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Comment by specialp | Hacker News Reader

For $299 I can sure buy a lot of lithium ion batteries. There are already many such products out there that are very cheap. 290w/h is 58000 mah at 5v. I can buy a 11,000 mah pack for 29.99 on Amazon and surprise it weighs 1/4 the weight. Even if I bought 5 of them to equal the energy capacity it would be 1/2 the cost. (But it is not a REACTOR) There really is nothing novel at all about this product, and it is overpriced. I guess I am doing something wrong when shoving 3 lbs of commodity Li ion batteries into a tube and making some fancy name can yield a 100% profit margin.

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It has three high power voltage converter circuits which are needed for it to support USB Power Delivery. Those are more expensive than the batteries and no other device has three of them.

Lithium-ion packs are measured at 3.7 volts, not 5.

Buck or SEPIC based DC/DC conversion systems absolutely do not cost more than even a single LiIon cell. And to have multiple converters is far from a novel concept.

I think this is a neat implementation but there is no technical justification for this price tag, and the idea is far from unique. Looks cool though, and I guess for some that's all that will matter.

This isn't just a simple unidirectional converter. Power must flow in both directions.

We are also using ultra high efficiency parts and may also increase the power to over 100 watts if we can get it approved/ make it safe.

I can't imagine the hassle of having to charge five battery pack.

The bigger battery pack I found on amazon with decent reviews was 32000mAh for $119.99 (http://www.amazon.com/dp/B00DN0KBXU).

The trontium still cost more than two of those but the difference is shrinking.

Yeah, you'd have to rig up your own charger (if you wanted to make it easy to charge) and USB power output manually, and then make those things effortlessly portable.

I've had a lot of experience with Li-Ion batteries and more advanced chemistries, and I have to say I'd be scared to try rigging up something that can handle the kind of amps the Reactor is promising.

The only lithium-ion-like batteries I know of that can handle any sort of reasonable amp draws (100W at 5-20V = 5-20A currents) are e.g. really modern LiMn2O4 (hybrid? I'm not sure) cells like [1], not standard LiFePO4 or whatever. So if they happen to have really nice high-draw cells in them, with protection circuitry added to each and all the stuff to make it safe, then they're definitely in the right value range. Keeping batteries from failing dramatically and exploding when subject to abuse, electrical or otherwise, is not trivial.

[1]: http://illuminationsupply.com/batteries-c-48_50/18650-sony-u...

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