Installing shunt

[T1 Terry]

As the inverter must run 24/7, the standby load and light run load is already taken into account powering the fridge, the addition load of the 240vac to 12vdc is likely to be in range of 10% to 15% inefficient, an improvement on the 20% plus inefficiency of a 24v to 12v converter. You finding will be very interesting and could open a whole different view on 12v aux house battery charging with 24v systems. I wonder how a switch charger would go doing the same job, they are supposed to be in the 90% plus efficiency range.

T1 Terry

[learjohn]

Terry, once all hooked up, I turned off all appliances, and disconnected the solar. Inverter was drawing between .1 and .3 of an amp. turned on 240 ac to 12dc unit. 1.2 amp draw. Switched on fridge,it drew 10 amps for 5 or 6 seconds, then settled back to 2.2 amp total draw. When 8 of the led's were switched on, add another 1.4 amp
John

[T1 Terry]

What does the fridge draw on it's own after it settles? The jump from 0.1/0.3 amps to 1.2 amps would partly be caused by the inverter changing from standby to light load, they are very inefficient at light load as the majority of the power used is just keeping the circuitry alive, the output load may still have only been small. From your testing the fridge added 1 amp to the draw so it will interesting to see the inverter plus fridge draw without the 12v power supply, I'm expecting it to be more than 1 amp. From that we might get a clearer idea of how much extra load the 12v power supply adds to the total inverter load.

T1 Terry

[learjohn]

Terry, I opened the fridge door to get it working. When it started it drew 8.5 amps for 15 minutes. Then settled back to 0.2 amps. This is more than likely the inverter draw, as the fridge is not running at all. The inverter is a Latronics 1000w.
John

[T1 Terry]

8.5 amps is the fridge draw plus the inverter running overhead, the 0.2 amps is the inverter in standby power saver mode. Still in the dark as far as the portion of the load used by the inverter while powering an appliance as the 12v power supply plus the fridge was 10 amps, the fridge on it's own was 8.5 amps and the power supply on it's own was 1.2 amps, so the fridge on it's own and the power supply on it's own adds up to less than the 2 running at the same time..... and that doesn't compute The same issue with the 2 units in standby mode, the 2 running at the same time adds up to more than the sum of 2 running independently, it should be the other way around

[learjohn]

Will go through it again tomorrow Terry, and write down each figure.
John