Would you like to review my 48v system plan?

[Palonko Chonko]

Hello all of you

Thanks in advance to Will because of this forums existence and also everybody here contributing to it.

I am planning to do a solar system. It will be my first.

Introduction:

I am involved in creating an off grid permaculture farm in Denmark. I am just starting to build the house i am going to be living in with my family.
I therefore need a power system to support the building process while being able to expand it in the future depending on our power needs. This mean the system need to be able to power all standard tools needed for building a house... i know this is very general, but i mean disk grinders, cirkular handsaws, mortar mixer etc.
Because of the need to exspand it i am planning to do a 5kw 48v system and build my own battery from raw cells. To me it seems to be best in the long run, but i would like to hear you out if my thinking is flawed.

This is the system i plan to build:

16pc. 230ah eve cells bought from Amy Zheng from Docan tech.
1 JBD 16s 100A Smart BMS also from Amy Zheng from Docan tech.
Cells and BMS are quoted at 1850 USD including DDP shipping to Denmark
1 PIP-5048MGX from MPP solar http://www.mppsolar.com/v3/catalogs/PIP-MGX.pdf Quoted at 999USD including DDP shipping to Denmark

I've yet to decide how much solarpower to add to the system. I will mostly use the system during the summer, although some winter usage will be useful.
I have come across these deals on solar panels:

455Wp solar panel 220 USD a piece VOC49,7 - unknown producer
380Wp mono crystaline from Hannover Solar 232 USD - https://www.hanoversolar.de/_files/ugd/5f6140_266a1a5b17e342f3859f6838ef7b3abf.pdf
260Wp mono crystaline from Winaico model: WSP-260M6

How for solar power would you suggest will be needed to power this system?

Overall questions:

1) Does the JBD bms from Docan have a low temperature cutoff?
2) Can i simply buy more 230ah cells in let's say 5 years and add it to the system?
3) What is i want to expand the battery bank in the future with different ah cell eg. 280ah
4) If i want to expand the amount of solar panels, but i am unable to source the same panels again, can i buy a different set of panels and add to the system?
4) Do i need anything else except the wires to connect it all, two breakers for the battery and the panels and a solid box for the cells?


Looking forward to hearing your suggestions on this system

 

[MichaelK]

It is well-known that MPP AiO units have little or no surge capacity, so it is going to be a poor choice for running power tools. Anything that runs on an electric motor has what is called "starting surge", or "inrush current", that might last for a second or so. Inverters like the MPP have a 200% surge for only ~16 milliseconds. You should be selecting an inverter that has 200% capacity for at least 5 seconds. I'd suggest looking at inverters from Magnum, Outback, and Schneider as quality components that are good at starting motors. Shop only for "Sine-Wave" inverters. Cheaper inverters quickly burn out appliances running electric motors.

I would select the panels with the highest watts per dollar ratio, or watts per Euro in your case. I'd be looking at 3600W as the low end. For future expansion, the only critical parameter is the string voltage. You might even have strings with different numbers of panels, as long as the string voltage is within 5% of the other parallel strings.

Companies market boxes called "power centers" the have busses and breaker mounts to incorporate both DC and AC components in an clean, organized container. Helps to eliminate the spagetti wiring you see around many DIY systems. Many of these power centers are custom designed to fit a particular inverter/controller configuration, making a seamless connection between the two units.

 

[rmaddy]

The first issue I see is that the battery (BMS) can't provide enough discharge current to fully power the inverter.

A 5000W 48V inverter can pull up to 5000W / 48V / 85% efficiency = 122A from the battery. But the BMS only supports 100A. With just a single 48V battery with a 100A BMS you can only use up to 4000W from the inverter. Adding a second battery in parallel in the future will allow you to use the full 5000W.

Questions:
2) Yes. You can build another 48V battery and add it in parallel to the first.
3) The additional battery does not need to be the exact same capacity.
4) You can always add a stand-alone solar charge controller if you add several new, and different, solar panels.

 

[Palonko Chonko]

It is well-known that MPP AiO units have little or no surge capacity, so it is going to be a poor choice for running power tools. Anything that runs on an electric motor has what is called "starting surge", or "inrush current", that might last for a second or so. Inverters like the MPP have a 200% surge for only ~16 milliseconds. You should be selecting an inverter that has 200% capacity for at least 5 seconds. I'd suggest looking at inverters from Magnum, Outback, and Schneider as quality components that are good at starting motors. Shop only for "Sine-Wave" inverters. Cheaper inverters quickly burn out appliances running electric motors.

