Power (W) vs. current (I) - please explain the relations

Water on a Lithium fire splatters melted bits of burning lithium all over the place and makes the fire burn hotter.
It is not the electrolyte that burns, it is the extremely active metal. Lithium burns white hot like magnesium in a flare or like titanium in a jet engine.

Regarding price for charging 4 batteries, please look to my posting #8. Even with 30% overall efficiency, it will be well below 0.1 kWh, so if you know your Euro/kWh ratio you have some indication without spending money on an energy meter without specs.

Generally fast charging (say around or within an hour) has lower efficiency, and less useful life of the batteries.

@audioguru: Only primary Li-batteries have metallic lithium, and that goes wrong with water. Li-ion has no metallic Li, so if you have nothing else, you can use water to extinguish the fire. The water will at least absorb heat so avoiding that the fire will spread.

WimRFP said:

Regarding price for charging 4 batteries, please look to my posting #8. Even with 30% overall efficiency, it will be well below 0.1 kWh, so if you know your Euro/kWh ratio you have some indication without spending money on an energy meter without specs.

Generally fast charging (say around or within an hour) has lower efficiency, and less useful life of the batteries.

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That's quite cheap, then

Regardless the lack of US/CAN certification, what do you personally think of **broken link removed** battery charger? I need a charger that can charge 4 batteries (18650) simultaneously, and when finished, it will stop the current float, so that no overcharge can occur.

There might be various reasons for the missing certificates, not only it is not safe. For example, they might not have controlled it yet.

I can't judge a charger just based on an image, but you may check this review:
https://www.candlepowerforums.com/v...arger-Review-(V2)-current-voltage-comparisons

Hopefully the link does work, It shows CE.

When it does its job, it is an efficient charger, otherwise the plastic would melt.

WimRFP said:

Hopefully the link does work, It shows CE.

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Yes, I have already checked it, based on the review, I thought of buying this one; very good features and lots of it (various kinds of batteries charging simultaneously etc...)

CE = you mean the certification on the back of it?

WimRFP said:

When it does its job, it is an efficient charger, otherwise the plastic would melt.

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I don't understand this fully. So it is very efficient, but with efficiency that high, there is a risk that it will burn? Which plastic do you mean? Basically the entire housing / case?

Regards

With efficiency I mean the ratio between (energy delivered to the batteries)/(energy consumed from the mains).

If the charger itself has low efficiency (so generates heat by itself), the plastic case would melt. This is a modern charger with a switch-mode circuitry, so the overall charge efficiency (including heat loss in the batteries) will be > 50%. So charging 4 batteries costs around 0.01Euro.

When the charger really meets the CE directive (indicated by the "CE" marking on the back), it would be safe to use. As many EU countries show low activity w.r.t. inspection, there is a risk that the CE mark was fixed to the product without actually being tested.

When a certain brand is on the EU market for relative long time, there is a higher change that the products do meet the CE requirements.

Whether safe or not, charge yuor batteries on a non-flammable surface (or in an open non-flammable box) so that when something goes wrong, fire doesn't spread.

I do not know why there are different safety certifications in the world.
CE is for Europe. UL is for United States. CSA is for Canada.