Help me design my system

[dddem]

Hello,

I am new here and new to solar systems. I have an engineering background and decent basics in electricity. I am from Belgium but I live in the Philippines (single phase 240V, 60Hz). Our electricity provider is expensive, unreliable and does NOT offer net metering. We experience blackouts for several hours almost every day. I have a diesel generator (shared with the neighbouring houses) but electricity from the generator is even more expensive than from the provider.

I am consuming about 750kWh per month. Most of the consumption happens at night when I run my 1.5HP inverter AC (runs almost only at night, could be 9pm to 5am or midnight to 8am). Other major loads are a 1HP inverter AC in the second bedroom (almost never runs), a 2500 W water heater, washing machine, dryer (rarely used), two 1/2HP pumps for my water system, hot and cold water dispenser, inverter ref/freezer, electric oven, fans, chargers, laptops, vacuum cleaner, hair dryer, CCTV system etc. I have south-oriented roof space for about 5kW of solar panels.

My goal is to minimize my electricity and diesel bills. Note that the generator is running anyway for the neighbours when there is a blackout from the supplier. There is however a few minutes between the start of the blackout and the startup of the generator.

My plan is as follows (please comment as you see fit):

- install about 5kW worth of 545W solar panels on my roof

- get a 8kW MPP Solar / EG4 / PowMR / Anern / PowLand / Chinese clone inverter - I am very open to recommendations for my application

- purchase 30kWh worth of LiFePO4 batteries (pre-built packs or build the packs myself) - also very open to recommendations for pre-built packs and/or cells + BMS

Questions:

- correct me if I am wrong, but I think I need the MPPT in the inverter needs to be at least 104 Amps to make to best of the 5kW solar array (5000W / 48V = 104A)?- reason I am asking is that I see some 8kW inverters with only 80 Amps MPPT...

- are MPP Solar / EG4 / PowMR / Anern / PowLand / SunGold / Rich Solar etc all rebranded clones of the same equipment? Or are there differences in the components etc? Looking at the manuals, the software certainly looks to be the same between the brands

- would I be better off with a Sol-Ark? I won't be doing grid export but is it really the only difference between the Sol-Ark and "normal" inverters of equivalent power? The price difference is so enormous, there must be something else to it?

- has anyone been able to establish battery comms with a MPP Solar-like inverter, if using self-built battery packs, say with a Daly BMS or chinese-built packs? I see that the software has comms presets for some well-known brands. Are these presets usable with some different BMS or pre-built packs?

- without battery comms to the inverter, how can I be alerted remotely that one of the BMS / packs has tripped?

 

[dddem]

For inverter, I am lurking at the 8kW MPP Solar 8048MAX. I can order it directly in Taiwan from MPP Solar and my freight forwarder will ship it to me in the Philippines. Would that do the job?

MPP Solar Inc » PIP-MAX SERIES

www.mppsolar.com

 

[DThames]

Just some advice, add more panels if you have space and the money. I am not saying what you have planned is not enough but saying more is always better. More panels allow, more power on less than ideal solar conditions. More panels charge your batteries faster and for more hours of the day, you can get better power. More panels allow more daytime load while still charging strong for the night. If you can shift loads to the daylight hours and do that work will still charging, that is a good thing.

BMS comms.....you should set the inverter to shut down or switch off of battery to the grid before the BMS trips. This becomes more important if you have more than one battery/BMS. If one trips and the other does not, the voltage on the two batteries can be different, complicating bringing the tripped battery back into the battery bank.

I didn't double check but I think Sol-Ark are low frequency (iron/copper transformer) inverters. They are also just good, which makes them pricey.

 

[dddem]

Just some advice, add more panels if you have space and the money. I am not saying what you have planned is not enough but saying more is always better. More panels allow, more power on less than ideal solar conditions. More panels charge your batteries faster and for more hours of the day, you can get better power. More panels allow more daytime load while still charging strong for the night. If you can shift loads to the daylight hours and do that work will still charging, that is a good thing.

BMS comms.....you should set the inverter to shut down or switch off of battery to the grid before the BMS trips. This becomes more important if you have more than one battery/BMS. If one trips and the other does not, the voltage on the two batteries can be different, complicating bringing the tripped battery back into the battery bank.

I didn't double check but I think Sol-Ark are low frequency (iron/copper transformer) inverters. They are also just good, which makes them pricey.

Thank you. Yes I am limiting the panels to 5kW because of limited adequately oriented / non-shaded roof space (I have a "tall" neighbour, luckily on my North side and a couple of big trees near the house). I may be able to squeeze more but I have not yet taken measurements and observed the sun conditions / shading during a whole day.