I would select the panels with the highest watts per dollar ratio, or watts per Euro in your case. I'd be looking at 3600W as the low end. For future expansion, the only critical parameter is the string voltage. You might even have strings with different numbers of panels, as long as the string voltage is within 5% of the other parallel strings.

Companies market boxes called "power centers" the have busses and breaker mounts to incorporate both DC and AC components in an clean, organized container. Helps to eliminate the spagetti wiring you see around many DIY systems. Many of these power centers are custom designed to fit a particular inverter/controller configuration, making a seamless connection between the two units.

Hi Michael and thank you for your reply.

I wrote to MPP solar about the surge capacity of their PIP5048MGX model and they write:

"Yes. The surge capacity of our inverters is rated power *2 for 5 seconds.

However, we do NOT recommend using surge capacity as a reference for planning your load because surge capacity test done in lab is based on testing with only "resistive load" and no inductive load. (Since the inductive load doesn't have uniform draw so can't be used as a standard for comparison).

Therefore, to avoid under-estimation of load power, we strongly recommend customers to always use ONLY "nominal max continuous rated power" as a reference for sizing the inverter."

I dont know what to make of it. Anyhow i found this chart on a website with general power consumption and surge power of different tools.

🥇 Power Tools & Contractors Appliances: Wattage Chart & Requirements (2022 UPDATE)

Hey! CLICK HERE ✅ to Discover the Power Tools & Contractors Appliances: Wattage Requirements Chart on Generatorist.com CLICK HERE NOW!

generatorist.com

It is only very few tools that even has a surge power going beyond 5kw. I wonder if it is an issue at all.

Would you say that MPP solar in general is of a poor quality? I just picked it because Will speaks well of them on his YT-channel.

I have also considered a Phocos

PSW-H-5KW-230/48V​

---------------------------

Thank you for your considerations regarding the size of the solar array and expandablity

 

[Palonko Chonko]

The first issue I see is that the battery (BMS) can't provide enough discharge current to fully power the inverter.

A 5000W 48V inverter can pull up to 5000W / 48V / 85% efficiency = 122A from the battery. But the BMS only supports 100A. With just a single 48V battery with a 100A BMS you can only use up to 4000W from the inverter. Adding a second battery in parallel in the future will allow you to use the full 5000W.

Questions:
2) Yes. You can build another 48V battery and add it in parallel to the first.
3) The additional battery does not need to be the exact same capacity.
4) You can always add a stand-alone solar charge controller if you add several new, and different, solar panels.

I will order a JBD 16s 200A BMS instead. This would give me some head room. Do you know how BMS acts in regard to surge power?

Ordering from Docan technology unless someone here has better suggestions.

 

[MichaelK]

I dont know what to make of it. Anyhow i found this chart on a website with general power consumption and surge power of different tools.

🥇 Power Tools & Contractors Appliances: Wattage Chart & Requirements (2022 UPDATE)

Hey! CLICK HERE ✅ to Discover the Power Tools & Contractors Appliances: Wattage Requirements Chart on Generatorist.com CLICK HERE NOW!

generatorist.com

It is only very few tools that even has a surge power going beyond 5kw. I wonder if it is an issue at all.

Would you say that MPP solar in general is of a poor quality? I just picked it because Will speaks well of them on his YT-channel.

I've seen reports from other users on this site about various MPP inverters not being able to run the motor-driven tool they wanted to power.

I'm not going to say the MPP is of poor quality. I'll just say that I would never consider buying one for myself because of WHAT I need to run.

Keep in mind that just because something runs on a electric motor doesn't automatically mean it has a large surge. Testing a free-spinning window fan, I saw an inrush of only 1.1X the running power. Even how you use an piece of equipment effects the starting surge. Take a circular saw and just press the on button, and you will get one inrush value. Jam the blade into a 2X4 first, then press on and you will see the inrush go up. Jam it in tight enough and what you will see is the "locked rotor" amps, and likely burn out the motor.

 

[da9el84]

Hello all of you

Thanks in advance to Will because of this forums existence and also everybody here contributing to it.

I am planning to do a solar system. It will be my first.

