Multiplus overload questions

[740GLE]

How is the multiplus managing the battery SOC, do you have a shunt, or is it based off voltage only?

 

[SoakedUp]

Do you have the Dynamic Current Limiter setting clicked on the MP? This helps allow the generator respond better to large surge loads. Also, try turning off the UPS Function.

 

[Sportzfann]

I will go in and look at the dynamic limiter to see what it is set at . I have to get the laptop and connect to see it I believe.
I have a shunt but it’s a renogy (saving up for the smart shunt.)

 

[Sportzfann]

Do you have the Dynamic Current Limiter setting clicked on the MP? This helps allow the generator respond better to large surge loads. Also, try turning off the UPS Function.

The dynamic current limiter is enabled, I clicked it thinking it would be best to let the multiplus adapt to changing volts from the generator.
I think this setting allows for dirty power if you happen to have an older no inverter generator? My genny is an inverter model tho.
But thought anything you can do to help the multiplus adapt would be good? This could be wrong thinking?
Thanks for the replies.

 

[Sportzfann]

Do you have the Dynamic Current Limiter setting clicked on the MP? This helps allow the generator respond better to large surge loads. Also, try turning off the UPS Function.

What is the UPS function? I don’t recall seeing that setting.

 

[Checkthisout]

The dynamic current limiter is enabled, I clicked it thinking it would be best to let the multiplus adapt to changing volts from the generator.
I think this setting allows for dirty power if you happen to have an older no inverter generator? My genny is an inverter model tho.
But thought anything you can do to help the multiplus adapt would be good? This could be wrong thinking?
Thanks for the replies.

"Accept Wide A/C" ON

And

"Disable UPS function"

 

[Checkthisout]

What is the UPS function? I don’t recall seeing that setting.

Quick changeover when the generator is shut off/AC power is removed.

However the A/C signal must be perfect. This can result in more frequent disconnects if the power from your inverter gen gets dirty.

Also note what Eggo said about Ripple.

And also, there are "i" next to the settings that you click which explain the setting.

 

[SoakedUp]

Quick changeover when the generator is shut off/AC power is removed.

However the A/C signal must be perfect. This can result in more frequent disconnects if the power from your inverter gen gets dirty.

Also note what Eggo said about Ripple.

And also, there are "i" next to the settings that you click which explain the setting.

Yup. I had a similar problem as the OP where my multiplus would switch from “passthrough” to “inverting” then back to “assist” when big loads would kick in. It was mostly solved by turning the UPS function off. My guess is the multiplus saw a drop in volts coming from the generator for a split second when the surges of power hit and was trying to protect the devices connected to the MP from shutting off. I don’t really have any sensitive devices connected so I didn’t need the real fast switch over.

 

[Sportzfann]

Great thanks, I am trying to wrap my head around this solar equipment and get it to operate properly.
I am slowly getting the issue with the multiplus tripping which I think I can correct. (Check settings again)
I believe the UPS function works great the multiplus will transition from genny to inverter with out a blink or any disruptions.
I believe that’s what UPS carries the load till inverter picks up?

I am also looking at rewiring my solar panels to a parallel configuration due to my over paneling on the roof and a miscalculation on my part.
I will start another thread with the questions I’m sure I will have.
Thanks for the help,Sportz

 

[RCinFLA]

Battery wiring is often a problem causing too much voltage drop at inverter input terminal.

The more voltage drop to inverter DC input, the more current the inverter must draw from battery for the same AC output load.

A 3kW, 12v inverter is on the verge of being impractical due to 12v inverter systems having so little margin for voltage drop tolerance. Problem is usually compounded as an inexperienced user not knowing they should not be buying a 12v, 3kW inverter will also be less likely to deal with the extremely high battery line currents it will be creating.

On 12v systems, a fuse needs to be used instead of circuit breaker on DC input due to most breakers having too much series resistance because of their short circuit detection magnetic trip coil resistance. High current breaker with short circuit detection will have about 4-5 milliohms of series resistance.

At 5 milliohms and 200 amps, there will be about 1v drop just across breaker. A quality fuse will be less than 1 milliohms of series resistance.

 

[740GLE]

Battery wiring is often a problem causing too much voltage drop at inverter input terminal.

The more voltage drop to inverter DC input, the more current the inverter must draw from battery for the same AC output load.

A 3kW, 12v inverter is on the verge of being impractical due to 12v inverter systems having so little margin for voltage drop tolerance. Problem is usually compounded as an inexperienced user not knowing they should not be buying a 12v, 3kW inverter will also be less likely to deal with the extremely high battery line currents it will be creating.

On 12v systems, a fuse needs to be used instead of circuit breaker on DC input due to most breakers having too much series resistance because of their short circuit detection magnetic trip coil resistance. High current breaker with short circuit detection will have about 4-5 milliohms of series resistance.

At 5 milliohms and 200 amps, there will be about 1v drop just across breaker. A quality fuse will be less than 1 milliohms of series resistance.

Agreed there is a reason the MPII at 12v has dual battery terminals, they recommend what dual 1/0? Again to combat voltage sag. That auto xfrmr in the unit can suck up the current it taxed.

 

[Sportzfann]

I ran 4/0 about 2’ long from battery to MP in front compartment of the fifthwheel, I have 2 x 200=400 ah Litime batteries it passes thru a 400a class T fuse and disconnect.

 

[Brucey]

I ran 4/0 about 2’ long from battery to MP in front compartment of the fifthwheel, I have 2 x 200=400 ah Litime batteries it passes thru a 400a class T fuse and disconnect.

Which specific litime 12V 200Ah? Are they the plus model with 200A BMS? Their regular 200Ah only has a 100A BMS.

 

[740GLE]

I ran 4/0 about 2’ long from battery to MP in front compartment of the fifthwheel, I have 2 x 200=400 ah Litime batteries it passes thru a 400a class T fuse and disconnect.

Not to be nitpicky but dual 1/0 isn’t the same as 4/0.

Should 4/0 be good enough, probably, but still not what victron specifies.

 

[Sportzfann]

Which specific litime 12V 200Ah? Are they the plus model with 200A BMS? Their regular 200Ah only has a 100A BMS.

Yes I bought the plus model 200a BMS. When I bought them they didn’t offer the heated model, or I would have bought them…

 

[Brucey]

Yes I bought the plus model 200a BMS. When I bought them they didn’t offer the heated model, or I would have bought them…

Good thing you didn't their heated option is for some reason using the base models 100A BMS.

 

[Sportzfann]

Good thing you didn't their heated option is for some reason using the base models 100A BMS.

Oh haha good to know thanks.