mppt vs pwm

Salvo wrote:
You take a fairly large hit when going series. Look at the Rogue 3048 efficiency graph on pg. 43.

At 10A:
the 85V system is 93% efficient
the 51V system is 95% efficient
the 17V system is 97% efficient

That a loss of 0.4A when operating at 85V. 4% loss is significant. When on average, mppt is only 5% better than pwm, you're losing your advantage. I don't see it as a big deal to increase wire size for the 17V system to keep losses at 1%. RV cable runs are so short the cost is insignificant.

12thgenusa wrote:


I don't know about other controllers, but Rogue's published efficiency curves show that at a 20 amp output, 17-volt panels to a 12-volt system are about .2% more efficient than 34-volt panels, both right at 96%.

How many folks are running an 85-v input? I thought we were talking about series configuration to produce ~34v input. The greater the difference between input and output, the greater the inefficiency without question. The example was not comparing mppt to pwm, but series vs parallel using mppt. If the example given was truly 44-v input, that is about 1% less efficient than 34-v input.

If a person is only getting 48 amps out of a 960 watt system he has other problems.