Introduction:

I am involved in creating an off grid permaculture farm in Denmark. I am just starting to build the house i am going to be living in with my family.
I therefore need a power system to support the building process while being able to expand it in the future depending on our power needs. This mean the system need to be able to power all standard tools needed for building a house... i know this is very general, but i mean disk grinders, cirkular handsaws, mortar mixer etc.
Because of the need to exspand it i am planning to do a 5kw 48v system and build my own battery from raw cells. To me it seems to be best in the long run, but i would like to hear you out if my thinking is flawed.

This is the system i plan to build:

16pc. 230ah eve cells bought from Amy Zheng from Docan tech.
1 JBD 16s 100A Smart BMS also from Amy Zheng from Docan tech.
Cells and BMS are quoted at 1850 USD including DDP shipping to Denmark
1 PIP-5048MGX from MPP solar http://www.mppsolar.com/v3/catalogs/PIP-MGX.pdf Quoted at 999USD including DDP shipping to Denmark

I've yet to decide how much solarpower to add to the system. I will mostly use the system during the summer, although some winter usage will be useful.
I have come across these deals on solar panels:

455Wp solar panel 220 USD a piece VOC49,7 - unknown producer
380Wp mono crystaline from Hannover Solar 232 USD - https://www.hanoversolar.de/_files/ugd/5f6140_266a1a5b17e342f3859f6838ef7b3abf.pdf
260Wp mono crystaline from Winaico model: WSP-260M6

How for solar power would you suggest will be needed to power this system?

Overall questions:

1) Does the JBD bms from Docan have a low temperature cutoff?
2) Can i simply buy more 230ah cells in let's say 5 years and add it to the system?
3) What is i want to expand the battery bank in the future with different ah cell eg. 280ah
4) If i want to expand the amount of solar panels, but i am unable to source the same panels again, can i buy a different set of panels and add to the system?
4) Do i need anything else except the wires to connect it all, two breakers for the battery and the panels and a solid box for the cells?


Looking forward to hearing your suggestions on this system

Greetings from a fellow dane

Regarding batteries, these come highly recommended(I haven't received mine yet, but comms where great, and they've received great reviews from others) and shipping is a lot cheaper than what you've been quoted.

This product is no longer available.

This product is no longer available.

www.alibaba.com

For solar panels, there's a danish community buy in progress for Riesen panels, 1140dkk all included for 400w panels, picked up in Køge.
Link to group: https://www.facebook.com/groups/163970821084259

And good luck with your build

 

[mrzed001]

This is the system i plan to build:

16pc. 230ah eve cells bought from Amy Zheng from Docan tech.
1 JBD 16s 100A Smart BMS also from Amy Zheng from Docan tech.
Cells and BMS are quoted at 1850 USD including DDP shipping to Denmark

I would suggested the JK BMS. It can transfer 200A and has a 2A active balancer.
Nothing is better to keep the cells balanced

1 PIP-5048MGX from MPP solar http://www.mppsolar.com/v3/catalogs/PIP-MGX.pdf Quoted at 999USD including DDP shipping to Denmark

If 5kW is not enough you can put parallel an other MGX and you have 10kW then. You can go up to 9 inverters in parallel.
And it is relatively cheap. You can buy four of 5kW MGX from the price of one 5kW Victron.
And you know, if you have only one and that goes wrong ... you sit in the dark :D
The MGX inverter has an 500Voc MPPT. But do not put more than 400-420Voc solar panels on it.
And calculate with the solar panels Temperature Coefficiency of Voc.
One inverter can handle about 5kWp solar panels.
Or you can put 5kWp to East and 5kWp to West and parallel them

Overall questions:

1) Does the JBD bms from Docan have a low temperature cutoff?
2) Can i simply buy more 230ah cells in let's say 5 years and add it to the system?

Yes. You can build as much 48V packs and parallel them together as you like

3) What is i want to expand the battery bank in the future with different ah cell eg. 280ah

No problem, not a big difference. The packs are parallel.

4) If i want to expand the amount of solar panels, but i am unable to source the same panels again, can i buy a different set of panels and add to the system?

Until its Impp is about the same, no problem.

4) Do i need anything else except the wires to connect it all, two breakers for the battery and the panels and a solid box for the cells?


