Back after a multi-year absence from the hobby
10-25-2021, 07:31 AM
#1
Back after a multi-year absence from the hobby
I am at a point where I can finally concentrate on building and flying. Kids are all gone, house and other obligations are being handled, and we just fed the dogs! The last field permit I have is from 2015. That is probably the last time I was at the field. My planes are all glow of the 60-96" variety. The batteries I have all all either nicads or NiMH. They have been mostly replaced in the last 5years and are charged and have been cycled. My question is are the newer Lipo and other new batteries that much better than Nicads and NiMH batteries? I can still find NiMH batteries that are reasonably priced. Even though it is late in the year, I am going to head back to the field in the next coupe of weeks to see if anyone is there to talk to. Please feel free to comment. Thanks, Tracy.
10-25-2021, 08:08 AM
#2
I still use fresh nimh batteries in my tranny and receiver packs for my glow birds.......just got back into it this year after a long layoff. I bought my first lipos for an ep sailplane earlier this year.......needed new receivers and escs and chargers to play nice with them.
I don't really see the need to go lipo for receiver packs so, I'd go with what you got.....
I don't really see the need to go lipo for receiver packs so, I'd go with what you got.....
10-25-2021, 12:36 PM
#3
I know you've likely read all of the tales of woe regarding LIPO fires & such, but I think you'll find that if you look into LIFE you'll learn to love lithium
Last edited by init4fun; 10-25-2021 at 12:45 PM.
10-25-2021, 02:23 PM
#5
https://en.wikipedia.org/wiki/Lithiu...sphate_battery
https://www.batteryspace.com/LiFePO4...Batteries.aspx
Here are a couple of links about them ....
https://www.batteryspace.com/LiFePO4...Batteries.aspx
Here are a couple of links about them ....
10-25-2021, 08:15 PM
#7
The only real downsides to continuing with NiCad or NiMH is that most have increased in capacity greatly from the old days. Which means longer charge times. And if you have a weight sensitive plane, finding small (lighter) packs can be hard to very hard.
Lithium Iron Phosphate (LiFe) are a great alternative to the older chemistries for flight packs. Nominal voltage per cell is 3.3v, so what is known as a "2S" puts out 6.6v. This is just a bit more than what 5 cell NiCads put out. Most systems will tolerate it very well, and give a bit more speed and torque to the servos. If pushing things makes you skittish, it is easy enough to find voltage regulators to put in line that will bring them down a bit, to be extra cautious. It sure is nice to be able to be able to routinely recharge in an hour (or less, depending on how low they are). Capacity is much higher, they are much lighter, and pretty safe from accidental fires. They must have a charger that is made to charge them. Almost all current multi-purpose charges do have the correct settings. While some do assemble their own packs from cells, it is better to buy pre-assembled.
A "3S" (9.9v) pack should substitute for 9.6v transmitter batteries too. But pack sizes and configurations that fit may be harder to find. And they generally have to be removed for charging, as the in-radio charging capabilities would no longer work for them.
Lithium Polymers (LiPO's) by themselves pack too much voltage for most old gear, They peak at 4.2v per cell hot off the charger. So a single cell is not enough, while a double cell is too much. Ditto for older TX's. They require their own charging routine, different than LiFe's. But again, recent chargers will have that as well.
The exception is an electric plane - they usually have an Electronic Speed Control for the motor that also supplies power to the rest of the plane, which has been regulated to 5v or so. So in those cases, LiPO's would be very useable for older equipment. With due care, they can be moderately safe, but standard recommendations are to always charge out of the plane/equipment, be monitored while charging, and be charged in an area where if something does happen they won't burn down your house, etc. Battery fires are actually pretty rare, but as Spiderman says "With great power comes great responsibility".
Slightly later editing: I should note, that LiFe's come off their high point after charge very quickly, and then put out their nominal voltage for almost the entire use of the pack. Then they fall off the cliff VERY fast. So using a meter to gauge remaining capacity is useless. Best is to fly a few typical flights for fixed amounts of time. Then see how many milliamps it takes to recharge. From there you can figure a rough idea of how many flights you can get out of a pack. It will be a lot! LiPO's have a bit of variation from start to finish, so a good meter can help you judge. But with electric planes one generally depletes the pack in one flight, so no need to try and guess "Do I have enough to go up again?" One almost never does,
Lithium Iron Phosphate (LiFe) are a great alternative to the older chemistries for flight packs. Nominal voltage per cell is 3.3v, so what is known as a "2S" puts out 6.6v. This is just a bit more than what 5 cell NiCads put out. Most systems will tolerate it very well, and give a bit more speed and torque to the servos. If pushing things makes you skittish, it is easy enough to find voltage regulators to put in line that will bring them down a bit, to be extra cautious. It sure is nice to be able to be able to routinely recharge in an hour (or less, depending on how low they are). Capacity is much higher, they are much lighter, and pretty safe from accidental fires. They must have a charger that is made to charge them. Almost all current multi-purpose charges do have the correct settings. While some do assemble their own packs from cells, it is better to buy pre-assembled.
