EcoRenovator - View Single Post - Off-the-grid with grid-tie inverter?

SergeyAU · 08-30-11, 02:03 AM

Hi everyone.
Interesting discussion.

The problem that I have with proposed setup, is that my PV system is setup to a very high voltage (350V) per channel, thus getting it to the batteries is a bit of a problem with a proposed setup.

But, I thought to myself, why cannot I just use 240v battery charger from the mains (Australia), that is only running during a day (timer switch). Since the solar is channeled to the mains through grid tie inverter, I'll be able to charge batteries using 240v charger. I know it would probably be less efficient, but way less wiring.

Once the batteries are charged (and not used), the charge controller would not pull much from the mains. If there is a power outage, all I would have to do is switch off the master switch (so that voltage does not go back to the mains and no one gets hurt), and connect the battery>240v inverter to the batteries. Turn it on - presto! Grid tie will think that there is power, so will start using solar to 240v conversion, which will charge the batteries through 240v>battery charge controller (plus whatever else needs power around the house)

What do you guys think? I already have 3.8kW grid tie solar installed, the only cost would be the batteries, charge controller, quality 240v inverter and some wires and switches.

Sergey

(the only thing is that batteries must be charged before the blackout)

08-30-11, 02:03 AM	#35
SergeyAU Lurking Renovator Join Date: Aug 2011 Location: Australia Posts: 6 Thanks: 0 Thanked 0 Times in 0 Posts	Hi everyone. Interesting discussion. The problem that I have with proposed setup, is that my PV system is setup to a very high voltage (350V) per channel, thus getting it to the batteries is a bit of a problem with a proposed setup. But, I thought to myself, why cannot I just use 240v battery charger from the mains (Australia), that is only running during a day (timer switch). Since the solar is channeled to the mains through grid tie inverter, I'll be able to charge batteries using 240v charger. I know it would probably be less efficient, but way less wiring. Once the batteries are charged (and not used), the charge controller would not pull much from the mains. If there is a power outage, all I would have to do is switch off the master switch (so that voltage does not go back to the mains and no one gets hurt), and connect the battery>240v inverter to the batteries. Turn it on - presto! Grid tie will think that there is power, so will start using solar to 240v conversion, which will charge the batteries through 240v>battery charge controller (plus whatever else needs power around the house) What do you guys think? I already have 3.8kW grid tie solar installed, the only cost would be the batteries, charge controller, quality 240v inverter and some wires and switches. Sergey (the only thing is that batteries must be charged before the blackout)