Protected cells totally discharging
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glockboy
Flashlight Enthusiast
Maybe they did shut down before that happens, try jump start it.
ChrisGarrett
Flashlight Enthusiast
When you say "totally discharge (sic)", what do you mean by that?
What reading are you getting from your digital multi meter?
Could be the protection circuits have tripped and that's why you're seeing a 0.0vdc reading, believing that your cells are dead, when they're not.
Try resetting the PCBs and then take a voltage measurement.
Chris
All 4 cells were reading 0.0 vdc. I charged them and they took a charge to 4.19 vdc. Are you saying the protection did kick in and when it does they read 0.0 vdc? I didn't do any manual reset of any kind. I used a Nitecore Intellicharger i4. Since I didn't do a reset on the batteries is there a way to tell if they totally discharged or the protection kicked in?
terjee
Enlightened
Just to expand on what ChrisGarrett said...
What should the low voltage look like? Well, it cuts the power, so you should see zero volts (or about there). How do you know it's lockout? If it wasn't, you'd expect the light to diminish for a long time, not cutting off.
Also, when you drop the load, battery voltage should recover a bit when you're using a "naked" cell, not show zero straight away.
One thing I find a bit odd though, is that they are all showing zero. If Are all the batteries in parallel in this light? That could explain. In a series setup, one battery shutting down would break the circuit, and stop draining the others.
What should the low voltage look like? Well, it cuts the power, so you should see zero volts (or about there). How do you know it's lockout? If it wasn't, you'd expect the light to diminish for a long time, not cutting off.
Also, when you drop the load, battery voltage should recover a bit when you're using a "naked" cell, not show zero straight away.
One thing I find a bit odd though, is that they are all showing zero. If Are all the batteries in parallel in this light? That could explain. In a series setup, one battery shutting down would break the circuit, and stop draining the others.
vadimax
Flashlight Enthusiast
You are right, protected cells electrically disconnect inside in case of voltage too low. In real they still ~2.8V.
I believe the batteries are set up in series in the Niwalker Minimax. The batteries drained were not in use but in standby-lockout mode on this light. The endcap does not lockout on this light and it has a very high standby drain on cells. I enacted a switch lockout which was supposed to alleviate that or lessen that at least.
I did not do a manual reset on the cells, is that normally necessary? I am also curious if they were actually at 0 vdc how the charger knew they were lithium batteries. It is a multi chemistry charger.
I did not do a manual reset on the cells, is that normally necessary? I am also curious if they were actually at 0 vdc how the charger knew they were lithium batteries. It is a multi chemistry charger.
ChrisGarrett
Flashlight Enthusiast
It looks like, from a photo on Bangood, that they're set up in parallel, as all positive ends face the tailcap and not a mixture of the 4 cells, so perhaps they all drained and disconnected at various times?
Some chargers, like my older Xtar WP2 II will not reset a tripped PCB, so we have to jump them + to + and then bridge the negative contacts, or vice-versa.
Chris
For what it's worth Selfbuilt's review stated the cells are in series. From the review "As before, the four 18650 cells are in series, not parallel." http://www.candlepowerforums.com/vb/showthread.php?385451-Niwalker-MiniMax-Nova-MM15-(2xMT-G2-4x18650)-SHIPPING-Review-RUNTIME-BEAMSHOTS/page3.
I used a Nitecore Intellicharger i4.
As always thanks for any input it is much appreciated.
I used a Nitecore Intellicharger i4.
As always thanks for any input it is much appreciated.
ven
Flashaholic
The light does have parasitic drain with the elec lock out. Best option with this light , if not being used for a week or more is to remove the cells completely. Sounds like it's drained the cells under 3v and tripped them out at their low protection voltage.
ChrisGarrett
Flashlight Enthusiast
Yeah, I see that, but I think he's wrong on the 'series' part, having looked at a German review on the light with pictures of the battery carrier stuffed.
http://www.ms-it-consulting.biz/blo...ax-series-nova-mm15-2-x-mt-g2-5233-lumen-max/
Anyhow, 4*3.7v cells, in series probably isn't going to give you 2+ hours at 5,000+ lumens and that would be 16.8v hot off the charger.
Good luck and as others have stated, just keep the cells out of the light until you decide to fire her up.
Chris
I'm no expert but I believe the cells have to either be in series or possibly series/parallel. If I recall correctly an MTG2 led needs a min of 6vdc or thereabout.
ChrisGarrett
Flashlight Enthusiast
Yeah, you're right about that: 6v, 9v and 36v, but I'm confused due to the picture in the link above, showing the rear portion of the battery carrier and the contact board.
They're all in parallel at first glance, but we can't see the negative end of the carrier and perhaps it's wired in 2S2P inside the head of the light? I'm no expert.
Anyhow, good luck!
Chris
terjee
Enlightened
Quick thing about the voltages: it all depends on the driver. It's be entirely possible to have four batteries in parallel, for max. 4.2V, and then have a booster circuit in the driver.
Changing brightness modes requires changing the voltage anyhow (unless pure PWM), so you know there's a regulator in there. It's easier to just drive one way (either boost or buck), than have a regulator that supports both. Most will therefore want to keep the battery level outside the range the LED works in, and that's more important than if the battery voltage is above or below.
Changing brightness modes requires changing the voltage anyhow (unless pure PWM), so you know there's a regulator in there. It's easier to just drive one way (either boost or buck), than have a regulator that supports both. Most will therefore want to keep the battery level outside the range the LED works in, and that's more important than if the battery voltage is above or below.
