LiFe battery questions?
11-10-2010, 04:00 PM
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LiFe battery questions?
I just ordered a couple of the new LiFe packs to try out. question one is how do I know when the pack is getting low, will a voltwatch work for this also what about a volt meater would that work?. Also what about charging them without a balancer or quick charging them without having to physically remove them from the airplane? Could I make it where i can charge them through the plane by making and adapter to charge through a servo lead? I am used to charging lipo's with a balancer for my rc cars and electric planes but these packs are for my nitro powered planes that get shoved up under a gas tank for weight and balance of the model sometimes or gets put in tight spaces thats hard to remove the battery every time i fly. thanks in advance
11-10-2010, 05:06 PM
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RE: LiFe battery questions?
As far as i know there is no way to check a life battery except to charge it and see how much you put back in. They have a very flat discharge curve and using a voltmeter or voltwatch will not work. I charge mine in the plane most of the time. I take them out every month or so and balance charge them.
11-11-2010, 10:33 AM
#3
RE: LiFe battery questions?
drbenz is correct; there's no suitable way to volt check either those batteries or their more expensive, higher output cousins the A123's.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
11-11-2010, 08:39 PM
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RE: LiFe battery questions?
I strongly recommend that you visit www.hangtimes.com. There is a lot of very useful info and setup recommendations there on A123s, including a few unique product offerings that make balance-charging these packs without removing them from the plane a breeze.
11-11-2010, 11:13 PM
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RE: LiFe battery questions?
thanks guys for the information and I will check out that website, I have done some research on here but can't really find the answers what i'm looking for also can a electrifly triton eq charge a123 batteries since it can charge the life batts.? My nimh batts are really giving me trouble by running down quick and I do charge them before each flight I mean like 15 min. before and after two flights its run down and they are all 6volt 2300mah packs. Also Zeeb you have had me ask you another question by bringing up the 50cc gas engine. I just bought a dle 20 to put on my 60 size gp extra, what mah battery would you run on a small gas engine like this. This will be the first gas engine for me and I also plan to put a smoker on the plane as well and I thought I could run one pack for the ignition and smoker and one pack for the rx. also could you use the ignition pack as a back up to the receiver pack by just plugging it into one of the non used servo ports on the rx?
11-12-2010, 10:22 AM
#6
RE: LiFe battery questions?
Ummm.... May I suggest that for your first venture into gassers you are pushing the envelope?
First; DLE's don't like anything over 6.0 volts input on the ignition. They say you can run 'em that way and some folks do, but Jody at Valley View (DLE dealer and service) and other knowledgeable folks agree, says it'll shorten the expected life of the ignition module if you exceed the 6.0 volt input limit. The nominal voltage on a 2 cell A123/LiFe pack is about the same as a five cell NiCD/NiMH at about 6.6 volts but they come off the charger at 7.2 volts.
Second; As I mentioned, I balance charge mine and the Triton will not do that by itself even if it has LiFe programming.
Third; while some folks are running a single battery for the rx/servos and the engine ignition, I'm not ready to go there yet. If you do, you need to pay attention to how that is setup. Some folks have thought it was okay to pull power for the ignition module from the rx buss, it isn't.
Fourth; smoke is kind of cool but it ads an average of 1lb. in weight to the model and for stuff the size you're talking about 1lb. is a LOT. Smoke systems can be fraught with issues from setup to leaks and getting that smoke oil out of the wood inside the model should it leak, is nearly impossible.
While it may be a bit frustrating doing the searches, all these questions have been covered extensively in various places here, other forums and manufacturer's websites as Beavis pointed you at and some folks will have different opinions than mine which you would probably benefit from hearing before you make a decision about how to proceed.
First; DLE's don't like anything over 6.0 volts input on the ignition. They say you can run 'em that way and some folks do, but Jody at Valley View (DLE dealer and service) and other knowledgeable folks agree, says it'll shorten the expected life of the ignition module if you exceed the 6.0 volt input limit. The nominal voltage on a 2 cell A123/LiFe pack is about the same as a five cell NiCD/NiMH at about 6.6 volts but they come off the charger at 7.2 volts.
Second; As I mentioned, I balance charge mine and the Triton will not do that by itself even if it has LiFe programming.
Third; while some folks are running a single battery for the rx/servos and the engine ignition, I'm not ready to go there yet. If you do, you need to pay attention to how that is setup. Some folks have thought it was okay to pull power for the ignition module from the rx buss, it isn't.
