Life Battery Status/Cycling
11-18-2018, 05:13 PM
#1
Thread Starter
Life Battery Status/Cycling
OK, so I've seen the light, tossing all of the old NiMh batteries and switching over to Life batteries. Found some inexpensive ones at Value Hobby and thought I'd give them a try (GForce 5C 1500mAh 2S 6.6V LiFe RX Pack - LiFe Batteries - Batteries - Power | Value Hobby ). Ordered several and charged them up. Charger cut off at 7.19 or 7.2 each time. While checking the cell balance noticed that the (collective) voltage was falling even as I was checking the balance charge directly off the charger. Five packs. After a bit, maybe a couple of hrs or so, every one was down to somewhere in the neighborhood of low 6.8something to high 6.7 something.. OK, so I thought first charge, let's balance charge them. Well, same results. OK, let's try cycling them. Even after reading thru several threads not sure of safe cutoff voltage so chose 6.4V. end of charge/cycle, same results for all packs. Unfortunately didn't keep track of MA discharged or put back in but it wasn't near advertised capacity.
First, is it normal for overall voltage to fall that quickly?
Second, what is a good/recommended cutoff voltage for cycling these cells?
Third, what is an acceptable spread between cells when balancing?
Haven't been able to get the vendor to answer their phone line so no help there.
Oh yeah, these "packs" seem to be made up of two cylindrical cells (like NiMh) as opposed to a more flat pack.
Are these cells useable/reliable for aircraft use and, if so, what is the best maintenance/check procedure.
TIA for your insight.
G42
First, is it normal for overall voltage to fall that quickly?
Second, what is a good/recommended cutoff voltage for cycling these cells?
Third, what is an acceptable spread between cells when balancing?
Haven't been able to get the vendor to answer their phone line so no help there.
Oh yeah, these "packs" seem to be made up of two cylindrical cells (like NiMh) as opposed to a more flat pack.
Are these cells useable/reliable for aircraft use and, if so, what is the best maintenance/check procedure.
TIA for your insight.
G42
11-19-2018, 03:28 AM
#2
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Go to Hangtimes Hobbies and read their LiFe battery section. The answer should be there for all your questions.
Frank
Frank
11-19-2018, 05:11 PM
#3
Thread Starter
Go to Hangtimes Hobbies and read their LiFe battery section. The answer should be there for all your questions.
Frank
Frank
In spite of all of the valuable information on Hangtimes I still can't find answers to my questions.
Doesn't anyone cycle their Life batteries to determine capacity?
Seems like my Hobbico and Spektrum batteries are also displaying the same quick voltage drop after being charged on two different chargers (Hitec X4 and a Turnigy)
I'm baffled and concerned.
11-19-2018, 07:43 PM
#4
TI went to your link at Value and read their writeup on this pack. In their description they mention A123 which these cells are not likely as per their pricing....too low. Kind of insinuating but not stating outright. UNLESS , they are recycled cells someone has split up and taken out the better cells and re-assembled packs.
A123 Systems has never made a 1500 mah cell that size , only 1100,2200 and 2500 mah in a cylinder. Some shifty retailers or assemblers inflate their numbers by discharging the pack to the minimum threshold of 2v per cellfor 4v in a pack which is useless. Minimum 2S pack should be about 2.5v per cell or 5v as then they drop quickly.
There are many out there that use cheap Life cells that really don’t supply the goods and inflate the numbers.
You should be able to charge the packs to 6.6v and when discharging ... down to 5 volts for a 2S pack. All this information
should be supplied by the retailer.
If you had access to some battery heat shrink tubing you could pull the covering to see what brand they are and go from there.
A123 Systems has never made a 1500 mah cell that size , only 1100,2200 and 2500 mah in a cylinder. Some shifty retailers or assemblers inflate their numbers by discharging the pack to the minimum threshold of 2v per cellfor 4v in a pack which is useless. Minimum 2S pack should be about 2.5v per cell or 5v as then they drop quickly.
There are many out there that use cheap Life cells that really don’t supply the goods and inflate the numbers.
You should be able to charge the packs to 6.6v and when discharging ... down to 5 volts for a 2S pack. All this information
should be supplied by the retailer.
If you had access to some battery heat shrink tubing you could pull the covering to see what brand they are and go from there.
Last edited by stegl; 11-20-2018 at 11:05 AM.
