Planning an off-grid hybrid solar system

[JBChiangRai]

I think I got luck with my LiFePo4 batteries, I paid 80,000 baht for 28.8KwHrs.  My now deceased friend with a Chinese wife sourced them in China and sent them over "Thailand Special Line" duty free

[Encid]

I just discovered that SOFAR also manufacture LiFePO4 batteries... starting with the BTS E5~E20-DS5 (5kWh) which can be expanded by adding additional packs up to 20kWh.

 

Link

 

 

Does anyone have any experience with these or know any dealers here in Thailand?

 

[JBChiangRai]

I have changed my view on batteries for ESS, having taken delivery of an MG4 a week or so ago and got into the settings, and reading  posts on a forum in the UK.

 

I wouldn't buy an expensive battery or install a generator to cover PEA blackouts.  If I was to go down this route again I would simply use the V2L capability of an MG4 and wire it into the house circuit using an ATS (Automatic Transfer Switch), permanently plugging the V2L adaptor into the car and setting the discharge cutoff to something like 40% SoC.

 

Tests carried out in the UK suggest it will sustainably deliver 6.5Kw of power.

[Encid]

On 2/9/2023 at 5:07 PM, Encid said:

I just discovered that SOFAR also manufacture LiFePO4 batteries... starting with the BTS E5~E20-DS5 (5kWh) which can be expanded by adding additional packs up to 20kWh.

 

Link

 

Does anyone have any experience with these or know any dealers here in Thailand?

 

Bump!

 

I didn't get any answers to this so I am asking again.

 

I have no immediate plans to get an EV as our two ICE vehicles are relatively new, so V2L is not in the immediate picture.

 

It's getting closer to the time that I need to specify my system, and I need to find a compatible battery system...

 

2 x 10S strings of 340W panels (total 6.8kWp)

1 x Sofar HYD 5000 ES on-grid hybrid inverter (5kW) (PEA approved list)

2 x 5kWh batteries or maybe a single 10kWh battery

 

Any suggestions for suitable batteries?

[BritManToo]

23 minutes ago, Encid said:

Any suggestions for suitable batteries?

https://www.lazada.co.th/products/nmc-48v-218ah-1130kw-smart-bms-i4012666097-s15581149965.html

[Muhendis]

19 minutes ago, Encid said:

Any suggestions for suitable batteries?

I'm going for lead carbon gel batteries. 

https://www.hiteksolar.co.nz/blogs/news/106430214-why-should-i-consider-using-lead-carbon-batteries

https://link.springer.com/article/10.1007/s41918-022-00134-w

There are loads of scholarly articles about them, but briefly they are about the same as LiFePO4's life expectancy but a lot less expensive and don't require a BMS to look after them. They will charge very quickly but they are very heavy which isn't an issue for stationary batteries.  

[Encid]

Just now, BritManToo said:

https://www.lazada.co.th/products/nmc-48v-218ah-1130kw-smart-bms-i4012666097-s15581149965.html

Thank you.

A bit industrial looking but that's a very good price.

Just have to hide it behind a door... 

[Encid]

Just now, Muhendis said:

I'm going for lead carbon gel batteries. 

https://www.hiteksolar.co.nz/blogs/news/106430214-why-should-i-consider-using-lead-carbon-batteries

https://link.springer.com/article/10.1007/s41918-022-00134-w

There are loads of scholarly articles about them, but briefly they are about the same as LiFePO4's life expectancy but a lot less expensive and don't require a BMS to look after them. They will charge very quickly but they are very heavy which isn't an issue for stationary batteries.  

They certainly look good value for money too...

Have you found any distributors in Thailand yet?

[Muhendis]

I'm getting 12 of these direct from the factory.

They should be here in a couple of weeks.

https://www.cspbattery.com/hlc-series-fast-charge-long-life-lead-carbon-batteries-product/

[Muhendis]

6 minutes ago, Encid said:

Have you found any distributors in Thailand yet?

No. I am my own import-export agency which is a pain but doable.

I had to organise my own transport from Bangkok port. I will need to pay VAT for everything (about 8K) in order to release the duty free goods.

[JBChiangRai]

14 hours ago, Muhendis said:

No. I am my own import-export agency which is a pain but doable.

I had to organise my own transport from Bangkok port. I will need to pay VAT for everything (about 8K) in order to release the duty free goods.

