Runtime of KL1 on 2AA? on 3AA?

Hi Folks,

I tried the search function, to no avail... I was wondering what the runtime is on a KL1 running on 2AA and on 3AA?

/ubbthreads/images/graemlins/yellowlaugh.gifI finally realized that my 123 cell extender will let me run 3 123s or 2 AAs. I might even be tempted to get a AA extender if the runtime becomes some ungodly amount of time on 3 AAs.

BTT...

I did some more searching, and found refrences to rough estimates. They mentioned something like 2 hours on 2 AA and 3 hours on 3 AA.

Does that sound about right? Anybody have a more exact answer?

Thanks

I think my last test showed 3 hours on 2AA with Q3K HD modded KL1 @ standard current using 2 2100ma Sanyo NiMhs.

I´ll try to do some runs with 2AA and 3AA and will report back

later

Klaus

Edit - putting my two best 2100AA Sanyos on the charger as I type
Edit - test started at 11:15 AM CET with cells fresh off the charger

/ubbthreads/images/graemlins/thumbsup.gifthanks Klaus!

Excuse my battery ignorance... but will your 2100AA sanyos perform in a similar manner as off the shelf alkalines? (e.g. energizer/durecell) If not, can you guesstimate what would the difference likely be?

And would a stock KL1 tend to perform better or worse than your Q3k HD?

At around three hours on 2 AA this will surely replace my inova 5XT as my dog walking light /ubbthreads/images/graemlins/smile.gif

Datasaurusrex,

I doubt the Alkalines will provide the runtime of 2100ma NiMhs - at high loads (and we are talking probably around 500ma here - but need to check that) Alkalines don´t deliver much power, Lithium AAs are better but then why go with AA instead of 123s in the first place. For Alkaline runtime probably Roy can do some runtime testing.

From this comparison of Energizer E91 and L91 cells

Load/h E91 L91
Operating Time 1400mA 0.2 1.3
(Hours to 0.90 Volt) 1000mA 0.4 2.1
400mA 2.7 5.7
20mA 117.0 122.0

I would guestimate the KL1 might run 2 to 2 1/2 hours on Alkaline AAs - did you check the review section for Roys runtime graphs - Brock did some too I think on Alkalines.

The Q3K HD is more on the high side of the LS Vf range so the runtime of a stock KL1 might be even better - but it will depend on the actual Vf of the LS in your KL1.

But now to the pretty nice results:

KL1 with 2AA 2100ma Nimh Sanoys - 3 3/4 hours
KL2 with 3AA 2100ma NiMh Sanyos - 5 1/4 hours

I would have expected the 3AA to be sightly longer or 2AA slightly shorter and the 3AA aproaching or even beating 2AA x 1,5 as the Vin is closer to the Vf and the circuit should have better efficiency, but maybe I´m wrong and the circuit running buck is less efficient than boost. Also I wasn´t really doing a scientific test a là Roy with runtime vs brightness graphs and was only comparing to another LS to see where the light was out of regulation - so these time might be off by a quarter of an hour or so. But still I´m pretty happy with those results for the KL1 on NiMhs.

Klaus

Edit - I just measured 360ma current draw on 3 AA Nimhs and 470ma on 2 AA Nimhs - so I would **guestimate** 2+ and 3+ hours runtime on 2 and 3 AA Alkalines.

More Edit - Roys AA runtime chart is here

Try looking in the Reviews forum for the runtimes on the UBH set.

Thanks Roy, I didn't think of searching for the UBH! Now I see your runtime graph for the UBH KL1 2AA.

Search for "Run-Time Plot - UBH" in the Reviews Forum for the complete reports.