Looking forward to hearing your suggestions on this system

You need fuses.
For the battery fast (and expensive) Class-T fuse or here in EU we can use cheap NH00-NH2 blade fuses.
And cheap fuse holders for them:

Switchgear - Apator

Produkty dedykowane do rozdziału energii tj. łączniki krzywkowe serii 4G, rozłączniki izolacyjne, podstawy bezpiecznikowe, ograniczniki przepięć, osprzęt uzupełniający.

www.apator.com

Cables az least 35mm2 but 50mm2 is better for battery.

You need fuses for the PV string too. Also DC overcurrent protector.

Breakers and RCD for the AC side.

 

[Smokin]

I am planning to do a solar system. It will be my first.
Man can't do anything right the first time so plan on doing it at least 3 times to get it half right.
That included the money or hire someone to do it for you.

 

[Palonko Chonko]

Greetings from a fellow dane

Regarding batteries, these come highly recommended(I haven't received mine yet, but comms where great, and they've received great reviews from others) and shipping is a lot cheaper than what you've been quoted.

This product is no longer available.

This product is no longer available.

www.alibaba.com

For solar panels, there's a danish community buy in progress for Riesen panels, 1140dkk all included for 400w panels, picked up in Køge.
Link to group: https://www.facebook.com/groups/163970821084259

And good luck with your build

Hej Daniel

Thanks for your answer. I did not see your message In time for the first group buy, so I am on the waiting list now in case there are enough buyers for another container full of panels. I will cross my fingers because these panels are a real steal!

I have already ordered my battery cells EV LF280K from. Docan technology and I feel confident that I am going to receive some good cells

Do you mind me writing to you directly about where to find other supplies for building a system here in Denmark?

 

[Palonko Chonko]

I would suggested the JK BMS. It can transfer 200A and has a 2A active balancer.
Nothing is better to keep the cells balanced




If 5kW is not enough you can put parallel an other MGX and you have 10kW then. You can go up to 9 inverters in parallel.
And it is relatively cheap. You can buy four of 5kW MGX from the price of one 5kW Victron.
And you know, if you have only one and that goes wrong ... you sit in the dark :D
The MGX inverter has an 500Voc MPPT. But do not put more than 400-420Voc solar panels on it.
And calculate with the solar panels Temperature Coefficiency of Voc.
One inverter can handle about 5kWp solar panels.
Or you can put 5kWp to East and 5kWp to West and parallel them



Yes. You can build as much 48V packs and parallel them together as you like


No problem, not a big difference. The packs are parallel.


Until its Impp is about the same, no problem.



You need fuses.
For the battery fast (and expensive) Class-T fuse or here in EU we can use cheap NH00-NH2 blade fuses.
And cheap fuse holders for them:

Switchgear - Apator

Produkty dedykowane do rozdziału energii tj. łączniki krzywkowe serii 4G, rozłączniki izolacyjne, podstawy bezpiecznikowe, ograniczniki przepięć, osprzęt uzupełniający.

www.apator.com

Cables az least 35mm2 but 50mm2 is better for battery.

You need fuses for the PV string too. Also DC overcurrent protector.

Breakers and RCD for the AC side.

Hi @mrzed001

I finally get back to answering your message. First off thank you for your answer

So at last i went with the JK 24S 200A BMS with 2A active balancing
I have ordered the cells for my system: 16 pcs 280 ah from Docan.
I have also ordered 10 pcs 400W solar panels through the danish group buy going on at the moment. I might change how many panels depeding on what charge controller i decide to go with.

These are the specs of the solar panels:


Nominal Power 400 W
Voc 41,3V
Vmmp 34,4V
Cell type Mono


So it is great to have a at least a few pieces "locked in place". Now i just have to get the other things in place.

I have a question, now that you mention fuses. Of course i have seen many diy LiFePO4 videos on youtube and the all talk about Class-T fuses for a 48v system. I have searched a bit and yes... they are quiet expensive. Now you mention NH00-NH2 blade fuses. Since in a new to all this may i ask if it is this you mean? Like this one or This one.
Very much cheaper than the Class-T fuses. Side question: why are these fuses reserved to europe?
I am thinking that a gL / gG type fuse (Very fast acting) at 225A must be good enough with the 200A bms. Anything else i would have to look for?

I will continue my thinking train in this post. Feel free to comment as you like

Charge controller and inverter considerations:

Since i am in the process or building my future off grid homestead i will need a system the can power tools. circular saws, drills, mortar mixer, compressors and so on. Mostly one at a time maybe two sometimes Afterwards when i move into the house a low idle power consumption on the inverter is going to be important as the inverter will be running 24/7.

