- Welcome to A Forum run by Enthusiasts of MidNite Solar .
News:
To visit MidNite Solar click this link www.midnitesolar.com
Recent posts
#51
The Rosie / Re: Rosie is dead.
Last post by HIT99 - October 13, 2026, 11:35:16 AMI got my Rosie back from Midnite - fixed under warranty. The aux power supply died for some reason. The aux power supply has been repaired and updated along with a few other H/W updates. My unit is an "older" revision.
Besides the inconvenience of no power (besides a generator) and an unscheduled "vacation" to the city - the process and dealing with Midnite was prompt and straightforward.
I will head back "beyond the grid" tomorrow and put it back into service and hopefully run for years to come.
Besides the inconvenience of no power (besides a generator) and an unscheduled "vacation" to the city - the process and dealing with Midnite was prompt and straightforward.
I will head back "beyond the grid" tomorrow and put it back into service and hopefully run for years to come.
#52
The Rosie / Re: Is there a way to get the ...
Last post by bigbillsd - October 13, 2026, 10:38:44 AMBrucey, does Ruan work for Midnite? I am not familiar with him. I hadn't thought about autotransformer, but I went with Midnight so I didn't need to do something like that in the first place. In all my discussions with the folks at Midnite no one mentioned my Onan 120/120 would have This issue, we did have discussions about the Onan not working at all, but they assured me that was fixed, and it is working, but only at 1/2 capacity.
Now with Diesel at gold pricing running the genny twice as long for the same charge seems like punishment for not going with the Victron Kludge.. -Bill
Now with Diesel at gold pricing running the genny twice as long for the same charge seems like punishment for not going with the Victron Kludge.. -Bill
#53
The Rosie / Re: Is there a way to get the ...
Last post by Brucey - October 11, 2026, 03:54:23 PMRuan had mentioned he would discuss with team on how they could tweak the firmware to allow for 60A charging to be selected when running at 120V input. I don't think there's a technical limit as such.
#54
The Rosie / Re: Is there a way to get the ...
Last post by ClassicCrazy - October 11, 2026, 11:41:45 AMI don't know the exact answer to your question.
I was curious though since I am considering getting a big rosie ( I have little rosie )
So I just asked AI and I had a suspicion it had to do with phasing from your generator.
The google AI says it did . Here is the explanation from AI
The core issue described in this Midnite Solar Forum post stems from a phase mismatch between how a sub-10kW Onan generator delivers 120V power and how the MidNite Solar Rosie inverter/charger expects it.
The Root Cause: Out-of-Phase vs. In-Phase 120V
The user's Onan generator does not output a true 240V split-phase supply. Instead, sub-10kW Onan Marine/RV generators are usually dual-in-phase 120V generators. They feature two distinct 120V windings (Leg 1 and Leg 2) that are perfectly in-phase with one another to keep the neutral wire from overloading.
Conversely, the MidNite Solar Rosie is built natively as a true split-phase (120V/240V) system. To achieve its full continuous 7,000-watt output and maximum 120-amp charging capacity, it expects 240V across Leg 1 and Leg 2—meaning the two legs must be 180° out-of-phase.
When you feed the Rosie dual-in-phase 120V lines from an Onan:
1. Phasing Conflict: The Rosie reads 0V across L1 and L2 because they are in phase. It determines it is not receiving valid 240V split-phase power.
2. Fallback Behavior: The Rosie drops back to single-leg mode, qualifying only one 120V leg (Line to Neutral) for charging.
3. Half-Capacity Charging: Because it only draws from one leg, it is restricted to half of its charging capacity, resulting in extended generator run-times, excess diesel consumption, and noise.
Is it a hardware or a firmware limitation?
The user's buddy is correct that the internal layout resembles two combined 3,500W modules. However, a firmware update alone cannot easily resolve this.
• The Hardware Problem: If the internal charging bridges are hardwired across a single 240V rail or strictly tied to 180° phase-separated inputs, firmware cannot magically bridge the two independent, in-phase lines without triggering a direct short-circuit or overloading internal parallel components.
