lipo battery charge under load

[brendonshaw]

I have a small electronics data logger board which I want to run remotely and plan to use a RC car Lipo battery pack. There are loads of small package batteries and the ideal for by project.

I can buy a charger, but there might be a need to run the electronics and the batteries while on charger. I plan to use a simple 7805 or dc-dc converter, to get the right voltage.

My question is there any problems with the above circuit plan? My concern not getting correct charge as there is a load drawing current from the battery while on charge.

 

[Audioguru]

Many RC cars use a "7.2V" Ni-Cad battery that is about 8.4V when fully charged and it drops to about 6.6V when the load should be disconnected.
Will the 5V from a 7805 regulator be used for powering the data logger?
The charging circuit will probably over-charge the battery when the data logger is running because it will not be able to detect the low charging current when the battery is fully charged.

 

[brendonshaw]

Thanks for the quick response, the 7805 will regulate the battery voltage down to 5v.

I have to think if it's possible to isolate the battery charger from the current load, to allow the battery to be charged which the data logger is running.