Shopping for an inverter: 12 VDC vs. 240 VDC

It's a lot of amps for the battery to handle. It will do it, briefly.

The real concern: what can the DC-DC converter actually supply? It normally replenishes the 12v battery from the high voltage system, but I don't know what continuous rate it can handle.

I really doubt it'll keep up with an 80-100A draw on the 12v side.

I looked into this shortly after we got our Prius, and quickly determined that it works great for small inverters for small needs, but it costs more than it is worth to scale it up for whole-house backup power. $800 goes a long way to getting a decent genny & interfacing it with your home panel.

 

There was a thread with extensive discussion - someone wanting to run some Medical gear while camping - you might find it in a search.

EDIT - also someone wanting to run a security camera 24/7.

 

It won't be coming from the 12 V battery, because of course you won't be using it except when the car is in READY, and the power will be coming from the DC/DC converter. Per lots of past discussions here, the 83 A is probably a good limit for what you can expect to siphon off from the converter (which has generally been rated somewhere in the 100 to 120 amp ballpark depending on generation) while still leaving some to run the rest of the car. That's assuming you don't have the other heavy loads simultaneously on, like lights, defogger, supplemental heat elements, etc.

I don't know about Gen 4, but in the first 3 generations anyway, the DC/DC converter has an output signal called IDH. It asserts this signal when it is near overloaded. In the stock configuration, the only thing it's used by is the ECU controlling the heat, which will shed the supplemental heat elements if they are on and the converter asserts that signal. If you are going to add any load up around 83 amps, you might consider tapping that signal and monitoring it somehow, either for some automatic load shedding or just for a red LED or buzzer for your own information.

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Where did you find one? I haven't looked in a while. An outfit called ConVerdant used to offer some for Prii, but they seemed to go away.

-Chap

 

If I needed the kind of information you want I would contact professor John Kelly at Weber University.


John Kelly

 

Now that I read your question in more depth - I see that it's to run a house.

Check out PriusChat threads - I typed in "house power" and came up with quite a few - mostly old:

 

These previous postings might be informative, if not helpful—I have no recommendations:

Prius Whole house Converdant Inverter | PriusChat
Prius Whole house Converdant Inverter | Page 2 | PriusChat

Please explain 12V system to me--how to keep battery charged while using accessories? | PriusChat
Please explain 12V system to me--how to keep battery charged while using accessories? | Page 2 | PriusChat

For fourth-generation cars, it’s listed in the Repair Manual as a Data List item (“PTC Heater Activate Permission Status/Prohibition Signal(IDH)”), but the separate wire appears to have been removed.

 

Professor Kelley is a Genius!

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Just to offer it- We've been using inverters from Exeltech of Fort Worth TX. Outstanding quality and support. Extremely clean power, good manners in bad conditions too- clean cutoff & de-bounce lock, no brownouts or weird behavior. I haven't asked them about the possibility of a high voltage DC input version, but they have previously been open to custom variations. They would be my go-to.

We've had one of their 12V 1kW models for nearly 20 years, and more recently I installed the 24V XPX 2kW model as the primary power for the beach cottage.

My primary home is rural enough that I need 240VAC for water pumping, so my own storm outage solution needs to account for that. That's a lot of why I'm biased towards using a generator instead. Currently getting by with a 4kW jobsite rig, though it probably ought to be a 7kW. Next time.

 

Pure Sine?

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Those are all great advantages. You're right, the Toyota will burn less fuel, it'll burn it with lower emissions and less noise. From that angle the Prius is a great way to get your emergency power.

The downside for me is the adaptation cost. My emergency power needs would mean a > $3000 inverter system, or a $750 generator. (and I already have the genny)

On days like today, the generator really wins because I'm home and my wife has the car on a business trip 150 miles away. Factor that in.

IF you can power enough of your home on a 1kW rig, I say go for it.

 

I'd be concerned about unintended adverse consequences on the Prius's electrical system with this arrangement. Perhaps a battery/inverter system might be more suitable for a power standby system. Mine is Solar/Battery system, around 1800 watts solar, 3kw Prosine inverter/charger, 4 Trojan 6v flooded cells, in a 24 volt system.

 

That is possible provided there is no inadvertent damage to the Prius's electrical system, if there is however, your warranty would not apply; which could turn into a very expensive proposition. You's also have to add a step down converter, as most inverters are 12, 24, or 48vdc inputs.

 

The whole point is to avoid that intermediate step-down because it is too restrictive. Granted, there aren't many high voltage DC inverters on the market, but there are some. Somebody has previously made a business of modifying commercially available inverters to work with the exact voltage the prius traction battery provides. I understand they're no longer in business, but the point is it's been done, and it can be done again.

One quick google turned this up. Looks like it could work unmodified.

 

This.
And.....if you can fuel the gen with natural gas or propane it becomes really easy.