I was running trains and wanted to see how long it would run. It ran for about 4 hrs. till it stopped. Now the battery will not take a charge. It is a Li-ion 14.8 V 5200 mAh. The charger is Tenergy TB6B.
Are you getting an “Undervolt” or “Low Voltage” error message on the TB6B when you commit to the charge? If so, it means that they were over-discharged. The PCB didn’t cut off soon enough.
I have a couple of packs that were abused that will do this. I put them on my Universal Smart Charger (really a dumb charger) and it doesn’t care and will bring them up. They don’t have the shelf life that a good pack does - like I said they were abused and I’m just squeezing what little life I can get out of them.
I don’t see my dumb charger listed on-line any more. Probably because it’s not very good and has been replaced by chargers with a little more smarts.
Could he use a wall wart, or something, to trickle charge them for a short time? Just to get them up to where the smart charger can “see” how many cells are there and then be able to charge the pack. I do not know, that is why I am asking.
Theoretically that’s what a dumb charger is. I don’t know what voltage and current to use that would be somewhat safe - so I really can’t answer that.
Its not recommended you attempt to bring back an over discharged Lithium battery, yet anecdotal evidence abounds of same.
My recollection is the reanimated cells tend to short out. The Ions don’t reattach to the foil or something similar.
And remember trickle charging Lithium’s is NOT recommended, yet is the method used herein. If you go here do NOT leave the battery unattended, pay attention to the batteries temperature, only charge for a short time IMO.
Michael
Just to be sure I understand, the idea here is to put enough charge into the cells to “unlock” the cutoff circuitry, not actually perform a charge cycle.
So would it be best to apply some charging current, then connect a smart charger?
Greg
Greg,
There must be some voltage present to start with. So as John alluded to if the charger suggests “low voltage” the PCB did NOT kick in and perhaps the battery can be resurrected (again this is NOT an OEM recommended practice). Smart Chargers will not initiate a charge if the voltage is below a known parameter based on cell count settings.
If the PCB is open an actual smart charger will suggest “open circuit or connection break”. Resetting the PCB is a must.
I can’t recall the specific method or needs to unlock a PCB that has interrupted the potential path. Some chargers claim to be able to do same.
Michael
I’m getting an over voltage warning on the charger. I checked all my settings and they are correct.
Louis,
“OVER VOLTAGE” suggests the battery is providing some voltage but is below that of the minimum voltage parameter required of the battery under charge. This is a factor of the batteries cell count. A 14.8V/4S setting is required for the battery you note above. Unbeknownst to most users, Li-Ions cells are actually rated at 3.6V, NOT 3.7V as you note. Accordingly if your charging them at 14.8V/4S your slightly overcharging them. Your charger can be set-up for Li-Ion voltage and should be!
Something to ponder, your 5200mAh battery is comprised of two four cell 2600mAh batteries (4S1P) wired in parallel and is recognized as 4S2P 5200mAh battery. Its plausible one of the batteries is suspect not both. In any event a single cell of either battery can be the culprit herein.
Notwithstanding assuming you believe your battery pack is charged, one can ascertain there is an issue with said battery by load testing it. If voltage degradation occurs with a 1 amp load, one of the 4S1P batteries is suspect.
Do you have a DC voltmeter, if so note the batteries current voltage please.
Michael
Problem solved, user error. Sorry guys.
Let me take this opportunity to thank everyone that has helped me with my past problems. I seem to only ask for help and not offer much in return.
I will be posting some photos and maybe a video of my layout in the near future.
Lou
Louis,
Please enlighten us?
Are you charging as Li4S @ 14.4V?
Michael
Louis,
And I may I suggest you NOT run the battery down until such time the train stops. Doing so is detrimental to your batteries life cycle. It seems to be a common practice but is NOT recommended… And will undoubtedly cause premature battery failure. Best case is to run for a reasonable time interval and recharge. There is no consideration for charging a partially depleted Lithium, recharge it at any state of discharge as often as you like.
Michael
I installed my first Airwire drop in decoder in my USA F3. It has a charging jack built in. I was trying to charge thru the battery jumper from the A unit to the B unit.
I’m powering the A and B unit with one decoder, battery in both units, and one sound card with a speaker in both units.
Michael Glavin said:
Louis,
And I may I suggest you NOT run the battery down until such time the train stops. Doing so is detrimental to your batteries life cycle. It seems to be a common practice but is NOT recommended… And will undoubtedly cause premature battery failure. Best case is to run for a reasonable time interval and recharge. There is no consideration for charging a partially depleted Lithium, recharge it at any state of discharge as often as you like.
Michael
This is great advice that I wish someone had given me a couple of years ago. I assumed since LiIons have a limited number of charge/discharge cycles that by running the pack for as long as I could that I was going to get more use out of those limited cycles. It does make sense that running them down to the PCB cut-off voltage discharges them deeper than the ideal. I will be changing my recharge habits immediately.
Thanks Michael. I was not aware of that.
John,
While its true Lithium batteries have a suggested charge/discharge cycle life of 300-500 cycles. Proper charge regimens and minimum DOD (depth of discharge) is king herein. That said in my experience our batteries nary ever saw 500 cycles, yet failed to provide rated voltage/current anywhere between one and five years(R/C aircraft flight systems). To that end some lived much longer yet were unable to supply rated voltage under load. Lithium cells are a consumable, and have an anticipated life cycle of five years or so. Life begins once the chemicals are combined at the manufacturing facility. Matters not how many cycles one realizes, even a properly maintained lithium battery will eventually succumb to age and fail.
Most of the PCM’s offered interrupt at 2.5V well below the OEM 3.0V recommendation. Excessive DOD lends itself to most early cell failures, heat is right there too.
Michael
Louis,
Your quite welcome, have fun.
Michael
Daktah John said:
Michael Glavin said:
Louis,
And I may I suggest you NOT run the battery down until such time the train stops. Doing so is detrimental to your batteries life cycle. It seems to be a common practice but is NOT recommended… And will undoubtedly cause premature battery failure. Best case is to run for a reasonable time interval and recharge. There is no consideration for charging a partially depleted Lithium, recharge it at any state of discharge as often as you like.
Michael
This is great advice that I wish someone had given me a couple of years ago. I assumed since LiIons have a limited number of charge/discharge cycles that by running the pack for as long as I could that I was going to get more use out of those limited cycles. It does make sense that running them down to the PCB cut-off voltage discharges them deeper than the ideal. I will be changing my recharge habits immediately.
Louis and John: Add me to the list of engineers who will never again run the power down to where the train stops. Somehow I, too, thought that running them all the way down was a good thing. Read and Learn I guess!
Are there any ill effects from an incomplete charge? My truck’s stereo has a USB port for music in and charge out. I often charge devices as I drive, the charge stops when I stop the motor, sometimes after short travels, then I’ll finish the charge later.
Thanks for your time.
John
John,
Far as I know, minimal DoD and partial charging is best for lithium batteries with regard to cycle life across the board. There is information from reliable sources that suggest estimated life cycle counts grow exponentially with soft discharge and early charge termination.
The 300-500 life cycles offered by the OEMs is predicated on complete charge discharge cycles. Partial discharge and recharge skews the estimate in favor of increased cycles.
Michael