Is there a way to get the Rosie to Charge at 120 amps using my Diesel Onan 7500w?

[Wizbandit]

Did you try setting topology to 120/120 and see what it does? I have never tried that without at least paralleling AC ins. It probably won't work but try it. It probably needs a new section in firmware to allow it but wouldn't expect to see any firmware work this year or even early next year.

Now two little Rosies working independently would work fine, they can't be stacked so they don't care about phase.

[bigbillsd]

Did you try setting topology to 120/120 and see what it does? I have never tried that without at least paralleling AC ins. It probably won't work but try it. It probably needs a new section in firmware to allow it but wouldn't expect to see any firmware work this year or even early next year. Now two little Rosies working independently would work fine, they can't be stacked so they don't care about phase. 

Yeah, Ryan had me try that.  It didn't make any change at all so after a few charges I moved it back to 120/240.  -Bill

[Brucey]

Did you try setting topology to 120/120 and see what it does? I have never tried that without at least paralleling AC ins. It probably won't work but try it. It probably needs a new section in firmware to allow it but wouldn't expect to see any firmware work this year or even early next year.

Now two little Rosies working independently would work fine, they can't be stacked so they don't care about phase.

My understanding of the issue is that the Rosie firmware assumes 120/240V operation, and therefore it halves the max breaker size value, even when set to 120/120V mode.

[bigbillsd]

My understanding of the issue is that the Rosie firmware assumes 120/240V operation, and therefore it halves the max breaker size value, even when set to 120/120V mode. 

I will keep my fingers crossed that they can change that assumption with a firmware fix. 

Should I call them to officially request this fix?  That one fix would make the Big Rosie a real world device for the majority of the diesel pusher world! The only other thing that is odd is the grid support but maybe other folks would think that is normal as I don't have any experience with other implementations of grid support.   

[FNG]

I would check with onan and see if the 2 outputs can be paralleled for 120V, if they can Wizbandint is right

1- Set Rosie for 120/120
2- Physically connect L1 and L2

Now the 26A charge rate will get you 120A dc charge with 60A breaker size BUT do not try this unless Onan says its ok. A quick sanity check would be to measure between AC Hot one and AC Hot two on the onan and see if you get any voltage? If the 2 neutrals are connected and you measure 0v between the 2 hots than they are in phase but still double check with onan

[bigbillsd]

I would check with onan and see if the 2 outputs can be paralleled for 120V, if they can Wizbandint is right 
1- Set Rosie for 120/120
2- Physically connect L1 and L2
Now the 26A charge rate will get you 120A dc charge with 60A breaker size BUT do not try this unless Onan says its ok. A quick sanity check would be to measure between AC Hot one and AC Hot two on the onan and see if you get any voltage? If the 2 neutrals are connected and you measure 0v between the 2 hots than they are in phase but still double check with onan

I believe we already tested that back in June?   The Onan is wired to l1 and l2, you had me change to 120/120 and it still only produced half the amperage.  Am I misunderstanding something, are you saying to connect both those hots to L1, and not to l2? Or?  This is quickly becoming a difficult way to do tech support.  -Bill 

[ClassicCrazy]

I would check with onan and see if the 2 outputs can be paralleled for 120V, if they can Wizbandint is right 
1- Set Rosie for 120/120
2- Physically connect L1 and L2
Now the 26A charge rate will get you 120A dc charge with 60A breaker size BUT do not try this unless Onan says its ok. A quick sanity check would be to measure between AC Hot one and AC Hot two on the onan and see if you get any voltage? If the 2 neutrals are connected and you measure 0v between the 2 hots than they are in phase but still double check with onan

I believe we already tested that back in June?   The Onan is wired to l1 and l2, you had me change to 120/120 and it still only produced half the amperage.  Am I misunderstanding something, are you saying to connect both those hots to L1, and not to l2? Or?  This is quickly becoming a difficult way to do tech support.  -Bill 

This is what I think both Wizbandit and Ryan are saying.
Contact Onan and ask them for your particular Onan generator model if the two 120v phases can be hooked together. Then if they say yes, connect to L1 and L2 of the Rosie , and then use a piece of wire to connect L1 and L2 together. And then do the rest of the stuff they said - breaker size and other rosie setup.

