i’m so confused with the taranis battery thing…
let’s say there’s a whatever its name is solid rectangle lipo battery 2s, 7.4v, 2000 mah
also there’s 6 aa nimh batteries 1.2v each (7.2v), 1900 mah (that’s also each am i wrong?? so 11400 mah……??????? even if each cell for the rectangle battery itself is 2000 mah, than it’s 4000 mah overall, still less than 11400 mah)

then why are rectangle batteries considered more efficient and convenient than aa please what am i misunderstanding

also i have the lipo battery that i described above (2s 7.4v 2000 mah) that i use for taranis, its owner says "its 100% charge is 8.0v" (should be 8.4 no?) (he also said the whole lipo subject “doesn’t really bother him") so is he wrong?
i wonder if i should charge this battery to 8.4v
also should i unplug it the every time i use it just like i would with a drone?

for anyone who read this and is gonna reply thank thank thank thank thank you are the best

Lipo, 4.2v full, so 2s is 8.4v like you said. Some li-ion 4.1v, some 4.2v. when in doubt charge only up to 4.1v max per cell. No need to disconnect the battery from the taranis or even storage charge on the batteries since a bit of resistance doesn't mean a thing on lower current demanding devices. Now mAh means the storage capacity of the battery. Don't thrust every number you read, test it yourself.

My Taranis x9d+se tops off at 8.2v when charging on USB. I've thought of charging it on the charger or getting a replacement version of the battery from RDQ but I've had no issues so far needing more power. I can get more than two sessions of 8+ batteries while running a TBS Tracer TX on board and the lowest I've seen is 7.4v

My experience with NIMH is they're degrade too fast compared to lithium. I'd give Li-on a shot or an RDQ or similar aftermarket replacement before NIMH but I also have some laying around that I use in a few things.

Hi Luna,

Well, here we go...

Considering LiPo batteries:  Each Cell has a nominal voltage of 3.7 {3.8 for HV LiPo}. 
A 3.7 volt LiPo has a range from about 3.5 Volts discharged to 4.2 Volts {4.3 for HV} fully charged.
So, a 1S LiPo is 3.7 volts, a 2S is 7.4 volts, a 3S is 11.1 volts...and so on...

The LiPo battery you describe is likely a 2S 2000 mAh battery pack which is basically 2 1S 2000 mAh LiPo batteries in series to  produce 7.4 volts with the mAh remaining the same as a single cell; 2000 mAh. When batteries are connected in series the mAh is NOT increased, only the voltage. 

If 2 1S LiPo batteries are connected in parallel, you end  up with 3.7 volts at 4000 mAh. The parallel connection maintains the voltage and increases the mAh even with the same 1S cells used in the series example. 

By the way, this is the same for all other types of batteries as well:
When connected in series, the voltage is increased, but the mAh remains the same.
When connected in parallel, the voltage remains the same, but the mAh is increased.

From a purely electrical perspective, the transmitter doesn't know or care what type of battery you connect to it as long as it has a nominal 7.4 voltage { 7 v to 8.4 v}. Yes, it is possible to use AA batteries {or any other for that matter} which have a nominal 1.2 voltage per cell. Seven of these would yield 8.4 volts at the mAh rating of a single battery. So, if you connect 2 sets of 7 series connected AA batteries in parallel, you essentially have the same as a 2S 7.2 {Max voltage of 8.4} pack with double the mAh of a single AA battery.  That is 14 batteries total which likely will not fit the bay, so you would need an external holder. I can't say how long the speculated AA pack would last nor would it be comparable to a Li-Po or Li-Ion pack. So, technically, you could construct a battery pack from AA batteries, but it would take some work and would likely need to be external to the transmitter...would it be worth it...

So, there are other considerations:

1) Will the batteries fit the compartment. {technically, you could build an external holder}
2) Is there enough mAh to provide sufficient time before the batteries drain down.
3) How fast do the batteries discharge.
4) Are the batteries rechargeable.

For what it's worth I'm still rocking the original green triangular 2000mAh 7.2V NiMH battery that originally came with my FrSky Taranis X9D+ SE and it's still going strong almost 3 years later. I did buy a spare that I carry with me in case I run out of juice in the field or in case something happens to my original, but I've never had to use it or swap it into my transmitter during a flying session.

I flew 14 LiPos yesterday and that original NiMH battery was still showing 7.4V after 60-70minutes of actual flight time in the air (it started off at 8.4V). And this is also running a Crossfire module set to 250mW dynamic power. For this reason I have never felt compelled to replace the NiMH battery with a Li-ion or LiPo equivalent which I would then either have to modify the battery bay for or worry about storage charging (LiPo). At the end of a flying session I just fully recharge the NiMH battery ready for the next flying session and not have to worry about it sitting at full voltage for weeks on end 

@iFly4rotors and @OP, I would not recommend 7 AAs, because 1.2V is nominal. 1.4v-1.6V is charged. So 9.8-11.2V is charged for AA, while 8.4V is charged for lipo. If the radio cannot handle 3S, the radio can burn from over voltage. 6 AA is safer.

As far as pack size, li-ion has the highest power to size density. Then lipo. And then AA (NiMh). So the smaller pack, for a given size would be li=ion.

I have both the FrSky 6 cell NIHM pack and also a slim 2s Lipo that can be used with the fatshark goggles (barrel connection) or Taranis using the balance lead.
I just switched to a 2 cell 18650 holder and it seems to me that, from the 3 methods, is the best method in terms of efficiency and usability.

thank you all so so so much for your replies!!
@iFly4rotors, thank you for the deep explanation, omg all of it finally makes sense!

(06-Jun-2021, 06:29 PM)luna Wrote: thank you all so so so much for your replies!!
@iFly4rotors, thank you for the deep explanation, omg all of it finally makes sense!

Hi Luna,

Thank You. I am really glad that it helped you understand.

Although it would technically work, personally, I would never use AA batteries because there are better options.

Have a wonderful day.