Problem: Lumintop SD10 4xAA nimh doesn't work or is dimmer than 1xD

I got this Lumintop SD10 from Even though the page and the box itself says it’s a 3xAA light, the battery carrier I got was a 4xAA. For some reason, the SD10 failed to turn on today with my Tenergy Centura AA batteries, even though they had previously worked. So I ran some tests, and the results didn’t make sense.

(Note that for the SD10, the user interface requires you to hold the button to turn on and off the light.)

1xD Tenergy Centura

- The battery is 1.25 volts.

  • When I hold the button, the light turns on.

4xAA Tenergy Centura

- Each battery is 1.27 volts.

- When inserted into the battery carrier, the battery carrier is 2.56 volts.

- When I press the button, the green light blinks, indicating there is power.

  • When I hold the button, the light does NOT turn on.

4xAA Eneloop

- Each battery is 1.32 volts.

- When inserted into the battery carrier, the battery carrier is 2.66 volts.

  • When I hold the button, the light turns on, but the high mode is noticeably dimmer than the 1xD high mode.

4xAA Duracell alkaline

- Each battery is 1.52 - 1.57 volts.

- When inserted into the battery carrier, the battery carrier is 3.11 volts.

  • When I hold the button, the light turns on. To my eyeballs, the high mode is roughly similar in brightness to the 1xD high mode.


- Why would the 4xAA Eneloop be dimmer than the 1xD Tenergy Centura?

- Is it normal for the battery carrier to show only twice the voltage despite having 4 batteries in it? Or is that a problem with my battery carrier?

  • Does anyone have a Lumintop SD10 with the 4xAA carrier? Can you check the voltage from your battery carrier?


Yeah, 4 AA batteries.

I got 2.6A on 4 Eneloops, same as you. Of course boost circuitry is required for the D cell and 4 AA cell configurations, and boost circuitry can be finicky. It's possible it's more efficient with a lower input voltage, not sure. Mine is the BLF SD10 which came with a pretty high quality 4 AA carrier, and two tail springs. You need the bigger hole spring in order to run the AA carrier, at least with mine. What they are shipping now, not sure - dunno.

Mine has been fully modded with a FET+1 driver. I took off the protection circuit from a TrustFire 32650 and got incredible results with it! All measurements done with a clamp meter at the tail w/heavy gauge wire loop:

TF 32650 @4.09v: 6.67A

SAM 30Q #2 @4.21v: 6.60A

SAM 30Q #4 @4.20v: 6.53A

EFEST 26650 4000 #4 @4.22v: 7.03A

BASEN 26650 4500 #1 @4.22v: 6.82A

BASEN 26650 4500 #3 @4.22v: 6.93A

BASEN 26650 4500 #4 @4.22v: 6.89A

TF 32650 @4.22v: 7.58A

The "unprotected" TrustFire 32650 must have incredible IMR power to beat those other cells, and it beat them significantly.

With the stock XM-L2 U2 3C on a 20 mm Noctigon, and the unprotected TF 32650 @4.22v, I got:

lumens: 1734 @start, 1578 @30 secs, 43 kcd (415 meters)

AFAIK, the only Lumintop SD10 that has come with a 4xAA carrier is the BLF Edition from WWEFANS group buy. The carrier is wired 2S2P. The driver is very special though. I’ve been told it has three different circuits for the three different battery configs it supports - 1xD, 4xAA, 1xLi-Ion. I haven’t heard of anyone having problems with the light not coming on, or the high mode with 4xAA being lower than the 1xD cell. IIRC, it’s been observed that with 4xAA NiMH cells, the moon mode won’t light up, although it works with every other config, including 4xAA alkalines. This is a known issue with the BLF Edition.

Edit: OOPS, forgot. I was going to say that if you have problems with the light not working with a specific battery config, then it’s probably something wrong in the hardware for that one circuit. You should be able to get a replacement light.

This is what I discovered yesterday when I took apart the battery carrier, examined the traces on the PCBs, and poked around with my multimeter. 2S2P would explain why the battery carrier is outputting 2.56 volts instead of 5+ volts like the battery carrier in my Thrunite TN4A and Sunwayman D40A. It would also explain why I was able to read 2.56 volts from the battery carrier even though I inserted only 2 batteries into the carrier.

I got this light at half price because I initially ordered a neutral white SD10, but banggood sent me a cool white. They asked me to wait until after Chinese New Year to see if the manufacturer has more neutral whites. After Chinese New Year, they told me the manufacturer was out of stock and may not have any more, so they offered a 50% refund if I kept the light. I figured that paying $25 for this light was OK, so I accepted.

At this point, I’d rather just keep the SD10 as a 1xD flashlight than ask for a replacment from banggood. Additionaly, there’s a BLF group buy for the Lumintop SD4A in discussion, so I can wait for that one to add another neutral white 4xAA soda can flashlight to my collection.

Thanks to all who responded to my problem.

Yeah, I sold my BLF SD10, which I loved and used every day, several months ago, in anticipation of the new SD4A group buy light. Since then, I’ve been having DT’s from the waiting. If I’d known they were still selling the BLF SD10 AND that the SD4A was going to be this long a wait, I’d have told the guy to get his own, instead of selling him mine. Now, I don’t have the money to buy myself a new one, because of reduced hours at work. :-((

One thing you might try, if you’re not scared to take it apart, is to look at the driver and see if there is anything obviously wrong that you might fix, like a bad solder joint or something.

I don’t think they’re selling the BLF SD10. From what I’ve researched, the light that I received is the Lumintop SD10 with high > med > low and a hidden strobe. Someone decided to stick in the BLF 2S2P battery carrier into the Lumintop SD10, perhaps because they ran out of 3xAA carriers, or they had some extra BLF carriers, or because the BLF carrier is polarity protected so you don’t fry the light when inserted in the wrong direction.

I suspect the Lumintop SD10 is designed for 3xAA in serial or a single lithium ion, which means a voltage range of somewhere around 2.7 - 4.5V, not 1.8 - 3.0V of a 2S2P 4xAA configuration.

That’s a good idea, except I don’t know how to take apart the head of the light, at least not without breaking it. Maybe some day in the future after I get some practice and experience taking apart and putting back together crappy I-dont-care lights, but not today.

Beware! The SD10 do not have reverse polarity protection!

I have one fried SD10, accidentally put the 3AA holder inverted.

Dang, I’d take the fried SD10! Perfect for modding. Too bad you are several 1000 miles away…

Someday I will make a mod that I thought, I have the things, but when I will make it will be obsolete…

The group buy has been going nowhere for months now.
I woudn’t hold your breath… :frowning:

Not much info on this light, but they no longer list a LiIon cell, 32650 or otherwise, as an option:

They list it as available now, ships in 1-2 days. Shame - I have no interest running primary cells in it.

That information is copied from the Lumintop SD4A page, and although their description claims to support 1×18650/26650, their features and specification sections don’t.

Now that’s confusing.