MPP lv2724-mr; solar load and utility charging confusion

[Thales]

Hi everyone,

I have been reading a bunch here (so great) but am still confused how to get my system to do what I want it to do. Maybe I am missing something basic.

I have this PIP 2724LV-MR 24V 2.7kW 120V Inverter https://watts247.com/product/pip-2724lv-mr/ and a EG4 LifePower4 Lithium Battery 24V 200AH https://eg4electronics.com/backend/wp-content/uploads/2022/07/EG4LL-24V-Spec-Sheet-1.pdf as emergency back up on my aquarium system. It has been working great so far doing what it is supposed to do - keep the battery charged and switch over to battery power when there is a power outage. I am adding solar panels, 4 200 watt panels in parallel as advised by watts247.

I would like the power from solar panels to be providing power to the equipment plugged into the MPP where there is sunlight, and would like mains power to be keeping the battery charged in case of an emergency. I am having trouble making that happen as the MPP seems to want to make the panels charge the battery unless I set the unit to Utility first in program 1. Instead of relating all the settings I have tried, I thought I could share how I have the MPP programed and see if you all know how to make it do what I want, or let me know if I am just wrong and it won’t do what I want.

Thank you in advance for helping me try to figure this out because I am a bit lost, and I hope I posted this in the correct forum. If I can provide more information, please let me know.

My current settings are


1 SOL
2 25a
3 UPS
5 USE
6 lrd
7 trd
9 60hz
11 15A
12 25.5
13 27
16 snu
18 bOn
19 esp
20 lOn
22 aon
23 Byd
25 FEN
26 28.1
27 27
29 23
30 ed5
31 29.2
33 60
34 120
35 30d
36 ad5


Thanks! Rich

 

[sunshine_eggo]

I would like the power from solar panels to be providing power to the equipment plugged into the MPP where there is sunlight, and would like mains power to be keeping the battery charged in case of an emergency.

This isn't possible.

The circuitry that inverts DC to AC is the same circuitry that charges DC from AC - Just run in reverse. You can't both invert DC to AC and charge AC to DC at the same time using the same circuitry.

When mains power is used for charging it MUST be passed through to the loads. The PV may also charge the battery when this is happening, but it can't power the loads.

I am having trouble making that happen as the MPP seems to want to make the panels charge the battery unless I set the unit to Utility first in program 1. Instead of relating all the settings I have tried, I thought I could share how I have the MPP programed and see if you all know how to make it do what I want, or let me know if I am just wrong and it won’t do what I want.

In SOL, setting #12 determines when it falls back to grid. Unfortunately, 25.5V is a fairly low state of charge for LFP, and it's not very useful.

I would try setting 16 to CUt and see if that helps.

Have you inquired with Ian? He generally provides good support and would know of any solutions.

 

[OffGridForGood]

I would like the power from solar panels to be providing power to the equipment plugged into the MPP where there is sunlight, and would like mains power to be keeping the battery charged in case of an emergency. I am having trouble making that happen as the MPP seems to want to make the panels charge the battery unless I set the unit to Utility first in program 1

If you set up the inverter to Utility First UE1 (okay not letter E more like upside down F)
anyway if the inverter is set to Utility first on a smart plug or timer control, you can cut off the utilty on a schedule to match sun-up. When the Utility is unavailable in this setting the inverter first looks for solar, then for battery. Effectively this will give you what you are looking for.
A smart plug can be set to a schedule and controlled with your phone, so you can switch it back on if the sun and battery are both low.

 

[sunshine_eggo]

I was wondering if that would work, but I was hesitant to suggest it. I'm setting up a PowMr 24/3kW, and that's how I plan to configure it. I'll allow charging during off-peak times and then disconnect during peak times via timer.

 

[OffGridForGood]

I was wondering if that would work, but I was hesitant to suggest it. I'm setting up a PowMr 24/3kW, and that's how I plan to configure it. I'll allow charging during off-peak times and then disconnect during peak times via timer.

Yup it works, I have done this with my own MPP2724, works well.

