[ 40,000 Lumen Manker MK38? - A Review and Teardown ]

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loneoceans
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Correllux wrote:
Fantastic review. Question: Running on turbo at a distance of 30cm, how long does it take to melt a quarter-pound stick of room temperature unsalted butter on a standard ceramic butter dish?

Thank you. I'm not sure about that, but it begins smoking any remotely dark-coloured paper held up near the lens on turbo almost immediately. You definitely want to make sure it's on lock-out mode (4 clicks) when transporting. There is no physical lock-out switch though, so I'd set the single click on to the lowest mid-mode (~900 lumens).

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roostre
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loneoceans wrote:
... 3S is a good idea. I don't understand individual-cell lights that use 3P since it can be quite dangerous ...

Why are lights with multiple individual cells connected in parallel more dangerous than lights with multiple individual cells connected in series?

I am new to this hobby and have several multi-cell lights with 3P and 4P battery configurations and some of those contain built-in charging ports.

I have avoided purchasing multi-cell lights with batteries configured in series since I was under the impression (apparently a false-impression) that series battery configurations were more dangerous since they do not keep all of the batteries at the same voltage.

With my limited understanding, I assumed that an individual cell (even in a matched set) would be more likely to fail over time in a series connected battery configuration (than in a parallel connected battery configuration) because in a series connected battery configuration, an individual cell could be discharged more (potentially even over-discharged) than the other cells while using the light and an individual cell (the same or a different cell) could also be over-charged if charged in series with the other cells if a "Balanced Charging” mechanism was not implemented.

I also wonder, if an individual Li-ion cell failed catastrophically while inside of a multi-cell light, would this cause all of the other adjacent cells to also fail catastrophically (from the intense heat created by the initial failure) whether the cells were connected in a series or parallel configuration.

Thanks again for this interesting thread. I have also enjoyed reading your posts from other threads.

How many flashlights does a "real man" need?

None, real men are not afraid of the dark.

loneoceans
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roostre wrote:

loneoceans wrote:
... 3S is a good idea. I don't understand individual-cell lights that use 3P since it can be quite dangerous ...

Why are lights with multiple individual cells connected in parallel more dangerous than lights with multiple individual cells connected in series?

I am new to this hobby and have several multi-cell lights with 3P and 4P battery configurations and some of those contain built-in charging ports.

I have avoided purchasing multi-cell lights with batteries configured in series since I was under the impression (apparently a false-impression) that series battery configurations were more dangerous since they do not keep all of the batteries at the same voltage.

With my limited understanding, I assumed that an individual cell (even in a matched set) would be more likely to fail over time in a series connected battery configuration (than in a parallel connected battery configuration) because in a series connected battery configuration, an individual cell could be discharged more (potentially even over-discharged) than the other cells while using the light and an individual cell (the same or a different cell) could also be over-charged if charged in series with the other cells if a "Balanced Charging” mechanism was not implemented.

I also wonder, if an individual Li-ion cell failed catastrophically while inside of a multi-cell light, would this cause all of the other adjacent cells to also fail catastrophically (from the intense heat created by the initial failure) whether the cells were connected in a series or parallel configuration.

Thanks again for this interesting thread. I have also enjoyed reading your posts from other threads.

To begin, I'm not a battery expert and I'm sure that there are lots more people out there who are a lot more knowledgeable about the topic so please correct me if I am wrong and I'd love to learn more about this topic myself. 

There is nothing fundamentally wrong with putting battery cells in series or parallel; these is often done in the industry. Electric cars are a great example. However, typically cells which are assembled into packs are often from the same batch and are specifically binned to be matched. Like you mentioned, ideally S packs will have a BMS to ensure charge balancing and pack monitoring as well. 

For parallel individual cells, the main problem I see is that it is very easy for batteries to be mismatched by the user - these could be batteries from different batches, completely different cells, or cells with differing states of charge. Typically the cells used are individual cells which have NOT be connected together prior to being installed in a flashlight. It's not too difficult to see a situation where a user could mistakenly put 2 full and 1 empty cell into a 3P flashlight, and cause a fire hazard as the full cells try to charge the empty cell. This does not apply to a P battery pack that cannot be taken apart - such battery packs do have benefits since they are inherently balanced (which is not the case for series cells). 

That said, even in situations where the cells are the same, the user has no easy way to determine the specific characteristics of each cell, for example, internal resistance. Even a small mismatch in internal resistance, especially at the huge power draw rates in modern flashlights, can cause significant acceleration in the degradation of the cell. 

There are still concerns to be said for individual series cells, but these can be mitigated with a BMS (which ideally should be implemented). For a flashlight of this power, a properly designed battery pack is the safer and more efficient option. 

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
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roostre
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loneoceans wrote:
To begin, I'm not a battery expert ...
... For a flashlight of this power, a properly designed battery pack is the safer and more efficient option.

Thanks for the clarification.

I'm definitely not a battery expert either, but have become a frequent user.

Hopefully I will not have any adverse battery issues with my multi-cell lights since I have worried enough about the potential dangers of Li-ion batteries to become somewhat knowledgable, but still feel safest with single-cell Li-ion lights.

Also, your website listed in your signature is fascinating. Thanks for sharing those projects.

How many flashlights does a "real man" need?

None, real men are not afraid of the dark.

texas shooter
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roostre wrote:

loneoceans wrote:
… 3S is a good idea. I don’t understand individual-cell lights that use 3P since it can be quite dangerous …

Why are lights with multiple individual cells connected in parallel more dangerous than lights with multiple individual cells connected in series?