I could be wrong, but that is how I read it.
Hope it works out for you.

Larry

[FNG]

I would check with onan and see if the 2 outputs can be paralleled for 120V, if they can Wizbandint is right 
1- Set Rosie for 120/120
2- Physically connect L1 and L2
Now the 26A charge rate will get you 120A dc charge with 60A breaker size BUT do not try this unless Onan says its ok. A quick sanity check would be to measure between AC Hot one and AC Hot two on the onan and see if you get any voltage? If the 2 neutrals are connected and you measure 0v between the 2 hots than they are in phase but still double check with onan

I believe we already tested that back in June?   The Onan is wired to l1 and l2, you had me change to 120/120 and it still only produced half the amperage.  Am I misunderstanding something, are you saying to connect both those hots to L1, and not to l2? Or?  This is quickly becoming a difficult way to do tech support.  -Bill 

This is what I think both Wizbandit and Ryan are saying.
Contact Onan and ask them for your particular Onan generator model if the two 120v phases can be hooked together. Then if they say yes, connect to L1 and L2 of the Rosie , and then use a piece of wire to connect L1 and L2 together. And then do the rest of the stuff they said - breaker size and other rosie setup.

I could be wrong, but that is how I read it.
Hope it works out for you.

Larry

Exactly, When in 120/120 mode with L1 and L2 paralleled it will draw the rated current up to AC breaker size, so if breaker size is set for 60 for example it will draw a max of 30 on L1 and 30 on L2.

Another solution in future cases may be 2 Little Rosies as it seems that's what they generator is really looking for is 2 completely isolated systems. I will be very curios if the 2 windings can be phased together

[FNG]

So I did a bunch of research on that generator and all info I find advises DO NOT parallel the two outputs even though they are in phase.

[bigbillsd]

Brucey mentioned you were going to discuss this with engineering to see if firmware could fix it. 
I was also wondering if my gennys 37amp output on each leg could be tuned to allow it to charge 60a at 56v. There should be enough watts available (4400w vs 3360 needed), I think I was told the Rosie allows 3500w on each side.  There are 10's of thousands of these gennys out there in diesel pushers. I know Tiffin installs 240v Induction stoves in their most expensive coaches if they didn't require the genny running to use them would be a really sweet upgrade. -Bill

PS.  I talked to lots of Midnite folks prior to buying the Rosie, sure wish someone had mentioned this gotcha so I could have made a more informed choice. Now each time I run the genny I am reminded of this issue. 

 

[FNG]

So I understand you currently have the generator feeding the Rosie so that one 120V side feeds L1 and the other side feeds L2 correct? And if you run in 120/120 mode the max charge you can get is less than 60A DC? It would seem to me that with L1 and L2 in phase and Rosie set to 120/120 it should charge as though it was a single 7500 watt inverter. Can you check this for me by going to these pages and snapping a picture while the genny is running and charging

SETUP--> SYSTEM CONFIG (So we can see the topology etc)
INV button and scroll to the right one click and snap a pic of this

[bigbillsd]

Ryan, I screwed up the subject line.  It should read 120 amps.  The full charge power from the big rosie. 

I am only getting half that so using twice the diesel and twice the running hours to get my batteries charged. 

Here is my original post from August https://midniteftp.com/forum/index.php?topic=9830.0

[bigbillsd]

I charged my batteries yesterday with the genny and noticed this behaviour.  Topology was set to 120v120v, Charging was set to a max of 26AAC  Breaker was set to 60a 

SolarAssistant showed me the Inverter was using 1.63kw on Both Legs from the Genny.(14.5a)  Battery charging showed ~3200 watts going into the batteries. 

If its only using a single side of the inverter to charge the batteries, shouldn't it be using a single leg?