question about hybrid inverters and dc charging sources

[1201]

if you have grid export on a grid interactive inverter like solark 15k and eg4 18kpv,

lets say there is separate mppt charge controller that's also charging the battery -, when the battery is full, will the inverter export from battery to grid to keep SOC or voltage from climbing too high?

 

[chrisski]

For my Outback 8048, inverter charger, with separate MPPTs, can be either depending on the settings. I prefer the battery staying close to 100% so in case of power outage, going into the night I have a full battery.

When charging from the MPPTs, now the Outback will occasionally export a couple hundred watts to the grid, but usually not. Its mostly keeping the battery at a constant state. When I first had it installed, the battery was reaching a full state of charge and slowly going down to 60% daily, but the installer tweaked the settings and battery now stays close to 100%.

After a full battery charge from the charger attached to the grid, the Outback will export 7 kw, the max output, to the grid and after a few minutes, the battery has normalized and the battery is staying at a constant rate of charge.

 

[1201]

For my Outback 8048, inverter charger, with separate MPPTs, can be either depending on the settings. I prefer the battery staying close to 100% so in case of power outage, going into the night I have a full battery.

When charging from the MPPTs, now the Outback will occasionally export a couple hundred watts to the grid, but usually not. Its mostly keeping the battery at a constant state. When I first had it installed, the battery was reaching a full state of charge and slowly going down to 60% daily, but the installer tweaked the settings and battery now stays close to 100%.

After a full battery charge from the charger attached to the grid, the Outback will export 7 kw, the max output, to the grid and after a few minutes, the battery has normalized and the battery is staying at a constant rate of charge.

thanks for this information. the mppt charge controller is a standalone unit?

 

[chrisski]

thanks for this information. the mppt charge controller is a standalone unit?

The MPPT is a stand alone unit. The MPPT is a Outback Flex Max 100 amp, so it is designed specifically to work with the "Universe" of Outback products.

 

[1201]

The MPPT is a stand alone unit. The MPPT is a Outback Flex Max 100 amp, so it is designed specifically to work with the "Universe" of Outback products.

That's very cool. Thanks.

 

[DIYrich]

You could configure the solark to export until batteries reach a certain SOC (say 90%). The question is how accurate is the soc with everything that is going on.

 

[1201]

You could configure the solark to export until batteries reach a certain SOC (say 90%). The question is how accurate is the soc with everything that is going on.

What I mean is , let's say for some reason I have pv attached to a victron charge controller that's feeding the battery. If the battery gets full will the solark transfer power from the battery into the grid so the soc /voltage doesn't continue to climb?

 

[DIYrich]

What I mean is , let's say for some reason I have pv attached to a victron charge controller that's feeding the battery. If the battery gets full will the solark transfer power from the battery into the grid so the soc /voltage doesn't continue to climb?

Program it to export when batteries are at 95% or higher. If you want perfection, the don't kludge a solution.

 

[1201]

Program it to export when batteries are at 95% or higher. If you want perfection, the don't kludge a solution.

ok, that's a solution that I can use. thanks.
My sunny island automatically does this. if an external charger is raising the voltage higher than the sunny island setting then the sunny island will export as needed to maintain the voltage.
I just needed to know if other hybrids do this since I may be switching soon

 

[JBertok]

A consideration you might integrate into your strategy, any battery bank with a BMS should be allowed to regularly at spend some time at 100% SoC for the BMS balancing and self-calibration functions to work right. A common workout for that is to schedule a time window late in the solar day that minimizes export to hold the batteries at a full SoC.

 

[1201]

A consideration you might integrate into your strategy, any battery bank with a BMS should be allowed to regularly at spend some time at 100% SoC for the BMS balancing and self-calibration functions to work right. A common workout for that is to schedule a time window late in the solar day that minimizes export to hold the batteries at a full SoC.

Good point. The way my setup works right now is it stays at full battery until I disconnect the grid after sunset. The new hybrids are different so I'll have to develop a strategy for that. Thanks for pointing that out