Is it ok to purchase buy 1 take 1 power banks?

[InbetweenDreams]

The biggest problem I have with the portable power packs, or however they're being marketed is that they seldom have the capacity advertised. For instance, my Samsung S7 has a 3,000 mAh battery, some of the power packs only have 5,000 mAh and you can be certain that the usable capacity will be much less. So I can probably charge my phone once. Now for bigger devices, like my iPad, it has a 9,000 mAh battery, so yeah, why bother if I can't charge it up completely?

I suppose they're handy in a pinch, but if they're really cheap, don't expect to get anywhere near the capacity they claim it has or for it to last long. Also, be careful with cheap Li-ion, or LiPo batteries, they can catch fire and explode. Better off seeking better quality products.