Fourth; smoke is kind of cool but it ads an average of 1lb. in weight to the model and for stuff the size you're talking about 1lb. is a LOT. Smoke systems can be fraught with issues from setup to leaks and getting that smoke oil out of the wood inside the model should it leak, is nearly impossible.
While it may be a bit frustrating doing the searches, all these questions have been covered extensively in various places here, other forums and manufacturer's websites as Beavis pointed you at and some folks will have different opinions than mine which you would probably benefit from hearing before you make a decision about how to proceed.
11-12-2010, 02:52 PM
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RE: LiFe battery questions?
zeeb
I know im probably going to have way to much power for the 60-90 size extra but it does fall in the same weight as a 125 saito four stroke(which the 1.2 fourstroke is recommended for the plane). and i'm going to go with some good hight torque light weight servo's to make up some of the weight as well also the life batts should less weight than the standard nimh. Also i'm not wanting to run one single batt for the set up i was just thinkink i could run a stand alone rx battery and then also maybe feed the ignition battery to the rx as well incase the rx battery would fail, i figure radio control is more important than the engine running if i did run the ignition/smoke battery down. Do I need to regulate the voltage to the dle ignition box somehow or run a 4.8 volt nicd or something? again thanks for your info and I will continue to do seraches and the website was a lot of help and has saved me some money after reading about the nimh and how to condition them. Thanks again for the help and responses they are greatly appreciated
p.s. the triton charger I got is the newer eq model that has balancing integrated on it, unless i'm missing something which is very easy for me to do.
I know im probably going to have way to much power for the 60-90 size extra but it does fall in the same weight as a 125 saito four stroke(which the 1.2 fourstroke is recommended for the plane). and i'm going to go with some good hight torque light weight servo's to make up some of the weight as well also the life batts should less weight than the standard nimh. Also i'm not wanting to run one single batt for the set up i was just thinkink i could run a stand alone rx battery and then also maybe feed the ignition battery to the rx as well incase the rx battery would fail, i figure radio control is more important than the engine running if i did run the ignition/smoke battery down. Do I need to regulate the voltage to the dle ignition box somehow or run a 4.8 volt nicd or something? again thanks for your info and I will continue to do seraches and the website was a lot of help and has saved me some money after reading about the nimh and how to condition them. Thanks again for the help and responses they are greatly appreciated
p.s. the triton charger I got is the newer eq model that has balancing integrated on it, unless i'm missing something which is very easy for me to do.
11-13-2010, 10:38 AM
#8
RE: LiFe battery questions?
Well okay a few more thoughts/opinions and as I've indicated, there will be other opinions for you to consider.....
First; the DLE is about 5oz. heavier than the Saito, add in 3-4oz. for a four cell battery to run the ignition and you're 1/2lb. over the glow engine. Add a pound for smoke and you're 1 1/2lbs over what the manufacturer figured on for model weight. There are two "rules" about aerobats; bigger fly's better, lighter fly's better. Adding an extra 1 1/2lbs. to a model that should come in somewhere in the 8 to 9lb. range is a bunch on the aerobats especially since they don't have wing washout, you'll aggravate the tendency to do what the modelers call a "tip stall". From your sig, I'm guessing your a full scale guy so I'll explain that they use this term to describe a stall which rather than occuring first at the wingroot like a full scale with wing washout, the tip goes first and you get a snap which seems to happen most often on a short final and you know what happens when you snap the puppy on short final.
Second; I seriously doubt that the little gasser will run with the Saito let alone have more power. I've got an old Funtana 90 with a YS-110 in it, weighes about 9lbs and really seems to be a pretty good combination up here at 4500' ASL. There are a couple of those models at our club running small gassers with one running the Zenoah 26 and the other running that RCC or whatever they call that brand which has the red cylinder heads. Both those models are heavier than mine and mine will run circles around either one. Now the YS puts out a chunk more power than the 125 Saito does, more like what a 150 Saito will do, but those guys are running bigger gas engines than what you have so I think the comparison is valid. Last point of this discussion is that the Funtana's have a chunk more wing area than an Extra so some weight gain on those models isn't as big an issue as it will be with an Extra.
