Computerizer
New Member
- Joined
- Apr 23, 2022
- Messages
- 8
I'm in the planning stages for a 48 V on/off-grid system for backup at home. I was given 2 kWh of brand new LiPo cells from my employer (they'd purchased them for a project that we never ended up doing). I know LiPo isn't the best for this, but they were free, so... I'll use them for now and maybe replace with something better later.
I'm currently leaning toward a 5000 W PowMr hybrid inverter/charger, however I'm open to suggestions if there's something else with similar capabilities that's worth looking at. Lower power is fine, actually; our emergency loads would be less than 1.5 kW under most circumstances, so a 2 kW inverter is sufficient (but hard to find 2 kW all-in-ones with 48 V).
Although it's not a requirement, I would like to have a 12 V tap off my batteries for various 12 V accessories I already own.
For now, I will charge the batteries from the grid. During grid outages, we'll use the inverter to run the fridge/freezer as needed.
If the outage lasts more than a day, we will then charge from one of our EVs. We have two EVs, one with a 66 kWh battery and one with an 82 kWh battery. I intend to use a 12 V - 48 V DC-DC charger for that, like this. I know both EV's own DC-DC chargers can put out at least 1000 W at 12 V, so that 560 W charger won't be a problem.
If an outage lasts long enough to use up a significant portion of our EV charge, then I would hook up solar panels. I'd have all the equipment ready, so I could just go out to my 12 kW grid-tied array, unhook a portion of the modules from their Enphase inverters, and connect them in series/parallel (as needed) for the charge controller. It's a ground-mounted array and very easy to access all of the connections.
Here is an electric diagram of my plan:
The biggest question I have, is what's the right way to do my 12 V tap on parallel batteries? I drew in diodes before the 12 V bus, which seems like a good way to prevent energy from flowing between the parallel batteries, but would that really work? Or is there a better way? Or no way?
In addition to that, am I missing anything? Any suggestions to improve our plan? Questions?
TIA!
I'm currently leaning toward a 5000 W PowMr hybrid inverter/charger, however I'm open to suggestions if there's something else with similar capabilities that's worth looking at. Lower power is fine, actually; our emergency loads would be less than 1.5 kW under most circumstances, so a 2 kW inverter is sufficient (but hard to find 2 kW all-in-ones with 48 V).
Although it's not a requirement, I would like to have a 12 V tap off my batteries for various 12 V accessories I already own.
For now, I will charge the batteries from the grid. During grid outages, we'll use the inverter to run the fridge/freezer as needed.
If the outage lasts more than a day, we will then charge from one of our EVs. We have two EVs, one with a 66 kWh battery and one with an 82 kWh battery. I intend to use a 12 V - 48 V DC-DC charger for that, like this. I know both EV's own DC-DC chargers can put out at least 1000 W at 12 V, so that 560 W charger won't be a problem.
If an outage lasts long enough to use up a significant portion of our EV charge, then I would hook up solar panels. I'd have all the equipment ready, so I could just go out to my 12 kW grid-tied array, unhook a portion of the modules from their Enphase inverters, and connect them in series/parallel (as needed) for the charge controller. It's a ground-mounted array and very easy to access all of the connections.
Here is an electric diagram of my plan:
The biggest question I have, is what's the right way to do my 12 V tap on parallel batteries? I drew in diodes before the 12 V bus, which seems like a good way to prevent energy from flowing between the parallel batteries, but would that really work? Or is there a better way? Or no way?
In addition to that, am I missing anything? Any suggestions to improve our plan? Questions?
TIA!