• The "Victron Kludge" Reality: This is exactly why users looking for high-amperage mobile setups default to Victron. In a Victron ecosystem, you can utilize a 120V/240V autotransformer to convert parallel 120V lines into proper split-phase power, or network multiple independent MultiPlus units to handle un-synchronized inputs dynamically.
Current Workarounds
Until MidNite Solar adds structural firmware changes or internal bypass hardware to support dual-in-phase 120V inputs, users with this exact configuration generally fix it outside the inverter:
• The Autotransformer Fix: Install an external 120V to 120/240V step-up autotransformer between the Onan generator and the Rosie's AC input. This mechanically shifts the parallel 120V lines into a genuine 240V split-phase supply, allowing the Rosie to charge at its maximum 120A rate.
• Dedicated Standalone Chargers: Run a secondary industrial battery charger (like a dedicated AC-to-DC chargeverter) directly off the generator's second 120V leg straight into the 48V battery bank, bypassing the Rosie's internal charger altogether
I was curious though since I am considering getting a big rosie ( I have little rosie )
So I just asked AI and I had a suspicion it had to do with phasing from your generator.
The google AI says it did . Here is the explanation from AI
The core issue described in this Midnite Solar Forum post stems from a phase mismatch between how a sub-10kW Onan generator delivers 120V power and how the MidNite Solar Rosie inverter/charger expects it.
The Root Cause: Out-of-Phase vs. In-Phase 120V
The user's Onan generator does not output a true 240V split-phase supply. Instead, sub-10kW Onan Marine/RV generators are usually dual-in-phase 120V generators. They feature two distinct 120V windings (Leg 1 and Leg 2) that are perfectly in-phase with one another to keep the neutral wire from overloading.
Conversely, the MidNite Solar Rosie is built natively as a true split-phase (120V/240V) system. To achieve its full continuous 7,000-watt output and maximum 120-amp charging capacity, it expects 240V across Leg 1 and Leg 2—meaning the two legs must be 180° out-of-phase.
When you feed the Rosie dual-in-phase 120V lines from an Onan:
1. Phasing Conflict: The Rosie reads 0V across L1 and L2 because they are in phase. It determines it is not receiving valid 240V split-phase power.
2. Fallback Behavior: The Rosie drops back to single-leg mode, qualifying only one 120V leg (Line to Neutral) for charging.
3. Half-Capacity Charging: Because it only draws from one leg, it is restricted to half of its charging capacity, resulting in extended generator run-times, excess diesel consumption, and noise.
Is it a hardware or a firmware limitation?
The user's buddy is correct that the internal layout resembles two combined 3,500W modules. However, a firmware update alone cannot easily resolve this.
• The Hardware Problem: If the internal charging bridges are hardwired across a single 240V rail or strictly tied to 180° phase-separated inputs, firmware cannot magically bridge the two independent, in-phase lines without triggering a direct short-circuit or overloading internal parallel components.
• The "Victron Kludge" Reality: This is exactly why users looking for high-amperage mobile setups default to Victron. In a Victron ecosystem, you can utilize a 120V/240V autotransformer to convert parallel 120V lines into proper split-phase power, or network multiple independent MultiPlus units to handle un-synchronized inputs dynamically.
Current Workarounds
Until MidNite Solar adds structural firmware changes or internal bypass hardware to support dual-in-phase 120V inputs, users with this exact configuration generally fix it outside the inverter:
• The Autotransformer Fix: Install an external 120V to 120/240V step-up autotransformer between the Onan generator and the Rosie's AC input. This mechanically shifts the parallel 120V lines into a genuine 240V split-phase supply, allowing the Rosie to charge at its maximum 120A rate.
• Dedicated Standalone Chargers: Run a secondary industrial battery charger (like a dedicated AC-to-DC chargeverter) directly off the generator's second 120V leg straight into the 48V battery bank, bypassing the Rosie's internal charger altogether
#55
The Rosie / Is there a way to get the Rosi...
