Greetings from Monterey Bay, California

[Electronic]

Hello folks, I am looking into adding battery backup for our townhouse as we are getting far too many power outages. Earlier this year and last year some power outages lasted over a day. So I am looking at having enough backup to power small appliances + lights + fridge for over a day. I will probably create a separate panel for the battery backup circuits. Anyhow I have been looking at EG4 batteries and Schneider inverters. I only need about 4kw and will probably not add solar panels since we do not get that much sunshine and roof space is limited due to HOA rules. I am thinking of using 2 x 48v EG4s and a Conext SW 4048. Any suggestions or recommendations? I will be doing the work myself (EE and have electrical work experience in UK and DIY work in US). But if you know someone in Monterey Bay area who can help I would not mind having a chat.

Cheers,
Frank

 

[Craig]

Hi Frank I am in Hollister if i can help.

 

[Electronic]

Hi Frank I am in Hollister if i can help.

Hey Craig, I will PM you soon you so we can talk about my project.

 

[MisterSandals]

I am nearby too, just over the hill (in more ways than one!). I have a recently unboxed SW4048 that i am bench testing right now. I'd be happy to show you what it looks like and see it in action.

 

[Hedges]

Battery but no solar, so you need an accurate estimate of average power draw and guesstimate of power outage duration.

Consumer energy label is a good place to start, available on-line for your fridge etc.
Kill-a-Watt can measure it directly, feeding a power strip that feeds all loads.

Common choice of battery is 48V 100 Ah server-rack LiFePO4, around $1500.
LiFePO4 also available 12V similar size to automotive batteries and larger.
For just occasional backup, AGM can be good. But prices are approaching same these days, so consider both kinds.

48V is great for big systems. The loads you've listed might be OK for a 12V battery & inverter. That gives you the option of portable use, charge from car alternator, etc.
Get pure sine wave, better for motors.
Key parameter is max current or surge current (and time in seconds) able to start fridge.
Defrost cycle of fridge is a big drain. Would like to be able to disable that, which you could do by adding switch to defrost timer. And switch off icemaker.

Consider portable PV panels, maybe hang off the balcony during a power failure or on a car roof rack, or just in driveway (secured somehow.)

 

[Electronic]

I am nearby too, just over the hill (in more ways than one!). I have a recently unboxed SW4048 that i am bench testing right now. I'd be happy to show you what it looks like and see it in action.

Sounds great, thanks. I live in silicon valley part of the time. Should be easy to set up a time to check it out. I am looking at UL listed reliable inverters and thought SW4048 would fit the bill.

 

[Electronic]

Battery but no solar, so you need an accurate estimate of average power draw and guesstimate of power outage duration.

Consumer energy label is a good place to start, available on-line for your fridge etc.
Kill-a-Watt can measure it directly, feeding a power strip that feeds all loads.

Common choice of battery is 48V 100 Ah server-rack LiFePO4, around $1500.
LiFePO4 also available 12V similar size to automotive batteries and larger.
For just occasional backup, AGM can be good. But prices are approaching same these days, so consider both kinds.

48V is great for big systems. The loads you've listed might be OK for a 12V battery & inverter. That gives you the option of portable use, charge from car alternator, etc.
Get pure sine wave, better for motors.
Key parameter is max current or surge current (and time in seconds) able to start fridge.
Defrost cycle of fridge is a big drain. Would like to be able to disable that, which you could do by adding switch to defrost timer. And switch off icemaker.

Consider portable PV panels, maybe hang off the balcony during a power failure or on a car roof rack, or just in driveway (secured somehow.)

Thanks Hedges for the suggestions. I have considered portable backup with solar panels and doing a piecemeal solution for the fridge etc. I can still do piecemeal and limit to fewer circuits. That would reduce the need for a 4kw capacity. I have a kill a watt and I already have done a back of the envelope estimate. A single 48V 100Ah would be sufficient for 95% of the outages. But PG&E never ceases to disappoint more so I am thinking 2x 48V 100Ah would cover it and then some. Down the line I will look into adding solar panels after replacing the roof and getting HOA to clarify a bunch of things (including charging EVs even further down the line).