10 Kw Goodwe EHB inverter with 5 x Pylontech 3.55 kWh  Powercube High voltage batteries. 10 x 385W JA solar panels.

5 Kw Goodwe Es inverter with 8 x Dyness 2.4 kWh Low Voltage batteries. 20 x 340W JA Solar panels.

Only 10Kw inverter connected to the grid. Everything else is essential load to the 10kw inverter.

The inverters are technically in series.

Looks great! Curious why did you choose Goodwe over other brands? What benefit do you get using the Goodwe?

Great quality product. Just a shame the technical after sales service is not that great, but they are trying there best to help where they can.

I upgraded to the 10Kw EHB inverter which is a high voltage inverter on the battery side. If you have 5 batteries you dc input is 250V. If you have 9 batteries your input DC voltage is 432V. That makes for a much more efficient system. P=I x V. I currently don't know of any other high voltage inverter manufacturer available in SA. Everybody thinks the 48V inverters are the best, but they are not. They are the most popular but not the most efficient.

If you draw 5000W from the inverter at 48V, your current is 104 Amp. If your battery voltage is 432 V, your current is 11,5 Amp. This in return equates to less energy loss (less heat generated) and your inverter components are smaller. Its the way to go. All the electric car manufacturers battery architecture is between 400V - 800V. Makes much more sense than staying on 48V batteries. 

8 minutes ago, FuzzyBullets said:

That makes for a much more efficient system.

Not really, just makes for thinner conductors, as it is you are putting 48V batteries in series to get to the higher voltage, is there a mechanism in place that balances these 48V batteries? Either way, for most households 48V is fine since mostly the power usage doesn't stay at high levels for too much time, when running off batteries and on our end, we don't run the kettle at night or any other high usage consumers... can't afford the battery capacity for this... our 8k2W battery lasts the night still at anywhere between 20% and 33% charge remaining by the time the solar panels wake up and generate a few W the next morning.

If you want a true high tension system, then you'd need a BMS that allows for..... 240*1.414/3.2=lets call it 105 Cells in series so a 105S BMS and go and make your own, but not too many inverters out there that would be happy with a 389V peak battery for home use... at a reasonable cost, from what I can see... but hey, I'm happy with my 48V setup and happy to limit my current to 25A for now, which we never reach overnight.

There is a level 2 BMS on these battery packs.

Here is some technical specs on the inverter.

 

5 hours ago, Kalahari Meerkat said:

Not really, just makes for thinner conductors,

No, it does work out more efficient, but not for all the reasons listed. There are a lot of tradeoffs - higher voltage switching devices might have a lot more switching losses, depending on topology, and also higher resistive losses (for the same order of magnitude of price).

But the biggest advantage is that the lower current lowers copper losses a lot. You can use much smaller inductors, which need shorter copper paths and with losses being the proportional to I² and R, it makes a big impact. So it can work out a lot more efficient and smaller if you design carefully. The EHB is a very nice design, the biggest issue I have with it is that you cannot parallel them.

 

PS, those are high voltage batteries - you cannot put normal 48V batteries in series, the BMS MOSFETs will blow on the first one that disconnects.

Edited August 11, 20224 yr by P1000

47 minutes ago, P1000 said:

No, it does work out more efficient, but not for all the reasons listed.

since

6 hours ago, FuzzyBullets said:

P=I x V.

the higher efficiency, would have to be marginal and measured in "basis points" ie. less than 1% more efficient for the HV vs the 48V systems, I'd think, but will be happy to have my  opinion proven wrong...

My main hobby, traditionally uses equipment that uses "valves" aka. "vacuum tubes" and the higher voltages around these is off-putting, so I stick with the lower voltage semi-conductors rather, nothing like getting bitten by a 5kV capacitor (or dog forbid the PSU still running), when you're not paying attention... or the coffee hasn't helped you out yet...