Last post by bigbillsd - October 11, 2026, 11:20:17 AMMy Onan produces 120v twice, basically like all the sub 10Kw Onan Diesel Genny's in larger motor-homes. Today I can only charge at 1/2 that charger capacity requiring me to use twice as much diesel ($$$) to charge my batteries, not to mention twice as much noise and twice as much exhaust that the wify loves to tell me all about. I already add a Gentauri to move the exhaust up and over the coach when boondocking more than a couple nights where the 20Kwh of battery isn't going to be enough.
I have been told, more than a few times on support calls, the Rosie is more like 2 different inverter/chargers tied together (3500w each) suggesting to me there might be a way to wire it to use both inputs to get the charger to output its maximum charge. Maybe it would require Firmware change and not different wiring. My buddy the electronics engineer is coming over for beers tonight so I will probably ask him to look at that from his knowledge base.
There are quite a few diesel pushers in this country with those same diesel Onan's that produce that same power as mine, so if it needed a firmware update there is easily a ROI to be discussed. Personally, that is the only thing now that prevents me from telling everyone that follows my blogs to install one of these and ditch the Victron Kludge..
I have been told, more than a few times on support calls, the Rosie is more like 2 different inverter/chargers tied together (3500w each) suggesting to me there might be a way to wire it to use both inputs to get the charger to output its maximum charge. Maybe it would require Firmware change and not different wiring. My buddy the electronics engineer is coming over for beers tonight so I will probably ask him to look at that from his knowledge base.
There are quite a few diesel pushers in this country with those same diesel Onan's that produce that same power as mine, so if it needed a firmware update there is easily a ROI to be discussed. Personally, that is the only thing now that prevents me from telling everyone that follows my blogs to install one of these and ditch the Victron Kludge..
#56
The Rosie / Re: Trying to figure this out....
Last post by bigbillsd - October 11, 2026, 11:04:21 AMAgain, the Firmware Thread does Not show that firmware.. Can someone update that Thread?
#57
Little Rosie(MNLR4548RE and MNLR3648M) / 24 or GASP, 12 V Lil Rosie
Last post by JohnsIsland - October 09, 2026, 01:39:49 AMI am a big a BIG Midnite Solar fan. I have three Classic 250's, with 4 Rolls S6 L16-EX (2S 2P) and a puny Victron 1200 VA inverter. I would love to be able to buy a Lil Rosie. Hindsight says I should have bought 8 batteries. When I see those beautifull Rolls batteries, I kick myself in the a**.
Will Midnite ever make a 24 V version of the Lil Rosie? If not, why not.
Jeff
Will Midnite ever make a 24 V version of the Lil Rosie? If not, why not.
Jeff
#58
Hawke's Bay / Re: Why does charging stop in ...
Last post by FNG - October 08, 2026, 11:23:58 AMSo it could be the battery is full and lying to you. What I mean is all lithium batteries do not judge low power well. EcoWorthy is no exception. It will take around 3 amps of power for 4 of them to see it and SOC will drift bad on systems that are energy misers.
The key is what is the battery voltage during this time. It could be the CMOS has opened on the batteries and the Hbay is throttled.
If you could tell us the following:
Firmware Version-
Battery voltage during the 5 minute 0 power-
Battery voltage after it ramps up-
Does it ever say resting during this 5 minutes? if so what is the reason for resting, SETUP--> MPPT CONFIG-->HBAY--> FINE TUNING--> DEBUG SCREEN and tell us what A6 is
The key is what is the battery voltage during this time. It could be the CMOS has opened on the batteries and the Hbay is throttled.
If you could tell us the following:
Firmware Version-
Battery voltage during the 5 minute 0 power-
Battery voltage after it ramps up-
Does it ever say resting during this 5 minutes? if so what is the reason for resting, SETUP--> MPPT CONFIG-->HBAY--> FINE TUNING--> DEBUG SCREEN and tell us what A6 is
#59
The "Classic" charge controller / Re: FLA Charge current Setting...
Last post by ClassicCrazy - October 08, 2026, 10:30:47 AMThis is link shows the whole Classic Knowledbase - maybe the links work in it ?
https://web.archive.org/web/20200725113721/https://www.midniteftp.com/support/kb/faq.php?cid=1
yes they do !
