Going Blue!

[Antony]

17 minutes ago, plonkster said:

Indeed. An MPPT is slightly cheaper than a PV-inverter. And with a PV-inverter you have additional issues during extended outages. A PV-inverter only works if it has AC to tie with. When the grid goes down, so does your PV. So you have backup, but no way to use your PV. The way to get around this, is to tie the PV-inverter to the output of the Multi. But that has one additional caveat: The dead battery deadlock. If the battery goes too low the Multi switches off. When the Multi is off, no AC to tie with... no way to use the PV to charge the batteries.

The way to break the deadlock: You either need another AC source (battery), or another charging source (put a small number of panels on a small MPPT).

So the additional caveats plus the additional cost generally means that for a small (residential size) setups, you might be better off taking the efficiency hit and just going with MPPTs (or the Easysolar). For office buildings and large scale things where power is used during the day... you absolutely must go AC-tied.

Easysolar will give me

1. standby from PV (or battery when funds become available to buy some) during loadshedding ?
2. draw from grid if load is greater than PV/battery?
3. work without battery till funds become available to buy some?

[___]

8 minutes ago, Antony said:

draw from grid if load is greater than PV/battery?

It attempts to power everything from the battery until the battery SOC drops too low, then it falls back to the grid. If you draw more than the capacity of the inverter, it also takes the rest from the grid. You can set a lower limit (other than the inverter capacity).

16 minutes ago, Antony said:

work without battery till funds become available to buy some?

No, not this one. Easysolar can't work without a battery.

[Antony]

 

So if I have a "small" battery bank, it will work, and also when the SOC drops quicker, it will fall back to grid to supplement the inverter.

Will it then charge the batteries again (is this set as a priority?) and when it reaches SOC+ it will revert to battery again when supplement is needed , and so the "loop" of this action?

The risk however is that this could repeat a few times during the day and inevitably reduce the lifespan of the batteries because it is cycling too many times?

It can also leave the batteries at low SOC if PV is ineffective or will it charger from grid to ensure night time power?

I guess it is absolutely vital to size the inverter and PV panels properly to prevent this as far as possible.

[Guest]

Penny just dropped. Easysolar does not have a NRS 097 certification. 

 

18 minutes ago, Antony said:

So if I have a "small" battery bank, it will work, and also when the SOC drops quicker, it will fall back to grid to supplement the inverter.

I have a small bank, by design. I set the battery usage to a SOC of 80% - or any setting you want.

ESS will ensure the battery is charge fully regularly, but it is not the focus per se based on loads. It will use some of the battery power, like say it is on 85% and there is a big load, it will add all the panels can give and what the batteries (down to 80%) has, with Eskom, to power the load.

Once i hits 80%, only panels and Eskom, and recharge say tomorrow.

So no, the focus is not on charging all the time. ESS software manages that quite nicely.

Or you can set it to keep batteries charged all the time ... my plan is to use that once the batteries near end of life. :-) 

Plonkster can add much more detail.

Edited January 9, 2019 by Guest