Third; if you can find a NiCD battery for the ignition that would be great but I think you'll find that hard to do as the NiCD is going away due to environmental concerns, same issue which caused the change in the chemistry of the NiMH resulting in the peak detecting chargers having issues charging those batteries and false peaking especially if charged at too high a rate. So when you look at NiMH for an ignition or rx operation, you have to pay attention to the cells IR because if that's high like a lot of inexpensive cells are, they won't provide the needed current. Easiest way to spot those if the IR numbers are not available, is to look at the continous/burst output capability of one brand vs. another. Sanyo cells seem to be among the best for our hobby use, but refer to the hangtime hobbies/NoBS battery FAQ for more information on that issue.
Fourth; I have to plead ignorance on your charger as I have an older Triton which I use for lead acid charging and pulling down my A123's for cycling purposes and since I now use FMA chargers I wasn't aware of the capabilities of your specific Triton model. You'll just need to decide what type of balance lead you want to use and adapt things accordingly.
Fifth; if you choose to run something other than a 4 cell NiMH on that ignition, you should use a regulator or there is a mod where you intall one or two (depending on how much voltage drop you want) diodes inline with the power feed to the ignition module. There are threads about it here on RCU and the gas engine forum would be a good place for you to look and start watching for ideas about running gas engines in general. You could also get more input on the advisability of running higher input voltages to that ignition module from folks who have, and have not, done it.
Last; changing over to gassers isn't really that difficult and once you do I think you'll find it hard to go back, but there are some caveats to keep in mind when you make the move. Keep reading the forums as there's lots of information/ideas/solutions available and not all of 'em are going to agree with me and what I prefer to do so please keep in mind what I've said here is my opinion and not necessarily gospel.... lol
edit info:
Okay I was just over on the gas engine forum and there is a HUGE thread on your engine started by Jody from Valley View. He's one of the most respected posters here and is a DLE importer/service outfit, check it out.....
http://www.rcuniverse.com/forum/m_9863953/tm.htm
First; the DLE is about 5oz. heavier than the Saito, add in 3-4oz. for a four cell battery to run the ignition and you're 1/2lb. over the glow engine. Add a pound for smoke and you're 1 1/2lbs over what the manufacturer figured on for model weight. There are two "rules" about aerobats; bigger fly's better, lighter fly's better. Adding an extra 1 1/2lbs. to a model that should come in somewhere in the 8 to 9lb. range is a bunch on the aerobats especially since they don't have wing washout, you'll aggravate the tendency to do what the modelers call a "tip stall". From your sig, I'm guessing your a full scale guy so I'll explain that they use this term to describe a stall which rather than occuring first at the wingroot like a full scale with wing washout, the tip goes first and you get a snap which seems to happen most often on a short final and you know what happens when you snap the puppy on short final.
Second; I seriously doubt that the little gasser will run with the Saito let alone have more power. I've got an old Funtana 90 with a YS-110 in it, weighes about 9lbs and really seems to be a pretty good combination up here at 4500' ASL. There are a couple of those models at our club running small gassers with one running the Zenoah 26 and the other running that RCC or whatever they call that brand which has the red cylinder heads. Both those models are heavier than mine and mine will run circles around either one. Now the YS puts out a chunk more power than the 125 Saito does, more like what a 150 Saito will do, but those guys are running bigger gas engines than what you have so I think the comparison is valid. Last point of this discussion is that the Funtana's have a chunk more wing area than an Extra so some weight gain on those models isn't as big an issue as it will be with an Extra.
Third; if you can find a NiCD battery for the ignition that would be great but I think you'll find that hard to do as the NiCD is going away due to environmental concerns, same issue which caused the change in the chemistry of the NiMH resulting in the peak detecting chargers having issues charging those batteries and false peaking especially if charged at too high a rate. So when you look at NiMH for an ignition or rx operation, you have to pay attention to the cells IR because if that's high like a lot of inexpensive cells are, they won't provide the needed current. Easiest way to spot those if the IR numbers are not available, is to look at the continous/burst output capability of one brand vs. another. Sanyo cells seem to be among the best for our hobby use, but refer to the hangtime hobbies/NoBS battery FAQ for more information on that issue.
Fourth; I have to plead ignorance on your charger as I have an older Triton which I use for lead acid charging and pulling down my A123's for cycling purposes and since I now use FMA chargers I wasn't aware of the capabilities of your specific Triton model. You'll just need to decide what type of balance lead you want to use and adapt things accordingly.
Fifth; if you choose to run something other than a 4 cell NiMH on that ignition, you should use a regulator or there is a mod where you intall one or two (depending on how much voltage drop you want) diodes inline with the power feed to the ignition module. There are threads about it here on RCU and the gas engine forum would be a good place for you to look and start watching for ideas about running gas engines in general. You could also get more input on the advisability of running higher input voltages to that ignition module from folks who have, and have not, done it.
