I recently installed one of these on my boat. I was hoping to connect my primary auto bilge pump to the load out so as to avoid running the batteries flat in case of a pump fault. When I do this the battery reading on the app fluctuates wildly from 2v to 13v and the pump seems slow and turns on an off while pumping, it's reading as only drawing 0.9a. Is this not a good use for the load out? I can't find the specs for the port and it's rated loading.
The tech spec are in the online manual.
Load port is the same as the amp output of the MPPT in the 75v input range.
There is a possibility that the initial current draw is too high to get the motor going.
If it's ok directly from the battery and not from the load output, it's likely to be high resistance/poor contact in the load or MPPT/battery connections. Check for hot spots etc. If you have a clamp meter, check the current difference between load and battery sources. And measure the voltage at different parts of the circuit while the pump is running.
You might need a smoothing capacitor across the load output, but I wouldn't know where to start with that.
Personally I'd rather have a flat battery than a sunken boat.
It's not the only bilge pump, just the lowest one for keeping the rain water out. Got another auto one about 100mm higher directly connected to the battery as a backup, Just thought it would be handy having the primary on the charge controller in case it failed in the on position to avoid a flat. Just found it odd that when monitoring in the app the battery voltage fluctuates wildly but the dash voltage is steady when the pump is running and connected to the load out. Just wanted to make sure this was a valid use for the load out but as it's rated for 15 amps it should be.
