Battery Question - AA eneloop 2100s vs eneloop Pro in very high drain devices...the#s

Background
I have a strange question regarding NiMH cells, regarding the comparison of a standard LSD/ULSD cell to a high-drain NiMH with LSD inferior to the latter.

I have used eneloop and Tenergy NiMH AAs and AAAs for years. I have owned eneloops since generation 2. I am progressively replacing my older Tenergy and Eneloops (some with well over 500-750 cycles) with the newer eneloop 2100s and eneloop Pros. As I am in the US, this applies to Japanese made eneloops and not the Chinese made ones (which I hear are very inferior.) (My choice to move solely to eneloop is because, while the Tenergy AAs have been less than half the purchase price, my long-term cost of ownership is significantly less with the eneloops. This is not just because of the longer service life but actually because the eneloops hold a much higher capacity as the cells age.)

Historically, the eneloop XX (now Pro) has been marketed for use in high drain devices versus the standard eneloop marketed for cross-platform usage, ultra-low self-discharge, and a long life (which now exceeds 2,000 cycles, which is incredible.) With the considerably higher price of the XX/Pro, the faster rate of self discharge, and less than ¼ of the service life, the eneloop 2100 makes sense for usage in all but the most power hungry applications.


Current Gen AA Specs
The current generation eneloop 2100 is a minimum capacity of 1900 mAh. The current generation eneloop Pro (formally XX) is a minimum capacity of 2450 mAh. Like previous generations, both models consistently have higher capacity ratings that far exceed the advertisements, unlike the large bulk of NiMH cells on the market. This new generation makes incremental/evolutionary improvements over the last, but there is no doubt this new generation does a better job in temperature extremes, and the standard eneloop 2100 does a better job with higher drain devices than its predecessor.


My Comparison Issues
On most forums, the general response of a comparison of these batteries is that the eneloop XX gives about 25% more run time over the standard eneloop (and consequently, the price is hard to justify in most cases.) However, my experience has run completely contradictory to this.

Low Drain/Standard Applications
On one hand, with lower drain devices, I have found the standard eneloop to in some cases give 3-5 TIMES the run life of the XX. Presumably this is because these ultra low power applications benefit from the standard eneloops slower rate of self-discharge. That is easily explained and nothing out of the ordinary and it is a clear illustration of why the standard eneloop is the better choice for everyday applications and has an overall lower running cost.

High Drain/Power Hungry Applications
Here's where I get confused, with high drain applications. Based solely on capacity, numbers would suggest that the XX/Pro would provide about 25% longer run time. But my experience is completely different. When using the XX (and now Pro) with applications that tend to put a brutal drain on a battery, quite often the XX/Pro gives SIGNIFICANTLY longer run times over the standard eneloop that far exceeds the 20-30% increase based on standard capacity figures. For example, when I power a 16 foot high output LED strip, the 8+/- hour usable run time of the standard eneloop is better than alkaline, but the 12-14 hour usable run time of the eneloop Pros blow both away. With some other high drain devices, I see similar outcomes in which the run time increase is closer to 50% or greater. However, this is not always consistently across the board as the gain is much greater with some high drain devices than others.

HELP
On paper, that makes no sense. A battery with a min capacity of 2450 mAh versus a battery with a min capacity of 1900 mAh should not be all that different. But in the worst drain applications they sometimes are. Why?

Can someone explain this to me? I am currently debating whether to buy quite a few eneloop Pros for the purpose of running high-output LED light strips. I am playing with numbers and if what I am observing is NOT a fluke or error, my cost of ownership with the eneloop Pro would actually be LESS than the standard eneloop because the less frequent charging may offset the higher purchase price and lower service life. Additionally, the longer run time would benefit me since the power blocks that run these LEDs are in the far back corner of my safe and kind of a pain to replace. So am I making some sort of clerical error or does the eneloop Pro giving a benefit to high drain devices that is greater than the numbers would indicate?

I doubt this matters but I generally use a NiteCore D4 Digicharger/Intellicharger 2015 revision. In some cases I use an older Lacrosse. Thanks in advance.

I think the reason you are seeing much better results is that Eneloop Pros are designed to function a lot better in high drain devices. It's kinda like a bigger cup of water. The bigger cup you have the more water you can use. But if you only use a 1/3rd of the water as if you would with a regular cup of water all that unused water just becomes stale. Which is why Eneloop Pros function better in higher drain devices. You get a much steadier stream of power with the Pros if they are being used in high drain devices because of the higher current rates are being used.

Standard Eneloops do work great in just about any device you throw it in but simply give out quicker than the Pros do. There is also a downside of using the Pros which is reduced cycles in which doesn't really make a huge difference because unless you are draining the cells on the daily basis you probably won't exceed the cycle usage of those cells either, certainly not the standard Eneloops. The self discharge is also different as well. Standard Eneloops retain 90% of their charge after a year (about 1700-1750mAh remaining) while the Pros retain 85% after 1 year (which is about 2100mAh). While i haven't tested the AAA Eneloop Pros (which is only about 100-200mAh difference from the standard)
mainly because i do not have standard AAA Eneloops yet i got those in the hopes of getting longer runtimes on my T7 Led Lenser, but only really will use those in an emergency as i will generally do with any high capacity LSD cells.

I think though, you have proven that the Eneloop Pros (at least the AA's) are indeed worth the extra cost and reduced cycle usage in the event you need that extra 25% capacity.

My guess is his LED power strip is voltage-sensitive. If he's getting a 12-14 hour run time from the Pro's, that's using less than 200mA of current. Both the pros and regular Eneloops can easily handle that much current, and still deliver their full capacity. So, if he's only getting 8 hours on the regular's (instead of about 10 hours which is what he should expect), then it's probably because he's not using all the capacity out of them. He probably isn't using all the capacity from the pros, either.

The reason might be because as the batteries drain, their voltage will decline. It might be that when they get down to 50% capacity, the voltage is too low to power the LED strip, and it shuts off. The LED strip may not have any boost driver, which prevents it from running off low-voltage batteries. The regular Eneloops would get down to this cut-off voltage faster than the Pros.

That's my guess on it. It might be wrong.

One solution to the problem is to add another cell in series to your battery pack. I'm not sure how many cells you use in your pack, but if you're using 4 cells, try sticking a 5th cell in series. That will boost the voltage, and allow the LED strip to use all the available capacity. Just don't boost it too much, or you might burn-out the LED strip.