I am new to this hobby and have several multi-cell lights with 3P and 4P battery configurations and some of those contain built-in charging ports.

I have avoided purchasing multi-cell lights with batteries configured in series since I was under the impression (apparently a false-impression) that series battery configurations were more dangerous since they do not keep all of the batteries at the same voltage.

With my limited understanding, I assumed that an individual cell (even in a matched set) would be more likely to fail over time in a series connected battery configuration (than in a parallel connected battery configuration) because in a series connected battery configuration, an individual cell could be discharged more (potentially even over-discharged) than the other cells while using the light and an individual cell (the same or a different cell) could also be over-charged if charged in series with the other cells if a “Balanced Charging” mechanism was not implemented.

I also wonder, if an individual Li-ion cell failed catastrophically while inside of a multi-cell light, would this cause all of the other adjacent cells to also fail catastrophically (from the intense heat created by the initial failure) whether the cells were connected in a series or parallel configuration.

Thanks again for this interesting thread. I have also enjoyed reading your posts from other threads.

loneoceans nailed down most of the issues. In this hobby most series set ups don’t have a BMS. In parallel BMS isn’t needed as the cell are forced to balance. Biggest concern is picking the right cells, in the same batch, with the use, at the right voltage. Most recommend buying the cells together, marking them and never using them for any thing else. If my flashlight maxes at 10 amps per cell then I get at least 15 amps cells. Buy only the same cells. Mark them with the light and 1,2,3,etc as needed. Place them in the light fully charged as this keeps them all at the same voltage. We are safe. Mixing different cells, with different cycle counts, with different capacities. Danger is there, the more variables the greater the risk.

Loneoceans thanks for the review! Your review leaves me with the feeling that Manker is running this light past max. That this light really needs twice the electronics to have a longer life. That 4 batteries instead of 3 would be safer and more durable.

SKV89
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Thanks for the write up! If this came with XHP70.3 HI 4000k 90CRI, I would buy instantly

Pöbel
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Having cells in parallel is inherently safer. But it has its drawbacks.

The current (from battery to driver) is much higher, thus you will need to design all components (springs, cables, switches, traces) with this current in mind. It can also be less efficient, since more current means more heat related losses, because in a flashlight you will always have to compromise because of weight, cost, space.

Its always a very good practice (and recommended) to handle devices with several individual cells like Texas Shooter has described above.
- get matched cells (same type, same batch, same age)
- always use and charge them together
- only use them in this light

Parallel configuration:
Even if you have cells from different manufacturers or even (slightly) different states of charge, it will most likely work. You will lose performance and you will tax individual cells beyond what is recommended.
The load distributes in relation to the internal resistance of the cells, so the “fitter” cells (low IR) will have to do the work harder while the “not só fit” cells (higher IR) will carry less load. If there are differences in SOC to begin with, the cells will balance. If you mix empty and full cells, the balancing currents will be extremely high in the first seconds.
So always use matched cells! Do not mix cells!

Serial configuration
is a different story. It offers potentially more efficiency, as you have lower currents for the same power request. All cells will have to carry the exact same current. If one cell has worse IR than the others, it will sag a lot more and this can potentially end catastrophic if the load is not reduced.
If the cells are of high quality and matched to begin with, cell drift can be minimal. You might get away without balance charging (for a while). Cell drift becomes evident with higher loads. So if you often run cells at the max of their rating or beyond, then you absolutely will need to balance them.
Balancing just means, that during charging the voltages of all the cells are equalized, so that they all have the same voltage. This can either be done via BMS (battery management system) which is permanently fixed to the battery or it can be done by the charger (either by charging cells individually or, in the case of a pack, using the balance leads of the pack)
You MUST NEVER mix cells in a serial configuration. In contradiction to the parallel setup this will get you into trouble very quickly. The “fitter” cells cannot work harder as we experience in a parallel configuration, since all cells carry the exact same load.

loneoceans
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It was foggy yesterday so I was able to do a quick beam-shot. 

The MK38 with XHP70.2 LEDs is quite floody (as expected) with a bright central spot - this is my preferred use case. When using it to walk around at night, the XHP70.2 version excels for wide-illumination of open spaces (e.g. good for group events, work light, etc), or for enclosed spaces such as hiking in a dense forest. However, it's wide-nature is not ideal for throw (as expected), and I wouldn't consider the XHP70.2 an effective search light - the SFT40 should be far more ideal, and may even appear more impressive, as throwers often do. 

www.loneoceans.com/labs/

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Thanks for the nice review with teardown. Cool Thumbs Up

I wanted to know what this light looks like inside. I already asked Manker on AE if they would sell the MCPCB and the reflector but they said no.

loneoceans
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Thanks for the feedback everyone and for the lively discussion of battery packs. 

The design and engineering of a battery pack, even more so for high-drain applications, to be safe and reliable, is not a trivial engineering task. Here's an example of a fairly low cost battery pack made using Samsung cells (they're very cheap but now sold out). Check out the BMS board as well as how the interconnects and all are designed.

https://www.youtube.com/watch?v=ZW6FxARACfg

Note: the youtuber doesn't seem too familiar with the design aspects but you should be able to see the minimum work that is typically needed to make a battery pack. On board appears to be a balancing system, short circuit protection, possibility for a fuel gauge, and possible heating element for cold weather operation. 

www.loneoceans.com/labs/

- Next-gen Switching Drivers: Lume X1 and Lume1
- High Power Boost Drivers: GXB100 GAN 100W, GXB172 17mm 50W
- Others: GXF22, GFS16, GXB17 & GXB20 / Random items for
Sale / Manker MK38

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