Either way, I still think if the need is there for 200+V batteries, then they should be done properly and not this half baked, lets add a bunch of 48V modules together, even if they have been changed to try and prevent things from letting out the magic smoke... how do you know these cells ever get balanced properly over all the separate 48V modules? I reckon a single large bank is likely a betterer solution, but also potentially lethal and problematic... don't like these HT DC things...

I remember seeing some APC UPSes some while back that had a boatload of SLA 12V batteries in series, I think it was 24, maybe, either way, 200+V DC, good for keeping the cabling dimensions in check, when you're trying to supply 10+kW, but for most home inverter installations, we hardly ever need that kind of power sustained over any length of time.... as an example look at my batteries graph for the last 12 hours, one major peak charging the battery, for not very long before the values look a lot more reasonable... that peak was 48-odd Ampere for less than 10 minutes... maybe this household is an exception and the rule is a lot higher current to the battery on average, in which case, a higher tension battery would make sense, but I suspect our usage is average and yes, sure for the 50 to 100Ampere potential draw you'd need appropriately thick cabling (and keep it short...), but that's not too problematic vs the more lethal 200+V DC cabling the HT batteries would run with...

Edited August 11, 20224 yr by Kalahari Meerkat

2 hours ago, Kalahari Meerkat said:

Either way, I still think if the need is there for 200+V batteries, then they should be done properly and not this half baked, lets add a bunch of 48V modules together, even if they have been changed to try and prevent things from letting out the magic smoke... how do you know these cells ever get balanced properly over all the separate 48V modules?

The Powecube H2 he has bought is specifically designed as a High Voltage System and comes with an external BMS to balance the individual batteries.  This is clearly stated in his post above.

IIRC the Solax brand also make a HV battery inverter.

85-400V DC from battery.

3 hours ago, Kalahari Meerkat said:

 not this half baked, lets add a bunch of 48V modules together,

Yeah, that is clearly not what's going on here. But it looks like someone might be half-baked 🤪.

1 hour ago, P1000 said:

Yeah, that is clearly not what's going on here. But it looks like someone might be half-baked 🤪.

Yes blame Eskom. It's LS. 🤔

Very nice setup, what are those LCD displays in the trunking ? Volt meters ?

Pardon my ignorance, but what's the benefit in combining the HV and LV inverters? That should negate the benefit of using HV (less copper, less losses, etc.).

How is this system better than just using a 12kW Sunsynk with a big 48V battery bank?

1 hour ago, GreenFields said:

Pardon my ignorance, but what's the benefit in combining the HV and LV inverters? That should negate the benefit of using HV (less copper, less losses, etc.).

How is this system better than just using a 12kW Sunsynk with a big 48V battery bank?

Lots of large FETs to conduct say 250A DC @ 48V than say 50A at 250V DC. Then all the thicker swirling and PCB tracks to name a few.

 

Since a HV battery is similar in current and voltage characteristics to a normal solar array, they can utilise similar transformerless inverter technology. In addition to being more efficient than traditional transformer-based inverters, transformerless inverters are also significantly cheaper since they are much smaller and use far fewer components (this also can make them more reliable!). This means that you can add battery storage to your new or existing solar system more cheaply.

One of the realities of a technology industry like solar is each year, the technology gets better and cheaper. So if you are installing a new solar system but want to wait a few years to install batteries, AC-coupling with HV batteries will allow you to do this at a lower cost in the future compared to choosing a DC coupled hybrid inverter now and buying batteries later. This is because in the years between installing your battery ready PV system and buying your batteries, technology will have got cheaper for both the inverter and the battery. It can also be worth considering when installing a solar system, whether you should install a battery or wait some time to determine your self-consumption and then decide on the correct sized battery for your individual needs. If however you originally decided to install a hybrid inverter, you realised a higher cost for the technology rather than being able to purchase AC-coupled storage at a lower future cost. The other advantage about choosing AC-coupled storage rather than a DC coupled hybrid inverter is that you still have the opportunity to take advantage of future technology developments. For example, if you had invested in a hybrid inverter in 2014 and decided to buy batteries in a few years, you would not have been able to take advantage of newer and lower cost battery solutions like those from LG Chem and BYD. With AC-coupled storage, you can take advantage of such future developments because the solar and battery systems are independent of each other.

