Battery Nerd Alert - R1T and Home Backup

[zipzag]

For home backup I'm fine with 3000w peak and an ~800w average. Charging one of the systems below from the R1T while it is discharging should work for my home backup.

This setup will likely cover a 240V well pump and most 240V HVAC air handlers. No AC, of course.

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[jemkewl]

The Eg4 batteries from signature solar can be had slightly cheaper during sales. This is an awful comparison on price. Not portable, no outlets, no 120 loads without a transformer. Price becomes similar at that point. However, different purposes and consumer market.

 

[fhteagle]

For the prices Rivian is now quoting for R1S and R1T, they both should come with much stronger power exporting capabilities. 240v 30 amp at a minimum in my mind. Having to buy an extra battery / inverter setup to daisy chain in with the truck is a huge negative. It's one of the reasons I haven't purchased yet.

 

[jjswan33]

My current home energy setup I wouldn't need 240V. I had done a setup similar to your suggestion with a Goal Zero power station (with 120V) and I can power my fridge, air handler, modem, TV and some lights. Even since I sold my GZ with my van I can still use the truck just as long as I don't connect the ground between the truck and my transfer switch.

Output would be <500W by my estimate so I could power those limited circuits for a week or more with a 70% SOC.

 

[zipzag]

My current home energy setup I wouldn't need 240V. I had done a setup similar to your suggestion with a Goal Zero power station (with 120V) and I can power my fridge, air handler, modem, TV and some lights. Even since I sold my GZ with my van I can still use the truck just as long as I don't connect the ground between the truck and my transfer switch.

Output would be <500W by my estimate so I could power those limited circuits for a week or more with a 70% SOC.

Are you using extension cords or a transfer switch?

 

[jjswan33]

Are you using extension cords or a transfer switch?

I have a transfer switch. 4 circuit, 3 15A and one that I upgraded to 20A for my Fridge circuit.

 

[zipzag]

The Eg4 batteries from signature solar can be had slightly cheaper during sales. This is an awful comparison on price. Not portable, no outlets, no 120 loads without a transformer. Price becomes similar at that point. However, different purposes and consumer market.

transformer?

 

[Dark-Fx]

For the prices Rivian is now quoting for R1S and R1T, they both should come with much stronger power exporting capabilities. 240v 30 amp at a minimum in my mind. Having to buy an extra battery / inverter setup to daisy chain in with the truck is a huge negative. It's one of the reasons I haven't purchased yet.

I haven't tried it with any vehicle yet, but apparently the Bolt EV doesn't actually do any verification of expected HV output, meaning you could hook into one of the distributed HV lines without triggering codes. I'd be very tempted to actually try it if I had an inverter that could take that much DC voltage as an input, but even the 5kW inverter I have is still designed off 12V.

 

[zipzag]

I have a transfer switch. 4 circuit, 3 15A and one that I upgraded to 20A for my Fridge circuit.

I have similar. I think people who camp are satisfied with basic power. But some people want everything to work as normal.

 

[jemkewl]

transformer?

A split phase transformer aka autotransformer which will take in the 240 single phase and output two 120 single phase that are 180 degrees separated (opposite). Need to be careful and balance loads so one phase isn't overloaded and the neutral doesn't exceed rated capacity. If loads are equal on each phase, the neutral will be 0. The main unit mentioned in that video doesn't do split phase.
In US, our houses have two 120v lines that are opposite phase (180 degrees out of phase from each other). I am oversimplifying here, but hopefully this helps answer your question.

 

[zipzag]

A split phase transformer aka autotransformer which will take in the 240 single phase and output two 120 single phase that are 180 degrees separated (opposite). Need to be careful and balance loads so one phase isn't overloaded and the neutral doesn't exceed rated capacity. If loads are equal on each phase, the neutral will be 0. The main unit mentioned in that video doesn't do split phase.
In US, our houses have two 120v lines that are opposite phase (180 degrees out of phase from each other). I am oversimplifying here, but hopefully this helps answer your question.

The split phase versions of the inverters mentioned in the video list L1 and L2 as 180 degrees out of phase, and don't show an additional transformer.

But the solar inverters he showed aren't the correct devices as they can't charge from AC while operating the inverter. Inverters made for boating are probably correct. These can charge from multiple sources and don't have an integrated MPPT controller for solar. On the higher end Victron likely makes an appropriate device. On the lower end there are likely devices made for large RVs that would work.

 

[doit82]

I wish I had a way I could trickle charge our powerwalls in case of emergency through the R1T. Anybody know if that is possible?

 

[zipzag]

I wish I had a way I could trickle charge our powerwalls in case of emergency through the R1T. Anybody know if that is possible?

It is not possible AFAIK. What would work with a 7kw vehicle inverter is to choose between Powerwall and vehicle. The blending of sources is obviously the future.

In the future buying less Powerwall energy capacity because vehicles have big batteries becomes attractive. Perhaps Tesla now selling a CCS wall connector is requiring customers to own only Tesla isn't realistic.

If I was installing solar plus battery today I would certainly look at using server rack style batteries. 5kWh increments at $1600 for high quality cells is attractive.

 

[jemkewl]

The split phase versions of the inverters mentioned in the video list L1 and L2 as 180 degrees out of phase, and don't show an additional transformer.

But the solar inverters he showed aren't the correct devices as they can't charge from AC while operating the inverter. Inverters made for boating are probably correct. These can charge from multiple sources and don't have an integrated MPPT controller for solar. On the higher end Victron likely makes an appropriate device. On the lower end there are likely devices made for large RVs that would work.

OH! And those inverters can be run without issue if only using L1 without L2 or vice versa? Still same power output if only using L1 or only L2?

I believe the "better" Eg4 models can charge from multiple sources, but I believe only 1 source at a time. Many buy chargers to charge batteries directly to overcome these cheaper all in one inverter/mppt devices.

 

[jemkewl]

I wish I had a way I could trickle charge our powerwalls in case of emergency through the R1T. Anybody know if that is possible?

Buy a charger, plug-in to truck outlets and connect to batteries in powerwall. Or is powerwall meant to be a specific proprietary product VS a generic term?

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