solar system

[Hans Zurne]

Hello
I Live in New Zealand and i just bought a property, i got a quote from the power board to bring power onto my place, for about halve the money i can buy a 10 Kw solar system in China from Huaya
the system is 96 volt has 28 panels 360 w , a combiner ,controller , inverter and 16 200 A/H 12 v gel batteries.
I do not have much experience with solar power, What do you people think ?is 10 KW good for an average house ? gel batteries from China , any good ?
The reason i went to Huaya is, that i have had dealings with them before and they where always good and reliable so i think i can trust them .
It is still a lot of money ,about USD 9500 fob , so, What do you people think ? is this worth buying ?
any comments ?
Kind regards.
Hans

[Rob Beckers]

Hi Hans,

Welcome to the forum!

I would advice extreme caution regarding Chinese products. Some is very good; we sell EP Solar charge controllers by the hundreds and I can still count the number of failed ones on one hand. Much is VERY bad. Warranty is generally non-existent, even for the better brands (somehow warranty is just not a Chinese business concept, it's all about the sale, and once that's done you're on your own).

Also keep in mind that off-grid systems outside of China tend to be 12/24/48 Volt. In fact code makes anything above 48V difficult in many places (and dangerous!). So if you need to meet code, or ever need replacement parts that are not Chinese, using 96V could paint yourself in a corner.

For what it's worth..

-RoB-

[Ralph Day]

Hi Rob
Are EPsolar controllers small units, like for sheds, rv's and such?

Ralph

[Rob Beckers]

Ralph, mostly yes, they are 10 ... 60 Amp. While they work well, they don't meet Canadian electrical code: They are not CSA listed, and do not have AFCI or GFCI (required over here). For a simple cottage system that is not going to get inspected they are great though.

-RoB-

[Hans Zurne]

Thanks Rob, I will do some more home work and will stick to 48 volt, do you have any experience with
gel batteries from China ?
i will let the forum know what i buy and how it is going.
Thanks again and kind regards hans

[Amin saleh]

Hi Hans,

Welcome to the forum!

I would advice extreme caution regarding Chinese products. Some is very good; we sell EP Solar charge controllers by the hundreds and I can still count the number of failed ones on one hand. Much is VERY bad. Warranty is generally non-existent, even for the better brands (somehow warranty is just not a Chinese business concept, it's all about the sale, and once that's done you're on your own).

Also keep in mind that off-grid systems outside of China tend to be 12/24/48 Volt. In fact code makes anything above 48V difficult in many places (and dangerous!). So if you need to meet code, or ever need replacement parts that are not Chinese, using 96V could paint yourself in a corner.

For what it's worth..

-RoB-

Yes I agree with you, one should be careful when buying products like [Admin: Gratuitous backlink removed] solar system for home products from China. while there are many good suppliers, there are also bad ones. It it recommended to start with a few orders first or visit the supplier or use third party helper.

[Laxman Sarthi]

Usually gel batteries are good than AGM. They are good for projects that need a very slow deep discharge. Still whenyou buy it from China, you need to check the quality.

[Hans Zurne]

Hi there
A while ago i asked this forum advise about a solar system i was going to buy.
I decided that a 48 volt system was probably best for me
So, i installed 28 panels 380 W , 2 100 Amp charge controllers , 1 10KW inverter , 24 2 V AGM batteries 1000 A hours , everything i bought in China .
The system is up and running for about 3 month now and up to now it works fine.although we do not live there yet
This system has to provide power for everything , cooking ,fridge , freezer , hot water, heating etc
the heating is water pipes in 100 square meters concrete floor warmed up by inverter heat pump ,this works real good and uses not much power.
I can see that the battery bank is may be not big enough, but it has to do., and the climate here is good for solar , most days we make plenty of power.
one thing that annoy me is the noise the cooling fans make, the controllers have two fans each , and they go almost all the time, and they go not because they run hot but because a lot of power is being made , i will try to slow the fans down to about half speed and see what happens.
The inverter is quite noisy to, and i am going to build an other one , I have a big 20 KVA transformer 26 volt in and 220 volt out and i have ordered a 12 KW mother board in China for the new inverter.
The transformer is about 110 KG . Would this transformer not be to big ? Would it use more power ?
and it will not need a cooling fan i hope ? Is there somebody who can advise me ?
Thank you