If the price and freight totaled is more than 30,000 baht, you may need an import licence, sometimes customs apply it, sometimes they don't.

[Muhendis]

2 hours ago, JBChiangRai said:

If the price and freight totaled is more than 30,000 baht, you may need an import licence, sometimes customs apply it, sometimes they don't.

That doesn't make sense. I have done this a few times now. Always for my own personal use and never any problem.

It would help if you could send the link for the import license regulation.

[Crossy]

17 hours ago, Encid said:

Thank you.

A bit industrial looking but that's a very good price.

Just have to hide it behind a door... 

 

Do be aware that these are NMC batteries which is a flavour of lithium-ion rather than LiFePO4. I don't think I'd have these inside the house.

 

That said, our LiFePO4 packs are well outside the house too.

[Crossy]

17 hours ago, Muhendis said:

I'm going for lead carbon gel batteries. 

https://www.hiteksolar.co.nz/blogs/news/106430214-why-should-i-consider-using-lead-carbon-batteries

https://link.springer.com/article/10.1007/s41918-022-00134-w

There are loads of scholarly articles about them, but briefly they are about the same as LiFePO4's life expectancy but a lot less expensive and don't require a BMS to look after them. They will charge very quickly but they are very heavy which isn't an issue for stationary batteries.  

 

How much cheaper than LiFePO4 are these chaps?

[Muhendis]

2 minutes ago, Crossy said:

Do be aware that these are NMC batteries

Err. I thought I mentioned lead carbon which is genus lead acid.

 

1 minute ago, Crossy said:

How much cheaper than LiFePO4 are these chaps?

Depends if you are talking "power wall" or box of assorted bits n' pieces but generally 33% to 50% of a DIY jobby. 

[Crossy]

3 minutes ago, Muhendis said:

Err. I thought I mentioned lead carbon which is genus lead acid.

 

Yes, lead carbon are a type of lead acid, this I know.

 

I was responding to Encid's comment on these; -

 

https://www.lazada.co.th/products/nmc-48v-218ah-1130kw-smart-bms-i4012666097-s15581149965.html

[JBChiangRai]

35 minutes ago, Muhendis said:

That doesn't make sense. I have done this a few times now. Always for my own personal use and never any problem.

It would help if you could send the link for the import license regulation.

Speak to your customs agent/freight company here and see if it is required.  A certain order value or weight often triggers the process.

 

For me it involved registering to use the customs e-customs system.  I was bringing in ATV's and later parts, but in an individual not a company name.  It was about 12 years ago if I recall correctly.

 

Customs in Mae Sai were actually very helpful even though everything came through Laem Chabang.  As a further note, your registration expires after 12 months of disuse.

[JBChiangRai]

Further, I think if you are ordering multiple identical items, customs may consider they are not for personal use and then an import licence is needed.  It's entirely down to the customs officer on the day.

 

Wherever possible, I would recommend importing goods "Special Line" if it is available, I used it when I imported 32 LiFePo4 batteries of 272 AHr each from China, the freight rate is a little higher but no duty or VAT is payable at destination country and it sails through customs.

 

One of the issues you may face if your batteries are coming from Australia, is where they are made, because the FTA for Australia only applies to goods made (not assembled) in Australia, sometimes a COO (certificate of origin) is needed stating over a certain percentage of each item was made in Australia.

Edited April 20, 2023 by JBChiangRai

[unheard]

17 hours ago, Muhendis said:

I'm getting 12 of these direct from the factory.

They should be here in a couple of weeks.

https://www.cspbattery.com/hlc-series-fast-charge-long-life-lead-carbon-batteries-product/

Thanks for the link.

Never heard of that battery tech before.

It does sound like a very good value.

Please keep us posted.

[Encid]

2 hours ago, Crossy said:

 

Do be aware that these are NMC batteries which is a flavour of lithium-ion rather than LiFePO4. I don't think I'd have these inside the house.

 

That said, our LiFePO4 packs are well outside the house too.

Thanks for pointing that out... it does change my thinking on battery location for the Guest House.

 

Are yours in a temperature controlled environment Crossy?

 

For the start of our system I was planning to have the batteries outside but under cover where they (and the inverter) will not get wet or get any direct sunlight.

 

Later, (when we build our Main House and double the size of our PV array) I will probably have a temperature controlled room in the garage for all the kit.