Larry
Frequently Asked Question
All Categories » CLASSIC CHARGE CONTROLLER - Features and Programming
CLASSIC - ENDAMPS - How do I figure what ENDAMPS should be?
Last Updated 6 years ago
Lets first tell you what ENDAMPS is...
ENDAMPS is the current the Lead-Acid type battery will "draw" from the charging source when it is 100% charged and can take no more charge. It is this point if the current is not reduced the battery electrolyte and the battery will heat up. Too much and things can get ugly very fast.
The Classic has the ability to terminate the Absorb cycle using Whizbang JR as the ENDAMPS source. For this to work most systems will require a SHUNT and the WBjr option. The WBjr is a current measuring option for the Classic and KID charge controllers. It sends data on the amps in or out of the battery, it is important for things to work to have this and the shunt installed properly.
How to figure what YOUR battery needs for ENDAMPS.
First. lets look at what effects ENDAMPS.
#1 - Battery age
#2 - Battery condition
#3 - Battery type (Flooded, GEL, AGM, other)
#4 - Some battery manufacturers have this number for you, but be warned, for a NEW battery
The Best way to figure out YOUR Battery ENDAMPS is this way:
Take a day, turn off all LOADS while testing for ENDAMPS.
Set ABSORB TIME to something high, like 8 hours.
Remember what your time was, write it down.
Let the Classic (or KID) get to absorb, then come back after the time your wrote down has passed.
Lets say default 2 hours you are back.
Get a notebook, mark off lines every 10 minutes for about 2 hours, 12 lines like this:
:10
:20
:30
:40... and so on.
Go to the WBjr page, 3rd page on the STATUS BUTTON and watch the amps.
They should be a positive number between 1 and 20 amps or so, depends on your battery total Ah rating.
Write down the AMPS every 10 minutes for 2 hours.
You should see a point where the AMPS do not drop any further, your ENDAMP setting will be this number plus maybe 1/2 or 1 amp.
You should set your absorb time to be only about a hour longer that normal. ENDAMPS will drop the Classic to FLOAT at exactly the setting you put in. If everything is right, your battery will always go to float at 100% SOC.
You may need to do this every 6 months to a year as your batteries age.
https://web.archive.org/web/20200725113721/https://www.midniteftp.com/support/kb/faq.php?cid=1
yes they do !
Larry
Frequently Asked Question
All Categories » CLASSIC CHARGE CONTROLLER - Features and Programming
CLASSIC - ENDAMPS - How do I figure what ENDAMPS should be?
Last Updated 6 years ago
Lets first tell you what ENDAMPS is...
ENDAMPS is the current the Lead-Acid type battery will "draw" from the charging source when it is 100% charged and can take no more charge. It is this point if the current is not reduced the battery electrolyte and the battery will heat up. Too much and things can get ugly very fast.
The Classic has the ability to terminate the Absorb cycle using Whizbang JR as the ENDAMPS source. For this to work most systems will require a SHUNT and the WBjr option. The WBjr is a current measuring option for the Classic and KID charge controllers. It sends data on the amps in or out of the battery, it is important for things to work to have this and the shunt installed properly.
How to figure what YOUR battery needs for ENDAMPS.
First. lets look at what effects ENDAMPS.
#1 - Battery age
#2 - Battery condition
#3 - Battery type (Flooded, GEL, AGM, other)
#4 - Some battery manufacturers have this number for you, but be warned, for a NEW battery
The Best way to figure out YOUR Battery ENDAMPS is this way:
Take a day, turn off all LOADS while testing for ENDAMPS.
Set ABSORB TIME to something high, like 8 hours.
Remember what your time was, write it down.
Let the Classic (or KID) get to absorb, then come back after the time your wrote down has passed.
Lets say default 2 hours you are back.
Get a notebook, mark off lines every 10 minutes for about 2 hours, 12 lines like this:
:10
:20
:30
:40... and so on.
Go to the WBjr page, 3rd page on the STATUS BUTTON and watch the amps.
They should be a positive number between 1 and 20 amps or so, depends on your battery total Ah rating.
Write down the AMPS every 10 minutes for 2 hours.
