Charging battery at vin?

Projects General Guidance
1

Hi,

I'm making a little computer project with arduino and I was wondering if I could power my board and charge it while still using it by doing the following.

I have the charger for a 7.4v battery which is a barrel charger.

I'm powering my uno board with a 7.4v battery and to charge it I want to use the 8.4v barrel charger and connect it to the power jack. Since vin supplies power to the board and power coming from the power jack can be accessed through vin, could this possibly work?

If you need any more clarification please ask.
Thanks,
Jaden

2

There is a protection diode between the power jack and Vin. This will cause a 0.6V drop and will prevent the charger from sensing the battery voltage (if it is a smart charger).

3

Ok thank you...
Is there any way I could charge the battery while powering the arduino? I've looked around and all the charging boards only support a 5v input. For an example see the link.

http://m.ebay.com.au/itm/Micro-USB-5V-1A-TP4056-Lithium-Li-Battery-Charging-Board-Charger-Module-5-pcs-Ne-/262857341609?hash=item3d3384baa9%3Ag%3AzV4AAOSw32lYptC-&_trkparms=pageci%253Ab7facdf7-2d6a-11e7-a40c-74dbd180e0a2%257Cparentrq%253Abd74d98915b0a86674058eb8fffe6924%257Ciid%253A14

4

Connect the charger to the battery.
Connect the 7.4volt battery to the DC jack (not to V-in).

Or use a 3.3volt Arduino powered by a single cell LiPo.
Leo..