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Distributed vs monolithic home batteries

Sauteer

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May 28, 2024
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Tried searching for previous discussion on this but perhaps I'm using the wrong search terms.

Recently I purchased a portable power station for my wife's business as she is a musician and often needs to run her PA with no mains power available. I was really impressed by the quality and price of the new Lifepo4 portable power stations. It got me thinking about my own home power set up.

I currently have a 7kw system mains connected on my home. I've been considering a battery but the large upfront cost might be hard to get signed off the with wife.

I work on software and one general theme of the last 6 or 7 years is the migration of monolithic to microservice architecture. Where large platforms that speak to most of the broader system are being replaced with purpose built distributed microservice. The advantages of this approach include the following:

- easier to test, POC, and implement MVP

- dedicated specialisation and sizing for the task

- easier to scale

- easier to decomission

- greater flexibility in vendor negotiation


When I think about this with respect to battieres in the home I wonder if I should consider independent batteries in my home in the appliance groups I need them. I.e:

- kitchen group (oven, fridge, dishwasher)

- living room (tv, lamps, router)

- laundry (washing machine, dryer, heatpump hot water).

The rest of the house can run off mains as the remaining draw is minimal.

Pros and cons of this approach vs a single battery connected to my house-wide fusebox:
Pros:

- lower unit cost allowing me to take phased roll-out approach

- modular design means upgrading certain parts can be provider and type agnostic

- plug and play design using wall plugs and networked switches for load shifting

- portability of batteries as stand alone power stations. I could take them with me or use for other things.

- local DC current available for appliances that can use it rather than losing efficiency when converting to AC.

- less insurance liability (when DIY) as no house wiring needs to be changed.

- ability to have isolated redundancy for critical systems like fridge. In other words your kids can leave a resistance heater on and drain all power for critical systems overnight.


Cons:

- likely a higher cost per Kilowatt hour as the cells would be purchased in smaller amounts.

- 3x cost of (BMS, case, inverter etc). Albeit smaller

- less ideal ability to monitor the group in aggregate (though I suspect I could overcome this with the right power stations).


Interested to hear the communitie's thoughts on this
 
Most people here generally go with one big battery because we're using DC coupled solar, and in that case splitting it up is likely to cause mismatches in supply and demand.

In an AC supplied context there could be some merit, but I'm sold on central batteries.
 
Tried searching for previous discussion on this but perhaps I'm using the wrong search terms.

Recently I purchased a portable power station for my wife's business as she is a musician and often needs to run her PA with no mains power available. I was really impressed by the quality and price of the new Lifepo4 portable power stations. It got me thinking about my own home power set up.

I currently have a 7kw system mains connected on my home. I've been considering a battery but the large upfront cost might be hard to get signed off the with wife.

I work on software and one general theme of the last 6 or 7 years is the migration of monolithic to microservice architecture. Where large platforms that speak to most of the broader system are being replaced with purpose built distributed microservice. The advantages of this approach include the following:

- easier to test, POC, and implement MVP

- dedicated specialisation and sizing for the task

- easier to scale

- easier to decomission

- greater flexibility in vendor negotiation


When I think about this with respect to battieres in the home I wonder if I should consider independent batteries in my home in the appliance groups I need them. I.e:

- kitchen group (oven, fridge, dishwasher)

- living room (tv, lamps, router)

- laundry (washing machine, dryer, heatpump hot water).

The rest of the house can run off mains as the remaining draw is minimal.

Pros and cons of this approach vs a single battery connected to my house-wide fusebox:
Pros:

- lower unit cost allowing me to take phased roll-out approach

- modular design means upgrading certain parts can be provider and type agnostic

- plug and play design using wall plugs and networked switches for load shifting

- portability of batteries as stand alone power stations. I could take them with me or use for other things.

- local DC current available for appliances that can use it rather than losing efficiency when converting to AC.

- less insurance liability (when DIY) as no house wiring needs to be changed.

- ability to have isolated redundancy for critical systems like fridge. In other words your kids can leave a resistance heater on and drain all power for critical systems overnight.


Cons:

- likely a higher cost per Kilowatt hour as the cells would be purchased in smaller amounts.

- 3x cost of (BMS, case, inverter etc). Albeit smaller

- less ideal ability to monitor the group in aggregate (though I suspect I could overcome this with the right power stations).


Interested to hear the communitie's thoughts on this
I have a Delta 2 max running all my base loads in the house (around 500W), connected to 17.5 kWh of assorted batteries to comprise a 48V bank. a Victron 48/1200 runs as pass thru for around 1000W of load/charging, and then the two 500W solar inputs are connected to the power bus as well. All major demand loads (water heater, dryer, stove, oven, furnace) are on propane except central AC and well which are 240V. I'm just running extension cords around the house. 4500W of panels laying on the ground on the backyard and a 450/100 SCC. Batteries were around $800-900 per 48V 100Ah (5kWh) capacity unit.

What I would suggest is multiple batteries, but generally these would be located in a single area due to the need to be close to the inverter(s). That way if any one 48V battery fails (bad cell, BMS failure etc) then the other batteries take the load, no worries.

For system redundancy could go with parallel inverter units (generally these will require reconfiguration to move from a parallel pair to a single unit after a failure) and SCCs. Or daisy chain one inverter into the other.
 
I have a Delta 2 max running all my base loads in the house (around 500W), connected to 17.5 kWh of assorted batteries to comprise a 48V bank. a Victron 48/1200 runs as pass thru for around 1000W of load/charging, and then the two 500W solar inputs are connected to the power bus as well. All major demand loads (water heater, dryer, stove, oven, furnace) are on propane except central AC and well which are 240V. I'm just running extension cords around the house. 4500W of panels laying on the ground on the backyard and a 450/100 SCC. Batteries were around $800-900 per 48V 100Ah (5kWh) capacity unit.

What I would suggest is multiple batteries, but generally these would be located in a single area due to the need to be close to the inverter(s). That way if any one 48V battery fails (bad cell, BMS failure etc) then the other batteries take the load, no worries.

For system redundancy could go with parallel inverter units (generally these will require reconfiguration to move from a parallel pair to a single unit after a failure) and SCCs. Or daisy chain one inverter into the other.
Sorry I should have been clearer im considering stand alone batteries with their own inverters as a "portable power station". So a centralised inverter wouldn't be necessary.
 
Sorry I should have been clearer im considering stand alone batteries with their own inverters as a "portable power station". So a centralised inverter wouldn't be necessary.
Yes then the issue is how do you get the solar/DC to them for the charging part of things.

You can do this fairly resonanbly with the newly released 120V multiplus 12/1200, $480, connect it to a 12V 280Ah ecoworthy battery that's $550 and now you have a 1000W 3.5kWh UPS unit that can charge from AC at 50A. Create as many of these combos as you desire/have budget for. You could daisy chain them via ve.bus (cat 5) to have overall monitoring and control.
 
Yes then the issue is how do you get the solar/DC to them for the charging part of things.

You can do this fairly resonanbly with the newly released 120V multiplus 12/1200, $480, connect it to a 12V 280Ah ecoworthy battery that's $550 and now you have a 1000W 3.5kWh UPS unit that can charge from AC at 50A. Create as many of these combos as you desire/have budget for. You could daisy chain them via ve.bus (cat 5) to have overall monitoring and control.
I'd just charge with with mains AC.

I can buy mains power at $0.06 to $0.16 during daylight hours as I get wholesale realtime rates with my provider. As my panels are also mains connected I could charge the batteries from wall socket AC provided by the solar as well. I get that that's a little inefficient but the price difference should make up for that
 

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