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I have three strings of solar going through my Solis inverter, before output to a Powerwall.

Could I divert one of the strings to a DC battery storage solution, which could then feed the Powerwall through the Solis when the Powerwall gets gets low.

I see it as simple on my head, but leccy not my strong point! Any advice on what I would need to buy if this is doable would be appreciated

I'm not quite following what you intend to achieve here, more battery capacity ?

Are you suggesting feeding a battery through one of the solar inputs of the solis ?
I believe your inverter is not a hybrid type.

nowty wrote: ↑Wed May 24, 2023 1:30 pm I'm not quite following what you intend to achieve here, more battery capacity ?

Are you suggesting feeding a battery through one of the solar inputs of the solis ?
I believe your inverter is not a hybrid type.

Yes, more (read cheaper) storage.

Was hoping a DC storage solution could be converted to AC using existing inverter and fed to Powerwall. DC from the solars is effectively being converted this way or am I misunderstanding what I need?

Thanks

NikoV6 wrote: ↑Wed May 24, 2023 1:40 pm

nowty wrote: ↑Wed May 24, 2023 1:30 pm I'm not quite following what you intend to achieve here, more battery capacity ?

Are you suggesting feeding a battery through one of the solar inputs of the solis ?
I believe your inverter is not a hybrid type.

Yes, more (read cheaper) storage.

Was hoping a DC storage solution could be converted to AC using existing inverter and fed to Powerwall. DC from the solars is effectively being converted this way or am I misunderstanding what I need?

Thanks

But why feed it to the Powerwall you would just be better feeding the house loads as it requires it.

Fintray wrote: ↑Wed May 24, 2023 2:17 pm

NikoV6 wrote: ↑Wed May 24, 2023 1:40 pm

nowty wrote: ↑Wed May 24, 2023 1:30 pm I'm not quite following what you intend to achieve here, more battery capacity ?

Are you suggesting feeding a battery through one of the solar inputs of the solis ?
I believe your inverter is not a hybrid type.

Yes, more (read cheaper) storage.

Was hoping a DC storage solution could be converted to AC using existing inverter and fed to Powerwall. DC from the solars is effectively being converted this way or am I misunderstanding what I need?

Thanks

But why feed it to the Powerwall you would just be better feeding the house loads as it requires it.

Powerwall supports the house if solar is not generating. Looking for options to expand storage capacity to be used when solar is down and Powerwall is getting low.

Does your Solis inverter keep working when the grid is down?

You'd need to build a high voltage battery as the turn on voltage of the inverter is 120V so we are in lethal DC land. Also the impedance of the supply of a battery is significantly lower than that a solar string so you risk damaging the inverter. The inverter is expecting the voltage to drop rapidly as current flows but it wont from a battery.

Saying that I have personally done something similar in the past to transfer grid power to an OffGrid system. I used several grid powered PSUs in series to get the DC voltage up to about 130V and connected it to a standard SMA grid tie inverter with a power limit output set on the inverter to stop the power supplies overloading.

Thankfully those days of craziness are over for me, I would not recommend what you are thinking. You could sell on your Solis and replace it with a hybrid model which takes batteries. Then you need to work out how to get the inverter and the powerall to play nicely.

Don't do this at home folks, especially if you don't like bangs and magic smoke.

Fintray wrote: ↑Wed May 24, 2023 2:34 pm Does your Solis inverter keep working when the grid is down?

Yes, Powerwall isolates the house and allows solars to keep generating

nowty wrote: ↑Wed May 24, 2023 2:39 pm You'd need to build a high voltage battery as the turn on voltage of the inverter is 120V so we are in lethal DC land. Also the impedance of the supply of a battery is significantly lower that a solar string so you risk damaging the inverter. The inverter is expecting the voltage to drop rapidly as current flows but it wont from a battery.

Saying that I have personally done something similar in the past to transfer grid power to an OffGrid system. I used several grid powered PSUs in series to get the DC voltage up to about 130V and connected it to a standard SMA grid tie inverter with a power limit output set on the inverter to stop the power supplies overloading.

Thankfully those days of craziness are over for me, I would not recommend what you are thinking. You could sell on your Solis and replace it with a hybrid model which takes batteries. Then you need to work out how to get the inverter and the powerall to play nicely.

Don't do this at home folks, especially if you don't like bangs and magic smoke.

Thought it seemed a bit too simple in my head! Many thanks!

So more solar into DC storage through hybrid inverter which can be switched to supply house when solar and Powerwall are off??

Whats your solis inverter model number as I know in the manual for some of the solis inverters it says its possible to run the inverter from battery only ?

Moxi