For the BMS comms, I do understand that I have to program the inverter to not exceed the limits of the BMS, but what I really meant is CAN/RS-485 where the BMS passes on information to the inverter via a dedicated comms cable between the BMS board and the inverter. This information can then be integrated with the remote management app and do stuff such as raise a remote alert if one of the BMS trips etc.

 

[dddem]

Questions:

1) for single phase 240V, is there any reason one would use two inverters in parallel, rather than one bigger inverter? (say 2x 5kW inverters in parallel vs 1x 10kW)

2) I am lurking at the Deye 8kW Sun-8k-SG01-LP1-EU. However the specs says "mac continuous AC passthrough 50A". Is that not a little low for a 8kW-rated inverter? The main breaker of my house is 80A. I do not expect to exceed 50A much at all, but that *could* happen if I run everything in the house at the same time...

3) for the battery pack, I am set on a 2p16s 560Ah or 608Ah configuration. I am torn between Luyuan's grade A cells or "non grade A". The options are as follows:
- 32x grade A EVE 304 Ah cells: $5,376 ($168/piece)
- 32x grade A EVE 280 Ah cells: $4,688 ($146.5/piece)
- 32x grade A-/B EVE 280Ah cells: $3,504 ($109.5/piece)

The grade A are capacity-matched and come with the paperwork with the test results. Would I still need to top-balance when I get them and/or need to rebalance every so often? If I do get the grade B and properly do my initial top-balancing and Parallel Cell Capacity Balancing, then use the JK BMS with active balancer, can I get away with not having to top-balance again?

 

[Danke]

How about two Deye Hybrids 8k in parallel? Then you’d have plenty of power and redundancy in case one is down for repairs/replacement.

$2132 each plus shipping.

Deye Low Frequency Mppt Hybrid Solar Inverter 5kw 8kw 10kw 12kw Single Phase 3 Phase Inverter Netherlands - Buy Low Frequency Mppt Hybrid Solar Inverter,Deye 12kw 3 Phase Hybrid Inverter,Deye 5kw 8kw 10kw Hybrid Inverter Netherlands Product on Alibab

Deye Low Frequency Mppt Hybrid Solar Inverter 5kw 8kw 10kw 12kw Single Phase 3 Phase Inverter Netherlands - Buy Low Frequency Mppt Hybrid Solar Inverter,Deye 12kw 3 Phase Hybrid Inverter,Deye 5kw 8kw 10kw Hybrid Inverter Netherlands Product on Alibaba.com

www.alibaba.com

 

[pilotdrh]

I found an 8 kW on Lazada. ₱95k ($1,727 USD) It says the seller is in Cebu, shipping shows as 995 pesos for me and I live in Lipa Batangas. Also amps is determined by dividing watts by voltage, 8000/240 (my voltage is 230 here) is under 35 amps. The spec sheet that is posted is a US version which will also work but I'd get the seller to take pictures and send them.

8KW Deye Hyrbid On Grid and Off Grid Solar Inverter | Lazada PH

hybrid grid tie inverter with limiter. solar grid tie inverter with limiter. powmr hybrid inverter 48v off grid. on grid solar panel complete set. off grid solar system set 5kw

www.lazada.com.ph

 

[adamantium]

- correct me if I am wrong, but I think I need the MPPT in the inverter needs to be at least 104 Amps to make to best of the 5kW solar array (5000W / 48V = 104A)?- reason I am asking is that I see some 8kW inverters with only 80 Amps MPPT...

Your numbers are correct. You would need a 104A charger to get 5kW per hour out of your array. An 80A charger would provide up to 19kW per day of power. There are however better options out there. Some 6kW inverters have 120A chargers, and new 12kW inverters have 200 and 250A chargers. Beware that a 30kWh battery will have to be drained 83% to use that power, but since you will probably use some of that power during the charging period you won't max out your battery.

 

[pilotdrh]

For inverter, I am lurking at the 8kW MPP Solar 8048MAX. I can order it directly in Taiwan from MPP Solar and my freight forwarder will ship it to me in the Philippines. Would that do the job?

MPP Solar Inc » PIP-MAX SERIES

www.mppsolar.com

Do you have to pay duty and VAT on that? I tried finding info but you know how it is in the PI.

 

[adamantium]

- are MPP Solar / EG4 / PowMR / Anern / PowLand / SunGold / Rich Solar etc all rebranded clones of the same equipment? Or are there differences in the components etc? Looking at the manuals, the software certainly looks to be the same between the brands

I don't know about some of the brands you have listed, but I do know that there are only minor differences between the MPP Solar, EG4, and SunGold inverters. For some models, the firmware and cards are even compatible.