The above was written a few years ago. We only seeing it now locally on some designs.

Edited August 12, 20224 yr by Scorp007

https://www.banggood.com/DC-Multifunction-Battery-Monitor-Meter-50A-or-200A-or-300A-LCD-Display-Digital-Current-Multimeter-Voltmeter-Ammeter-for-Cars-RV-Solar-System-p-1608007.html?rmmds=myorder&cur_warehouse=CN

 

https://www.banggood.com/KEWEISI-AC-50~300V-20A-or-100A-Digital-Electricity-Meter-Voltmeter-Ammeter-With-CT-Power-Current-Voltage-Temperature-Measurement-p-1722757.html?rmmds=myorder&cur_warehouse=CN

 

 

The 5 kw 48V inverter I installed in 2020. At that time there was not a lot of hybrid inverters available bigger than 5 kw. I was a complete noob when that project started.

I discovered the limitations of a 5 kw inverter and the 48V system during that year to power my whole house. 2 mppt inputs (6.5kw max). I was at maximum capacity on the solar panels and that could not be expanded further.

On the batteries, 8 x 2.4 kWh was technically the maximum as well. I could add more batteries but I was battling to get the 8  full during the winter months. Summer was not a problem.

Then we get to the 5 kw inverter. The house draws 1000W on average , then the wife "starts"  the deep fryer and the microwave and the inverter will restart due to overloading. That was annoying at times. We managed to get that under "control" LOL.

So my plan was to upgrade to the newly released 10kW inverter, ( 4 x mppt 15000W max) but I could not use my old battery system. The new inverter uses the HV batteries as mentioned above and faze the 5 kw inverter and 48V batteries out over time. 

PS Try to sell your old system (12 months old) and try and recover at least some of the cash outlay to purchase the new system. Not many people that has 100K lying around for a second hand system. 

So this year Feb I purchased the 10kW inverter and added the 10 panels and 5 batteries with level 2 BMS in May. I was not sure if it was going to work with 1 inverter supplying the second. I tried it and it works fine.

That is why I have both systems running currently. When the 8 x 48V batteries are down to 20% the 10 kw starts supplying the load. 

It actually works out nice. The 5 kw will supply its essential load up to 5 kw or the non essential side up to 5 kw. If more power is needed above 5 kw on the non essential side the 10 kw just supplements the rest.

Now I can expand the system if needed. 3 mppts open on the 10 kw and the high voltage batteries can be expanded up to 6 stacks. In my voltage range for the inverter I can have 9 x 3,55kWh batteries in series = 432V = 32kWh.

That can be expanded to 6 stacks of 32 kWh each.

It removed all the limitations that was frustrating me.

I hope that explains why 2 systems.

 

On 2022/08/11 at 10:28 AM, FuzzyBullets said:

Great quality product. Just a shame the technical after sales service is not that great, but they are trying there best to help where they can.

Another reason for the 5 kw Goodwe Es inverter was that it was passively cooled. No fan noise.

Look at the beautiful sunny day  here in KZN.

PS. Can we volunteer on the Eskom app to be loadshedded ? 🤣

I'm ready.

10kW system

 

 5 kW system

Give us a 👍 if you are ready.

How did your installer join those thick 16mm2 wires to extend to the inverter?

Also what happens if the inverter fails between the supply mains and your Earth Leakage? 

Why does an inverter out from your main db need a double pole breaker but not your geyser or plugs etc? My Axpert also needed a double pole breaker but I still don't understand why

4 hours ago, Lee2 said:

Why does an inverter out from your main db need a double pole breaker but not your geyser or plugs etc? My Axpert also needed a double pole breaker but I still don't understand why

As you need not just isolation but to isolate inverter neutral from grid neutral. If not you can become the earth for fault current from the grid mini sub.

Your geyser has to be fitted with a double pole for isolation within easy reach from it

Edited November 13, 20223 yr by Scorp007