Large Scale Central

Taking the Plunge - Li-ion

Electronics Power and Sound
#61

Just taking one of the many good points Michael made:

“Why hasn’t anyone inquired about the effects of slow charging our Lithium cells/batteries???”

Because, reading carefully from the responses of the people who sell them and people who assemble them and users, the ASSUMPTION has been made that slower charging is safer and “simpler”…

No facts to back this up except people claiming no issues. Do they know if the lifetime/power capacity has been compromised? I’m pretty sure not.

The problem at this point in the thread, is further discussion would involve statements like: “Just selling batteries does not make you an expert”, or the fact that it has worked so far does not mean it is the best way.

I have no wish to polarize or cause issues here, Michael has stated what my engineers and my research as an engineer has yielded. I run a small company of electronic engineers that design things and we always go by the manufacturer’s specifications, and work the their recommendations first.

Anyway, I stopped “trickle charging” batteries about 30 years ago, as I had shorter battery lifetimes as predicted by the people who were battery experts at that time.

Greg

#62

Greg Elmassian said:

Just taking one of the many good points Michael made:

“Why hasn’t anyone inquired about the effects of slow charging our Lithium cells/batteries???”

Because, reading carefully from the responses of the people who sell them and people who assemble them and users, the ASSUMPTION has been made that slower charging is safer and “simpler”…

No facts to back this up except people claiming no issues. Do they know if the lifetime/power capacity has been compromised? I’m pretty sure not.

The problem at this point in the thread, is further discussion would involve statements like: “Just selling batteries does not make you an expert”, or the fact that it has worked so far does not mean it is the best way.

I have no wish to polarize or cause issues here, Michael has stated what my engineers and my research as an engineer has yielded. I run a small company of electronic engineers that design things and we always go by the manufacturer’s specifications, and work the their recommendations first.

Anyway, I stopped “trickle charging” batteries about 30 years ago, as I had shorter battery lifetimes as predicted by the people who were battery experts at that time.

Greg

In my case I until this thread came along I was not aware know trickle charging could damage Li chemistry batteries I will now change that.

I have been charging my NiMH batteries (yeah I know its an unrelated subject) for over 10 years at slightly over 1/10C (0.3A for 2750mAH) and they are still just chugging on, this is why when I switched to Li I just started treating them the same way, biggest influence were all the horror stories that are floating around on forums and the net (also talking to model plane flyers at the local club) so I went down the safety path.

As for OEM specs on my batteries I have no idea who made them and I am fairly sure that the seller (Hobbyking) would either know or would share the knowledge.

I think the majority of users, having no technical/engineering training, would not be able to understand OEM specs, and not to mention being able to access them in the beginning, so they rely on the sellers to do the work for them and provide matched batteries and chargers when first starting out.

They probably don’t even consider, let alone log, performance. I suggest they just run them till they die and replace them with the same thing (Devil you know).

Might I suggest that Greg and Michael collaborate and write an informative article on this subject and have it posted on Greg’s site and as a “Sticky” in FAQ (if this forum has that facility) for all to read and thus reduce the instance of future “going round the buoy again” posts on this subject.

#63

Greg Elmassian said:

Just taking one of the many good points Michael made:

“Why hasn’t anyone inquired about the effects of slow charging our Lithium cells/batteries???”

Because, reading carefully from the responses of the people who sell them and people who assemble them and users, the ASSUMPTION has been made that slower charging is safer and “simpler”…

No facts to back this up except people claiming no issues. Do they know if the lifetime/power capacity has been compromised? I’m pretty sure not.

The problem at this point in the thread, is further discussion would involve statements like: “Just selling batteries does not make you an expert”, or the fact that it has worked so far does not mean it is the best way.

I have no wish to polarize or cause issues here, Michael has stated what my engineers and my research as an engineer has yielded. I run a small company of electronic engineers that design things and we always go by the manufacturer’s specifications, and work the their recommendations first.

Anyway, I stopped “trickle charging” batteries about 30 years ago, as I had shorter battery lifetimes as predicted by the people who were battery experts at that time.

Greg

Why hasn’t anyone shown video of “their” trains running using Li-ion batteries yet? Do they really work or is this just a discussion about how to make them work properly with no proof that they really work ?

#64

Rooster ’ said:

Why hasn’t anyone shown video of “their” trains running using Li-ion batteries yet?

I have in a previous post.

I build my own.

My Bachmann’s pull 7 cars for about 4 hours. I’m not sure of the ma hours of these packs because I make them from defective battery operated power tool battery packs. I’m the equipment manager for a large contractor and when a battery pack comes in as defective, I dispose of it…

Adam

#65

What tests do you do to determine which you salvage?

#66

Greg Elmassian said:

What tests do you do to determine which you salvage?

I separate all the cells, from the battery packs, and check their voltage with a digital multi meter.

What I have found most often then not is the BMS has given up the ghost. Or, occasionally, one cell has very low voltage. I’m surprised, most cells are within .05 volts of them selves.

I buy the 18650 battery holders and 4S BMSs from ebay and wire it all up so I can swap battery packs out easily. The BMSs are not “balance charge” BMSs just over charge/undercharge and over current, 4 or 5 amp. I always have extra battery packs charged and ready to go. I started putting the date on the batteries so I can try and keep track of how old they are and what ones seem to not perform as well.

I have two chargers, both Tenergy’s. One charges at .5ah and is manual voltage select-able, 1-4 S. The other charges at 1ah and is fully automatic. These seem to work fine for me.

I’ve never owned a brand new Li-ion battery pack and have never did any “scientific” testing on the packs that I’ve built, so I don’t really know how good these are. I know I can run my Bachmann 4-6-0s with Revolution controllers and MyLocoSound cards pulling seven cars for about four hours at a prototypical speed, or about 48-52% on the Revolution controller. I’m not sure if I can ask for something better?

I’m very happy with these, never had a mishap. And, the cost to me is minimal.

Adam

#67

I’ve found similar failure modes in lithium packs, I get more from laptop packs than tools, but same experience, although the electronics around the laptop cells is sometimes more sophisticated, and some do indeed have “taps” between the cells.

I typically mark the terminal voltage, and I have a charger that will monitor the amount of charge in mah that goes “into” the cell. When the cell stops accepting a fair amount of charge, I dispose of the batteries.

The battery holders worry me a bit, but probably better than soldering to the batteries themselves, and I don’t have the spot welder to put new jumpers on.

My experience that with name brand batteries, they wear more evenly, and ones that have no name on the outside, it is often just like you say, a single cell in the series array.

Greg

#68

Greg Elmassian said:

I’ve found similar failure modes in lithium packs

I thought your RR equipment was strictly DCC?

#69

Greg Elmassian said:

The battery holders worry me a bit,

I’ve purchased the 18650 holders from a number of different sellers on ebay and found all to work well. They hold the batteries tight.

I made 2S packs and installed them on all my passenger cars. I epoxied the holders to the bottom of the cars after removing the original 9 volt battery holders. I’ve been running these for a couple of years now and not one battery has fallen out or even became loose, they’re hanging upside down. As a mater of fact, I have to pry them from the holders. it’s pretty hard to remove them with just your fingers.

I’m very happy with my battery setups. No flickering lights. No track cleaning. No special block or reversing track wiring.

Just like the real thing, the locomotive carries it’s own fuel.

Adam