Hi guys, so, I've read this subject to death - but cannot seem to find any real answers that pertain to my scenario.

History: Started RTR 1/8 buggy, over time improved servos (nothing exotic) but stayed with the 4xAA pack. I've seen no real issues but lately noticed my twin brushless conversion turns much better than my nitro. The buggies are not identical which forced me to look at many factors, but I question now the AA pack.

Currently:
Everybody knows Lithium is the way to go - I will not (yet at this time). So the real question is stay with the AA 1.5V, put in rechargeable AA 1.2V - or nimh 5 cell hump pack? Strictly in terms of performance (don't care about replacing AA batteries as I am satisfied with the life). What can I expect between these 3 power sources in a nitro 1/8 buggy with simple decent servos?

Lithium is a way to go, not THE way. It will only be an option if the electronics can handle the higher voltage. But Lithium is a word with a wide meaning. LiPo is way up in voltage that can burn any 6v electronics, I know many claim their 6v servo's run fine on LiPo but still, would you take the risk?
Anoter type of lithium is LiFePo4, also known as LiFe. These batteries have a slight higher voltage compared with a normal 6v pack and could be the best "lithium" option.

But there is nothing wrong with the 5 cell NiMh packs. Yes, they may be old fashion but they are still the easiest batteries to use and provide enough power. No balance charging required, in case of some racing rules, no charging bag needed and do survive a winter perion of no using much better.

This is very helpful, thanks. Any lithium based tech is something I do not desire in the receiver at this time - for many reasons including maintenance. However may I clarify what to expect between nimh vs AA alkaline, this was really the true question in my mind. Is there any real advantage to nimh other than saving money on AA or should I expect better steering and throttle performance?

The 1.2V NiMH cells have a lower initial voltage, but a flatter discharge curve. For the 4x1.5V AA setup this means the servos will run slower at full charge compared with 4xAA Alkaline, but the voltage will be more consistent throughout the run and the servo won't slow down as quickly as with the Alkaline. Out of these two AA options I'd definitely pick NiMH.

The 5 cell pack will have the same discharge characteristics but the extra cell means the voltage will be higher throughout the run and you'll be closer to 6.0v. Out of all the options you've mentioned, this is the best.

https://www.powerstream.com/AA-tests.htm

life batteries are way more forgiving to users .. Id check some vids out. I have run A123 batteries for 12+ years . and my kids have packs of 4 in there glove boxes for years they still will jump A dead cars battery after 8 years...

Very good opinions, some more scientific than others of course. I'm not sure I agree with the LiFE booster, I'm a mechanic and everyone I know including myself who owned one only got a few years with decent (albeit not textbook) maintenance then they were not strong nor hold a charge well. Of course, I'd agree far better than other types of lithium. I think the 5 cell nimh pack is likely the best choice for me. Can anyone guess at amount of hours one can expect from the common 1700mAh packs?

I run 1/8 onroad and in a 30 minute final I have drawn about 500mAh

Your general off the shelf AA maybe. I only use these AAs in anything electronic. https://data.energizer.com/pdfs/l91.pdf

Im not talking about whats called the life packs of today Im talking about A123 system batteries only . I know the life of today fail soon as in short life.(lol).but choose what you believe in or want

Yes, I'm quite fond of these batteries myself, in my point and shoot camera - they get many hundreds of shots vs about 50 with regular alkaline. Are you suggesting these would be better than the life or nimh options?

Oh I get it, just searched for that battery and found there are life options available. In this case then, I guess one would have to build a custom pack? (The A123 is used in many cameras, will clearly not work in the AA case and would need balance ports - no?)

Yes, they're better, but they are also lithium batteries which OP is wanting to avoid for some reason.

I'm kinda surprised to see many posts lately about the 'hassle' or 'maintenance' of LiPo batteries... the extent of the 'maintenance' needed is to plug it in to the charger and run a storage charge.

marcosphoto- yes, if you make a pack with the A123 cells you'll need a balance lead, or another alternative may be using a battery holder and then an external charger for the A123 cells.

I am a bit cinfused. Are you talking about the brand A123 who are known for their LiFePo4 batteries or are you talking about the CR123 dimension batteries?
The CR123 dimension is the same as the 2/3A cells which are used in many NiMh receiver packs.

I have looked into the CR123 LiFe cells but They are not the ideal batteries to use. They are low in capacity and are no real high current providers. Even when building a 2S2P pack it still will be questionable how it will work. I am looking into the 14650 LiFe cells which can be found with a capacity up to 1200mAh, light weight and, handle currents up to 10A (the right cells) and 2 cels are like a receiver flatpack (used in many onroad and several offroad cars)

My mistake, I saw the number posted above and was confused myself with the battery size you mention! I'm not familiar with these cells in particular, just wanting to give an alternative for charging.[

Compared to rechargeable AA cells or off the shelf AA cells, these will be much better.

Compared to LiFe & NiMH (based on charts I could find):
These AA cells should provide 6v to 6.8v (1.5v - 1.7v x4) depending on load.
A LiFe 2s pack should sit around 6.4v (3.2v x 2).
NiMH sit around 1.2 per cell so a 5 cell would be about 6v.

I switched to LiFE in my transmitter a few years ago and have been very happy. If I ever get around to building my nitro race sedan it will use a LiFE pack. That being said I have used the Energizer AA cells in my nitro bashers going back to the early 2000's and really don't have a complaint other than the cost of batteries needing replaced. Now that I race electric and have awesome chargers, for me it just makes sense to switch to LiFE for the radio equipment.