Lithium-ion battery safety 101

[snerkler]

@how crazy is this

@snerkler

Are you saying that it will get too hot at 2000 lumens/6A? The reason I thought this would be OK is that a fellow dog walker uses an Exposure Diablo which apparently is 1800 lumens and it only gets slightly warm. Obviously I have nothing to measure that it’s at 1800 lumens and so it could indeed be lower than that but it’s plenty bright enough :+1:

It only gets slightly warm because it has thermal management and that won’t let the light get that hot. 5A 6A for 1800 or 2000 lumen seems in the ballpark. Different LEDs have different efficiency.

Luminus SST-40, a N4 BA bin tested

Don’t know what light they use and I am not certain how the electronics inside the light will change the output vs the chart linked above. Nearly certain the output would have to be be lower than the chart but not sure how much. The specs for the light pretty much confirm that your friend is not walking around at 1800 lumen the whole time. They list a minimum run time of one hour with a 3500 mAh battery. That would be an average of 3.5 Amps. Looks like you coud get maybe 1400 lumen from that but given the fact that it starts at 1800 Lumen it would be drawing more for some time and therefore must settle down lower than 3.5A. Hopefully someone who understands how an actual flashlight is different from that chart can add to this.

Wow these things are complicated, whatever happened to just turning a light on and off again lol.

So if I’m understanding this correctly, whilst I might set my flashlight to 2000 lumens (hypothetically) it might only stay there for several mins and then drop down to stop it from overheating? If so is there something in the specs that tells me what the max setting is that it will run at without dropping down (at least for an hour or two)?

P.S. The Astrolux EA01s I’ve ordered is the XHP 50.2 version, I’ve no idea how efficient these are.

[snerkler]

@jon_slider

here is a runtime test, to help visualize how different output levels behave:

.
pic is a link to a review with more details

Thanks, interesting that if you want any kind of decent runtime it has to be below 1000 lumens. I’ve no idea whether that will be bright enough as my current light ‘claims’ to be 2500 lumens but the fact it runs off 3 x AAA alkaline batteries, and my friend’s Exposure Diablo that claims to be 1800 lumens is much brighter, clearly my current light is not 2500 lumens.

[snerkler]

Hi,

The link in the original post isn’t working and I was wondering what the best way is to ‘store’ batteries when the flashlight is not being used for an extended period of time? For non-protected Li-ion batteries is it best to remove from the light and store in a plastic case, or is it best to leave in the light so that it benefits from the low voltage protection supplied by the flashlight (Anduril). Likewise for a protected battery, I assume for a protected battery its own LVP would protect it regardless?

Any help would be appreciated.

[Lightbringer]

Which link? There are like 80 links in just that post #1…

[snerkler]

@Lightbringer

Which link? There are like 80 links in just that post #1…

Sorry, the one regarding long term storage.

[Notmyrealname]

@snerkler

@jon_slider

here is a runtime test, to help visualize how different output levels behave:

.
pic is a link to a review with more details

Thanks, interesting that if you want any kind of decent runtime it has to be below 1000 lumens. I’ve no idea whether that will be bright enough as my current light ‘claims’ to be 2500 lumens but the fact it runs off 3 x AAA alkaline batteries, and my friend’s Exposure Diablo that claims to be 1800 lumens is much brighter, clearly my current light is not 2500 lumens.

You may know this already but beam characteristics can make a big difference in the perceived brightness of a flashlight. At the same distances a floody beam has the lumens spread over a wider area. A lower lumen narrower beam can have higher lux and can appear much brighter because the lumens are concentrated in a smaller area.
That can make it hard to judge the lumen output of a light.

[snerkler]

@Notmyrealname

@snerkler

@jon_slider

here is a runtime test, to help visualize how different output levels behave:

.
pic is a link to a review with more details

Thanks, interesting that if you want any kind of decent runtime it has to be below 1000 lumens. I’ve no idea whether that will be bright enough as my current light ‘claims’ to be 2500 lumens but the fact it runs off 3 x AAA alkaline batteries, and my friend’s Exposure Diablo that claims to be 1800 lumens is much brighter, clearly my current light is not 2500 lumens.

You may know this already but beam characteristics can make a big difference in the perceived brightness of a flashlight. At the same distances a floody beam has the lumens spread over a wider area. A lower lumen narrower beam can have higher lux and can appear much brighter because the lumens are concentrated in a smaller area.
That can make it hard to judge the lumen output of a light.

Thanks, yeah I appreciate that. After trial and error I’m finding roughly 800-1000 lumens on a flood beam works for us. I’m basing this on my P20ix being 850 lumen in high.