The start of my new 'Off grid' Solar install.

[007 RED]

On 3/20/2022 at 11:38 AM, BritManToo said:

Almost done ...... 9 panels about 3000w of solar, currently producing 1740w at 11:30am on a sunny day.

Hi @BritManToo,

 

Please don't take this personally, but I have to agree with @Eff1n2ret that the output from your 9 PVs is not very impressive.  According to your info, they were only producing 1740w when the sun would almost be at its highest point and, therefore, only producing about 58% of their potential output. 

 

I appreciate that you don't have your panels angled, but a 42% loss in efficiency is somewhat worrying as one would normally anticipate a maximum potential efficiency loss of around 25% due to heat, shading etc.  If I was in your 'shoes' I would be looking to try and figure out how to improve the PVs output efficiency.

 

My 4 x 415W half-cut monos are currently producing 1.23kW (at 13:02pm), which equates to approximately 74% output efficiency, and the system has produced 3.06 units this morning, as may be seen from the monitoring output graph below.

 

FYI... The big dip in output between approximately 10:30am and 12:30pm is due to me turning the NO EXPORT function on because my better half and I went shopping and we are expecting the local PEA to come any day soon to connect the new house opposite to the power pole which has our meter on it.  I've became a bit paranoid after my near brush with the meter reader coming early last month.

 

FYI.... On the 29th my system peaked at 1.43kW (at 12:19pm) and produced a record 9.16 units that day.  Again, I need to be careful that I regularly monitor the system to ensure I don't end up with a negative meter reading.

 

PS.... Good luck with your battery project.  I hope you get it sorted.

[BritManToo]

1 hour ago, 007 RED said:

If I was in your 'shoes' I would be looking to try and figure out how to improve the PVs output efficiency.

Not much point as I am now generating more power than I can store.

By 1:30-2pm the battery is full and the inverter is stepping down the power to just what I am using. Then at 3pm the solar panels are in shadow and just produce 300-500w until 5pm when the light has gone.

 

 

Before the heavy smog hit I was peaking at 2.25kW.

But again, by 12:30pm I had nowhere to store the extra power.

 

[007 RED]

2 hours ago, BritManToo said:

Not much point as I am now generating more power than I can store.

By 1:30-2pm the battery is full and the inverter is stepping down the power to just what I am using. Then at 3pm the solar panels are in shadow and just produce 300-500w until 5pm when the light has gone.

OK, I see your logic. 

 

If I recall correctly, you have split your home circuit into two, one running the heavy load equipment (AC, fridge etc) and the other your lower power equipment (computer, HiFi, TV etc), with your inverter and batteries connected to the lower power circuit only.  Is there any way of you being able to 'dump' any excess power beck to the grid which can then be used by the higher power appliances?

[BritManToo]

8 minutes ago, 007 RED said:

OK, I see your logic. 

 

If I recall correctly, you have split your home circuit into two, one running the heavy load equipment (AC, fridge etc) and the other your lower power equipment (computer, HiFi, TV etc), with your inverter and batteries connected to the lower power circuit only.  Is there any way of you being able to 'dump' any excess power beck to the grid which can then be used by the higher power appliances?

I suspect my grid consumption will be down to 40-70 units by next month.

It's only the air-con, water heater and the oven left on the grid now.

 

Probably not a good idea to try and go any lower.

[BritManToo]

Started building a 48V 100Ah battery using 16 second hand Sinopoly 100AH batteries. 8 arrived slightly swollen, 8 to come.

Found a teak box on Lazada that just about fits them for 170bht.

Decided to use washers and 2.5mm wire loops in place of bus bars to save money, 3 loops = 16A x 6 = 96A. Enough room in the box to put the Daly BMS in with the batteries.

 

[BritManToo]

On 3/31/2022 at 2:22 PM, 007 RED said:

Please don't take this personally, but I have to agree with @Eff1n2ret that the output from your 9 PVs is not very impressive.  According to your info, they were only producing 1740w when the sun would almost be at its highest point and, therefore, only producing about 58% of their potential output. 

Now the smog has been washed out of the air, I'm getting a lot more, even though the sky isn't blue (midday today).

