AA Lithium Rechargeables for PowerTac Valor 800 Lumen Light

[Kevlight14]

I just bought a PowerTac Valor, 2xAA (Cree XML-U3) light, right after receiving confirmation that the advertised spec of 800 Lumens for 1.1 hours using NiMH 2450 mAh rechargeables was correct. I used 2 pairs of fully charged Eneloop Pros and achieved Firefly(.53L), Low(93L) and Mid(358L) output. No change in output when clicking to Max(800L) mode. PowerTac had me replicate the test using fresh Alkaline 1.5V cells and a distinct increase in output was achieved in Max mode, presumably the rated spec of 650L for Alkalines. Very bright!

I'm exploring buying a new set of rechargables to achieve Max output, and have come across lithium AA cells by Gigastone, Amp Torrent and EBL. Does anyone have a recommendation for a proper rechargeable cell to achieve Max Mode (800L) with this light or have advice on what sort of runtime I should expect IF I can get 800L using Lithium rechargeable cells? I can't say I trust PowerTac for these answers. TIA

 

[Lynx_Arc]

I haven't checked into it but I'm not believing the claims of 800 lumens for an hour off 2AA batteries other than lithium ion batteries it is just IMO beyond a useful level of output from that format/chemistry. I would consider 650 lumens as in reality for the light a turbo mode not really a useable work output as it is plainly too high of a current drain and requires higher quality components in the driver and light itself to reduce power losses due to the higher current needed in the boost circuitry. Almost every light I've checked into out there that advertises outputs over about 500 lumens and most that do claim that output don't use boost circuitry but rather are either direct drive or linear regulated (dropping) or buck circuitry as boosting is always less efficient with similar attention to design you usually lose more power that could drive higher lumen output. I think that these people are likely guilty of hyping the output it may not even be an ANSI output unless maybe they were using Energizer lithiums (L91s). The only lithium rechargeables that would likely work with this light are not native AAs.... they are lithium ion cells with buck circuitry to drop the 3.7v to 1.5v and with that circuitry it can limit the power output of the battery itself likely making it less powerful than a lithium primary that is 1.6v or so (1.8v no load).

This is why the majority of us who want 400 lumens or higher for any respectable non turbo runtime have gravitated to 18650, 21700 and larger cells because 800 lumens is IMO too much for anything smaller. My advice is to be happy it even gets 600 lumens output and not waste a lot of money for the extra 100-200 lumens it may seem brighter but in use your eyes can adjust to it and make it not quite as huge of a deal. Spend $20 and get an 18650 light and use it when you need 1000-2000 lumens and forget about AAs and 500+ lumens and above.

 

[Kevlight14]

I haven't checked into it but I'm not believing the claims of 800 lumens for an hour off 2AA batteries other than lithium ion batteries it is just IMO beyond a useful level of output from that format/chemistry. I would consider 650 lumens as in reality for the light a turbo mode not really a useable work output as it is plainly too high of a current drain and requires higher quality components in the driver and light itself to reduce power losses due to the higher current needed in the boost circuitry. Almost every light I've checked into out there that advertises outputs over about 500 lumens and most that do claim that output don't use boost circuitry but rather are either direct drive or linear regulated (dropping) or buck circuitry as boosting is always less efficient with similar attention to design you usually lose more power that could drive higher lumen output. I think that these people are likely guilty of hyping the output it may not even be an ANSI output unless maybe they were using Energizer lithiums (L91s). The only lithium rechargeables that would likely work with this light are not native AAs.... they are lithium ion cells with buck circuitry to drop the 3.7v to 1.5v and with that circuitry it can limit the power output of the battery itself likely making it less powerful than a lithium primary that is 1.6v or so (1.8v no load).

This is why the majority of us who want 400 lumens or higher for any respectable non turbo runtime have gravitated to 18650, 21700 and larger cells because 800 lumens is IMO too much for anything smaller. My advice is to be happy it even gets 600 lumens output and not waste a lot of money for the extra 100-200 lumens it may seem brighter but in use your eyes can adjust to it and make it not quite as huge of a deal. Spend $20 and get an 18650 light and use it when you need 1000-2000 lumens and forget about AAs and 500+ lumens and above.

Thanks for the reply. I agree with all you say, especially the false claim about 800 lumens with AAs. And the use of Lithiums which drop from 3.7 to 1.5V would effect its runtime. I wish I knew the actual data of how this light performs with rechargeable Lithiums.

Specifically, the Valor was intended to serve as a bicycle light and an EDC. Should I deplete my AAs on tour, they are readily available at most stores. Most stores don't sell 18650/21700s. This model has served well for the last 10 years. The move to using the Valor was intended as an upgrade over my Thrunite Archer 2AV2 and 2AV3. When comparing the Archer 2AV3 vs Valor, both using Eneloop Pros, the Valor tops out at Medium mode. The Archer runs about 3 minutes in Turbo (450L), then drops to High (280L). There is no significant difference between Archer High and Valor Medium. In fact the Archer appears a tad brighter. The only benefit to the Valor is getting it to operate in High Mode, which currently seams impossible with rechargeable cells.

 

[Lynx_Arc]

Thanks for the reply. I agree with all you say, especially the false claim about 800 lumens with AAs. And the use of Lithiums which drop from 3.7 to 1.5V would effect its runtime. I wish I knew the actual data of how this light performs with rechargeable Lithiums.

Specifically, the Valor was intended to serve as a bicycle light and an EDC. Should I deplete my AAs on tour, they are readily available at most stores. Most stores don't sell 18650/21700s. This model has served well for the last 10 years. The move to using the Valor was intended as an upgrade over my Thrunite Archer 2AV2 and 2AV3. When comparing the Archer 2AV3 vs Valor, both using Eneloop Pros, the Valor tops out at Medium mode. The Archer runs about 3 minutes in Turbo (450L), then drops to High (280L). There is no significant difference between Archer High and Valor Medium. In fact the Archer appears a tad brighter. The only benefit to the Valor is getting it to operate in High Mode, which currently seams impossible with rechargeable cells.

Figure out how many AAs you go through in a week and divide that by 4 and that is how many 18650s will do the job for you and just get extras and AC and DC chargers and never look back.