A "3S" (9.9v) pack should substitute for 9.6v transmitter batteries too. But pack sizes and configurations that fit may be harder to find. And they generally have to be removed for charging, as the in-radio charging capabilities would no longer work for them.
Lithium Polymers (LiPO's) by themselves pack too much voltage for most old gear, They peak at 4.2v per cell hot off the charger. So a single cell is not enough, while a double cell is too much. Ditto for older TX's. They require their own charging routine, different than LiFe's. But again, recent chargers will have that as well.
The exception is an electric plane - they usually have an Electronic Speed Control for the motor that also supplies power to the rest of the plane, which has been regulated to 5v or so. So in those cases, LiPO's would be very useable for older equipment. With due care, they can be moderately safe, but standard recommendations are to always charge out of the plane/equipment, be monitored while charging, and be charged in an area where if something does happen they won't burn down your house, etc. Battery fires are actually pretty rare, but as Spiderman says "With great power comes great responsibility".
Slightly later editing: I should note, that LiFe's come off their high point after charge very quickly, and then put out their nominal voltage for almost the entire use of the pack. Then they fall off the cliff VERY fast. So using a meter to gauge remaining capacity is useless. Best is to fly a few typical flights for fixed amounts of time. Then see how many milliamps it takes to recharge. From there you can figure a rough idea of how many flights you can get out of a pack. It will be a lot! LiPO's have a bit of variation from start to finish, so a good meter can help you judge. But with electric planes one generally depletes the pack in one flight, so no need to try and guess "Do I have enough to go up again?" One almost never does,
Last edited by tedsander; 10-25-2021 at 08:35 PM.
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R L Watson (08-07-2022)
10-26-2021, 07:16 AM
#9
Call radical rc They can build you any size & shape battery that will fit in the transmitter compartment. I made my own A123 1000 mahr batteries to convert all 9 transmitters to LIFEPO4 cells. I have left the transmitter on over night & longer. Recharged to 90 or 100 % forever depending on how many decades old they were. A 123 can be stored for YEARS at full charge. Then recharged up to full power with no risk of a fire. Done it many times. I use a FMA Cell Pro 4 charger. I use ONLY the balance charger plug to recharge. No risk of a fire. No need to remove the battery from the plane to recharge. They DO NOT heat up as they discharge. If you only use the A 123 brand of LIFEPO4 cells. Mine are DECADES OLD.
11-01-2021, 09:31 AM
#11
I am at a point where I can finally concentrate on building and flying. Kids are all gone, house and other obligations are being handled, and we just fed the dogs! The last field permit I have is from 2015. That is probably the last time I was at the field. My planes are all glow of the 60-96" variety. The batteries I have all all either nicads or NiMH. They have been mostly replaced in the last 5years and are charged and have been cycled. My question is are the newer Lipo and other new batteries that much better than Nicads and NiMH batteries? I can still find NiMH batteries that are reasonably priced. Even though it is late in the year, I am going to head back to the field in the next coupe of weeks to see if anyone is there to talk to. Please feel free to comment. Thanks, Tracy.
Most servos / receivers that are more than 5 years old are rated at 4.8v to 6v (4-cell NiCad = 4.8v and a 5-cell NiCad = 6v).
So (in your case), if you simply swap out your Nickle-based cell packs for Lithium-based cell packs, there's a pretty good chance you will burn out the servos and/or the receivers.
Not to forget, but you would also need a charger that is designed to charge Lithium-based packs. If you try to charge a LiPo with a typical NiCad charger, they get angry.
You could do it if you wanted to add an adjustable output BEC with a 2-cell LiPo feeding the BEC (Battery Elimination Circuit) and adjust the BEC's output to 6v.
11-01-2021, 01:22 PM
#12
LiPo / LiFe / LiLon cells have a higher working voltage (4.2v) than a NiCad / NiMH cell (1.24v).
Most servos / receivers that are more than 5 years old are rated at 4.8v to 6v (4-cell NiCad = 4.8v and a 5-cell NiCad = 6v).
So (in your case), if you simply swap out your Nickle-based cell packs for Lithium-based cell packs, there's a pretty good chance you will burn out the servos and/or the receivers.
Not to forget, but you would also need a charger that is designed to charge Lithium-based packs. If you try to charge a LiPo with a typical NiCad charger, they get angry.
You could do it if you wanted to add an adjustable output BEC with a 2-cell LiPo feeding the BEC (Battery Elimination Circuit) and adjust the BEC's output to 6v.
Most servos / receivers that are more than 5 years old are rated at 4.8v to 6v (4-cell NiCad = 4.8v and a 5-cell NiCad = 6v).
So (in your case), if you simply swap out your Nickle-based cell packs for Lithium-based cell packs, there's a pretty good chance you will burn out the servos and/or the receivers.
Not to forget, but you would also need a charger that is designed to charge Lithium-based packs. If you try to charge a LiPo with a typical NiCad charger, they get angry.
You could do it if you wanted to add an adjustable output BEC with a 2-cell LiPo feeding the BEC (Battery Elimination Circuit) and adjust the BEC's output to 6v.
