I have a couple LiIon packs that don’t work as well as the others. Identical packs in identical locos with identical electronics have substantially different run times. I’m talking hours. Is the pack ruined? or just out of balance? is it fixable or should I dispose of them? For the record, I use the preset smart (dumb) chargers.
Thanks,
Terry
Hi Terry, it is possible to have a bad cell in a pack. If they are Cordless Renovation packs I can help you. Any other brand good luck. Can you tell me what the label on the pack states? Part # voltage and amperage. Then we can provide you with some help.
Don
Hard to say exactly what is wrong with out taking the pack apart and getting voltage measurements of each cell. It might be an imbalance issue or failing cell - both would give you reduced performance. The dumb charger isn’t helping you either.
I’ve not had good luck with the Tenergy cells as of late. A group of cells I bought just over a year ago and built into a 4 cell pack were left idle over the summer and the pack went flat-line (Zero Volts) on me and both my smart and dumb chargers refuses it. I’ll be disassembling and trying to see if it is a cell or a PCB issue.
Terry,
VERY common behavior of series-parallel battery packs with a damaged cell(s) resulting in the loss of one of the integral series batteries… The battery should be replaced. Its likely repairable with the right skill set and tools with the replacement of a cell or more. That said, without exactly the same cells it not really a good idea.
2200mAh battery = one set of 2200mAh cells wired series.
4400mAh battery = two sets of 2200mAh cells wired in series-parallel
6600mAH battery = three sets of 2200mAh cells wired in series-parallel
So if you lost one cell sets wired in parallel said capacity would be lost.
Those dumb PCB’s don’t know any better, another case for smarter PCB with balance charge capabilities and or balance charge pigtail equipped batteries.
Michael
This sounds like a good reason to stick with NiMh batteries! (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)
I’ve had good luck with Cordless Renovations batteries and charger. Not cheap, but have been fine for years.
How so? One bad cell in one pack reflects the entire technology?
LiIon has it’s advantages and disadvantages, but it’s no more or less reliable than other technologies, in fact it has none of the “memory effect” of NiMih that you suggest.
The reason that I comment is to avoid adding to “old wives tales” in the knowledge base, people are still learning, let’s help people with good information.
Back to the thread, I think there are a lot of substandard quailty, i.e. “seconds” hitting the market and being bundled up as sold as first quality.
Greg
Joe Zullo said:
This sounds like a good reason to stick with NiMh batteries! (http://largescalecentral.com/externals/tinymce/plugins/emoticons/img/smiley-wink.gif)
All my batteries are 14.8v LiIon. 2 are 2200 Mah (or 2400 or 2600 I don’t remember) bought from battery space I think powerizer? the other 2 are a 4400 and a 6600 Mah from all battery, tenergy.
I got away from NiMH due to weight size and run time. Plus I don’t take care of my batteries. I destroy about 1 NiMH pack a month with my RC cars. I take proper charging and battery care and throw that out the window 
I also ‘almost’ burnt my house down twice with LiPo batteries because I set the charger wrong. Hence why I use the ‘kinda smart’ chargers. I plug them in and walk away. Plus I usually charge 4 locos at a time so buying a pile of smart chargers may get a bit pricey.
All in all I cant complain though. In the nearly 100 installs I have done I have had 4 failures. Not to shabby. So, would it be worth getting a smart charger and trying to balance and charge the packs? Is it even possible to balance a LiPo pack with only a +/- lead on it? Inquiring minds want to know? Or should I just cut my losses and move on?
Terry
The balance charger needs to “read” the voltage of each cell, and to be able to charge each cell individually.
With connections only at the “ends” of a string of batteries in series, there’s no way to control or measure them them individually.
I’d toss the pack. Why? Because you can assume the batteries all came from the same place, so consider what the odds are of another cell doing the same thing? I’d say the probability was high.
Greg
Like Greg says, the balance charger needs a lead from every cell. I’ve done it, but it ain’t pretty…
That pack has the PCB removed and the cells connected directly to the balance charger. This revived it for a while, but the same pack is misbehaving again so it was probably not worth the effort. In your case you would need to buy the balance charger plus rip the pack apart on a 50/50 chance at best that you can get a little more life out of it. Again I agree with Greg that maybe cutting your losses is thr best option.
In the future, try and charge unused packs once a month. I need to do that too as I lost all my plow packs by letting them sit idle for a year.
