Batteries & Chargers Nicads, Nickel Metal Hydride, Lithium, LiPoly, Chargers, Cyclers, etc...

Nicad versus NiMh for 4.8 volt RC exl ignition

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Old 08-10-2018, 05:08 AM
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jester_s1
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NiCd- most durable type of battery, tolerates overcharge and over discharge the best, lasts the longest before losing capacity. Tolerates vibration well if the pack is welded construction. Is heavy.
Nimh- Lighter than a NiCd, less durable, tends to self-discharge faster unless you buy the special ones that don't, but they can't give you the amps that a standard one can
LiFe- Lighter than a Nimh, almost no self-discharge, can be charged quickly and can give a lot of amps. The soft pack type is fairly fragile and so shouldn't be used in a high vibration application (similar to a Lipo). The metal can cell types take vibration much better and can deliver more amps. Will start to chemically break down faster than Nixx types.

For your application, I'm a fan of the can cell LiFe, especially if this is a plane you plan to fly a lot. Of course, NiCd's still work as well as they ever did, and they last a good bit longer. If you don't fly the plane a lot, they may be a better choice.
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Old 08-10-2018, 05:12 AM
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On the RCExl ignition, the best voltage for it depends on when it was purchased. If you have one of the older 4.8-6v rated ones, they run cooler and more efficiently on 4.8v, and some were unreliable on 6v. So it became standard practice to run 4.8v with them. A few years ago, the company redesigned their product to allow use with a 2 cell lipo, and they actually work better now with more voltage. So 4.8v is a minimum that some won't run reliably with, with the recommendation being 6v minimum and over 7v being preferred. So if you have one that can use the 2 cell lipo and choose to go with a Nixx battery, get a 5 cell.
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Old 08-10-2018, 06:13 AM
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Thanks for all of your comments and suggestions. Like Truckracer I was quite hesitant in making the switch to Lixx chemistry batteries as I was very comfortable using Nixx power and which tolerated my sometimes very poor battery handling habits, but once I became exposed to Lixx batteries there was no turning back and as I mentioned earlier all my other models now use Life battery power for both Rx and ignition except this old banger in question, which now quite likely springing for this discussion will be fitted with a suitable sized Life battery for both Rx and ignition.
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Old 08-10-2018, 09:24 AM
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Originally Posted by jester_s1 View Post
On the RCExl ignition, the best voltage for it depends on when it was purchased. If you have one of the older 4.8-6v rated ones, they run cooler and more efficiently on 4.8v, and some were unreliable on 6v. So it became standard practice to run 4.8v with them. A few years ago, the company redesigned their product to allow use with a 2 cell lipo, and they actually work better now with more voltage. So 4.8v is a minimum that some won't run reliably with, with the recommendation being 6v minimum and over 7v being preferred. So if you have one that can use the 2 cell lipo and choose to go with a Nixx battery, get a 5 cell.
+1, good info for any RCexl owner.
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Old 08-10-2018, 09:34 AM
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Originally Posted by jester_s1 View Post
NiCd- most durable type of battery, tolerates overcharge and over discharge the best, lasts the longest before losing capacity. Tolerates vibration well if the pack is welded construction. Is heavy.
Nimh- Lighter than a NiCd, less durable, tends to self-discharge faster unless you buy the special ones that don't, but they can't give you the amps that a standard one can
LiFe- Lighter than a Nimh, almost no self-discharge, can be charged quickly and can give a lot of amps. The soft pack type is fairly fragile and so shouldn't be used in a high vibration application (similar to a Lipo). The metal can cell types take vibration much better and can deliver more amps. Will start to chemically break down faster than Nixx types.

For your application, I'm a fan of the can cell LiFe, especially if this is a plane you plan to fly a lot. Of course, NiCd's still work as well as they ever did, and they last a good bit longer. If you don't fly the plane a lot, they may be a better choice.
Good points but I can't agree with the LiFe types breaking down chemically before the other types. I have simply not seen this demonstrated in real life. With LiFe types and especially A123 cells, I see almost no degradation of performance up to 3 or so years and I still have batteries that are 8 seasons old (no longer in airframe service) that demonstrate 90% of new capacity. I challenge any Nixx based battery to meet those specs. Ask the portable tool industry about Lixx batteries. They made their tools much more efficient and practical and warranty replacement of batteries decreased by volumes. They don't miss the Nixx based batteries in any way. When still working, work crews would replace batteries just about every year and sometimes less, much longer service with Lixx types. Other than Eneloop batteries in a few transmitters, every rechargeable battery I have now (excluding Pb car and boat batteries) is Li based and I'm not looking back. And yes, I was a hard sell early on and glad I was. Some of the early Li based batteries were not so great either.
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Old 08-10-2018, 11:11 AM
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My very first A123 1100 mA 6.6 volt battery is now 5 years old and still gives 95% of it's original capacity.
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Old 08-11-2018, 06:59 PM
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I agree that quality LiFe cells, AKA genuine A123 can type cells, do have a good life span. The soft pack ones don't. I should modify my statement above that LiFe batteries don't compare favorably to Sanyo NiCd cells for durability, but probably will outlast Nimh which are a good bit more fragile.
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Old 08-12-2018, 03:12 PM
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I've always had good faith in the quality of NiCad battery packs made with Sanyo cells but to my dismay I yesterday found a 3 yr. old 4.8v 700 mA pack with the dreaded 'black wire syndrome' along the entire length of the negative lead including it's gold colored connector which was covered in a bluish deposit. I had thought that 'black wire syndrome' was all a thing of the past but this proves me wrong. Maybe it's because I have always kept this particular battery connected to it's on /off ignition switch as it's all buried inside the fuse.

Last edited by karolh; 08-12-2018 at 03:14 PM.
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