.2v Ni Mh packs you used in your Alco at 4500mah, I take it that that is the capacity of both packs that give a total of 14.4V at 4500mah (each 7.2V rated at 4500mah)

 

[CoggesRailway]

Thanks Ross and Ian
Ross, the quad charger has outputs for Li-ion and is fully automatic so it should be fine for any Li-ion pack. I was not sure if the balance boards were for Li-ion as well as Li-po,s so thanks for clearing that one up for me

Ian, you mentioned that the twin pack Li-ions had a diode between them to stop discharging into each other etc. How is that configured or should I ask Peter
If using NiMh twin packs it is just a case of connecting them in series and charging them as if one pack? How would a twin Li-ion pack be set up?
The 2 x 7.2v Ni Mh packs you used in your Alco at 4500mah, I take it that that is the capacity of both packs that give a total of 14.4V at 4500mah (each 7.2V rated at 4500mah)

Hi Mike,

The dischsrge in paralell diode protected approach is NIMH not Li-on. The 2095 did have a lion but with an LED on which could not be turned off with the loco. That battery is waiting another project and the twin set of NIMHs is in the 2095. The diodes are just beefy ones from maplins that stop one or the other set discharging to the other. They sit directly after each battery feed before they are place in paralell that way there is a discharge in paralell but nothing the other way. You have two sperate charge leads with a switch (or two sockets) that indepenently connect to each pack "before" the diode which allows independant charging. I always charge both to "FULL" on my charger but it probably doesn't matter.


Yes the alcos battery of cells is two 7.2vs in series giving 14.4v and 45000mah hour nominally although they actually sit at 16v+ for most of the useage time. The just charge in series using the charger I showed in the other thread.

I would not twin Li-on batteries - I know little about them but I would very much doubt it is recomended.

Ian

 

[beavercreek]

Hi Ian
How exactly is the diode wired when using twin NiMH packs?

 

[gregh]

Methinks tis a shame LiPos are getting such a negative press in this forum.
ROSS will probably jump down my throat but I'm still going to repeat what I have said before.
I'm for LiPos.
I and three of my friends use them. Two of those friends have used them for 5 years now. I have been using them for 2 years.
I charge them in the locos, and don't use balance charging. I have checked the balance on 2 of my locos after 2 years and every cell is the same voltage.
Obviously I use a correct charger for LiPos.
I typically use 2200-3000 mAh rated batteries, but have in one case used two, 3300 mAh in parallel (and no diodes etc, but that's another issue.)
I use 15C or 20C types which means they can supply 15 to 20 times their capacity rating. So mine are capable of supplying something like 30 amps minimum. As my trains seldom take more than a couple of amps, these batteries are just 'loafing' and so don't seem to need balancing.
Similarly I don't fast charge, just 300 mA typically, so again I'm not thrashing my batteries like aero modellers.
Just make sure your motor controller electronics has a low voltage cut-out, or you'll kill the battery if you discharge it completely - not catastrophically in a fire - it will just be dead.
Yes, they supposedly can catch fire if punctured (how likely is that in your train?) or overcharged - so use a good charger.

The only thing wrong with LiPos is that they are TOO light.

 

[beavercreek]

Hi Greg, Ross

Although I have not used Lipos and am a beginner with this chemistry (or Li-Ions) in trains , I have used them as part of other electronic gear like laptops, cameras etc. These obviously come with their own specific charger or alternative makers as spares.
I am aware of the care needed when using the LiPos (or even Li-Ions) and would, if I do go down this chemistry route, be using pre-made, well known and commercially available 'racing/flying' battery packs in conjunction with a charger that is suited (the quad one I have talked about in another thread).
I never 'muck about' or am careless with battery packs of high power (as opposed to the tiny ones I use for soundboard back-ups where I might be) as I have great respect for what can happen!

But having said this, I may stick with the route of NiMH or possibly Li-Ions and just 'try' one of the Lipos in an 'old crate of a loco' to get used to what transpires.
You only progress from being a beginner by learning and tryying stuff that is new to your experience............

 

[CoggesRailway]

Hi Mike. first I have only learnt this from the net and not an expert like some!

As you know diodes at there simplest are a bit like a one way valve. I bought 4 from Maplins for £2 which were rated at the highest amperage the loco could pull. (3a i think).

I took each NIMH pack I wanted to use in paralell and soldered a diode to both it's positive and negative terminals/leads such that the battery would operate as normal because the diodes or "valves" were in the appropriate direction. However if you applied a charger to the diodes it would register "no connection" because the "valves" would not allow it to apply current too the battery but only let it flow from it. I am not sure the the diode on the negative side is needed but for 50p I just did it rather than stop to ask!. Once you have attached the diodes to each pack you can the take feed from each "after" the diodes and place them in parallel. The resulting paralell connection will now have the MAH rating of all the packs connected together. If they did get out of balance they cannot back charge into each other and overheat which is the whole point of diode protecting the packs.

Don't forget you need a lead to each pack "before" the diodes to allow you to charge them separately, or indeed at once on you quad charger!

It may sound complex when you are trying to explain it in text but it really isn't. it is a £2 and 10 minute job which allows you to create extremely long lasting battery packs

Ian

 

[CoggesRailway]

Mike i just tried to PM you too. It says "beaver creek has decided not to receive PMs?"

Any hoo has our Mel woud say, I was just letting you know I had posted above and to say that you really do need to remember that you are trying to run a "railroad" not small LGB loco with three wagons/coaches. AAs with 2500mah ish is just going to disappoint. I think you want 5000mah+ from whichever approach in an american high amp draw loco operating on steep hills with big trains to avoid disapointment. Preparing flak jacket...

 

[beavercreek]

Hi Ian
The packs in parallel I am not sure about......surely two 7.2v 3200mah hour packs should be in series to give 14.4V at 3200mah...
I am obviously confused here...not unusual for me

 

[CoggesRailway]

Yes it would 2 x 7.2v 3200mah = 14.4v at 3200mah.
But TWO of the above packs into parallel will be 14.4v at effectively 6400mah.

My Alco is 2 x 7.2v 4500mah giving a pack of 14.4v at 4500mah
My 2095 has 4 x 7.2v 3600 in series and parallel. Therefore 14.4v at 7200mah
This is over the top for a 2095 but probably what you need for a big american if you are not going Li-on. It is 4 x tamyia car batteries + diodes and you could run, smoke, and sound all afternoon When I did this i got 4 for £45 of the web.

 

[beavercreek]

Ah Ian now I see. Four battery packs in one loco..nice bit of weight there. Your 2095 is nice and 'boxy' with plenty of room inside, might be a squeeze inside the narrower hood on my diesels.
Do you have just one charging jack to charge all four packs? Not sure how that would work?...........or Two jacks for the series ones and parallel ones...........
Or do you take them out and charge them individually?

 

[CoggesRailway]

two charging jacks so i could do them at the same time. in terms of fit I did have that inside the alco for a while until took two out I used them on another project. If you build a pack with one on top of the other four make about a big cucumber

 

[beavercreek]

If you build a pack with one on top of the other four make about a big cucumber

A powered cucumber,...now where might that be useful.......................