I have already exposed my interest in the MPP solar as they are AIO, but have a high idle power consumption and theres a concern that they wont be good a powering the tools that i need to power.

I have liste some other route i could take with this system.

One route: The cheap chinese
I have been inspired by @upnorthandpersonal through his blog post, since he is very much in the same situation as i am. apprently he is running some very cheap chinese solar charge controller from MUST energy and a low frequency inverter from the same company powering all big motors, while having a 1200W victron inverter with a low idle power consuption for off grid winter life. Since i am mainly going to use the power during the day and the summermonths during building time i could go with the same system and turn off the inverter while not working. Then when i move into the house I will have to consider getting a victron inverter of an apropriate size. This is one route. I have concern for the quality of the equipment becaus eit is so cheap, but @upnorthandpersonal says he has no problems so far.

The MUST solar charge controller has these specs:

145 max PV voltage
Max pv power 5000W
100A or 80 or 60

With the 10 solar panels i have ordered i guess it would be good to put the on strings of 3 with a VoC each or 41,3V * 3 = 124,2 V leaving room for unsually cold winter days and higher VoC. Ths means i would have to either have 9 or 12 panels connected and correct my order of panels to suit this.

UPDATE: I have spoken to MUST energy and they don't sell low quantity. Only 50 pcs controller and 20 pcs inverters. They have forwarded me to an "agent" who will sell low quantity, but i have not heard from him/her yet.

Second Route: The victron - once and for all

I have an opportunity to buy an unused Victron Multiplus II 3000 GX for 9000 DKK = 1200 EUR
It's from 2019 and has no warranty left.
For this is would need a charge controller preferably a Victron that can communicate with the Multiplus.
This has low idle powerconsumption. Is pricy, but good quality. The question is if it is enough to power my tools and future off grid house. I am quiet sure it can give enough power for my needs in the future, and otherwise by that time i could have another inverter to support it. But will it power my tools?

Third Route: MPP solar AIO
Cheap, but with a high idle power consumption and there's a concern that it won't be able to power my tools. Why do i have a concern that a 5Kw MPP won't be able to power my tools while thinking of buying a 3Kw victron?
Victron has 6Kw peak power
MPP has 10Kw peak power at a fraction of the cost.
Maybe the cost and quality of MPP is what concerns me.

I could also just bite the bullet and have two MPP solar as you suggest, but this wont help with the idle power consumption. On the contrary.


So this sums up my train of though at this point. Feel free to comment.

 

[mrzed001]

Hi @mrzed001

I finally get back to answering your message. First off thank you for your answer

So at last i went with the JK 24S 200A BMS with 2A active balancing
I have ordered the cells for my system: 16 pcs 280 ah from Docan.
I have also ordered 10 pcs 400W solar panels through the danish group buy going on at the moment. I might change how many panels depeding on what charge controller i decide to go with.

Good choice

These are the specs of the solar panels:


Nominal Power 400 W
Voc 41,3V
Vmmp 34,4V
Cell type Mono

Excellent. 10 panel in serial is 413Voc. It is lower than 450V
Check the panels temperature coefficient for V.
Usually Voc is given at 25 Celsius (sometimes at 40 Celsius) ... and if there can be -10 Celsius then (-10 to 25=35) ... so x35.
It is usually about +10%. So az -10Celsus this can reach 454V. So check it at wintertime and if goes near 450Voc then disconnect one panel.
344Vmpp is good. It is near the inverters 320Vmpp ideal MPPT Volt.

You can also parallel panels. But then you need at least a 7s2p configuration (below it the Vmpp would be too low, and if cloudy then less production)

So it is great to have a at least a few pieces "locked in place". Now i just have to get the other things in place.

I have a question, now that you mention fuses. Of course i have seen many diy LiFePO4 videos on youtube and the all talk about Class-T fuses for a 48v system. I have searched a bit and yes... they are quiet expensive. Now you mention NH00-NH2 blade fuses. Since in a new to all this may i ask if it is this you mean? Like this one or This one.
Very much cheaper than the Class-T fuses. Side question: why are these fuses reserved to europe?
I am thinking that a gL / gG type fuse (Very fast acting) at 225A must be good enough with the 200A bms. Anything else i would have to look for?

