I have been trying to runtime-test my KL1 on UBH with 2700ma NiMh A cells and in an E2e body with 700ma NiCd 2/3 A cells and had some interesting results I want to share and possibly start some brainstorming on the issue.
I had been doing those tests and started to measure the run-down voltage of the used cells as CM came up with interesting findings about the KL1´s used IC and its cut-off voltage of 2.5V which IMO seemed to explain the shorter-than-can-be calculated runtime of KL1s on 2 NiMh/NiCd cells or one 123 cell.
(You might try to look up CM´s threads about modding the KL1 to 5W - there is some talk about the KL1 circuit and the baseline is that the circuit is using an IC which operating voltage is 2.5V - which means Chris (CM) found the reason for the KL1 not operating as well with just 1 123 cell or two NiNMh/NiCds as the IC won´t properly regulate anymore when voltage drops too much (I think to around 2.25V or so) - if you compare the 1 x 123 runtime and Brocks data on 2 Alkalines or 2 NiMhs all of those are well below what one would expect given the current draw and 2 x 123 runtime - considering the 2.5V operating voltage everything starts to make sense - as the IC doesn´t regulate anymore a lot of juice is left in the single 123 cell of the NiMh/NiCd pair)
But actually what I found now is that ALWYAYS just one cell is run down while the other still shows plenty of life (like 1.05V to 1.25V) when the circuit starts to flicker - I´m still doing some tests but so far it seems that always the FIRST cell is run-down while the one at the back is still doing perfectly fine. I didn´t do large scale scientific testing and my sample rate is still below a hand-full but the results so far are very straightforward - the KL1 circuit runs the nearest cell down and keeps plenty of juice in the back one.
I would like to do more testing and if other CPF-ers would join in we might get faster and better results - how is it behaving with 2 or 3 123´s or 2 Alkalines´s or 2 Lithiums AA in an UBH - same behaviour with different discharge characteristics depending on cell placement or will the primary cells in contrast to rechargeables be depleted equally ?
To me this is of some interest as if my findings hold true one might pretty much be able to lengthen the run-time of this circuit (others maybe too) in swapping the cells half-way through the discharge cycle - swapping between the front and back cell.
I did saw some discussions lately between lemlux and other members discussing the theoretical and/or practical difference in cell placements while centering around different capacity and chemistry cells and this might be a similar topic where in theory what I am saying might make no sense but real life testing shows it to be true.
I challenge the theoretical camp to try on their own though
Klaus
I had been doing those tests and started to measure the run-down voltage of the used cells as CM came up with interesting findings about the KL1´s used IC and its cut-off voltage of 2.5V which IMO seemed to explain the shorter-than-can-be calculated runtime of KL1s on 2 NiMh/NiCd cells or one 123 cell.
(You might try to look up CM´s threads about modding the KL1 to 5W - there is some talk about the KL1 circuit and the baseline is that the circuit is using an IC which operating voltage is 2.5V - which means Chris (CM) found the reason for the KL1 not operating as well with just 1 123 cell or two NiNMh/NiCds as the IC won´t properly regulate anymore when voltage drops too much (I think to around 2.25V or so) - if you compare the 1 x 123 runtime and Brocks data on 2 Alkalines or 2 NiMhs all of those are well below what one would expect given the current draw and 2 x 123 runtime - considering the 2.5V operating voltage everything starts to make sense - as the IC doesn´t regulate anymore a lot of juice is left in the single 123 cell of the NiMh/NiCd pair)
But actually what I found now is that ALWYAYS just one cell is run down while the other still shows plenty of life (like 1.05V to 1.25V) when the circuit starts to flicker - I´m still doing some tests but so far it seems that always the FIRST cell is run-down while the one at the back is still doing perfectly fine. I didn´t do large scale scientific testing and my sample rate is still below a hand-full but the results so far are very straightforward - the KL1 circuit runs the nearest cell down and keeps plenty of juice in the back one.
I would like to do more testing and if other CPF-ers would join in we might get faster and better results - how is it behaving with 2 or 3 123´s or 2 Alkalines´s or 2 Lithiums AA in an UBH - same behaviour with different discharge characteristics depending on cell placement or will the primary cells in contrast to rechargeables be depleted equally ?
To me this is of some interest as if my findings hold true one might pretty much be able to lengthen the run-time of this circuit (others maybe too) in swapping the cells half-way through the discharge cycle - swapping between the front and back cell.
I did saw some discussions lately between lemlux and other members discussing the theoretical and/or practical difference in cell placements while centering around different capacity and chemistry cells and this might be a similar topic where in theory what I am saying might make no sense but real life testing shows it to be true.
I challenge the theoretical camp to try on their own though
Klaus