Last; changing over to gassers isn't really that difficult and once you do I think you'll find it hard to go back, but there are some caveats to keep in mind when you make the move. Keep reading the forums as there's lots of information/ideas/solutions available and not all of 'em are going to agree with me and what I prefer to do so please keep in mind what I've said here is my opinion and not necessarily gospel.... lol
edit info:
Okay I was just over on the gas engine forum and there is a HUGE thread on your engine started by Jody from Valley View. He's one of the most respected posters here and is a DLE importer/service outfit, check it out.....
http://www.rcuniverse.com/forum/m_9863953/tm.htm
11-14-2010, 09:52 PM
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RE: LiFe battery questions?
ORIGINAL: Beavis
I strongly recommend that you visit www.hangtimes.com. There is a lot of very useful info and setup recommendations there on A123s, including a few unique product offerings that make balance-charging these packs without removing them from the plane a breeze.
I strongly recommend that you visit www.hangtimes.com. There is a lot of very useful info and setup recommendations there on A123s, including a few unique product offerings that make balance-charging these packs without removing them from the plane a breeze.
11-15-2010, 08:35 AM
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RE: LiFe battery questions?
Thanks for the advice I'll check out that forum as well. And you are correct I'm a full scale pilot but have been flying models for over 15 years as well now, this is my first gasser though, I weighed the dle w/ muffler, ignition, and everything and it showed that it weighed the same as the 120 o.s. on tower's specs thats why I thought it would be okay, (I was planning on running dual batteries anyway too.) I know Im going to end up with a heavy model and after I test fly it and its not to my liking I'll just go to a os 95ax. but I already have the dle and want to try it on something. I have a couple of futaba 1100 mah 4.8 nicd packs, but i'll get over in the gas forum for that, but I think you have answered most of my questions about the life stuff, Thanks, it is greatly appreciated
11-16-2010, 07:09 AM
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RE: LiFe battery questions?
ORIGINAL: Zeeb
drbenz is correct; there's no suitable way to volt check either those batteries or their more expensive, higher output cousins the A123's.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
drbenz is correct; there's no suitable way to volt check either those batteries or their more expensive, higher output cousins the A123's.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
Rubbish, there are voltage and capacity checkers for LiFePO4 battery packs. Google is your friend.
HYperion EOSBAtery checker is one such devise.
11-16-2010, 08:29 AM
#12
RE: LiFe battery questions?
ORIGINAL: TimBle
Rubbish, there are voltage and capacity checkers for LiFePO4 battery packs. Google is your friend.
HYperion EOS BAtery checker is one such devise.
ORIGINAL: Zeeb
drbenz is correct; there's no suitable way to volt check either those batteries or their more expensive, higher output cousins the A123's.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
drbenz is correct; there's no suitable way to volt check either those batteries or their more expensive, higher output cousins the A123's.
As mentioned, what you do is to fly a couple of times and recharge noting the number of mah's replaced. Do that several times to get an idea of how much power your model uses and I break that down into how many mah's per minute. My little 50cc bird will use 13-15 mah's per minute on the rx and about 7-8 mah's per minute on the ignition, it has a 2300 mah battery on the rx and an 1100 mah on the ignition so you just charge accordingly. Best to not exceed 80% of capacity and less would be better....
They SHOULD be balance charged although it isn't necessary to do so each time, that is how most users operate. We don't push 'em hard enough with model use (A123's were originally introduced as cordless power tool batteries) and after a period of time you'll start to see some cell imbalance in the packs, that can be corrected by pulling 'em down hard several times and that usually matches them up again. The only way you'd know that an imbalance condition existed is if you balance charge. The packs also benefit from being balance charged for at least the initial 20 cycles or so and with A123's, cycling new packs 3 times usually helps as well.
You can charge through any setup you prefer or your charger can handle. I do use servo leads (20g wire with gold plated connectors) to charge mine and those connectors can take up to 4 amps continous and only get slightly warm. They are setup so you have the expected +/- leads and the signal lead is the balance tap on a two cell pack, then another servo lead is adapted to your charger's balance output lead type. Cheaper leads without the gold plated connectors should be restricted to about 3 amps max or whatever gets them any hotter than just slightly warm.
You don't need to pull 'em out of the model, they won't explode/burn like Li-Po's. If severly abused an A123 will just vent through a sealed hole in the case installed during manufacture. The only time I've seen someone do that is when they were intentionally overcharged to see what happens. Not sure about the LiFe stuff as those are copycats of the A123 and lots of manufacturer's put them out. Same chemistry but lower output capability compared with the A123.