For fuse holder and disconnector you can buy a cheap NH00 like these (can not find it in .dk ... but you can find a lot of international sources).
Costs about 208 dkk.

Biztosítós szakaszoló kapcsoló NH00 NKI késes biztosítékhoz 3 pólusú 160A Apator RBK00

Biztosítós szakaszoló kapcsoló NH00 NKI késes biztosítékhoz 3 pólusú 160A Apator RBK00.Közös karú szerelőlapra szerelhető szakaszoló biztosító aljzat....

www.onlinevill.hu

or this:

001690870 ETI POLAM - Fuse-switch disconnector | NH00; 160A; 690VAC; Poles: 3; 440VDC | TME - Electronic components

ETI POLAM 001690870 | Fuse-switch disconnector; NH00; 160A; 690VAC; Poles: 3; 440VDC - This product is available in Transfer Multisort Elektronik. Check out our wide range of products.

www.tme.eu

NH00 is for max 160A (cheapest)
NH1 is for max 250A
NH2 is for max 400A
You have to select the fuse holder and the fuse from the same NH class

Here is the data sheet for the NH fuses:

https://www.tme.eu/Document/7d253a9842855876dfe27734b478f852/Bus_Ele_DS_2142_NH.pdf

These are slow blowing fuses. If you have a 160A fuse and 200A load ... it will not blow.
But if you have a short (many thousand Amps ... really 7-15+ kA with LiFePO4) then in millisecond.

I will continue my thinking train in this post. Feel free to comment as you like

Charge controller and inverter considerations:

Since i am in the process or building my future off grid homestead i will need a system the can power tools. circular saws, drills, mortar mixer, compressors and so on. Mostly one at a time maybe two sometimes Afterwards when i move into the house a low idle power consumption on the inverter is going to be important as the inverter will be running 24/7.

I have already exposed my interest in the MPP solar as they are AIO, but have a high idle power consumption and theres a concern that they wont be good a powering the tools that i need to power.

I have liste some other route i could take with this system.

One route: The cheap chinese
I have been inspired by @upnorthandpersonal through his blog post, since he is very much in the same situation as i am. apprently he is running some very cheap chinese solar charge controller from MUST energy and a low frequency inverter from the same company powering all big motors, while having a 1200W victron inverter with a low idle power consuption for off grid winter life. Since i am mainly going to use the power during the day and the summermonths during building time i could go with the same system and turn off the inverter while not working. Then when i move into the house I will have to consider getting a victron inverter of an apropriate size. This is one route. I have concern for the quality of the equipment becaus eit is so cheap, but @upnorthandpersonal says he has no problems so far.

The MUST solar charge controller has these specs:

145 max PV voltage
Max pv power 5000W
100A or 80 or 60

With the 10 solar panels i have ordered i guess it would be good to put the on strings of 3 with a VoC each or 41,3V * 3 = 124,2 V leaving room for unsually cold winter days and higher VoC. Ths means i would have to either have 9 or 12 panels connected and correct my order of panels to suit this.

UPDATE: I have spoken to MUST energy and they don't sell low quantity. Only 50 pcs controller and 20 pcs inverters. They have forwarded me to an "agent" who will sell low quantity, but i have not heard from him/her yet.

Second Route: The victron - once and for all

I have an opportunity to buy an unused Victron Multiplus II 3000 GX for 9000 DKK = 1200 EUR
It's from 2019 and has no warranty left.
For this is would need a charge controller preferably a Victron that can communicate with the Multiplus.
This has low idle powerconsumption. Is pricy, but good quality. The question is if it is enough to power my tools and future off grid house. I am quiet sure it can give enough power for my needs in the future, and otherwise by that time i could have another inverter to support it. But will it power my tools?

Third Route: MPP solar AIO
Cheap, but with a high idle power consumption and there's a concern that it won't be able to power my tools. Why do i have a concern that a 5Kw MPP won't be able to power my tools while thinking of buying a 3Kw victron?
Victron has 6Kw peak power
MPP has 10Kw peak power at a fraction of the cost.
Maybe the cost and quality of MPP is what concerns me.

I could also just bite the bullet and have two MPP solar as you suggest, but this wont help with the idle power consumption. On the contrary.


So this sums up my train of though at this point. Feel free to comment.

