NiCd or NiMH 1.2 volt AA rechargeable batteries

This is the battery I recently got for a new project.  It's 200 mAh and weighs a half ounce / 15 grams.  I saw in Brad's (1/2A Nut) Nano thread that he found an even better battery by Reedy, the car motor folks, a 250 mAh that weighs two grams less.

Thanks Dave, maybe i should have said single batteries as in https://www.ebay.com/sch/i.html?_from=R40&_trksid=p2062857.m570.l1312.R4.TR0.TRC3.A0.H0.TRS5&_nkw=rechargable+aa+batteries&_sacat=48446

As far as I am concerned I use NiMH batteries in my small R/C planes for powering the RX and the servos, because their output voltage, even if overcharged, will not go over 5,6....Volts that is still in the right range for the RX and servos.

https://www.ebay.com/itm/4-8v-6v-120-400mAh-Vapex-Miniature-Receiver-Rechargeable-Ni-MH-RX-Battery-Pack/122165361905?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908131621%26meid%3D31817c87061247d5bebec03c974856e4%26pid%3D100678%26rk%3D4%26rkt%3D15%26mehot%3Dpp%26sd%3D153306161494%26itm%3D122165361905&_trksid=p2481888.c100678.m3607&_trkparms=pageci%3A6d07bc69-12a8-11e9-9ee7-74dbd1800b6d%7Cparentrq%3A29883adb1680ac1edd799009fffe7fc1%7Ciid%3A1

Servo voltage limitation is around 6V and I am afraid the 6,6 volts of LiFe batteries may damage the servos unless a voltage limiter is used?? May be I am wrong but better do not electrically overload the servos because a servo killed by voltage mid-air may lead to serious and costly consequences.

You do not want to use NiCd batteries.  They are an old chemistry that have a high self discharge rate, ie, they run down quickly when not even being used. The latest version of NiMh batteries have far longer self discharge rate.  They are often sold as "precharged" cells.  You charge them just like regular NiMh.

Panasonic Eneloops are such cells

I agree...the latest rechargeable AAA size batteries are rated at 1800mAh of which 4 pieces connected in series builds a 4xAAA size battery pack that I use in planes powered by the o49 and larger COX engines, that are strong enough to haul 4xAAA size battery packs onboard too.

https://www.ebay.com/itm/8x-AAA-battery-batteries-Bulk-Nickel-Hydride-Rechargeable-NI-MH-1800mAh-1-2V-Blu/252396413424?hash=item3ac3ffa1f0:g:geAAAOSwrnNXPqlA:rk:30

When fully/slightly over charged the 4xAAA pack provides 1800mAh at an initial voltage of around 5.6 Volts that sinks to around 4.6Volts after 8....12 flights of 10 minutes each (with intense use of the servos onboard), i.e. a voltage level still safe for a secure landing. The shelf-voltage of these batteries when fully charged remains constant for many months

I probably should have posted this link.  Hangtime won't likely have the batteries you'll want, but this link to FAQs has a lot of good info on the pros, cons, care and feeding of different battery types.  Good to know stuff, that's all.

http://www.hangtimes.com/rcbattery_faq.html

Servo voltage limitation is around 6V and I am afraid the 6,6 volts of LiFe batteries may damage the servos unless a voltage limiter is used?? May be I am wrong but better do not electrically overload the servos because a servo killed by voltage mid-air may lead to serious and costly consequences.

[/quote]

I have been told that LiFe batteries' voltage drop to 6 volts as soon as they are under a load. I have not measured this. But, I have never had any servo chatter on a freshly or even partially charged LiFe pack.

in response to your original question, NiCd or NiMH, like several have stated,  i wouldn't even think about nicads, NiMH are great for the Transmitters and AAA packs can be made for smaller gas birds, for electric powered go LiPo or LiFi

fit90 wrote:

balogh wrote:Servo voltage limitation is around 6V and I am afraid the 6,6 volts of LiFe batteries may damage the servos unless a voltage limiter is used?? May be I am wrong but better do not electrically overload the servos because a servo killed by voltage mid-air may lead to serious and costly consequences.

I have been told that LiFe batteries' voltage drop to 6 volts as soon as they are under a load. I have not measured this. But, I have never had any servo chatter on a freshly or even partially charged LiFe pack.

It has been a long while since I tinkered with electronics. Back in the day, a simple solution to drop voltage was use a diode in-line, would drop voltage 0.7V give or take. But I couldn't tell you what diode to use without further research, and having not done it myself with an RC set am reluctant to suggest such a move.

Nicad tech has improved some for AA use. I have the spektrum TX it is a thirsty radio I like the power the nicads can put out
not so much duration but handles hot summer days well. I don't mind charging the cells up before flying.

Yes as Dave said for RX side of the fence the Reedy 250mah / 15C if you can find as it is now a obsolete product.
200 is old tech improved by:
220mah Life cells are still floating around they hold there voltage and density better than any other
battery out there as long as you charge them correctly.

Thanks for all the good info on batt. pack and so forth... I went with the AA 3000mAh Ni-Mh 1.2 V so they will hopefully last longer than lesser mAh . I am thinking of moving up to the Life battery when the time arrives .

getback wrote:I am looking to purchase some rechargeable batteries for Radios , a Spektrum DX6i and Cox Sanwa and don't understand the difference of the numbers mAh And am looking for some suggestions of what to get and have had good experience with . Thanks

Hey bro.. there's two sides to this inquiry. The TX (transmitter) and the RX (receiver) batteries. Transmitters generally used to operate between 9.6 and 12 volts DC. This is because of the difference between battery types/chemistry. Most transmitters have a battery-box designed to contain either X8 individual AA size alkaline cells connected in series.. or a rechargeable battery "pack".

Your common (throw-away) alkaline cells have a charged voltage of 1.5VDC/cell. Eight of them (in series) equals 12 volts DC. Rechargeable transmitter battery options are generally "packs" which also have eight AA cells (in series). "Both" the NiCd and NiMh types have a charged voltage of 1.2VDC/cell. An 8S (eight cells in series) "pack"equals 9.6VDC.

From what I understand.. NiMh (Nickel Metal Hydride) technology is superior to the older NiCd (Nickel cadmium) technology. The older (NiCd) batteries needed to be "cycled" (completely discharged) before being recharged.. to avoid "cell-memory" and decreased service-life. The newer NiMh cells can be recharged at any state of charge.. without the concern of developing cell-memory.

There's a multitude of options for powering your RX (receiver) in the model. Many have been discussed already.

Do yourself a favor.. and look into sourcing a quality charger; one that will cover "ALL" of your hobby needs. I bought a "Thunder AC6" charger, which covers pretty-much everything.. and wasn't expensive. It had good reviews.. but I'm not sure if it is still in production.