Help me design my system

[DThames]

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

Common misunderstanding in electronics. The smoke is not magic. It is installed at the factory where the equipment is made. It is just regular smoke. But of course you can't (shouldn't) let it out.

 

[adamantium]

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.

Have you tried Qishou or Basen?

 

[dddem]

Have you tried Qishou or Basen?

Not yet. There have been a few horror story threads about these two if I remember correctly... Here is one

Experience purchasing EVE304Ah cells from Amy Peng @ Shenzhen Qishou Technology

Good Morning Folks, Could someone share their experience purchasing cells from Amy Peng @ Shenzhen Qishou Technology? She quoted me EVE 304AH $118/pcs. promising Brand New Grade A cells with no swelling blah blah... I saw Andy from the Off Grid Garage purchasing from her and he was happy...

diysolarforum.com

 

[adamantium]

Not yet. There have been a few horror story threads about these two if I remember correctly... Here is one

There are complaints about the vendors you have chosen. There will be as many complaints as there are complainers. Problems can occur with any vendor. Just because someone else got a good batch from one vendor last week doesn't guarantee you are going to get the same thing a month later. In the end you have to perform your own capacity and performance tests to find out what you got. Even then, there is no guarantee that the cells will perform the same throughout their life time. The cells all come from the same factory. No vendor has exclusive access to the best cells, and no vendor gets to cherry pick from their supply and send the rest back to the factory. The vendors get what they get, and they sell what they get.

There are plenty of places you can buy from that have EV grade A matched cells with documentation. If you are trying to get the best of the best of the best, then you will have to go to China and hand pick and test every cell yourself. A glossy color print of test results doesn't make the vendor's claims more credible. They can say and print whatever they want.

The price I mentioned above was from Basen about 10 days ago. It was actually a little better than what I mentioned. If the vendor has US stock like Basen, and you are willing to pay more, then you can get them in days, and it is easier to complain if there is a problem or return them.

Here is another quote I got today from Exliporc. Its a little more. All cells are EV grade A, matched and documented before shipping. 32pcs EVE 280K including DDP sea shipping from China $4250. They will even do a voice call to talk to you about what they provide and answer questions.

After all, it comes down to luck. There are no magic vendors.

P.S.
Most if not all of these battery vendors sell ESS class cells. The EV class is bought up in large orders from the EV companies. The vendors I have talked with say that all of the cells are getting more difficult to get because of increased EV production. So I am very skeptical about any vendor claiming that they sell EV class cells exclusively. Some may, but I would really have to see consistent test results of their cells shipped to every customer to believe it. EV class cells are supposed to have very narrow voltage and internal resistance ranges, for example: EV grade cells <0.001, <0.01mΩ; ESS grade cells <0.01V, <0.1mΩ. When I use my inverter, that kind of range difference is irrelevant.

 

[b1gf00t]

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?

I am exactly in the same situation but in a different country, however my problem is far worse, so maybe the folks can also comment on the idea i have in mind, it is madness that I dont even know if it works, but it might also work for you.

Adding to the above mentioned problems, when the building is tall story, have multi tenants, the roof space become small for everyone to benefit from dedicated solar system large enough to cater for the needs of all residents, in your case it can be yourself and your neighbour.

I was thinking about the below scenario and comments are welcomed please, as I dont know if it actually works or not and need to fill the holes in this concept.

1- Put as much solar panels as you can on your roof and your neighbor's
2- Install an On-Grid Inverter (comes cheaper than Hybrid) which is large enough to match the PV Panels; during sunhours the inverter will handle the electrical load
3- Connect the On-Grid inverter AC out to AC In on the Hybrid (I believe its called AC Coupling), mimicking a "Grid", and the extra energy rather than going to the Grid typically will charge the batteries since the Hybrid would think the Grid is on
4- When the sun set, the On-Grid Inverter shuts down, triggering the the Hybrid to kick in thinking Grid is down, and you will start utilizing from energy stored
5- Connect your neighbor's generator to the Hybrid as well to charge the batteries when they reach say 25%.

