3dbandit
100cc
I had one fail where the voltage fell to zero when it still had 75% of its capacity left though...
I am just most comfortable running lipo or A123 so that is my recommendation.
Life batteries
- Thread starter bjackson1206
- Start date
I had one fail where the voltage fell to zero when it still had 75% of its capacity left though...
I am just most comfortable running lipo or A123 so that is my recommendation.
Santi8
70cc twin V2
Gary, are those lion packs fromeco relions? The newer technology lions can be charged in lipo mode to 8.4, I haven't seen any 8.2 packs recently... I've been slowly switching my lipos over to lions. My fpv stuff is mostly lion.
gyro
GSN Contributor
No, they're original Li ion from TBM. Probably should upgrade them to 2600mah Relions at some point.
3dbandit
100cc
Here's what i have found on the matter; they are the same chemistry, but the A123 cells have a better construction.
http://www.fly-imaa.org/blog-posts/new-products-for-giant-scale-modelers
Q: What's the difference between A123 LiFe packs and ordinary LiFe PO4 packs?
First is the A123's patented “nano†plating technology, at a molecular level the negative plate material stands like a shag carpet rather than laying 'end-to-end'. This produces an incredible amount of surface area gain for A123's negative plate and it's why A123 can tolerate immense current loading without voltage sag. Another benefit to the nano plating technology is a huge increase in cell life. All stored energy systems consume negative plate over time, with 100+ times the negative plate surface area generated by any competitors plating process the lifespan of the A123 cell is extended immensely. Next, A123's are aluminum cased cylindrical cells with welded alloy end plates and towers like a NiCad cell. This enables a rugged welded strap pack assembly system (like NiCads) that is exceptionally robust and very resistant to vibration and hard knocks. The LiFeSource™ packs are built with wafer stacked 'bag' prismatic cells, like LiPoly. And, like LiPoly, they are fragile, the cell link tabs are very thin alloy strips and the entire assembly is as a result susceptible to rough handling and vibration. Further, the prismatic cells and their tabbing system are unable to handle anywhere near the current loading the A123 system can tolerate with ease.
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If you want to know for sure, then I would send TailDragger RC a PM. Chad is very knowledgeable and friendly, I bet he would be more than happy to explain/verify.
cwojcik
70cc twin V2
I have used a lot of Hyperion LiFe packs and when I need lower voltages I really like them. I think I have used them in about 5 different airplanes. Hobbico LiFeSource packs are generally heavier and more expensive than the Hyperion ones.
I have also seen genuine A123 cells fail twice, losing all capacity. So they are not bulletproof either.
Advantages:
1. Hyperion LiFe batteries can be charged at 5C. They charge very quickly. Also, LiPo, LiFe, and LiIon batteries all charge in two different modes...first it charges at a constant current, then when the pack voltage gets to 4.2V per cell, it switches to constant voltage, and when the current needed to keep the battery at 4.2V per cell reaches zero, the pack is full. What I have noticed with LIFe batteries is that the CV portion of the charge only lasts a couple of minutes, whereas with a LiPo it lasts maybe 15 minutes. So a LiFe battery charged at 3C will usually finish before a LiPo charged at 4C.
2. No regulator necessary in most all cases. Servos designed for use with 4.8 or 6V systems are fine with a LiFe battery at 6.6V, because these servos were designed for 5 cell NiCd or NiMh batteries, which are 6V nominal, and about 7V fully charged. About the same as a LiFe pack through their discharge curve.
3. They are lighter by far than NiMh or NiCd and can be charged more easily
4. The voltage is perfectly constant through the whole discharge phase. They are 7.2V fresh off the charger, and will go down to 6.6V after just sitting there for a few minutes. They will stay at 6.6V until they are dead and then they just shut off. Some pattern and IMAC guys would complain about servo power and speed changing with unregulated LiPo's as they discharge, this does not happen with LiFe.
5. They are safer than LiPo's. Like any high-current battery there is a lot of energy in them, but they won't go into thermal runaway with a short.
Disadvantages:
1. The voltage is perfectly constant through the whole discharge phase. So if you are at 98% capacity and you check the voltage it will say 6.6V. If you are at 15% capacity the voltage is still 6.6V. The voltage tells you nothing. You absolutely must do one flight, charge the packs, see how much goes back in, and then do some math to figure out how many flights you can do safely. You should also do a cycle with your charger from time to see how much capacity it really has. This also means that if you get a cell to deteriorate prematurely, you won't know until it's too late (as Jacob knows). There is very little warning to when they give out.
2. They are heavier and more expensive than LiPo's.
I have gone to more and more HV servos so I have used them less and less, but they still have their place.
I have also seen genuine A123 cells fail twice, losing all capacity. So they are not bulletproof either.
Advantages:
1. Hyperion LiFe batteries can be charged at 5C. They charge very quickly. Also, LiPo, LiFe, and LiIon batteries all charge in two different modes...first it charges at a constant current, then when the pack voltage gets to 4.2V per cell, it switches to constant voltage, and when the current needed to keep the battery at 4.2V per cell reaches zero, the pack is full. What I have noticed with LIFe batteries is that the CV portion of the charge only lasts a couple of minutes, whereas with a LiPo it lasts maybe 15 minutes. So a LiFe battery charged at 3C will usually finish before a LiPo charged at 4C.
2. No regulator necessary in most all cases. Servos designed for use with 4.8 or 6V systems are fine with a LiFe battery at 6.6V, because these servos were designed for 5 cell NiCd or NiMh batteries, which are 6V nominal, and about 7V fully charged. About the same as a LiFe pack through their discharge curve.
3. They are lighter by far than NiMh or NiCd and can be charged more easily
4. The voltage is perfectly constant through the whole discharge phase. They are 7.2V fresh off the charger, and will go down to 6.6V after just sitting there for a few minutes. They will stay at 6.6V until they are dead and then they just shut off. Some pattern and IMAC guys would complain about servo power and speed changing with unregulated LiPo's as they discharge, this does not happen with LiFe.
5. They are safer than LiPo's. Like any high-current battery there is a lot of energy in them, but they won't go into thermal runaway with a short.
Disadvantages:
1. The voltage is perfectly constant through the whole discharge phase. So if you are at 98% capacity and you check the voltage it will say 6.6V. If you are at 15% capacity the voltage is still 6.6V. The voltage tells you nothing. You absolutely must do one flight, charge the packs, see how much goes back in, and then do some math to figure out how many flights you can do safely. You should also do a cycle with your charger from time to see how much capacity it really has. This also means that if you get a cell to deteriorate prematurely, you won't know until it's too late (as Jacob knows). There is very little warning to when they give out.
2. They are heavier and more expensive than LiPo's.
I have gone to more and more HV servos so I have used them less and less, but they still have their place.
Rolling.Circle
100cc
Great information guys. Learn some new stuff every day. We appreciate it!