 

[adamantium]

- would I be better off with a Sol-Ark? I won't be doing grid export but is it really the only difference between the Sol-Ark and "normal" inverters of equivalent power? The price difference is so enormous, there must be something else to it?

Sol-Arks are Deye inverters, so there are differences between other brands but not really between Deye. Since Sol-Ark controls the US market for Deye, outside of the US, Deyes are 230V single phase. The price of Sol-Arks aren't justified in my opinion. Some people love them though. Although they are moderately heavy, I believe they are in fact high frequency inverters, and internally are designed as one small inverter on each phase. Because of this, some models have trouble with unbalanced loads. The 6kW MPPSolar models and equivalents I believe are still low frequency inverters and can handle imbalanced loads and surges better than the Sol-Arks. For under $1500 you can get a SunGoldPower 6k low frequency inverter with a 120A MPPT charger. For under $2000 you can get some good 8k inverters. Amensolar (Megarevo) has good 8-10k models for example. For under $3000 you can get some good 10 and 12k inverters with large 250A MPPT and AC chargers, GSL (LuxPower) for example. With a 5kW array you probably don't need more than a 6kW inverter, but if the price is the same go as large as you can. Just beware that some of the larger inverters have high idle power consumption.

 

[pilotdrh]

Questions:

- correct me if I am wrong, but I think I need the MPPT in the inverter needs to be at least 104 Amps to make to best of the 5kW solar array (5000W / 48V = 104A)?- reason I am asking is that I see some 8kW inverters with only 80 Amps MPPT...


-

The DC output on your PV panels is going to vary depending on how much sun they are getting. Your inverter PV input has a minimum value and a maximum value. So in this example the startup voltage from the panels is 150 VDC and the max is 500 open circuit voltage.

Model	SUN-5K-SG01LP1-US/EU	SUN-8K-SG01LP1 -US/EU
Battery Input Data
Battery Type	Lead-acid or Li-Ion
Battery Voltage Range (V)	40-60V
Max. Charging Current (A)	120A	190A
Max. Discharging Current (A)	120A	190A
Charging Curve	3 Stages / Equalization
External Temperature Sensor	Yes
Charging Strategy for Li-Ion Battery	Self-adaption to BMS
PV String Input Data
Max. DC Input Power (W)	6500W	10400W
PV Input Voltage (V)	370V (100V~500V)
MPPT Range (V)	125V-425V
Start-up Voltage (V)	150 V
PV Input Current (A)	11A+11A	22A+22A
No.of MPPT Trackers	2
No.of Strings Per MPPT Tracker	1+1	2+2

 

[adamantium]

- has anyone been able to establish battery comms with a MPP Solar-like inverter, if using self-built battery packs, say with a Daly BMS or chinese-built packs? I see that the software has comms presets for some well-known brands. Are these presets usable with some different BMS or pre-built packs?

- without battery comms to the inverter, how can I be alerted remotely that one of the BMS / packs has tripped?

Good question. I have wondered that as well. Since most if not all good BMSs support CAN bus and wifi, I think they are compatible, but I may be mistaken. I would really like to know this answer too if someone has tried it. The GSL batteries list themselves as being compatible with several brands using CAN bus.

Most BMSs provide their own mobile software for monitoring over wifi. You can just check status using their app.

 

[dddem]

How about two Deye Hybrids 8k in parallel? Then you’d have plenty of power and redundancy in case one is down for repairs/replacement.

$2132 each plus shipping.

Deye Low Frequency Mppt Hybrid Solar Inverter 5kw 8kw 10kw 12kw Single Phase 3 Phase Inverter Netherlands - Buy Low Frequency Mppt Hybrid Solar Inverter,Deye 12kw 3 Phase Hybrid Inverter,Deye 5kw 8kw 10kw Hybrid Inverter Netherlands Product on Alibab

Deye Low Frequency Mppt Hybrid Solar Inverter 5kw 8kw 10kw 12kw Single Phase 3 Phase Inverter Netherlands - Buy Low Frequency Mppt Hybrid Solar Inverter,Deye 12kw 3 Phase Hybrid Inverter,Deye 5kw 8kw 10kw Hybrid Inverter Netherlands Product on Alibaba.com

www.alibaba.com

2x 8kW is overkill for my application. I am trying to stay under $10,000 for the entire system, especially as Mindoro has no net-metering. It will be very rare that I need to pull more than 8kW. If that happens, the inverter will just fall back to pulling from the grid for that short time.

