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Batteries and charger for SUN-2000G
#1
Hello,
At moment I have solar panels connected directly to SUN-2000G, but I would like to add li-ion batteries to setup.

My problem is that I do not understand how to setup this.
SUN-2000G accepts voltage range from 45-90V as specified in specification, this, I should use more than "standard" 48V setup of batteries, which I understand is 14S.
Calculations show I should use at least 16S so my minimum battery voltage would be larger than 45V.
This is sort of clear.
But, now comes question about charger.
Which charger can charge batteries properly in 16S total combination?
Most chargers are rated with 48V output.
Do you have some suggestion what to use?
Would even this charger work?

Please help me with clarifying this setup.

Thank you
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#2
U need to research and choose a charger that charges to the voltages that u want and the charger needs to have adjustable parameters so u can charge lithium.. there chargers that can charge a 16s battery pack.. outback and midnite are a few
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#3
You're talking about this grid tie inverter with limiter, right?
http://s.click.aliexpress.com/e/pYX1jfvO

It's hard to say without knowing all the details, but something like the ESmart3 charger with a 14s Lithium Ion setup should work just fine.

The ESmart3 ( http://s.click.aliexpress.com/e/36sMXzck ) can handle PV input up to 150V, and charge the 14s battery to eg. 4.10V * 14cells = 57.4V. You might want to stop at 4.05v to increase lithium cell life.
The SUN-2000G can discharge the cells down to 45V, which is 3.21v * 14cells. This is a good voltage to stop discharging... probably better to stop at 3.3v or even 3.4v, again to maximize the number of cycles you can get out of your battery.
Modular PowerShelf using 3D printed packs.  40kWh and growing.
https://secondlifestorage.com/showthread.php?tid=6458
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#4
Great, thank you very much. I was looking to find similar setup, but I did not find some that all elements references so I can at least see what I need.

(10-10-2019, 11:08 AM)ajw22 Wrote: You're talking about this grid tie inverter with limiter, right?
http://s.click.aliexpress.com/e/pYX1jfvO

It's hard to say without knowing all the details, but something like the ESmart3 charger with a 14s Lithium Ion setup should work just fine.

The ESmart3 ( http://s.click.aliexpress.com/e/36sMXzck ) can handle PV input up to 150V, and charge the 14s battery to eg. 4.10V * 14cells = 57.4V. You might want to stop at 4.05v to increase lithium cell life.
The SUN-2000G can discharge the cells down to 45V, which is 3.21v * 14cells. This is a good voltage to stop discharging... probably better to stop at 3.3v or even 3.4v, again to maximize the number of cycles you can get out of your battery.

Yes, this is correct inverter (original site):
https://www.ev-power.eu/GridFree-Inverte...5-90V.html

I get your point, to have less capacity, but more life on batteries.
I will check also this approach. I knew about this but somehow I wanted to limit this by software, and not hardware.

Thank you for response and pointers where to look further.
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#5
Ajw, I own 2 of those inverters.. they stop producing any kind of power at like 50v, not 45v.. and anywhere close 50v the inverter will only produce a very small amount of power.. this is why I’m using 16s li-ion battery which puts the operating voltage of these inverters just slightly below half.. these inverters should be operated at 72-80v optimally to produce anywhere close to 1800w..
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#6
@ doin it
With 72-80v optimally you mean the solar panels?
And you must need a 16s instead of 14s to get the proper volt to let the device operate?

What i find funny is: the ones from China dont ship to the Netherlands and operate off grid.
The ones that ev is selling can only operate if it is grid connected, and those do ship to the Netherlands.

I think the solution is very simple, connect a smaller (car) inverter that will produce 220v to fool the bigger inverter?

As far for the operation to go back to the subject: instead connecting it to the solar panels connect it to the battery.
Charge the battery with a mppt charger and you are done, of course don't forget the dc switches....?

Probably some stupid questions, but hoping for a answer for myself and smarky
Thanks in advance
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#7
Hunter that’s the optimal battery voltage if using batteries and the optimal solar panel voltage if u are using straight solar (no battery) with solar panels I wouldn’t go over 72v due to the panels producing more voltage when they are cold, definitely don’t want the panels to go over 90v
It will operate with a 48v lead acid or less than 16s.. but supplying these inverters with voltages at the lower end of its operating voltage will cut back the max watts that can be produced..
example 64v 20amps=1280w inverter can supply max
50v 20amps=1000w inverter can supply max, but at lower end operating voltage the inverter just doesn’t operate very well, lucky to produce that 1000w. like it’s screaming for more voltage.. also using higher voltage with keep the amps lower..
Tricking the inverter with a smaller inverter has been done but is not recommended.. I forget why but I was convinced enough not to do it.. if a person wanted offgrid option aswell then they could just divert battery power to an offgrid power inverter when needed... the sun gtil2 has anti islanding so it shuts off when grid power is down to not kill someone working on the power lines
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#8
I like the old video's where the guy is thrown off a powerpost...i don't want that to happen in real life.

If i would go with a plain inverter from Victron and there "transfer switch" its all going to be safe right?
Or must it be a completely separated system?

https://stroomwinkel.nl/omvormer-lader/o...-230v.html

Its based on a relay, one of the two sides holds power.
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#9
Hello,
Thank you for suggestions and references.
I have decided to go with 20S48P for start.
This should be sufficient for my initial setup.

Thx
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