J2 and internal battery

[warmbells]

Hi,

I am building this kit and I noticed that it says in the assembly guide states that "Note: Do not simultaneously connect external and internal batteries". What is the reason for this? I have a connector for J2 which connects to a USB socket so the supply would be the same as that to the mini USB socket.

thanks,

Gerald

[GTNMUDY]

Good question.

There is a lot of questions on this build.

I think they may refer to the input Voltage of J2 can be more than the Li Ion battery. If J5 is closed it would cause over charging the Li Ion battery causing possible fire.

I also asked the question on input voltage to J2 as I dont know if BOB2 will regulate the voltage going to int battery (J5 open).

If you get a answer pls let me know

[warmbells]

Thanks for the reply,

Looking at the schematic, if D5 is in place and JP5 is open then the input from J2 should go through BOB2 as it does from the mini USB socket. All I can think of doing is give it a try and keep the battery out of the case and monitor its warmth.

Gerald

[GTNMUDY]

On my unit, I have J2 at 5Vdc and the + battery plug is 4.1Vdc. So it looks like BOB2 will regulate the input voltage of J2 to charge the int battery (li Ion 3.7v).

I just dont know what the Max input for J2 is.

Also, R32 (not installed) is for regulation the charging current for int battery.

So, with those 2 items (d5 and R32) not included in the kit it appears that you cannot (or should not) use both J2 ext battery and J2 int battery at the same time.

Just guessing......