You should see a point where the AMPS do not drop any further, your ENDAMP setting will be this number plus maybe 1/2 or 1 amp.
You should set your absorb time to be only about a hour longer that normal. ENDAMPS will drop the Classic to FLOAT at exactly the setting you put in. If everything is right, your battery will always go to float at 100% SOC.
You may need to do this every 6 months to a year as your batteries age.
#60
The "Classic" charge controller / Re: FLA Charge current Setting...
Last post by ClassicCrazy - October 08, 2026, 10:27:17 AMThe wayback machine worked !
https://web.archive.org/web/20210108160609/https://www.midniteftp.com/support/kb/faq.php?id=37
Frequently Asked Questions
All Categories » CLASSIC CHARGE CONTROLLER - Features and Programming
CLASSIC - WBJR - How do I limit Battery Current based on the Whizbang jr. ?
The purpose of this document is to explain how to set up a current limit on the Classic based off
the WBjr current. This will only control the specific Classic that has the WBjr connected to it so
if the desire is to limit more than one Classic each Classic shall have its own WBjr and need
these adjustments made.
The Classic MUST have firmware version 2096 or newer.
For the purpose of this example we are going to say we want to limit the charge current into
the battery bank to 135.5 amps max.
1- On the Classic that has the WBjr connected to it we need to press the "Main Menu"
button several times until CHARGE is highlighted.
2- Scroll to the right to highlight "Tweaks" and press Enter.
3- Press the right upper button under the word "More" (right soft key)
4- Hold the left arrow and press the upper right button (right soft key) 2 times.
5- The number under "address" should be highlighted, Scroll up or down to get to 4405 (Default 30000).
6- Now use the right arrow to scroll over and highlight the value under "Value"
7- Change this to the current limit you want times 10. As mentioned above we want 135.5
amps so 135.5 x 10 = 1355. Hold the left soft key to Speed-Scroll while press up or down arrows. (SHIFT)
8- After setting the current limit to the value you desire hold the upper left button (left soft key) and
press enter. (You should see "DATA SENT AND SAVED")
9- Press Status to return to the main screen
Now whenever the current into the battery exceeds 135.5 amps this particular Classic will back
its current down to maintain 135.5 amps
Help Topics: Charge Controller - CLASSIC
Last updated Wed, Aug 9 2017 12:58pm
https://web.archive.org/web/20210108160609/https://www.midniteftp.com/support/kb/faq.php?id=37
Frequently Asked Questions
All Categories » CLASSIC CHARGE CONTROLLER - Features and Programming
CLASSIC - WBJR - How do I limit Battery Current based on the Whizbang jr. ?
The purpose of this document is to explain how to set up a current limit on the Classic based off
the WBjr current. This will only control the specific Classic that has the WBjr connected to it so
if the desire is to limit more than one Classic each Classic shall have its own WBjr and need
these adjustments made.
The Classic MUST have firmware version 2096 or newer.
For the purpose of this example we are going to say we want to limit the charge current into
the battery bank to 135.5 amps max.
1- On the Classic that has the WBjr connected to it we need to press the "Main Menu"
button several times until CHARGE is highlighted.
2- Scroll to the right to highlight "Tweaks" and press Enter.
3- Press the right upper button under the word "More" (right soft key)
4- Hold the left arrow and press the upper right button (right soft key) 2 times.
5- The number under "address" should be highlighted, Scroll up or down to get to 4405 (Default 30000).
6- Now use the right arrow to scroll over and highlight the value under "Value"
7- Change this to the current limit you want times 10. As mentioned above we want 135.5
amps so 135.5 x 10 = 1355. Hold the left soft key to Speed-Scroll while press up or down arrows. (SHIFT)
8- After setting the current limit to the value you desire hold the upper left button (left soft key) and
press enter. (You should see "DATA SENT AND SAVED")
9- Press Status to return to the main screen
Now whenever the current into the battery exceeds 135.5 amps this particular Classic will back
its current down to maintain 135.5 amps
Help Topics: Charge Controller - CLASSIC
Last updated Wed, Aug 9 2017 12:58pm