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#41

The Rosie / Re: Is there a way to get the ...

Last post by Brucey - October 15, 2026, 02:31:22 PM

SO if you connect AC IN L1 and L2 together at Rosie and the generator does not barf you should see higher DC charging. You must also connect AC OUT at Rosie. 

So you think I should attempt to wire both my QD7500 outputs together?  I'm not an electrician, but that sounds like it might let the Magic Smoke out..  I worked with Ryan over the summer and he never suggested doing that.  That genny is Very expensive and I cannot afford to make is Smoke.  Is this something Midnitesolar says is ok?) 

He's saying to feed both 120V outputs from the gen to the Rosie (keeping them seperate). Not to connect them together before the Rosie.

Not to combine the 120V outputs

#42

The Rosie / Re: Is there a way to get the ...

Last post by Wizbandit - October 15, 2026, 02:30:05 PM

Check with Onan / Cummins to see if they can be put in parallel.  I don't know, but you may only get 50% of 60A if not.  Generally AC does not parallel well... They may be 120VAC each but slightly out of phase.

#43

The Rosie / Re: Is there a way to get the ...

Last post by bigbillsd - October 15, 2026, 12:39:12 PM

SO if you connect AC IN L1 and L2 together at Rosie and the generator does not barf you should see higher DC charging. You must also connect AC OUT at Rosie. 

So you think I should attempt to wire both my QD7500 outputs together?  I'm not an electrician, but that sounds like it might let the Magic Smoke out..  I worked with Ryan over the summer and he never suggested doing that.  That genny is Very expensive and I cannot afford to make it Smoke.  Is this something Midnitesolar says is ok?)   

#44

The Rosie / Re: Is there a way to get the ...

Last post by Wizbandit - October 14, 2026, 11:36:58 PM

But I used 60a for the breaker size.  The Midnite gets both 120v lines, one on L1 the other on L2. Still only get 1/2 the charging capacity, no matter the load being almost nothing to a microwave running.  Each leg maxes out around 4500 watts in prior testing.  Plenty to run both AC's and the microwave but not much else unless maybe on the other leg than the Micro. -Bill 
It almost certainly something in the firmware if there isn't a physical hardware problem. 
 

No, if you do not connect L1 and L2 together with wire at the L1L2 terminal block it may not work unless L1 and L2 are physically connected at the generator output.  If 2 legs of 120V come off separate windings of the generator and they can't be shorted together that will cause Rosie to use only L1 and pass L2.

I have a 40A 120V feed on #8 Awg wire feeding my RV 30 amp Receptacle and I set breaker size to 32 and I get 39A DC charging and if I run breaker size up to 60AAC and with about 800W of loads I see 55-56ADC charging.  I don't leave it very long so just to test tonight or it will trip the 40AAC breaker.

SO if you connect AC IN L1 and L2 together at Rosie and the generator does not barf you should see higher DC charging. You must also connect AC OUT at Rosie.

#45

The Rosie / Re: Is there a way to get the ...

Last post by bigbillsd - October 14, 2026, 11:07:36 PM

Try setting breaker size to 50A, topology to 120/120, parallel both AC in L1 and L2 and AC out.  I hope you are allowed to parallel the 120's from the generator.
This will give you maximum charging.  I run this setup in my RV with breaker size set to 32A as I'm on 30A shore power.
My generator is Onan 3600 120V Remember, loads effect power available to the charger section, loads are powered first and what is left gets routed to the charger. Rosie limits the AC in current to 75% of breaker size.  Your 7500 probably tops out at 6000 watts due to a .8 power factor. 

I tried all that over the summer.   But I used 60a for the breaker size.  The Midnite gets both 120v lines, one on L1 the other on L2. Still only get 1/2 the charging capacity, no matter the load being almost nothing to a microwave running.   Each leg maxes out around 4500 watts in prior testing.  Plenty to run both AC's and the microwave but not much else unless maybe on the other leg than the Micro. -Bill 
It almost certainly something in the firmware if there isn't a physical hardware problem. 
 

#46

The Rosie / Re: Is there a way to get the ...

Last post by Wizbandit - October 14, 2026, 09:40:36 PM

Try setting breaker size to 50A, topology to 120/120, parallel both AC in L1 and L2 and AC out.
I hope you are allowed to parallel the 120's from the generator.

This will give you maximum charging.

I run this setup in my RV with breaker size set to 32A as I'm on 30A shore power.
My generator is Onan 3600 120V

Remember, loads effect power available to the charger section, loads are powered first and what is left gets routed to the charger. Rosie limits the AC in current to 75% of breaker size.  Your 7500 probably tops out at 6000 watts due to a .8 power factor.

#47

The Rosie / Re: Is there a way to get the ...

Last post by bigbillsd - October 14, 2026, 12:16:26 PM

No one can change the past decisions or design choices so it probably isn't healthy to dwell on that and instead formulate a plan to move on to achieve your ultimate goal. But yeah it does sort of suck a bit to have to spend another 500 or $600 to do that.  Larry

You may want to go back and review Brucey's comment from Ryan. 

#48

The Rosie / Re: Is there a way to get the ...

Last post by ClassicCrazy - October 14, 2026, 11:10:21 AM

There are other reasons besides cost why the RV industry uses those 120/120 generators.
Most RVs these days don't have 240V loads and everything runs on 120V. So there is no need to put in a heavier, more costly 240V generator. The 120/120 design can more easily do load sharing between the two sides since they are both on the same phase. If you put a heavy load on one side, it can just pull fluidly from the generator's single power pool without overloading a specific leg like a 240V generator would.
Since it is a physical phase issue. If you want to use all the power your generator has to offer with the Rosie, you have two  hardware options:

1. Add a Victron Autotransformer: This will take your two in-phase 120V lines and physically convert them into the true 120/240V split-phase power the Rosie expects.
2. Use an External DC Charger: You can plug a dedicated charger (like an EG4 Chargeverter) into the generator's second leg and run it directly to your 48V battery bank. This bypasses the Rosie's AC input limits entirely and lets you charge at full throttle.
( if it was me I would probably go with charger option).

No one can change the past decisions or design choices so it probably isn't healthy to dwell on that and instead formulate a plan to move on to achieve your ultimate goal. But yeah it does sort of suck a bit to have to spend another 500 or $600 to do that.
 
Years ago I bought three 100 ah 48v lithium batteries when they were in high demand. Turns out they didn't use the best quality cells and had some physical design that wasnt' good. They still work but pale in comparison to the new 314 ah battery with excellent cells , a vastly better bms, and so much better breaker and fuse design.And the new battery was almost a third the price of the other three.  But that is the way it is and I moved on. If I had only waited  3 or 4  years I could have saved thousands of dollars for better product  , right ?  But that is a good problem that technology got better for less $$ .

Larry

#49

The Rosie / Re: Is there a way to get the ...

Last post by bigbillsd - October 14, 2026, 09:12:09 AM

If they can do that I would think the Big Rosie is Ready for Primetime!  And I could start recommending it to all the folks with my type of Onan Genny.  I only know a few folks with the 240v Onan's, but I know hundreds with the 6-8kw Onans and their crappy 120/120v systems.  I guess it was a lot cheaper to do it that way. Not sure how, but it had to save at least a Nickle..   

#50

The Rosie / Re: Is there a way to get the ...

Last post by Brucey - October 13, 2026, 10:01:10 PM

Sorry typo there, Ryan from Midnite.