Must is a MPP Solar clone too
Yes, they have LF inverters.
But LF inverters have MUCH higher IDLE consumption than HF inverters.
Also a worst conversion rate. And heavy as hell. A 5kW unit is 100kg+.
But yeah, they can run electric motor driven equipment like none other :D

Victron is a HF inverter with a big transformer.
Costs a LOT
For one Victron 5kW inverter and Victron 450Voc MPTT price you can buy 4-5 MPP Solar 5kW inverter (all with 500Voc MPPT)

MPP Solar is cheap, and can be easily expanded. Up to 9 units can be paralleled.
To run heavy tools I would suggest 2, maybe 3 5kW units.
Or you can buy the 8kW MAX or the new 11kW MAX unit too :D
That can be paralleled too, if not enough.

The power you need ...
The 3kW will not be enough for a house. With a running washing machine (and maybe microwave) ... and you can not start a coffeemaker
The house itself eats more than 3kW.

 

[Palonko Chonko]

Hi @mrzed001 and thank you for taking your time to respond. I appreciate it very much!

Must is a MPP Solar clone too
Yes, they have LF inverters.
But LF inverters have MUCH higher IDLE consumption than HF inverters.
Also a worst conversion rate. And heavy as hell. A 5kW unit is 100kg+.
But yeah, they can run electric motor driven equipment like none other :D

Victron is a HF inverter with a big transformer.
Costs a LOT
For one Victron 5kW inverter and Victron 450Voc MPTT price you can buy 4-5 MPP Solar 5kW inverter (all with 500Voc MPPT)

MPP Solar is cheap, and can be easily expanded. Up to 9 units can be paralleled.
To run heavy tools I would suggest 2, maybe 3 5kW units.
Or you can buy the 8kW MAX or the new 11kW MAX unit too :D
That can be paralleled too, if not enough.

Yes is realised that the conversion rate is poor. I think i am going to simply try out a system with the MPP solar AIO and if i get problems running my loads i will ad a LF inverter that i can switch on only when/if i need it. The MPP solar still runs a high idle power consumption and during winter time this is going to be an issue. But it will be a few years before i move in. By that time there might be a cheaper inverter with a low idle consumption which i can connect for winter time use.

I wonder if it is possible to just switch off the inverter in the MPP solar and just use the charge controller, while using a different external inverter???

I have drawn a simple diagram to make it easier to comunicate my understanding.



I think i am going to go with a PIP MAX as they have 500 VOC and then winter time shouldn't be an issue. calculated 476 VOC in -20 degrees celcius which in abnormally rare here in DK especially in daytime. I wonder if it ever happened.

As you see in my diagram i put just the class T fuse in the batterybox. I saw a thread in which you and @upnorthandpersonal discuss the usage of NH fuses and it came to my understanding that every battery should have a class T fuse, but when parallelling more batteries a NH fuse can be put between the inverter/charger and all the batteries. Is this correct? or would you simply replace the class T fuse as i have out in the diagram with an NH fuse?

I am happy that things are getting into place slowly

Now i have questions regarding Cables and Lugs

Any good suppliers og good quality in EU or through Ali?
Tinned or bare copper wires/lugs?
When sizing cables i am simply going to run a size 125% above max continous load?
and sizing for PV array simply for a low voltage drop?

Once again thank you! :D

 

[upnorthandpersonal]

Must is a MPP Solar clone too
Yes, they have LF inverters.
But LF inverters have MUCH higher IDLE consumption than HF inverters.
Also a worst conversion rate. And heavy as hell. A 5kW unit is 100kg+.

Around 40kg for the 6kW low frequency one I have - idle around 50W, maybe 75W.

 

[upnorthandpersonal]

UPDATE: I have spoken to MUST energy and they don't sell low quantity. Only 50 pcs controller and 20 pcs inverters. They have forwarded me to an "agent" who will sell low quantity, but i have not heard from him/her yet.

They do. Go through their Alibaba page, and either find the listings with an MOQ of 1, or the ones that have samples available. They're not easy to find, but they're there.

 

[mrzed001]

Hi @mrzed001 and thank you for taking your time to respond. I appreciate it very much!


Yes is realised that the conversion rate is poor. I think i am going to simply try out a system with the MPP solar AIO and if i get problems running my loads i will ad a LF inverter that i can switch on only when/if i need it.

