12000XP and Generator Switching – Page 6 – Main Thread

wardo5757 · 2025-02-18T21:39:11Z

I have 2 12000XP's and 1 Generac 10KW connected to both for when the grid is down. Switching from battery to gen is bad but switching from gen to battery is worse. It seems that the inverters switch to gen power almost immediately after closing the dry contacts then when charging is complete the inverters open the contacts then switch to battery which creates very bad brown and black outs. I'm aware the chargeverter would eliminate this, but the inverters should already be able handle this switching acceptably. It seems a very simple firmware update could fix this issue. It should (at a minimum for gen backup) go like this- when the inverter calls for generator, close the contact wait 10 seconds then switch to gen power- when charging is complete switch to battery wait 10 seconds then open the dry contact. Also, a 1-2 minute cold down period would be nice but not necessary. There is no way this gen switching feature was lab tested in its current form and someone said "it's good".

December 9, 2025 12:38 am

I am having the same issue with my 12000XP. I run a 20kW Briggs and Stratton generator, and when it exercises the frequency changes to 50Hz. I was told this was because at low idle the RPMs from the generator reduce the frequency to 50 and the inverter recognizes this. This is ridiculous, because it doesn't switch back to 60Hz when the power frequency increases up to 60Hz. So this idea of 'auto-switching' seems to be inconsistent in the reverse situation.

I disabled my exercise program on the generator and this helped for the first charge - there was no issue, but last night it was -30 degrees and my inverter called for generator power. It then sent my inverter back to 50Hz. I know the cold will reduce starting idle, but the inverter should accommodate with a delayed charging feature or warm up feature (as some of you above have suggested). I'm not sure what the time required for warmup should be, but I'm sure 60 seconds would do it for almost any generator. This is definitely a software issue. Alternatively, the inverter should have a setting that can be set to only accept power within the appropriate parameters (59-61 Hz for example). This seems to be a pretty simple fix.

I'm 100% off grid and if the gen fires up at night and I don't notice it, this lower frequency will fry my furnace fan motor. Then I'm in a heap of trouble!

If anyone has a workaround, please let me know. EG4 has not been helpful, even denying it is a problem and blaming my generator.

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