Extremely variable generator charge wattage

[Stotts47]

I have an EG4 18kvp and a PowerPro battery. I am currently using it as an off-grid generator only, no solar yet. When I recharge the battery with my 6000 running watts, 7500 peak 240v 30amp Champion generator hooked into the 18kvp generator inputs, the charge rate is typically only about 3500 watts, but it's also been as low as 1100 watts and as high as 6000. Generator functioning normally in all cases. And this wasn't just for a few minutes or something, it was for as long as I ran the generator, hours. Today it was charging at 6000 watts for a few hours, I shut off the generator, turned it back on 30 minutes later and it was 3500 watts. Yesterday it was 1100 watts every time I ran it. I would love for it to be 6000 watts all of the time, any ideas what is causing the variation? I saw on another post that the generator charge current limit setting should not be the generator Amps but rather the charge current limit of the batteries? It's currently set at 30 amps, so I should change it to 100amps (recommend charge current limit for PowerPro)?

Even if that setting is the main culprit, the fact that it's done 900 watts and 6000 watts should suggest something is not working properly, because it should be the same every time within a small margin based on the 30amp charge current limit setting. I am only using 3 wires from the generator, +,-, neutral, no ground and the generator is not grounded, not sure if that's a problem?

Any ideas what's causing this and how to get 6000 watts charge consistently?

Follow-up question, I have a rack of LifePower4s I plan to add to the mix, the recommended charge current on those is only 50amps, since it's a rack of six, is it 300amps? And do I add the 160 of the PowerPro to that for a total charge current limit of 460amps?

Thanks!

 

[sunshine_eggo]

I would prefer to run a non-diesel work-horse generator at no more than about 80% max continuous for generator longevity... shoot for 4500-5000W.

Are you 1000% certain that you're looking at actual charging power and not total generator draw?

When on generator, it's also passing through to loads, so you'll get variable consumption from the generator based on your loads.

If you're limited to a charge current of 30A, then you'll never get more that about 1700W of charging.

I would set it to 90A and see what you get.

Batteries in parallel add both capacity and charge/discharge limits; however, leave a 10-20% margin in case batteries aren't perfectly load balanced (almost impossible).

 

[Stotts47]

I would prefer to run a non-diesel work-horse generator at more than about 80% max continuous for generator longevity... shoot for 4500-5000W.

Are you 1000% certain that you're looking at actual charging power and not total generator draw?

When on generator, it's also passing through to loads, so you'll get variable consumption from the generator based on your loads.

If you're limited to a charge current of 30A, then you'll never get more that about 1700W of charging.

I would set it to 90A and see what you get.

Batteries in parallel add both capacity and charge/discharge limits; however, leave a 10-20% margin in case batteries aren't perfectly load balanced (almost impossible).

Thanks, I will give that a shot, still have no idea why the inverter is pulling different wattage from the generator on a given day, maybe a connection issue somewhere?

 

[sunshine_eggo]

Thanks, I will give that a shot, still have no idea why the inverter is pulling different wattage from the generator on a given day, maybe a connection issue somewhere?

Are you using loads while running the generator?

 

[Stotts47]

Are you using loads while running the generator?

Very minor, 165 watts for internet.

 

[Stotts47]

Looks like there are two settings on the 18kvp, Battery Charge Current Limit set to 160 amps, and Generator Charge Current Limit was set to 58 amps, (generator rated amps at 120v AC). Pulls about 3500 watts at those settings. If I change the Generator Charge Current Limit to 115 amps I get about 6000 watts. Also adjusted the Battery Charge Current Limit to the recommended 100amps rather than the 160 max rating.

Looks like the 18kvp wants the 48v DC Amps equivalent. So for example, 240v 30amp AC is the equivalent of 165.6amps DC at 48v. I wanted it to run at about 70% of capacity so I set the Generator Charge Current Limit to 115amps.

I used this handy calculator: https://www.batterystuff.com/kb/tools/ac-to-dc-amperage-conversion-run-through-an-inverter.html

If it drops again or goes higher I will see about troubleshooting wires and torques.

 

[sunshine_eggo]

Looks like there are two settings on the 18kvp, Battery Charge Current Limit set to 160 amps, and Generator Charge Current Limit was set to 58 amps, (generator rated amps at 120v AC). Pulls about 3500 watts at those settings. If I change the Generator Charge Current Limit to 115 amps I get about 6000 watts. Also adjusted the Battery Charge Current Limit to the recommended 100amps rather than the 160 max rating.

Still curious why it's variable at times.

If the generator is non-inverter, portable, and you move it around, very important to ensure the generator is level. I have a portable Predator that I wheel in and out of the container to charge. It's on a dirty screen substrate, and I have to work it into the surface until it's level... I literally check it with a level, or it's output is dirty, and it can produce a dirtier output... Voltage and frequency vary a bit more, and it doesn't respond to load changes as well.

Looks like the 18kvp wants the 48v DC Amps equivalent. So for example, 240v 30amp AC is the equivalent of 165.6amps DC. I wanted it to run at about 70% of capacity so I set the Generator Charge Current Limit to 115amps.

This is true of all inverter/chargers. Charging is relative to battery voltage. If you have an AC to DC 12V charger, you're going to specify the charger output, not the AC input.

If it drops again or goes higher I will see about troubleshooting wires and torques.

 

[Stotts47]

Still curious why it's variable at times.

If the generator is non-inverter, portable, and you move it around, very important to ensure the generator is level. I have a portable Predator that I wheel in and out of the container to charge. It's on a dirty screen substrate, and I have to work it into the surface until it's level... I literally check it with a level, or it's output is dirty, and it can produce a dirtier output... Voltage and frequency vary a bit more, and it doesn't respond to load changes as well.



This is true of all inverter/chargers. Charging is relative to battery voltage. If you have an AC to DC 12V charger, you're going to specify the charger output, not the AC input.

It's an inverter generator and seemed to be running normal. Thanks for your help!