PD or Iota for my upgrade?
I'm thinking about a converter and battery upgrade. The batteries will be wet cell lead acid 6 volt Possible T-105s or the 230AH, EGC2 from Sam's club. I'll probably go for four. (Does nayone have...
Forum Discussion
I'm not asking about ac voltage. What is the dc voltage (after rectification) at full load?
Calculation for minimum dc input voltage:
Vmin = (Np/Ns) * (Vreg + Vd) / pwm_max
Where:
Np/Ns is the primary to secondary turns ration of transformer
Np/Ns = 13/2 = 6.5
Vreg = 14.4V
Vd = diode voltage drop and other IR losses = 1V
pwm_max = max duty cycle = 80%
Vmin = 6.5 * (14.4V + 1V) /0.8 = 125Vdc
If your input voltage is that low then the only way to fix the converter is to replace the transformer. The transformer requires a lower turns ratio. Or, install a big-ass 120Vac step-up transformer on the front end.
If the converter suffers from low input voltage, then PD really mucked-up their design.
Sal
Calculation for minimum dc input voltage:
Vmin = (Np/Ns) * (Vreg + Vd) / pwm_max
Where:
Np/Ns is the primary to secondary turns ration of transformer
Np/Ns = 13/2 = 6.5
Vreg = 14.4V
Vd = diode voltage drop and other IR losses = 1V
pwm_max = max duty cycle = 80%
Vmin = 6.5 * (14.4V + 1V) /0.8 = 125Vdc
If your input voltage is that low then the only way to fix the converter is to replace the transformer. The transformer requires a lower turns ratio. Or, install a big-ass 120Vac step-up transformer on the front end.
If the converter suffers from low input voltage, then PD really mucked-up their design.
Sal
DryCamper11 wrote:Salvo wrote:
Have you measured the dc input voltage to the center tap of the push-pull transformer under heavy load? I did a quick calculation and determined you need a minimum 125Vdc to output 14.4V.
No, and I'm only getting about 105-106 volts AC under full load from the limited AC voltage on shore power at the RV.