There is LOTS of information on the forums including here at RCU on using A123/LiFe batteries, suggest you spend some time doing research as what I've touched on here is just kind of basic.
Hope that helps.
Rubbish, there are voltage and capacity checkers for LiFePO4 battery packs. Google is your friend.
HYperion EOS BAtery checker is one such devise.
11-16-2010, 09:23 AM
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RE: LiFe battery questions?
I have to agree with Zeeb. There are many threads, on RCU, discussing the merits of LiFe. They have many advantages, but it is well known that it is difficult to determine when the voltage will drop below acceptable levels when using just an ESV.
http://media.hyperion.hk/dn/sentry/m...ryMan12-EN.pdf
There is nothing in this manual that leads me to believe that this Hyperion ESV has some Magic making it easier, than any other ESV, to predict when a LiFe will run out of power. LiPos lose power at a predictable rate and keeping an eye on the voltage drop lets you know when it is time to recharge. This is not the case with LiFe.
http://media.hyperion.hk/dn/sentry/m...ryMan12-EN.pdf
There is nothing in this manual that leads me to believe that this Hyperion ESV has some Magic making it easier, than any other ESV, to predict when a LiFe will run out of power. LiPos lose power at a predictable rate and keeping an eye on the voltage drop lets you know when it is time to recharge. This is not the case with LiFe.
11-16-2010, 09:25 AM
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RE: LiFe battery questions?
Of course the Hyperion "checker" does not apply a load so it is in fact of little value for checking voltage. Unloaded voltage is a useless value to know. It is a nice device in that it shows individual cell voltage which "may" show you if something is starting to go wrong.
I use a charger that displays individual cell voltage during charge, which allows me to monitor the cell health easily.
The attached graph shows a discharge test done on a Hyperion 1,450 mAh LiFePO4 and a 1,500 mAh 2/3A 5-cell NiMH. Discharge load was 500 mA.
I use a charger that displays individual cell voltage during charge, which allows me to monitor the cell health easily.
The attached graph shows a discharge test done on a Hyperion 1,450 mAh LiFePO4 and a 1,500 mAh 2/3A 5-cell NiMH. Discharge load was 500 mA.
11-16-2010, 10:55 AM
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RE: LiFe battery questions?
At the risk of offending a few people (my apologies if I do) I would like to post some actual facts based on years of selling all this stuff.
1. A123s can be used unregulated with the Rcexl ignition as long as the manufacture date of the ignition is post 2007. This will include all DLE engines, as DLE did not exist (it was DL back then) in 2007. I verified this just a few days ago with the owner of Rcexl, and I have verified it with dozens of successful installations.
2. There is no acceptable way to test A123s' remaining power. A load test will do nothing and if you use it as the sole means of determining charge level eventually you will lose your plane. Just look at the above discharge curve, the battery reads the same at 10% discharge as it does at 80% and this is under a load. Read the paper linked below for a strategy that will work. I have used this approach for 2.5 years and never run out of battery.
3. A charger which shows individual cell voltage is a good thing with A123s and LIFE. Balance charge them as often as possible or they will get out of balance, but an occasional un-balanced charge won't hurt anything.
4. Many many people run their ignition off the same battery that is used for the receiver. 2.4 ghz radio receivers that I have tested this way (all brands, most models) are not affected by a properly operating rcexl ignition system. I have not tested other brands.
5. The G26 doesn't have nearly the power of a DLE-30.
http://wildharerc.com/downloads/docu...123-basics.pdf
Read this paper, Life is basically teh same as A123 with a little higher total capacity and a little lower current delivery ability.
TF
11-16-2010, 12:53 PM
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RE: LiFe battery questions?
thats a pretty picture. Tests i've conducted on my checker to verify thats it does what it says has shown it to be fairly conservative but accurate. After 6 flights of 15min each i checked the battery with the EOS sentry. It showed 57% capacity remaining of the 1700 mA.hr available. I popped the battery on the charger and it replaced just under 750mA.hr.I do this everytime i charge the battery and the checker and charger values are always within 3% of each other. According to the manufacturer and the distributor it does apply a load. Whether that is correct or not, the fact is it shows remaining capacity fairly accusrately
11-17-2010, 09:40 AM
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RE: LiFe battery questions?