[Rob Beckers]

Hi Hans,

Since you mention building an inverter; are you following a recipe such as the OzInverter (https://levivray.com/new-book--make-a-6kw-inverter.php)? It uses a Chinese controller board, but much more robust transformer and power electronics.

For a 12kW inverter a 100kg transformer sounds a little on the high side, but is not too far off... I've not build my own inverters (should be interesting though!) but that is from looking at the weight of various good transformer-based inverters that I'm familiar with, where 90+% of the inverter weight is the actual transformer. Larger transformers will have higher standby losses though. How much will depend on the quality of that transformer (and on the power electronics, how efficient the switching of the H-bridge is handled).

There are sizing rules that we've learned over the years when it comes to panels, inverters, and battery banks. I've written some of it down (https://www.solacity.com/how-to-size-a-solar-system-that-really-works/), in case you're interested. The essence is that the solar panels need to bring in as much energy as you're using per average day (after taking losses into account). The batteries are generally sized for 3 days of 'autonomy', that assumes nothing is coming in, and that means for our winters that you still need a generator to pick up the slack in winter at times. The inverter is sized to just cover the maximum loads that are assumed to be used concurrently, and that's the easiest one of the bunch.

-RoB-

[Glen Johnson]

just a suggestion too, Not sure about your side of the pond but if you can get your hands on a forklift battery, over here in Australia you can get a 600-700 ah ( 5 hr rate ) delivered with 5 year warranty for about 6 grand.. FLA are much more forgiving than gel/agm IMHO,

being the 5hr rate, and taking in the peukert rule, solar is incredibly easy on them even under "heavy loads" .. usually have a central watering system and all..


also as many on here know, i built my own inverter based around OZTULES suggestions and design, using the EG8010 chip as the " brains " ... incredibly robust but not for everyone... if you need do some research...

[Hans Zurne]

Hello
Thanks Rob and Glen for the replies
I have enough panels on the roof to fully charge the batteries most days
But on real dark days the batteries will not last 2 days , fortunately we do not have many of them
and i have a good ( Chinese ) generator
Hope my agm batteries will last a long time , it is hard for me to estimate the % of discharge , i do not let them go under 48 volt , is this all right ? is this about 50 % ?
I will read up more about inverter building , it seems straight fore wards to me , but i might run into all sorts of problems.
Also I will try to find a DC volt meter with an adjustable switch , so that , if the batteries go under say 50 volt some things will turn off automatic , has anybody experience with this ? are there other ways to achieve this ?
Hope i get some new ideas
Cheers
Hans

[Glen Johnson]

it is incredibly difficult too determine SOC with lead acid by voltage alone... basically, if it has ANY load on it, it will be wrong..

AU $47.93 17%OFF | VAT4300 DC400V 300A Wireless Connect Digital Voltage Current Watt Power capacity Digital Combo Meter Tester Dropshipping

https://a.aliexpress.com/_mqxfPA6

try one of these, they measure bidirectional current, tell you soc, ah used etc... also wireless or wired ...

if you need more range, it uses a common nrf24l01 module, so replacing it with one, with a " amplifier " for about 10 bucks... ive run it to a shed about 300 meters away...but not needed if the shorter range ok...

[Glen Johnson]

also, I have around 1100ah ( 550 usable ) and it regularly gets " under 48v " ..the batteries are in excellent condition etc... and I use about 30-40 % out of em every night

just to give you an idea....

[Hans Zurne]

Thanks Glen
I will buy one of those combo meters