Edit: WAIT A MINUTE - PowMr ? NOT VICTRON ????????????? (AKA Eurotrash!)

 

[sunshine_eggo]

Yup it works, I have done this with my own MPP2724, works well.

Edit: WAIT A MINUTE - PowMr ? NOT VICTRON ????????????? (AKA Eurotrash!)

Non-critical play project

 

[Thales]

This isn't possible.

The circuitry that inverts DC to AC is the same circuitry that charges DC from AC - Just run in reverse. You can't both invert DC to AC and charge AC to DC at the same time using the same circuitry.

When mains power is used for charging it MUST be passed through to the loads. The PV may also charge the battery when this is happening, but it can't power the loads.



In SOL, setting #12 determines when it falls back to grid. Unfortunately, 25.5V is a fairly low state of charge for LFP, and it's not very useful.

I would try setting 16 to CUt and see if that helps.

Have you inquired with Ian? He generally provides good support and would know of any solutions.

Thanks so much. I'll check with Ian - I wanted to talk with other folks as well so I posted. Thanks!

 

[Thales]

If you set up the inverter to Utility First UE1 (okay not letter E more like upside down F)
anyway if the inverter is set to Utility first on a smart plug or timer control, you can cut off the utilty on a schedule to match sun-up. When the Utility is unavailable in this setting the inverter first looks for solar, then for battery. Effectively this will give you what you are looking for.
A smart plug can be set to a schedule and controlled with your phone, so you can switch it back on if the sun and battery are both low.

Thanks! That is a real interesting idea. I could have the timer turn off utility power for 2 hours, then put it back on for an hour or so to keep the battery topped off, then repeat.

 

[Thales]

Oh, I can't be the only person to want to do this, is there a different MPP or different box that will do this? Thanks!

 

[sunshine_eggo]

Oh, I can't be the only person to want to do this, is there a different MPP or different box that will do this? Thanks!

Sorta, but they tend to be much higher priced units with greater capabilities. Even those units are subject to the rule that inverter/chargers can do both, but not both at the same time.

This as stated is not possible:

would like the power from solar panels to be providing power to the equipment plugged into the MPP where there is sunlight, and would like mains power to be keeping the battery charged in case of an emergency.

The feature that approximates your desire is to have the solar/battery power the loads until the battery is consumed to a certain threshold, then the grid takes over and charges the battery back up.

The issue with your equipment is you can't set a meaningful threshold where grid kicks in. Many other inverters can be programmed to have grid kick in at higher voltage and/or SoC if desired.

 

[Thales]

The issue with your equipment is you can't set a meaningful threshold where grid kicks in. Many other inverters can be programmed to have grid kick in at higher voltage and/or SoC if desired.

Thanks so much.
Can you suggest an inverter/controller simialr to the MPP unit I have that will do that? Maybe I can just replace it if Ian doesn't have a workaround.
Thanks again!

 

[sunshine_eggo]

Thanks so much.
Can you suggest an inverter/controller simialr to the MPP unit I have that will do that? Maybe I can just replace it if Ian doesn't have a workaround.
Thanks again!

I would check with Ian first. I doubt you want to spend 3-5X+ more than what you're paying for now. He might have a solution I'm not aware of.

 

[OffGridForGood]

I would check with Ian first. I doubt you want to spend 3-5X+ more than what you're paying for now. He might have a solution I'm not aware of.

And be sure to post what the outcome was, so we (and anyone following along) knows.

 

[Thales]

This is what I got back from Ian
"

What I would.do.in your case is set 01 to UTL and use a Christmas tree timer to send AC power to the unit say from midnight to 6am.

Setting 13 will be the max utility charging voltage.

12 is used in SBU mode, when battery voltage gets below 12 then charge from grid until battery V = setting 13

Ian"

It seems, as y'all pointed out, this MPP isn't able to trigger charging on my battery until the battery is more than 1/2 empty, which won't really work for me as this is more for emergency life support than solar. However, I will likely do the timer trick on utility power when it is sunny and/or will also likely get another battery so I can do it. At .25 cents a kwh, it seems worth it.