11-20-2018, 05:35 AM
#5
Here's the short answer, A123/LiFe packs discharge quickly to a stabilized voltage like you're seeing, its completely normal. Then they hold that voltage until they die and then drop off quickly so sticking a volt meter on them to determine remaining capacity is useless.
Charge them, fly once or twice, charge them again with a good charger and note how many mah you put back, come up with an average value per flight. From there you can use the capacity of the cells to determine a number of safe flights.
Say you get 350 mah per flight used, and its a 2000 mah pack, I'd probably fly 4 flights and charge, knowing you have a 5th flight in your pocket if you need it. That and they charge so fast there's no reason to push them.
Those packs don't benefit from cycling. If you want to do it occasionally as a capacity check, have at it, I just watch the numbers going back and look for anomalies. And I use A123 and LiFe batteries in a lot of planes including turbine jets.
Charge them, fly once or twice, charge them again with a good charger and note how many mah you put back, come up with an average value per flight. From there you can use the capacity of the cells to determine a number of safe flights.
Say you get 350 mah per flight used, and its a 2000 mah pack, I'd probably fly 4 flights and charge, knowing you have a 5th flight in your pocket if you need it. That and they charge so fast there's no reason to push them.
Those packs don't benefit from cycling. If you want to do it occasionally as a capacity check, have at it, I just watch the numbers going back and look for anomalies. And I use A123 and LiFe batteries in a lot of planes including turbine jets.
11-20-2018, 05:05 PM
#6
Thread Starter
Thank you for your replies and explanations....they've helped immensely.
What I gather from them is that:
First charge each pack, let it sit for a while.
Discharge to 5V. I'll have to use a NiMh discharge setting since my Life setting will do only 4 or 6.
Full charge using Life setting to 7.2V and note Ma put back in for tentative baseline(s). Plural used since each pack MAY be different.
Fly a couple of flights (each pack) to get approximate consumption baselines.
Go from there.....
Lastly: "You get what you pay for". Another lesson learned!
Wish you all a Happy Thanksgiving.
G42
What I gather from them is that:
First charge each pack, let it sit for a while.
Discharge to 5V. I'll have to use a NiMh discharge setting since my Life setting will do only 4 or 6.
Full charge using Life setting to 7.2V and note Ma put back in for tentative baseline(s). Plural used since each pack MAY be different.
Fly a couple of flights (each pack) to get approximate consumption baselines.
Go from there.....
Lastly: "You get what you pay for". Another lesson learned!
Wish you all a Happy Thanksgiving.
G42
11-20-2018, 06:07 PM
#7
Before you start to do anything with any lithium based cells with the charger you have there that seem to have many limitations I would invest in a proper smart charger before you end up with a lithium fire.... there is nothing that will put it out. Once it starts to burn it burns till consumed.
11-20-2018, 07:05 PM
#8
Thread Starter
Before you start to do anything with any lithium based cells with the charger you have there that seem to have many limitations I would invest in a proper smart charger before you end up with a lithium fire.... there is nothing that will put it out. Once it starts to burn it burns till consumed.
Problem is that both insist on taking 2S Life's down to 4V on a cycle setting.
If I choose to discharge (only) on an NiMh program I can have it cut off at 5V, A more realistic value for usable Ma.I can then charge again using the "proper" Life program.
But thanks for the warning.
11-21-2018, 01:55 PM
#10
Thread Starter
11-21-2018, 06:17 PM
#11
Looking at the manual of the Hitec X4 smart charger the lowest you can discharge a Life cell is 2 volts per cell or higher... that means to me that the 2V can be adjusted upwards.
BUT not less than 2V for safety's sake as set up by Hitec. Also you can select from 1 cell upwards.......to the max listed in the charger specs..which is 6 cells and that is because the balance boards are designed to accept that number and that is adjusted by the user.. Never charge or discharge lithium based batteries without using your balance board.
BUT not less than 2V for safety's sake as set up by Hitec. Also you can select from 1 cell upwards.......to the max listed in the charger specs..which is 6 cells and that is because the balance boards are designed to accept that number and that is adjusted by the user.. Never charge or discharge lithium based batteries without using your balance board.
Last edited by stegl; 11-22-2018 at 07:17 AM.
