Can I use a 5V USB cable to charge a bluetooth speaker that ask

>>25698
No, it will not work at all.

Imagine you needed a 6' ladder to change a lightbulb, and someone handed you a 2'6" one.

But it won't blow up unless you connect it backwards.

>>25704
Thanks but it seems to be working as the charging light comes up. WIll it wear down the battery to use a lower voltage?

>>25716
There's probably a voltage regulator in the device that's allowing it to work. Since you're using a lower voltage charger, make sure that the charger is not supplying more current than it's rated for. You can do this by grabbing a multimeter and measuring current.

Since I don't know enough about the devices, I wouldn't recommend using the 5V charger frequently on the device. Try and purchase a 12V one.