 

[worgeordie]

None of you Solar Lads  make full use of the Sun ,

and have solar water heating, ? it would save some of

your stored electric for use  with say A/c , 

 

I know nothing really about Solar electricity * , just basically

how it works, but I have had Solar water heating for about

30 years , and it's been great , expensive at the time ,but

it's paid for itself , and just having water in bathrooms and

kitchens is great , plus not having water and electricity  mix,

the number of water heaters I have gone through over the

years in our rental properties, quite a few.

 

Late last year had  tenant call , shower water heater leaking,

so I go around , he said it keeps tripping off , so I just keep it

pressed in with my finger while I shower !!!!! , 

*at 76 too old to start now, that and Bitcoin.........????

Regards Worgeordie

[Muhendis]

7 minutes ago, worgeordie said:

None of you Solar Lads  make full use of the Sun ,

and have solar water heating, ? it would save some of

your stored electric for use  with say A/c , 

 

I know nothing really about Solar electricity * , just basically

how it works, but I have had Solar water heating for about

30 years , and it's been great , expensive at the time ,but

it's paid for itself , and just having water in bathrooms and

kitchens is great , plus not having water and electricity  mix,

the number of water heaters I have gone through over the

years in our rental properties, quite a few.

 

Late last year had  tenant call , shower water heater leaking,

so I go around , he said it keeps tripping off , so I just keep it

pressed in with my finger while I shower !!!!! , 

*at 76 too old to start now, that and Bitcoin.........????

Regards Worgeordie

I made myself a flat panel solar water heater and brought it with me from UK. It's about 1 m² and has given excellent service for the past 10 years. Circulating pump is powered from a small solar panel and water is stored in a 200 litre insulated tank. Hot showers for all in the evening but only warm water left for the morning. At 76 you should be only just beginning. Well done.

[BritManToo]

On 4/3/2022 at 1:50 PM, worgeordie said:

None of you Solar Lads  make full use of the Sun ,

and have solar water heating, ? it would save some of

your stored electric for use  with say A/c , 

We don't really use water heating except for the kettle.

Cold showers are good for you.

[KhunLA]

On 4/3/2022 at 1:50 PM, worgeordie said:

None of you Solar Lads  make full use of the Sun ,

and have solar water heating, ? it would save some of

your stored electric for use  with say A/c , 

If I want solar heated water, all that is needed is a steel tank, as having in the past.  Got so hot sometimes, I had turn the cold on to cool it down a bit.  Simple & inexpensive.  Don't even need a pump, and gravity fed, providing good water pressure.

 

[Sophon]

A quick search turned up 345W poly panels for around 3,200 Baht and 450W mono panels for around 4,200 Baht. On a per watt base that is close to being equally priced. Any reason to go for one panel over the other?

 

At the same per watt price my initial reaction would be to go for the 450W panels, where 9 panels should theoretically produce about the same a 12 345W panels and would take up less space.

[BritManToo]

Today's efforts .........

New battery pack finished and charged.

The two -ve terminals out of the BMS will bolt together (middle bottom).

The +ve needed a strap (left of frame), made from 4x 4mm wires and a couple of crimp  connectors.

I'm assuming the 4mm wire is good for at least 25A so 4x 25 = 100A.

 

Waiting for the sun to go down to bolt them together, I'll turn off one BMS charge and discharge in the phone app when I do it, so I can switch between battery packs in the app.

 

 

[BritManToo]

2 minutes ago, Sophon said:

A quick search turned up 345W poly panels for around 3,200 Baht and 450W mono panels for around 4,200 Baht. On a per watt base that is close to being equally priced. Any reason to go for one panel over the other?

Mono usually give more watts for your buck.

I suspect the 345w poly for 3,200bht don't actually exist, more like 3,600 inc delivery at the moment.

[Sophon]

4 minutes ago, BritManToo said:

Mono usually give more watts for your buck.

I suspect the 345w poly for 3,200bht don't actually exist, more like 3,600 inc delivery at the moment.

It's possible, but it is a fairly highly rated seller and there are five star reviews of buyers of the panel within the last week.

[BritManToo]

6 minutes ago, Sophon said:

It's possible, but it is a fairly highly rated seller and there are five star reviews of buyers of the panel within the last week.

Yes, I've had 4 from them recently ........ 3,200 +240bht each post = 3,450.

I also had another order with them cancelled after a week 'out of stock'.

Not entirely reliable, but the only game in town at the moment.

