dredmorbius 3 days ago

NB: that's probably backwards. Batteries contain a lot of energy, they just don't release it particularly quickly.

Most explosives have relatively low energy density, however the energy they have is released far faster than with conventional fuels. By unit mass, TNT (or other comparable explosives such as C4, RDX, etc.) have about 1/10th the energy as liquid petroleum fuels (petrol, diesel, kerosene).

Though again most battery technologies also have fairly low energy densities. But those are probably roughly comparable with most mainstream explosives.

TNT has an energy density of 4.184 MJ/kg.

A LiON battery: 0.36–0.875 MJ/kg.

Motorola pagers (a widely used type) seem to typically take a 3.5V 500mAh battery, which if I'm doing my conversions correctly (mAh * V * 3.6) works out to about 23 kilojoule. That would be the energy equivalent of ~5g TNT. A light charge, but one you wouldn't want going off on your hip.

(Note: I've corrected an off-by-an-order-of-1,000 error above, earlier read 23 MJ / 180g TNT. As I said, I'm not entirely certain of my calculations, which are using the Wikipedia energy densities noted and GNU Units.)

<https://en.wikipedia.org/wiki/Energy_density>

Again, batteries won't explode as footage of the presumed Israeli attack on Hezbolla members shows. But they do contain appreciable energy. It would more likely burn rapidly at worst case.

  • amluto 3 days ago

    > Motorola pagers (a widely used type) seem to typically take a 3.5V 500mAh battery, which if I'm doing my conversions correctly (mAh * V * 3.6) works out to about 23 MJ.

    Batteries should really quote energy, not charge, for this reason. The voltage is not a constant.

    But something’s wrong with your math. Even assuming a constant 3.5V, that’s 1.75Wh, and 1Wh is 3600J, so that’s 6300J.

    23MJ would drive a car a respectable distance :)

  • [removed] 3 days ago
    [deleted]
  • flutas 3 days ago

    Also pagers typically use NiMH batteries, not Lithium. So take those estimates down another notch.

aitchnyu 3 days ago

Why waste it on a clever show instead of stalking their owners silently?

  • hersko 3 days ago

    The "clever show" has caused a mass casualty event of Hezbollah fighters. I would say it was an extremely effective attack.

    • diggan 3 days ago

      [flagged]

      • wing-_-nuts 3 days ago

        [flagged]

        • diggan 3 days ago

          Not sure if you've seen any of the videos that have circulated, but the created explosions was bigger than just getting a bruise on the waist from it. Seems it'd be enough to stand next to someone with one of those pagers to get hurt by it.

  • flutas 3 days ago

    I think the intent was to disable a bunch of fighters honestly.

    Make the pager ring, they grab it, it explodes in their hand disabling them for life and making them useless for the soldier role.

  • lxgr 3 days ago

    The entire point of using one-way pagers (instead of phones or other two-way communication devices) is that they're effectively impossible to locate.

    A supply chain attack could have probably added some sort of beacon, but that might show up on an RF sweep.

  • piva00 3 days ago

    Probably because they have been stalking for a while, and this escalation is a precursor to further action. Destroying lines of communication is usually done before military action.

  • jimbob45 3 days ago

    I think the "clever show" was the point. The physical damage may not actually justify the investment here. You need the resultant paranoia and suspicion from Hezbollah or it wasn't worth putting resources into.

  • bathtub365 3 days ago

    They’re likely already stalking their owners via software exploits on their phones