bikebasket

Does anyone know how many times one of the above could charge a small laptop?
I'm thinking that for them to be really worthwhile then they would need to be able to charge a laptop at least 4 times on only one charge if you were camping.

Is there a difference between an external battery and a portable charger?

Cheers

njkayaker

You haven't provided enough information to provide much help.

The external batteries have an indicated capacity. The laptop you want to use has a battery that has some indicated capacity. You also need to know how long the laptop will run on its internal battery.

You also need to indicate how many hours you want to use the device for.

Battery capacity is often expressed as "mA-hours". Laptop battery capacity is often expressed as "watt-hours". You have to convert on to the other to see how well they match up. Keep in mind that you might need an extra capacity (maybe as much as 25%) in the source (the external battery) to deal with charging losses.

Also, note that it takes time to charge the batteries from the wall.

Keep in mind that batteries are heavy and laptops can be somewhat delicate and not water resistant (and heavy). Smaller laptop/tablets will work better for that but tend to be harder to use. The power charger for laptops can also be heavy.

The power for a laptop can only come from two sources: a battery and a plug into a wall.

A "portable charger" seems like it would be a smaller transformer that plugs into a wall. A larger charger will charge faster but also be much heavier.

fietsbob

But, it takes less time to charge the batteries from the mains power , than a 6v 3w source like the hub dynamo powered converters

and so bring the charger power cord for your gear with you and stay in a motel for overnight recharging occasionally ,
and gain a little while eating in a cafe from their power...

external battery is a second battery to charge , it can extend the amp/hour capacity to their device's internal battery





...

njkayaker

A hub dynamo probably doesn't output anywhere near enough power to charge a laptop (a tablet might be pushing it).

Normally, one would have to bring the charger (for the external battery and the laptop) to recharge from the wall.