Hi folks.
For the Tamar, I'm using 4S Lipos to power the model, but obviously as this battery setup goes up to 16.8v, the likelihood of the LEDs, Marks Model Bits Foggy and a small water pump agreeing with such a voltage is slim to none.
For that reason, I bought two 4.5 amp UBECs, with the intention of putting them in parallel to give a maximum of 9A which should be more than sufficient.
However, when connecting the system together, the MMB foggy does not work. The power light on the 12 to 24 volt converter flashes. If you connect both of the UBECs up, it flashes slightly quicker, but still no smoke. Replacing the foggy with a 3 amp fan, which just pulses, suggests that the UBEC is just making 'blips' of power rather than a continuous voltage. Using the pump (the Hunter Systems water cooling one) is fine, it runs no problem at 80mA. I don't have an LED on me to test with at present.
MMB rates the foggy at less than 1 amp at 24v, and the voltage converter which goes with the unit (no longer on sale) steps 12v up to that 24v. So assuming that the amperage doubles when the voltage halves, and accounting for some losses in the converter, I suspect a draw of 2.5a at 12v isn't far off.
So either I'm missing something or the UBECs are maxing out way below 2.5 amps, or theoretically less than 1.25 amps because even two of them together isn't enough.
Are they really maxing out so low (9a rated, actual <2.5-3a)? Is there a better solution for converting 4S to 12v, with a varying load (as these things will be switched on and off)?
Help!