(I apologize if this has already been answered elsewhere. I swear I actually searched.)
I’ve had some trouble with my JetBeam RRT01 lately. It has completely discharged several quality cells in a matter of days or less. The design basically requires a button top.
Credit to ZeroAir Reviews
I’ve been using unprotected flat tops with a ~1.6x6 mm neodymium magnet. After some experiments, I think the magnet it is making contact with the silver ring, the one pictured above that has the philips head screw holding it. I used my multimeter and I can confirm there is continuity between the ring and the threads of the head.
My hypothesis is the magnet is touching the silver ring and positive terminal, causing a short circuit that drains the battery rapidly. The spacing and sizing is right.
I’m curious if other people think this is a plausible explanation and if you have had similar experiences.
Never use a magnet on the positive contact. It’s just a matter of time when the accident happens. Usually the host of the flashlight is the negative pole and if the magnet slips it will cause a short. You can use a magnet on the negative side if the battery is too short, but if the light requires a button top battery you need a button top battery.
Im pretty sure that is not the problem because the white plastic ring has elevated edges and your magnet is small enough to sit inside the ring
If the brightness control ring is turned all the way down, and your RRT-01 has no tailswitch (2011, 2012, and 2019 models), or the tailswitch is left On (2020 model), the parasitic drain should definitely not drain a battery in a few days.
Otoh, IF the control ring is not turned all the way down, on models w no tailswitch, or if the tailswitch is left On, that Will Definitely drain a battery in less than a week.
On rare occasions an RRT-01 driver can have a bad component, that creates excessive parasitic drain. If that happens, it is possible to purchase a replacement driver from info @ jetbeamlight.com
they have both 2019 and 2020 drivers, the latter costs a bit more, it adds thermal step down. I dont use maximum output on my lights, and I definitely do not tailstand them on maximum output, so imho, thermal step down is not required.
Parasitic drain drops to zero on the 2020 model, when the tailswitch is Off, no matter where the control ring is positioned.
I’m pretty sure I have the latest version of the RRT01: It has the switch and ring control, and I purchased it new within the last year. Does that mean even with the light switched off, the magnet could be interfering?
Okay that was my assumption. Let me lay out some additional facts.
The first time the battery fully depleted it was with the light switched on and ring at the lowest setting. Jon I think I actually did this after reading a thread you created or commented in about parasitic drain (or lack thereof) in the RRT01. This drain to 0 volts happened within a month.
The second time the battery fully depleted I had the light switched off. This drain also happened within a month.
The third time, I decided I needed to replicate the problem if I was going to make observations. I took a fully-charged, know-good, 18350 battery and logged the voltage over time. The voltage started at 4.098 and 17 days later it leveled out at 4.087. This seemed liked expected behaviour to me so on Nov. 2nd I took my last reading. I went to turn on the flashlight today, Nov 8th, and the voltage was 0.2-0.3.
All of these incidents involved different flat top 18350s and the tiny magnet I mentioned in my first post. Previously, I had removed the plastic ring around the positive contact and that allowed me to use flat tops without any issue AFAIK. I did notice this exposes some PCB.
My thoughts on next steps are to put a button top in the flashlight. If the button top fails, I’d start looking at the flashlight for failure points. If the button top works, I would try to find a way to determine if there is any contact between the magnet and outer metal ring when using a flat top. I’m not sure what the best way to do that is. Suggestions are welcome. I’m thinking of a specialized ink or paint.
> The voltage started at 4.098 and 17 days later it leveled out at 4.087. This seemed liked expected behaviour to me so on Nov. 2nd I took my last reading.
that all sounds good
> I went to turn on the flashlight today, Nov 8th, and the voltage was 0.2-0.3.
that sounds terribly frustrating,
the only way I know to connect the bottom of the battery to the circuit, is for the switch to be On. So, if you see the light turn off when you click the switch, then the circuit is open between the bottom of the battery, and the silver contact ring in the head.
> Previously, I had removed the plastic ring around the positive contact and that allowed me to use flat tops without any issue AFAIK
the purpose of the white plastic ring, is to prevent reverse polarity contact if the battery is mistakenly inserted backwards. That could fry the driver, and the light would no longer turn on.
I suggest you buy a protected button top, so your batteries stop getting overdischarged, until you figure out if the tailswitch is not turning off.
Maybe ask Jetbeam for a new tailswitch.
my present working hypothesis, is
either the switch is faulty and is not turning off,
or you are leaving the switch on by mistake,
I hope you get it sorted… and update this thread… I hate unsolved mysteries.
Thanks for all the help. I’ve thrown, what I assume is, a protected JetBeam battery in there.
You are right, even if the magnet is shorting the circuit, it isn’t a complete circuit without the switch being closed or a second short. I also couldn’t purposely get the magnet to short the circuit. I tested the switch and contact points thoroughly, and apart from one questionable solder, everything looks good.
User error was my first thought, but I’m leaning away from that now. I would have noticed if I left the light on at anything but the lowest setting. If I understood your past posts, leaving it on at the lowest setting shouldn’t be a problem. Perhaps I left it on at some point past the detent but low enough that there is no visible light emitted? I could probably do the math on that to see if it is plausible.
At this point, I think I’ll just reach out to JetBeam. I’ll be sure to update this thread if they provide an answer. Thanks again!
when the dial is turned to its full stop lowest mode, the parasitic drain is low enough that the battery should last about 2 Years, with the tailswitch ON
otoh, once the dial is turned, even the slightest bit, even while the LED is still not visibly lit, the parasitic drain will empty the battery in about 3 days, IF the switch is ON.
So, IF the switch is not shutting OFF, And the rotary dial is Not completely at its end stop, Then the parasitic drain would be high enough to cause the rapid drain you are experiencing.
This is all sounding very strange, and speculative… I look forward to some clarity.
UPDATE: It looks like my flashlight does have significant parasitic drain.
If I leave the switch on, but put the ring in the lowest position, the battery is dead in under 24 hours. I took voltage measurements with my consumer-grade multimeter in series with the positive and negative terminals seperately. The position of the multimeter in the circuit did not appear to make a difference.
Ring Max
Ring Min
Switch On
4.188 volts
4.188 volts
Switch Off
0 volts
0 volts
Battery Alone
4.188 volts
n/a
The ring position didn’t seem to affect the voltage measurement: the voltage was 0 or 4.188 volts depending only the switch position.
I’m going to assume I left the light on in the lowest position in the past, which would explain my dead batteries via parasitic drain. I’m curious if my flashlight is defective or if JetBeam made the change without letting customers know.
I’m hardly an electrical engineer, so please point out any mistakes I may have made.
Thanks for the info! I really do appreciate it. I’m making a concerted to better understand electronics.
I thought the voltage measurements at least showed continuity while the switch is on, even if the ring is set to minimum. I guess that isn’t new info though.
You are right: voltage isn’t useful, especially if I don’t know how the dimming mechanism works. What would you do next? Can I measure resistance then use Ohm’s law to determine current or would that not work here?
I thought if the switch was on and the ring was at minimum, there would be low parasitic drain. I was basing that on what Jon said.
This is why I assumed there would be no parasitic drain. Is this a contested statement or am I missing something else?
The latest model sure doesn’t have low-voltage protection or at least my specific light doesn’t. It drained a couple unprotected cells to 0 volts in under 24 hours. Definitely want to use a protected cell in it.
