Hello everyone!
In my project i want to charge two batteries connected in series,each 3.7V
can i do it with 5V charger
i.e., can 7.4v battery charged with 5v charger?
and what will happen if we do?

hope everyone got my question

 

Charging voltage must be higher than battery voltage, so no a 5 volt charger will not work.

 

Hello,

Looking at the given voltage, I assume the batteries are of the lithium-ion type.
Those need special chargers.
When they are not correctly charged, fire may happen.
Read this page for more info:
http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries

Bertus

 

i.e., can 7.4v battery charged with 5v charger?
and what will happen if we do?

hope everyone got my question

You can't get something from nothing. Battery won't charge.

 

The real answer is yes, but...

You would need a boost converter to create a higher voltage, amd a smart charging circuit including balancing for the two cells.

Bob

 

Hello everyone!
In my project i want to charge two batteries connected in series,each 3.7V
can i do it with 5V charger
i.e., can 7.4v battery charged with 5v charger?
and what will happen if we do?

hope everyone got my question

Charging lithium cells can be dangerous if you don't do it right. The options are; buy 2 USB to lithium charger boards and charge the cells separately, or use a boost converter to generate the required voltage overhead and buy a cell balancer board.