# Parallel battery supply

I want to parallel connect 4 x AA NiMH batteries rated each at 1.2V, along with 4 x 1N4001 simple diodes to prevent unwanted current flow (recharging) between batteries. The electric circuit is:

simulate this circuit – Schematic created using CircuitLab

I get an estimated output voltage of 0.7V (because of 0.5V voltage drop for the diode).

How can I rise up the voltage from 0.7V to 5V and also have the possibility of a minimum current of 1A for the load resistance? If wiring restructuring is needed, then please offer parallel design solutions, because I need as much as possible amp capacity (2700 mAh * 4).

I tried this U1V10F5 step-up voltage regulator from Pololu (https://www.pololu.com/product/2564) and it gives me 5V, but somewhere in this circuit I think there is a high resistance (possible some current blocking from the diodes?), because the output current can't power up even a regular LED, when it's put in place of a resistance load (with some adequate resistance for the LED of course).

Thank you so much!

• Why? Also, at that voltage level a diode drop is significant. Shottky is better but still, why? If one battery voltage is higher than the others, they will equalize. Mar 29 '17 at 12:12
• Why not put them in series and have a regulator do the rest, or even put more in series so it only needs to buck down? The diodes are throwing away a major portion of your energy Mar 29 '17 at 12:15
• I thought in parallel because more amp capacity would benefit a robot car with many passive components such as a 1x microcontroller, 4x DC motors and other stuff. It's kinda difficult to achieve this parallelism and I should stick with the series version as you said. Mar 29 '17 at 12:31
• If you're going into a step-up, follow @PlasmaHH's good point. It's the right way to do it Mar 29 '17 at 12:44
• Unless there's some specific reason you've chosen NiMH you'd be much, much better off with Li-ion in pretty much every way. Mar 29 '17 at 12:51