I just recently bought a Vinh modded ET S200C2 and according to some of the guys over at CPF, this torch will maintain brightness better with high discharge batteries. It pulls 4.5a, and apparantly protected cells can’t keep up with this discharge rate over time.
So I decided to buy 5 Panasonic NCR18650PF’s from IS (1 more the incoming light, and 4 extras for…well…I’m sure they’ll get used in the future )
It then occurred to me that all I own are protected panasonic NCR A and B’s…hmm…
So up until now I’ve always used quality batteries in a quality charger (i4) and haven’t really had to worry much about over discharging the batteries in my torches.
Now that I have unprotected batteries, is it essential that I also buy a multimetre? How will I know when I need to recharge these batteries?
What other precautions should I also consider with unprotected cells?
Will I get better performance from any of my other torches???
A good DMM should belong to every flashaholic. More important than just owning good cells, protected or not. A good analyzing charger/discharger is great for use in multi-cell lights as you not only need the same voltage of the cells, but more importantly those cells should have similar discharge capacities (about 200mah) recorded as not to mix use them, specially in high-drain lights. Your I4 cannot give you discharge capacities.
Quick and dirty answer: when the light starts dimming on high, it’s time to recharge. You won’t really see a lumen boost because the protection circuit does little to impede the flow of electricity. A multimeter is very handy but not truly necessary. If you have harbor freight down in Australia, they have deals on their free to cheap ($<4) MM from time to time. In this case, you don’t need a top of the line MM, but it would be worthwhile to really splurge and go for the best if you are going to start modding a lot.
As far a further precautions, don’t do anything stupid with them. In this case, it is safer to charge them if you are unsure if they are empty.
Really? Not all protection circuits are created equal. Some of the best ones (when installed with care), in addition to handling currents like that with ease, add so little resistance to the equation that the actual contact points in the light (springs etc) would be a bigger bottleneck. So while the advice you got over at CPF might be true in a lot of cases, I have my doubts that it’s true in all cases.
I have labelled 4 NCRB’s for my SRK, and they live in the torch. When I recharge, they all get done at the same time so they maintain equal charge as well as equal charge cycles.
Same with my TK75 and K40vn. Same batteries, same charge cycles, bought at the same time.
Cheap DMM’s can be had in Australia for about $20. I don’t plan on getting into the modding scene just yet, so the most basic of DMM should suit my needs (check voltage of batteries)??
Quote from Vinh himself:
Most if not all 18650 are “capable” and are rated at of draining 4.5A+. This just mean the chemistry can handle the current draw safely at that rate. However all protected batteries have higher internal resistance than IMR and/or unprotected cells so they will likely not get 4.5A.
The chance of getting one bad cell (meaning significantly low discharge capacity compared to the others) is actually very small, specially when you bought from the big companies (Panasonic, LG, Samsung, Sony) but just the same, if one wants to be sure, getting each cell’s discharge capacity is for me more important than just marking and charging those cells together. Also, having an analyzing charger is another avenue of enjoying this hobby. Remember Murphy’s law.
I used to have an FF4 and I have peace of mind using it since I’m sure I have all my cells tested for their discharge capacities.
As soon as HKJ gives the Opus BT-C3100 V2.0 the nod, I will probably order one.
I’ve been looking for a LONG TIME at getting a better charger than the Nitecore i4 Intellicharger, but every one I see reviewed by HKJ, has small issues / problems, even the Xtar ones.
Like I said, not all protection circuits are created equal. The best ones do not add a significant amount of resistance to the equation and both myself and others have seen protected cells put out more than 6A. But it’s not all about the amperage anyway. The best ones exhibit less voltage sag too.
On the other hand, if you have a DMM and you check your cell’s voltage every now and then rather than run down the cells in your lights till its last drop, that should not be a main concern at all. In this hobby, you can buy peace of mind, but of course perfection is very difficult to achieve.
I understand this, but without sounding like I’m trying to argue: can they maintain that discharge rate or does it slow over time due to internal resistance?
I don’t have any unregulated lights so I cannot say. Most regulated lights will give you some form of warning like blinking or going down a mode, (from Turbo to High)
The point is that a quality low resistance protection circuit, installed with care, will not significantly add to the internal resistance of the battery as a whole. The main limiting factor, at least at 4.5A or so, will be the battery chemistry itself. IMR cells are definitely superior in this respect, but there is not necessarily a big difference between protected and unprotected Panasonic cells. And at a mere 4.5A, I would struggle to see the benefit of IMR cells given the tradeoffs anyway.
Don’t lament your purchasing decision though. The Panasonic’s are pretty safe even without a protection circuit. Some basic commonsense battery management is all you need.
If you go and have a play with HKJ’s excellent 18650 comparometer and compare an unprotected Panasonic 18650B to the various protected versions of the cell, you’ll notice quite a large performance variance across differently branded cells at a 5A discharge rate. For example:
The Keeppower ones are very good as they use a decent protection circuit and lots of other sellers (www.intl-outdoor.com for example) carry re-branded versions of these same cells. But whilst they are indeed decent, they are not the best if you’re trying to match the discharge curve of an unprotected 18650B cell as closely as possible. What we want to see is something more like this:
I’ve had no personal experience with those particular Efest cells but they clearly demonstrate the existence of extremely low resistance protection circuits. I bet it has something to do with the differences you can see in the following tear down that RMM did here: Evva vs. Keeppower NCR18650B Protection PCB Visual Comparison
Notice that the Keeppower cells use a protection circuit that utilizes only two mosfets (which is undoubtedly already more than most), but that there are other protection circuits available that utilize 3.
It doesn’t look like our good friend HKJ has tested any of these yet but I bet they’d fare very well in a head to head comparison with unprotected cells at 5A.
Oh wow, I already own 4 of those exact cells, use them in my TK75 as I regard them as the best / most expensive cells I own.
Are you saying those would work well in the torch I have coming?
In your comparison charts above shouldn’t 1 of the cells have been an unprotected high discharge cell (compared to the NCRB’s)??
That seller is a 5 minute drive from where I live. But it’s hard to justify spending $70 on 4 cells…
)