[Pink7]

21 hours ago, BritManToo said:

https://www.lazada.co.th/products/nmc-48v-218ah-1130kw-smart-bms-i4012666097-s15581149965.html

This are new or used batteries?

 

Pink

[Crossy]

1 minute ago, Pink7 said:

This are new or used batteries?

 

I believe these are new NMC batteries.

[Pink7]

18 minutes ago, Crossy said:

 

I believe these are new NMC batteries.

Ok so its 52k for 218AH with BMS, just for price comparison I payed 140k for 2 x 280AH with 2 BMS. 

 

Pink

[Crossy]

3 minutes ago, Pink7 said:

Ok so its 52k for 218AH with BMS, just for price comparison I payed 140k for 2 x 280AH with 2 BMS. 

 

Do look at the cycle-life of NMC cells. It's rather less than LiFePO4, lower initial outlay but don't last as long.

[Crossy]

1 hour ago, Encid said:

Are yours in a temperature controlled environment Crossy?

 

Nope, we have LiFePO4 outside but very well shaded by the car port and a hedge.

 

At 14.30 the ambient in the shaded area is 39C battery temperature is 40.5C, we've just been banging 50A into the pack. Definitely a bit warm, but they are supposed to be OK up to 60C.

 

[Encid]

I have been looking at hybrid inverters, and am getting somewhat confused at times...

 

For example, from a Deye inverter datasheet:

 

 

 

The vendor says "the model give you a strong back up when no grid supply" and I can see that the 6K model does give a Max Continuous AC Passthrough of 40A, vs the Sofar 6K hybrid inverter's Max Output Current of 22.7A.

 

But what is confusing me in the datasheet excerpt above is the Max AC Output Current is 30/28.7A.

 

What is the difference?

 

Another observation on the datasheet excerpt above is that it doesn't give a Max Input Voltage figure, just a range from 125-500V.

Does that mean that the Max Input Voltage is 500V? 

 

According to the Sofar inverter datasheet the Max Input Voltage is 600V, so If I were to use 550W JA Solar mono panels (their Open Circuit Voltage (Voc) is 49.9V) I could install 2 strings of 6 panels (total Voc = 596), and 3300W per string x 2 = 6.6kW max PV array, which is under the max PV input which is 9kWp.

 

The Deye datasheet above shows a PV string max input power of 7800W, so with 2 MPPT's does that mean that the max PV input for the inverter is 15.6kWp?

 

Also it says that you can have 1+1 strings per MPPT, so with 2 MPPT's does that mean that you can connect 4 strings? (provided the total Voc per string is less than 500V and max PV power is less than 7800W per string).

 

It is sooo confusing... 

[driver52]

On 4/19/2023 at 11:14 AM, Muhendis said:

I'm getting 12 of these direct from the factory.

They should be here in a couple of weeks.

https://www.cspbattery.com/hlc-series-fast-charge-long-life-lead-carbon-batteries-product/

very interesting, how much did you pay for them? cheers

[Muhendis]

21 minutes ago, driver52 said:

very interesting, how much did you pay for them? cheers

118k Baht including transport to Bangkok Port. There will be a further VAT bill to come but, after contacting customs, they look like zero duty payable.

[driver52]

2 minutes ago, Muhendis said:

118k Baht including transport to Bangkok Port. There will be a further VAT bill to come but, after contacting customs, they look like zero duty payable.

cheers, how many watt/hours or whatever they call it are you hoping to get?

i'm trying to calculate how many I need to run say 250watt draw overnight, so say 12 hours which means I need 3kWh......ooh that sounds like a lot......maybe if I got my overnight usage down to 1kWh say, so 50% battery discharge I can get away with 2kw of batteries?

[Muhendis]

45 minutes ago, driver52 said:

cheers, how many watt/hours or whatever they call it are you hoping to get?

i'm trying to calculate how many I need to run say 250watt draw overnight, so say 12 hours which means I need 3kWh......ooh that sounds like a lot......maybe if I got my overnight usage down to 1kWh say, so 50% battery discharge I can get away with 2kw of batteries?

Each battery is 250Ah arranged in groups of four in series which, for the stringy fellows amongst us, is 3 parallel strings of 4 per string. Total Ah is therefore 750Ah which transforms to 36kWh. Aiming for 30% DoD we are looking at 10.8kWh at nominal 48V.