I found an 8 kW on Lazada. ₱95k ($1,727 USD) It says the seller is in Cebu, shipping shows as 995 pesos for me and I live in Lipa Batangas. Also amps is determined by dividing watts by voltage, 8000/240 (my voltage is 230 here) is under 35 amps. The spec sheet that is posted is a US version which will also work but I'd get the seller to take pictures and send them.

Price seems too good to be true but I'll always contact the seller... there are many Deye copycats on Alibaba using lower quality components etc... might be one of them.

Do you have to pay duty and VAT on that? I tried finding info but you know how it is in the PI.

Hopefully not, I'll import that using my balikbayan box service, so far I have paid nothing in duty including when using them to ship my $3,000 mountain bike from the US.

Your numbers are correct. You would need a 104A charger to get 5kW per hour out of your array. An 80A charger would provide up to 19kW per day of power. There are however better options out there. Some 6kW inverters have 120A chargers, and new 12kW inverters have 200 and 250A chargers. Beware that a 30kWh battery will have to be drained 83% to use that power, but since you will probably use some of that power during the charging period you won't max out your battery.

The 8kW Deye inverter I am lurking at has two MPPTs which can take two strings each for a total of 10kW of PV power, so that easily covers what I can install on my roof.

 

[dddem]

The DC output on your PV panels is going to vary depending on how much sun they are getting. Your inverter PV input has a minimum value and a maximum value. So in this example the startup voltage from the panels is 150 VDC and the max is 500 open circuit voltage.

Model	SUN-5K-SG01LP1-US/EU	SUN-8K-SG01LP1 -US/EU
Battery Input Data
Battery Type	Lead-acid or Li-Ion
Battery Voltage Range (V)	40-60V
Max. Charging Current (A)	120A	190A
Max. Discharging Current (A)	120A	190A
Charging Curve	3 Stages / Equalization
External Temperature Sensor	Yes
Charging Strategy for Li-Ion Battery	Self-adaption to BMS
PV String Input Data
Max. DC Input Power (W)	6500W	10400W
PV Input Voltage (V)	370V (100V~500V)
MPPT Range (V)	125V-425V
Start-up Voltage (V)	150 V
PV Input Current (A)	11A+11A	22A+22A
No.of MPPT Trackers	2
No.of Strings Per MPPT Tracker	1+1	2+2

My plan for now is for 10-12 (two series of 5 or two series of 6) 545W panels. Voc of these panels is usually 45 to 50V so the input Voc will be 225 to 300 - in range. I'll see if I can squeeze more panels but I doubt it. I still have to measure my roof.

 

[adamantium]

Questions:

1) for single phase 240V, is there any reason one would use two inverters in parallel, rather than one bigger inverter? (say 2x 5kW inverters in parallel vs 1x 10kW)

2) I am lurking at the Deye 8kW Sun-8k-SG01-LP1-EU. However the specs says "mac continuous AC passthrough 50A". Is that not a little low for a 8kW-rated inverter? The main breaker of my house is 80A. I do not expect to exceed 50A much at all, but that *could* happen if I run everything in the house at the same time...

3) for the battery pack, I am set on a 2p16s 560Ah or 608Ah configuration. I am torn between Luyuan's grade A cells or "non grade A". The options are as follows:
- 32x grade A EVE 304 Ah cells: $5,376 ($168/piece)
- 32x grade A EVE 280 Ah cells: $4,688 ($146.5/piece)
- 32x grade A-/B EVE 280Ah cells: $3,504 ($109.5/piece)

The grade A are capacity-matched and come with the paperwork with the test results. Would I still need to top-balance when I get them and/or need to rebalance every so often? If I do get the grade B and properly do my initial top-balancing and Parallel Cell Capacity Balancing, then use the JK BMS with active balancer, can I get away with not having to top-balance again?

A single inverter is better than two parallel inverters. In some cases that his how they are implemented inside though. Complexity, price, and half failure are the things to consider. I prefer single inverters since most of the time they are already priced less than two half sizes.

Yes a 50A pass-through is very small if you intend on putting everything on a single load panel. If not then its fine. Note though that the newer inverters are coming with large pass-through capabilities (200A) so that everything can be on the load panel. The Sol-Ark 15k (really a 12k inverter with 15kW MPPT) and GSL 12k (a real 12k inverter with 18kW MPPT controllers) have 200A pass-throughs.

Only buy "grade A". Get the 280Ah "K" cells. The new K model support 6000 cycle life. The 304Ah do not. I believe they are 3500-4000 cycles.