Hi guys, I tell my customers to pick two holidays and charge your lithium batteries at least twice a year.
Terry I sell the Cell-Con lithium smart chargers and CR-1 universal smart charger along with the Cordless Renovations 14.8v 2200 packs. For forum members take 5% off my web site prices. Our products are made in the USA. Only the cells are bought from Samsung.
Don
In my experience I have noted that most of the time users with series-parallel batteries with issues don’t recognize it… Those that do are generally running their batteries down to a DOD (depth of discharge) that is abusive and ultimately negates a long life cycle.
I learned of this shortcoming and or behavior with giant scale RC planes many years ago before Li-Ion batteries found their way to model trains. Voltage degradation under load was and is the tell. My planes like many had ten or more high powered digital servos together with two 4400mAh batteries; feeding said servos was a push as we later recorded several models pulling in excess of 24A momentarily while performing aerobatic maneuvers. A single 4400mAh battery can sustain rated voltage under an eight amp load for twenty minutes, after that the voltage falls off very quickly… I discovered many batteries with suspect batteries with an ESV (expanded scale voltmeter) generally these devices can provide a one or two amp load while displaying the voltage. A pre-flight to validate the flight system power supply was viable required connecting a voltmeter and or your ESV without necessarily engaging the load together with a quick stir of the transmitter sticks, this employed eight or more digital servos simultaneously. Batteries with a defective series sub–set of cells browned out every time…
In our circumstance if you’re accustomed to running your pride and joy for multiple hours on end and suddenly run time has diminished you now know the tale.
It is NOT recommended that Li-Ions be discharged completely to cut-out specifications as many allude to doing… Best case scenario is minimum discharge with re-charge intervals as often as desired! This is easily accomplished if you have a charger capable of providing the appropriate charging current value for your specific battery capacity and voltage. From what I have noted and observed this is rarely the case. The correct charger for your 2200mh battery is NOT the right charger for your 4400mAh or larger battery. Maximum time under charge for any depleted Li-Ion cell far as I know is THREE hours!
I’ll go out a limb and suggest anyone that suggests different is uninformed. It’s easy enough to validate my assertions by reading the OEM cell manufactures readily available data sheets.
Michael
I’ve used, and more importantly studied rechargeable batteries since before I graduated college in 1974… you are right on for everything I have learned Michael.
It’s unbelievable in today’s day and age that the old “rules” for completely discharging nicads (which was not a good idea in the first place) are applied to all battery chemistries by anyone, but I even see it from manufacturers.
There’s no such thing as memory, there are various types of damage that have symptoms ATTRIBUTED to the “theory” of battery memory.
Greg
I think people are fooled by the spec for number of charge/re-charge cycles of a cell or pack, thinking that by squeezing the most life out of each cycle that they are extending the amount of use they will get when in fact the effect is just the opposite.
I took me a long time to realize this. I used to always run my packs until they reached automatic cut-off before recharging. Thanks to what I’ve learned here I try and recharge long before that point is reached.
This is pretty easy with my trains as I rarely run any one system long enough to completely discharge, but with my cordless drill it’s usually not possible to figure out when the battery is falling off and get it on the charger before cut off. Even with this abuse the two packs that came with the drill 4 years ago are still strong - Ryobi must be using quality cells.
Since we are talking bad batteries, through the years I have accumulated several bad or old tech. batteries. What is the proper place to dispose of them?
Home Depot and Lowes both have recycling bins, I found our Lowes took batteries, flourscent lamps and cell phones.
Greg
I wasn’t aware that HD and Lowes had recycling bins, that’s great info… Radio Shack used to allow customers to drop-off old batteries, alas they are no more. Many hobby shops again allow customers to drop off discarded batteries too. And local Waste Management facilities (county dump) now offer recycling/drop-off of fluorescent tubes, batteries, paints and oils too.
Michael
yep all the lowes and HD’s here in Sandy Eggo have them in the store.
They are normally near the exits and/or customer service/return counters.
Greg
Michael Glavin said:
… Radio Shack used to allow customers to drop-off old batteries, alas they are no more.
Not all Radio Shack stores closed. Mine is still open as usual. IIRC they closed about 1700 stores nationwide though.
http://qz.com/340292/here-are-all-the-stores-radioshack-is-closing/
Thanks for the advice and tips.
Terry