[Muhendis]

47 minutes ago, Sophon said:

A quick search turned up 345W poly panels for around 3,200 Baht and 450W mono panels for around 4,200 Baht. On a per watt base that is close to being equally priced. Any reason to go for one panel over the other?

 

At the same per watt price my initial reaction would be to go for the 450W panels, where 9 panels should theoretically produce about the same a 12 345W panels and would take up less space.

Take a look at the spec. and in particular the weight of the respective panels. Then ask yourself how many big strong helpers you have available.

Bigger wattage panels should take a bit less space but will need more manpower to mount.

[Crossy]

On 4/2/2022 at 9:31 AM, BritManToo said:

Started building a 48V 100Ah battery using 16 second hand Sinopoly 100AH batteries. 8 arrived slightly swollen, 8 to come.

Found a teak box on Lazada that just about fits them for 170bht.

Decided to use washers and 2.5mm wire loops in place of bus bars to save money, 3 loops = 16A x 6 = 96A. Enough room in the box to put the Daly BMS in with the batteries.

 

How are the green cells performing??

 

[BritManToo]

43 minutes ago, Crossy said:

How are the green cells performing??

Not that great ......... out of the 16, one is high, 3 are low.

I've ordered another 4 so I can try to match the 16 cells.

I've also bought a 4 cell 5A capacitor balance (500bht), no need to balance 16 cells, I think I can just put the best and worst next to each other in the pack and just put a balance across them.

 

But the good news,

I now have enough storage to last 2 nights and a day in-between with no sun (lots of rain and cloud here). Today, my batteries were full by mid-day and I still had enough spare to cook lunch and run 2 computers and TVs most of the day.

[Sophon]

If you were to do it again would you still go for used batteries, or would you buy new batteries (like the one you mentioned in your OP)? 

[Crossy]

24 minutes ago, Sophon said:

If you were to do it again would you still go for used batteries, or would you buy new batteries (like the one you mentioned in your OP)? 

 

For me, even with the capacity we are getting, we are still ahead of the game compared with "known" new cells of the same capacity. Very approximate measurement (I've still not commissioned my accurate coulomb-counter) is that the "200Ah" cells are doing about 134Ah running to the "knee" on charge and discharge (10% to 90% ish).

 

It remains to be seen how many cycles we get before the cells are so worn they're not worth using. I'll probably just keep adding parallel packs until I run out of space. And, of course, lithium cells are re-cycleable (just not yet in LoS).

 

Still comparable with lead-acid and no maintenance.

 

[Crossy]

For a new/used price comparison you can get new EVE 105Ah LiFePO4 cells from Shenzhen Luyuan Technology Co., Ltd. on AliBaba for USD 60 a piece plus shipping (pack of 4). 

https://www.alibaba.com/product-detail/4pcs-EVE-105AH-LiFePO4-LFP-3_1600191337976.html

 

Shipping would probably be another USD 100 on 4 of them, then add duty at 10% and 7% VAT (both on the CIF value).

 

Looking at other solar energy fora Shenzhen Luyuan Technology Co., Ltd. have a good reputation for actually supplying what they say they will.

 

Compare that with the used 200Ah cells at USD 44 each, free shipping and no duty / vat.

 

You make your choices and pay your money. If you have the coin to drop then new of course, but for those of us who are poor...

 

Just under 3 Grand US ++ for a new 300Ah x 48V pack, time to start putting my 1Baht coins in a jar ???? 

 

EDIT To add to the mix - 200Ah deep-cycle lead acid are coming in at around 8,500 Baht (USD250 today) - If you get an equivalent life out of the used cells you're still ahead.

 

Decisions, decisions!!

 

[BritManToo]

17 hours ago, Sophon said:

If you were to do it again would you still go for used batteries, or would you buy new batteries (like the one you mentioned in your OP)? 

If I did it again I'd have purchased the battery pack in my OP.

Although I've learned a bit about building battery packs, an it hasn't cost me any more, so it wasn't a completely wasted experience.

[BritManToo]

1 hour ago, Crossy said:

EVE 105Ah LiFePO4 cells from Shenzhen Luyuan Technology Co., Ltd. on AliBaba for USD 60 a piece plus shipping (pack of 4). 

Compare that with the used 200Ah cells at USD 44 each, free shipping and no duty / vat.

I was paying $22-$24 inc for the used Sinopoly green 100AH batteries.

