after some search on the web, i saw there are other hight capcity battery in different size.
NiMH Rechargeable Cell: M-Size 1.2 V 26Ah (52A rate)
Tenergy D 10,000mAh NiMH Flat Top Rechargeable Battery
is there any review about theses batteries
the only down side i see to use 9x 22650 battery is recharching.
i will have two choice, remove the battery from the light to recharge it
or
manage external charger, don’t know if there is some charge who can do it.
Depends mainly on true capacity, driver efficiency.
5200mAh x9 = 46.8Ah
/2 because the emitter runs at 6V min = 46.8Ah
assume 90% driver/circuit efficiency (that includes things like tailcap spring resistance)
x0.9 = 42.120Ah
/4.8A = 8.78h
Remove the cells for charging, they’ll stay cooler and it will make the design of the light easier.
I think you cannot compare mAh of different voltage cells, thats not fair in favor of lower voltage cells. you should compare stored energy. As LiIons have approx three times the voltage of a Nimh, the Ah will be a third of that of an nimh whit the same energy stored. for example, same size batteries: efest 10440, rated at 350 mAh (measured around 300 at 0,1A) has 1,2 Wh (discharged at 01,A) Eneloop pro AAA (panasonic branded in its current generation) rated at 900 mAh (measured 921 at 0,1A), has 1,12 Wh (discharged at 0,1A too) Here you have the best age to compare batteries: HKJ’s page
And here the tests for the mentioned batteries in the example:
efest Test of Efest IMR10440 V1 350mAh (Black)
and eneloop pro AAA Test of Eneloop AAA BK-4HCC 900mAh (Black)
Im fairly sure I recall it being said that pound for pound, 18650 outdo the 26650. In absolute numbers, the 26650 has it, but is it worth looking at 18650s instead? If capacity is the goal, you would have room for more 18650s anyway.
I think Ejected Filament is right, for both space and Wh per $, 18650s are the reasonable choice. Take a look at what some of the ebike community is doing they should give you an idea of what you will need.
Just to be sure its understood, by protected I mean those batteries with circuits to shut them off if something bad happens. Its highly recommended with 2 batteries, let alone 9 or 12. Im assuming this will be a canister light, not a standard style torch.