We have solar without batteries - cheap way to have power during an outage

Forums › Home Workshop DIY › We have solar without batteries - cheap way to have power during an outage

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neb

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#3273290 18-Aug-2024 18:46

If you're only planning to use it very occasionally during a power outage, wouldn't a genset + manual changeover switch be the best option? That way you don't have to worry about the load (well, within sensible limits).

SomeoneSomewhere

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#3273291 18-Aug-2024 18:51

Gensets have noise, maintenance, fuel aging, and reliability issues. It's not cut-and-dried, but if you can do it cheaper with the parts already being installed, why not?

chimera

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#3273301 18-Aug-2024 19:42

FYI, re PW v2 vs v3, differences are:

Powerwall 2
- continuous output rate 5kw
- chemistry NMC

Powerwall 3
- continuous output rate 11.5kw
- chemistry LFP (safer)

Same capacity for both at 13.5kwh, both AC coupled, both 10 year warranty

chimera

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#3273305 18-Aug-2024 21:01

Oh nice, and powerwall 3 has built-in inverter. Just watched this video 2 mins ago and learnt a few more things about them, very good overview!

SomeoneSomewhere

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#3273311 18-Aug-2024 21:46

They're AC coupled; they have to include an inverter. Do you mean including a grid-tie solar inverter, arguably returning to a DC coupled system?

boland

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#3273315 18-Aug-2024 22:43

michaelmurfy: Don't worry about depreciation. New vehicles have always deprecated quite quickly but it's not like you're selling anytime soon. Work out the savings over the time of ownership (including maintenance which is nearly nil on EV's) along with having a new vehicle. The V2L capability is fantastic and I wish my Tesla had that (or Tesla's had it in general). For longevity the BYD's are the better buy due to the BYD blade batteries that are lasting really well.

We already have two EVs, never going back to ICE. Therefore a generator is not an option either.
Neither of our EVs has V2L. I've used one of them as backup power via the 12v battery but due to a design flaw in the inverter and user error on my part short circuited and destroyed the 12V battery (I moved the inverter and as the connectors were close together the two cables touched causing a poof)
Now my wife doesn't allow me to do that again :)

So a BYD would mean higher depreciation but indeed an awesome vehicle. I've put them on my favourite list.

I've seen the PW3 but as we already have a solar inverter don't think it's worth the upgrade for us.

Also the DIY route of ordering Li Ion batteries and inverters online myself is above my skill level.

chimera

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#3273333 19-Aug-2024 08:28

SomeoneSomewhere:

They're AC coupled; they have to include an inverter. Do you mean including a grid-tie solar inverter, arguably returning to a DC coupled system?

Yes meaning version 3 has a SOLAR inverter builtin

It can do AC or DC coupled by the looks

AliExpress

Shop now on AliExpress (affiliate link).

boland

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#3273345 19-Aug-2024 08:49

One question, if we get a car with V2L, and have this transfer switch installed, we can power the whole house with the car during a power cut, right? Just hook the car up to the 15A inlet, switch over, turn off unnecessary loads in the house, and smile?

I understand that in that case our solar panels won't work. That's fine.

Jase2985

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#3273368 19-Aug-2024 09:19

boland:

One question, if we get a car with V2L, and have this transfer switch installed, we can power the whole house with the car during a power cut, right? Just hook the car up to the 15A inlet, switch over, turn off unnecessary loads in the house, and smile?

I understand that in that case our solar panels won't work. That's fine.

Most V2L will only be 2-3kW output so technically won't be able to power your whole house, you would likely have to selectively turn off some things.

boland

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#3273373 19-Aug-2024 09:34

Jase2985:

boland:

One question, if we get a car with V2L, and have this transfer switch installed, we can power the whole house with the car during a power cut, right? Just hook the car up to the 15A inlet, switch over, turn off unnecessary loads in the house, and smile?

I understand that in that case our solar panels won't work. That's fine.

Most V2L will only be 2-3kW output so technically won't be able to power your whole house, you would likely have to selectively turn off some things.

Yeah understood. That was the step in bold, to turn off unnecessary loads. It's mainly for the fridges and some lights; I don't want to be running extension cords to them as I've done before.

SomeoneSomewhere

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#3273413 19-Aug-2024 11:58

A 32A transfer switch means you'll need to partition off a section of the board ('essential') that draws less than 32A and put it on a 32A breaker to protect the switch even in mains operation. Simpler and more flexible to get a 63A switch.

You only need the 15A socket; make sure V2L is 15A not 10A.

It's definitely cheaper to buy the bits separately as you don't need the 32A inlet.

I am still disappointed no reputable manufacturer makes a DIN rail breaker interlock.

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