Well I am greatful for all the input, didn't mean to cause any controversy though. So mainly I understand I can balance charge my LiFe batteries at my shop with the balance charger and wings off. Then when I take it to the airport for a couple of days, or the field for the day, I can just charge them through the switch to top it off after a two or three flights like i would a nicd or nimh correct?
11-17-2010, 10:16 AM
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RE: LiFe battery questions?
BH79,
If you go to the hangtimes hobbies web site Steve has excellent advice
http://www.hangtimes.com/a123rxsetup.html for setup - and http://www.hangtimes.com/a123_batter...iants_faq.html for general questions.
This will tell you all you need to know to make an informed decision on your battery questions. I for one would not trust any ESV type device currently on the market to tell me if it is safe to fly with A123's.
John
If you go to the hangtimes hobbies web site Steve has excellent advice
http://www.hangtimes.com/a123rxsetup.html for setup - and http://www.hangtimes.com/a123_batter...iants_faq.html for general questions.
This will tell you all you need to know to make an informed decision on your battery questions. I for one would not trust any ESV type device currently on the market to tell me if it is safe to fly with A123's.
John
11-17-2010, 10:50 AM
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RE: LiFe battery questions?
WRT the Hyperion checker I am curious about something, load or not, all it does is read cell voltages, correct? Take a look at the graph below.
From 30 minutes to 3.5 hours it reads 6.5 volts. So how exactly does the checker know where you are on the discharge curve??
You can check cell voltages all you want but without the time being known you cannot possibly know where you are on the curve.
From 30 minutes to 3.5 hours it reads 6.5 volts. So how exactly does the checker know where you are on the discharge curve??
You can check cell voltages all you want but without the time being known you cannot possibly know where you are on the curve.
11-17-2010, 12:56 PM
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RE: LiFe battery questions?
according to the distributor the discharge curve is not as flat as in your diagram. If a .1 scale is used then sure, its flat. But life cells discharge at 0.001V and the checker measures voltage that low. it also employs some algorithm to interpolate the minut voltage drop under load against a preset curve for the cell type, to calculate the remaining capacity in the battery. I'm probing for more information but for the last 6months its worked well and accurately. The 3% variance is well within the safety net i use to determine when its safe to charge. Which ultimately is what we require.use it, don't use it but I won't apoogise for stepping on the toed of "experts"
11-17-2010, 01:44 PM
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RE: LiFe battery questions?
Sounds reasonable. Makes it the more important to use good plugs and shortest possible wiring since at those types of voltage readings the line resistance becomes an issue. Pretty amazing that they can produce a $40 checker that is sensitive to 0.001 volts. Usually have to spend big bucks to get that kind of meter.
11-18-2010, 04:17 AM
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RE: LiFe battery questions?
Thats what I found surprising as well and at first I was very sceptical. However, the unit has addressed those fears after my constant cross referencing the capacity and voltages it registers vs the capacity charged into a battery after sufficient use. I have no doubt that it is a first gen device and its accuracy over time as battery enters old age may become an issue but I endeavour to keep my eye on that. With the Hyperion LiFePO4's rated at 1000 charge cycles I have no doubt that it will be a long while before the battery enters old age.
11-18-2010, 08:50 PM
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RE: LiFe battery questions?
While on Hangtimes site check out the voltmagic. I've been using it two years as a gas gauge for my A123's and it works very well. Just like a voltwatch for nicd/nimh, it also does some other cool things.
Also the DLE20 weighs 29 ounces with everything except battery, lots of fliers are using an ignition battery eliminator with great success. The Saito 125 weighs 25 ounces and requires 3 times the fuel load, and 15% of it stays stuck to the bottom of your plane, and yes the DLE 20 is out pulling the Saito 125. A simple use of the search button will find the numbers.
http://www.voltmagic.com/ Works for A123, check for life
Steve at Hangtime has been great to deal with. I have his battery's in my planes and my TX. Cheaper battery's out there but none better in my opinion. Good luck.
Also the DLE20 weighs 29 ounces with everything except battery, lots of fliers are using an ignition battery eliminator with great success. The Saito 125 weighs 25 ounces and requires 3 times the fuel load, and 15% of it stays stuck to the bottom of your plane, and yes the DLE 20 is out pulling the Saito 125. A simple use of the search button will find the numbers.
http://www.voltmagic.com/ Works for A123, check for life
Steve at Hangtime has been great to deal with. I have his battery's in my planes and my TX. Cheaper battery's out there but none better in my opinion. Good luck.