You should be able to get 32x new grade-A EVE 280K cells (China stock), capacity matched with paperwork, including sea freight, for under $4150 ($109/pc) (US door to door). Of course the shipping cost depends on your location. They should come equally charged from the testing. Just add your BMS and let it do the balancing. You don't want to fully charge. LiFePO4s live longer under their maximum. Keep them around 3.5V. You won't be losing much capacity based on the power curve. Yes one purpose of your BMS is to keep them balanced. You will be able to monitor their voltages and your weakest and strongest cells through the BMS. If your cells are radically different when you get them (never happens for new, tested, grade A cells), then just connect them all in parallel and let them level out. Then just put them together with your BMS and give them a charge. All the magic you see on YouTube around charging is overkill. People will probably disagree me, but there is no magic except in the BMS.

 

[pilotdrh]

A single inverter is better than two parallel inverters. In some cases that his how they are implemented inside though. Complexity, price, and half failure are the things to consider. I prefer single inverters since most of the time they are already priced less than two half sizes.

Yes a 50A pass-through is very small if you intend on putting everything on a single load panel. If not then its fine. Note though that the newer inverters are coming with large pass-through capabilities (200A) so that everything can be on the load panel. The Sol-Ark 15k (really a 12k inverter with 15kW MPPT) and GSL 12k (a real 12k inverter with 18kW MPPT controllers) have 200A pass-throughs.

Only buy "grade A". Get the 280Ah "K" cells. The new K model support 6000 cycle life. The 304Ah do not. I believe they are 3500-4000 cycles.

You should be able to get 32x new grade-A EVE 280K cells (China stock), capacity matched with paperwork, including sea freight, for under $4150 ($109/pc) (US door to door). Of course the shipping cost depends on your location. They should come equally charged from the testing. Just add your BMS and let it do the balancing. You don't want to fully charge. LiFePO4s live longer under their maximum. Keep them around 3.5V. You won't be losing much capacity based on the power curve. Yes one purpose of your BMS is to keep them balanced. You will be able to monitor their voltages and your weakest and strongest cells through the BMS. If your cells are radically different when you get them (never happens for new, tested, grade A cells), then just connect them all in parallel and let them level out. Then just put them together with your BMS and give them a charge. All the magic you see on YouTube around charging is overkill. People will probably disagree me, but there is no magic except in the BMS.

And I thought all of the magic was in the smoke. Of course BMS could really stand for bundle of magical stuff.

 

[pilotdrh]

2x 8kW is overkill for my application. I am trying to stay under $10,000 for the entire system, especially as Mindoro has no net-metering. It will be very rare that I need to pull more than 8kW. If that happens, the inverter will just fall back to pulling from the grid for that short time.


Price seems too good to be true but I'll always contact the seller... there are many Deye copycats on Alibaba using lower quality components etc... might be one of them.


Hopefully not, I'll import that using my balikbayan box service, so far I have paid nothing in duty including when using them to ship my $3,000 mountain bike from the US.


The 8kW Deye inverter I am lurking at has two MPPTs which can take two strings each for a total of 10kW of PV power, so that easily covers what I can install on my roof.

You'll have to let me know the details on your BB service. Do you know how much cream of wheat is here!

I'm planning on doing an elevated ground mount for my panels. I'd rather not have them up on the roof of the 2nd floor, then facing different directions and such. I want to elevate them so the low south facing side doesn't have shadow from the fence. My side of the fence is about 1.5 meters above ground so I want to have it at 2 meters. I'm planning on an array thats about 16.5 x 4.8 m, space for 28 panels (future expansion). 2 rows and 14 columns. Basically runniing E-W. My house sits right at 1000 feet altitude. Lipa weather is basically the same as Tagaytay which is about 27 km from in a straight line.

 

[adamantium]

And I thought all of the magic was in the smoke. Of course BMS could really stand for bundle of magical stuff.

This is where you can get a BMS refill...
Blue Magic Smoke (https://www.sparkfun.com/products/retired/10622)

 

[dddem]

Only buy "grade A". Get the 280Ah "K" cells. The new K model support 6000 cycle life. The 304Ah do not. I believe they are 3500-4000 cycles.

You should be able to get 32x new grade-A EVE 280K cells (China stock), capacity matched with paperwork, including sea freight, for under $4150 ($109/pc) (US door to door).

Where? Amy at Luyuan quoted $146.5 per cell for the grade A cells capacity matched with paperwork. $109.5 was the price for their "grade A-" cell, not capacity-matched but sample-tested between 274 and 285 Ah. I tried Docan but they are out of stock of EVE, only have CATL at the moment. They quoted $126/cell for the 302Ah CATL. Need to ask them about the grade, paperwork, capacity match and cycle rating.