The LF inverter needs to be on a separate circuit. It can not be paralleled with an MPP Solar.
You could put them in serial ... but better not

The MPP solar still runs a high idle power consumption and during winter time this is going to be an issue. But it will be a few years before i move in. By that time there might be a cheaper inverter with a low idle consumption which i can connect for winter time use.

I wonder if it is possible to just switch off the inverter in the MPP solar and just use the charge controller, while using a different external inverter???

Never tried :D Can work if inverter switch only disables inverting function

I have drawn a simple diagram to make it easier to comunicate my understanding.
View attachment 94483

PV side you need a PV breaker. We like to use cylindrical fuses with DIN holder.

I think i am going to go with a PIP MAX as they have 500 VOC and then winter time shouldn't be an issue. calculated 476 VOC in -20 degrees celcius which in abnormally rare here in DK especially in daytime. I wonder if it ever happened.

The 5kW MGX has also an 500Voc MPPT. But I suggest to never go over 450Voc even in winter.

As you see in my diagram i put just the class T fuse in the batterybox. I saw a thread in which you and @upnorthandpersonal discuss the usage of NH fuses and it came to my understanding that every battery should have a class T fuse, but when parallelling more batteries a NH fuse can be put between the inverter/charger and all the batteries. Is this correct? or would you simply replace the class T fuse as i have out in the diagram with an NH fuse?

NH fuse blows slower. This is the only bad thing about it. It is a real big fuse where you do not have to worry about an arc remaining :D
If you have LFP battery then you have a lot of thousands of Amps. And there it blows as fast as CLASS-T.

I am happy that things are getting into place slowly

Now i have questions regarding Cables and Lugs

Any good suppliers og good quality in EU or through Ali?
Tinned or bare copper wires/lugs?
When sizing cables i am simply going to run a size 125% above max continous load?
and sizing for PV array simply for a low voltage drop?

Once again thank you! :D

You have to size cable for max load, and max cable length, and losses under 3%
Good supplier in EU? Huhh that is not easy :D
Cables you can find for welder (usually only in black). Better the rubber cable.
But to find M6-M8 50-70mm2 ring terminal, with a long sleeve and wide opening ... that's a problem.
Even in Ali it is hard to find. I am searching for it right now :D

 

[upnorthandpersonal]

The LF inverter needs to be on a separate circuit. It can not be paralleled with an MPP Solar.

Simple transfer switch should do fine - that's what I do. Have the big 6kW running when I need it, switch to the 1200VA Victron when I don't.

 

[mrzed001]

Around 40kg for the 6kW low frequency one I have - idle around 50W, maybe 75W.

You are right, I had the 15kW 3phase LF in mind (about 80+kg).

The conversion rate is 85% (peak) at max for LF inverters

They do. Go through their Alibaba page, and either find the listings with an MOQ of 1, or the ones that have samples available. They're not easy to find, but they're there.

I also think you can buy 1 item.

Simple transfer switch should do fine - that's what I do. Have the big 6kW running when I need it, switch to the 1200VA Victron when I don't.

Of course a 1-0-2 transfer switch can do it ... but then you have only the 1200VA Victron for all loads.
Better to switch only separate circuits.
And the 1-0-2 switch has to do forced segregation (according to DIN VDE 0113)

 

[MichaelK]

Must is a MPP Solar clone too
Yes, they have LF inverters.
But LF inverters have MUCH higher IDLE consumption than HF inverters.
Also a worst conversion rate. And heavy as hell. A 5kW unit is 100kg+.
But yeah, they can run electric motor driven equipment like none other :D

Blatant misinformation! I think these are lies spread by the high-frequency companies to make their own products look better.

Let's look at the DOCUMENTED specs of typical tier-1 low-frequency inverters. I'll start with the one I have....

Schneider XW+6848 Background consumption: 29W; weight 121lbs (yes, this is the value I see)
Schneider Conext 4024 Background consumption: 11W; weight 77lbs (yes, this is the value I see)
SMA Sunny Boy 6048 Background consumption: 25W; weight 139lbs
Magnum MS4448PAE Background consumption: 25W; weight 55lbs
Outback Radian 8048: Background consumption: 34W; weight 125lbs

I challenge anyone here to DOCUMENT the specifications of any quality inverter that matches the statements of mrzed001 above.

 

[upnorthandpersonal]

I think @mrzed001 was specifically referring to the MUST ones...