02-01-2019, 01:25 PM
#12
Better late than never about the A123 cells...…………. I have them in a floor vacuum cleaner. I have a FMA very smart charger. It is set for ONLY LIFEPO4 cells I made the 3 & 4 cell packs 10 years ago ? I run it down to 5 % or 10 % left every weekend. They still charge up to between 90 & 100 percent 3.6 Volts per cell is maximum BALANCED full charge.
Yes you can store them fully or at about 25% charge & nothing bad has ever happened.. In all the years & over a dozen 3& 4 cell packs of A 123 Both 1100 & 2300 mahr sizes. Old stuff.
Yes you can store them fully or at about 25% charge & nothing bad has ever happened.. In all the years & over a dozen 3& 4 cell packs of A 123 Both 1100 & 2300 mahr sizes. Old stuff.
02-01-2019, 03:06 PM
#13
Better late than never about the A123 cells...…………. I have them in a floor vacuum cleaner. I have a FMA very smart charger. It is set for ONLY LIFEPO4 cells I made the 3 & 4 cell packs 10 years ago ? I run it down to 5 % or 10 % left every weekend. They still charge up to between 90 & 100 percent 3.6 Volts per cell is maximum BALANCED full charge.
Yes you can store them fully or at about 25% charge & nothing bad has ever happened.. In all the years & over a dozen 3& 4 cell packs of A 123 Both 1100 & 2300 mahr sizes. Old stuff.
Yes you can store them fully or at about 25% charge & nothing bad has ever happened.. In all the years & over a dozen 3& 4 cell packs of A 123 Both 1100 & 2300 mahr sizes. Old stuff.
I might mention also that A123 systems never made a 2300 capacity cell . there are sellers that will advertise it as such but only made the 1100 and the 2200. Sure you can discharge to almost zero and call it a 2300 but cutoff is recommended at 2.5 volts making it a 2200 cell.
02-01-2019, 04:58 PM
#14
I use the MAHR put back in method. FMA Cell Pro 4 shows all current put in. At 81 I cold be wrong On the 2300. But I thought tye bigger cell was more power for less weight. Will dig around on the labels with A123 & codes on it. I will surf the numbers.
02-01-2019, 05:20 PM
#15
I found the the ratings for the 2300 mahr cells in 2006 & 2007 on a forum promoting them. A123-M1 was the code & sold loose with a white wrapped paper sleeve B & D bought millions for their cordless tools.
The old guy still has it.
The old guy still has it.
02-01-2019, 07:01 PM
#16
Have been making up the A123 packs for some time so have done more than my homework. Example ; I have a so called 2300 mah pack here as labeled by a reseller and pulled the covering off. The numbers are exactly the same as the 2200 I sell and A123 systems advertises. Checking the A123 systems and on their specs they say to never discharge below 2v per cell and the recommended discharge cut-off voltage per cell is 2.5v . This is from A123 Systems themselves not a reseller. Sure I could advertise them as 2300 mah but what good is a 6.6v pack when it is down to 4v (2S).... to me that is false advertising . As for the brown paper sleeves on the B&D packs that was bulk ordered that way by B&D as a cost feature back a number of years ago. Since then pretty much all your cordless power tools have gone with Lithium-ion cells with various specs and done mainly as a cost saving measure plus they get slightly more in voltage . The cost saving between the A123 Systems and Lithium-ion is fairly substantial. when looking at many hundreds of thousands of cells per manufacturer.
02-02-2019, 08:53 AM
#17
You are a arrogant business person. Can not admit that my 2300 cells did GET SOLD in 2006 & 2007 by A123 & B & D. They were classified as Racing Type. Used in motorcycle that did o to 60 MPH in 1 second. The cycle was then setup for the 1/4 mile did a 168 MPH.
I do my home work better than you do about my cells.
I do my home work better than you do about my cells.
02-02-2019, 09:09 AM
#18
You are a arrogant business person. Can not admit that my 2300 cells did GET SOLD in 2006 & 2007 by A123 & B & D. They were classified as Racing Type. Used in motorcycle that did o to 60 MPH in 1 second. The cycle was then setup for the 1/4 mile did a 168 MPH.
I do my home work better than you do about my cells.
I do my home work better than you do about my cells.
I also might add that in my experience as well as many, many other users the A123 cells are one if not the best cell out there providing huge amounts of energy for such a small cell . I never said that they were no good. Lithium cells are always be evolved into something better and better as time goes on. The 2200 cell has been replaced by the 2500 cell... same size but more capacity.
Last edited by stegl; 02-02-2019 at 09:31 AM.