Had to buy 20 (15kbht) to get a decent 48V 16s 100AH matched pack.

 

I was paying $44 inc ffor the CALB blue 200AH batteries.

Had to buy 18 (27kbht) to get a decent 48V 16s 200AH matched pack.

 

I think the 2nd hand 100AH batteries are the way to go, if money is tight, as you can just add more in parallel later to your existing BMS to make a 'powerwall', and you can also team up the worst batteries you get stuck with the best to get reasonable pairs.

[KhunLA]

Having the knowledge and being able to is really good.  But ... since knowing I'm going solar, been following Will Prowse on YT, for way too long, and from DIY money saving, to a bit cheaper, to now, why bother, the packs have come way down in price, and way up in quality.  Along with actually being available.

 

Was the same with drones early on, as I built my own, better and cheaper, to now, I can't even get close to 'competing' with the quality, features for the price.

 

Even DIY system, to having an installer do everything.  Pricing the components, vs an installer, and it really isn't worth my effort to try.  Competition is a beautiful thing, and prices across the whole industry have dropped considerably.

 

Thank you China. 

 

Feel sorry, almost, for those stuck far away from China, as in the USA, and solar system pricing is still silly, even with govt incentives.  Much of that probably due to labor cost and regulations.

[BritManToo]

8 minutes ago, KhunLA said:

the packs have come way down in price, and way up in quality.  Along with actually being available.

Not in Thailand, and you don't know if the batteries going into those packs are new, rejects or 2nd hand. 

[Crossy]

17 minutes ago, KhunLA said:

Will Prowse on YT

 

Yeah, Will produces a load of great content, I assume you are aware of his forum.

 

There's a couple of good threads on there discussing DIY vs OTS (Off The Shelf) packs, plenty of, er, lively, discussion.

 

Of course it's invariably from a US based perspective, things are a bit different here.

 

[KhunLA]

8 minutes ago, BritManToo said:

Not in Thailand, and you don't know if the batteries going into those packs are new, rejects or 2nd hand. 

I would only go with name brand packs; BYD, SOLAX, Jakiper

[BritManToo]

36 minutes ago, KhunLA said:

I would only go with name brand packs; BYD, SOLAX, Jakiper

None available in Thailand as far as I can see.

Also the DIYSolarforum Crossy mentioned are US based, prices and availability are way different in Thailand. They estimate $245 per 1kWhr of storage (USA), I've paid around $150 per 1kWhr of usable storage (Thailand).

 

Here is a BYD pack 24V @ 200AH(no BMS) for 25,000bht (add BMS 4kbht).

https://www.lazada.co.th/products/byd-lifepo4-byd-1p8s-24v-200ah-bms-i3331661657-s12364925493.html

 

Doesn't look new to me.

But at best 200 x 24 = 4.8kWhr -20% (cos you can only use 10% to 90%) = 4kWhr of usable storage at best new condition. Works out at $240 per 1kWhr of usable storage.

 

Then you've got the Must powerwall at 75,000bht

https://www.lazada.co.th/products/must-10kwh-ess-tesla-powerwall-48v-200ah-lifepo4-battery-hybrid-grid-home-solar-energy-storage-system-i2777108044-s10101632895.html

 

This one is new, but 48v @ 200AH = 9.6kWhr (-20% you can't use = 7.6kWhr).

That's $310 per 1kWhr of usable storage.

 

[Crossy]

Those BYD packs look interesting, my major worry is that the cells are welded so it's "less than easy" to replace a failed cell.

 

 

The green 100Ah used cells do seem to be the best value at present, 200Ah ones seem to be running out of stock / prices going up.

 

[SomchaiDIY]

Second hand cell can be big saving if user handling of pack is good and cell purchase is not cheating with dead cell

 

I see many second hand cell pack with user trying get capacity maybe not good for the pack life or balance

 

I think pack made with second hand cell can require the careful setting of charge range

 

Pack of second hand cell can give happy life if settings adjusted to suit pack condition

 

Having tech knowledge to make custom bms setting and charge state calculation is big advantage for second hand cell pack owner

 

Some diy bms system available have custom setting and high balance current to help pack with not very equal cell group

 

 

mr roland has the large second hand lifepo4 pack where pack has custom charge state monitor and setting to avoid stress of used cell pack

 

Battery pack video link

 

https://www.youtube.com/watch?v=Xpom9DagCME