I dont know if this idea works, and am still exploring it.

In my case I also need to research Energy Meters with Quota so that tenants dont abuse battery storage kWh.

Goodluck

 

[pilotdrh]

I am exactly in the same situation but in a different country, however my problem is far worse, so maybe the folks can also comment on the idea i have in mind, it is madness that I dont even know if it works, but it might also work for you.

Adding to the above mentioned problems, when the building is tall story, have multi tenants, the roof space become small for everyone to benefit from dedicated solar system large enough to cater for the needs of all residents, in your case it can be yourself and your neighbour.

I was thinking about the below scenario and comments are welcomed please, as I dont know if it actually works or not and need to fill the holes in this concept.

1- Put as much solar panels as you can on your roof and your neighbor's
2- Install an On-Grid Inverter (comes cheaper than Hybrid) which is large enough to match the PV Panels; during sunhours the inverter will handle the electrical load
3- Connect the On-Grid inverter AC out to AC In on the Hybrid (I believe its called AC Coupling), mimicking a "Grid", and the extra energy rather than going to the Grid typically will charge the batteries since the Hybrid would think the Grid is on
4- When the sun set, the On-Grid Inverter shuts down, triggering the the Hybrid to kick in thinking Grid is down, and you will start utilizing from energy stored
5- Connect your neighbor's generator to the Hybrid as well to charge the batteries when they reach say 25%.

I dont know if this idea works, and am still exploring it.

In my case I also need to research Energy Meters with Quota so that tenants dont abuse battery storage kWh.

Goodluck

Why add in extra inefficiencies? Just use the hybrid. Use it for zero export or export and then use the batteries once the PV power drops down. This way you can also keep the grid as the backup for drained batteries.

 

[OffGridForGood]

Interesting to read the issues you face half way around the world from here, the points I feel I can comment on:
I have twin MMP Solar 6048's and am very happy with them. Watch for Stand-by consumption when you compare options.
AIO units like the MMP's have twin PV input so in the case of the 6048 they have two 80A solar inputs, but are limited to 145VDC which is at the low end of many other AIO inverter options, MPP have dedicated 230VAC units with much higher PV-inputs also available, but I have no experience with those, and can't comment further.
I have purchased 280Ahr cells (two sets of 16) and it is a bit of 'pay and pray' process not really knowing until they arrive what your getting. So far so good, I paid $85-90 USD per cell plus the shipping. Use a BT enabled BMS and you can monitor and change settings easily from anywhere.

 

[addieboy]

Not yet. There have been a few horror story threads about these two if I remember correctly... Here is one

Experience purchasing EVE304Ah cells from Amy Peng @ Shenzhen Qishou Technology

Good Morning Folks, Could someone share their experience purchasing cells from Amy Peng @ Shenzhen Qishou Technology? She quoted me EVE 304AH $118/pcs. promising Brand New Grade A cells with no swelling blah blah... I saw Andy from the Off Grid Garage purchasing from her and he was happy...

diysolarforum.com

How is the install going? I am also from Cebu, Philippines with a DIY system started just after the big typhoon that knocked out our grid for about 2 months. Good thing is I already purchased an MPP solar 5kw from Taiwan a few years back but didnt get the chance to install it until after the typhoon hit in December 2021. (Note: Only paid around $600 plus around $20 duties for it in 2021).

Inverter - MPP Solar 5kw off grid (MGK)
Panels - 9x540w Jinko Solar (locally available in Cebu)
Battery Bank - 32x280ah EVE 280k (available in Manila) for about P270k ($4800)
BMS - JK-BMS from alibaba but is already locally available here now.

Now, I got a DEYE 8kw hybrid (not installed yet) and curious about PowMR hybrid which is only around $600 for a 10kw inverter but only 1 MPPT. Might have to use 20x545w Canadian Solar (price down currently) with 2x10s