Thanks!

 

[OffGridForGood]

or the other option is the charge the battery without using the inverter AC input - use a battery charger separate from the inverter put the charger on a timer to use off peak utility.

 

[Thales]

Thanks. Is there an MPP or other company's device that you all can suggest that will do what I want?
I am not against selling the current mpp for something more newer that will do what I want and will allow me web access.

Thanks!

 

[OffGridForGood]

It seems, as y'all pointed out, this MPP isn't able to trigger charging on my battery until the battery is more than 1/2 empty, which won't really work for me as this is more for emergency life support than solar. However, I will likely do the timer trick on utility power when it is sunny and/or will also likely get another battery so I can do it. At .25 cents a kwh, it seems worth it.

Is there an MPP or other company's device that you all can suggest that will do what I want?

If the inverter you have will do what you need, I would just get a separate charger for the battery pack and put that charger on a timer control. I like to use smart plugs since these have built in timer and schedule settings - set to match off peak power periods - and allow you to control the charger anywhere your phone has service. Don't connect the Inverter to utility supply at all.

 

[sunshine_eggo]

Thanks. Is there an MPP or other company's device that you all can suggest that will do what I want?
I am not against selling the current mpp for something more newer that will do what I want and will allow me web access.

Thanks!

This isn't possible.

The circuitry that inverts DC to AC is the same circuitry that charges DC from AC - Just run in reverse. You can't both invert DC to AC and charge AC to DC at the same time using the same circuitry.

When mains power is used for charging it MUST be passed through to the loads. The PV may also charge the battery when this is happening, but it can't power the loads.

This isn't just your unit. It's all of them. Even my very expensive Victron hardware can't do this.

You can get analogous function to what you describe, but it works unlike you state and requires hardware capable of a grid interconnect and advanced management. Given that you in are Cali, this is going to lock you into an equipment list and regulatory hassle that is leaps and bounds more complex and costly than you have now.

You have been given two solutions:

1) a timer on the AC input.
2) a separate charger.

There isn't a realistic third.

 

[Thales]

This isn't just your unit. It's all of them. Even my very expensive Victron hardware can't do this.

You can get analogous function to what you describe, but it works unlike you state and requires hardware capable of a grid interconnect and advanced management. Given that you in are Cali, this is going to lock you into an equipment list and regulatory hassle that is leaps and bounds more complex and costly than you have now.

You have been given two solutions:

1) a timer on the AC input.
2) a separate charger.

There isn't a realistic third.

Thank you.

What I would like has changed from my initial post thanks to the responses helping me undersand more.
The battery is for power if there is an outage, so having it get down to half or below before it charges back up isn't what I need. The timer solution puts me in the same position if it is too cloudly.

What I think I now want is to be able to have my device use solar until the battery is at x level, then switch to utility to charge it up, then switch back to solar. It seems the MPP does this now, but it seems it can only switch from solar to utility when the battery hits 25.5v or lower - if that could be set to 26.2 (based on watching the unit in action) it seems it would do what I am after. Though I am new to this, it seems like this is a programming issue and that my MPP is limited to 25.5v max for the change to from solar to charging the battery from utility, and perhaps there is another unit that is more flexible. From my newbie perspective, it seems like I can't be the first one to want this - though I can understand if it just isn't possible.
I could be totally wrong and if so, I am sorry for wasting your time!

Rich

 

[sunshine_eggo]

If you can upgrade to 48V, this unit has much higher settings for #12:

Limited Special 3048LV-MK 48V 3kW 120V Inverter MPP Solar , 4kW Solar Charger (80A) , Parallel able and split phase up to 9 units, Zero Transfer Time – Watts247 Wholesale

watts247.com

The timer solution can be narrowed to whatever you like to maximize reserve battery capacity. Maybe you're off AC from 9a to 3p every day. You can probably implement and test the recommended timer solution very cheaply and see if it works for you.