You wouldn't use the inverter. First off, the inverter is only a driver, it is the HV ECU that actually operates the transistors in the inverter.

Instead, you could use an inverter and take advantage of the HV battery. Some have done some work on what you suggest but again, using the HV battery, with the ICE maintaining it as usual.

 

Thanks DanMan Thats what I want. Is the bus easy to get at?

 

Yes, I think it is. Hobbit accessed it to measure its voltage and current.
Be very careful though. No, not very careful, EXTREMELY careful.

Probably best to tap in on the inverter side of the relays, rather than the battery side. This way you have some level of protection and emergency disconnect.

 

Here is a link to a company that designs a system to use the Prius as a generator to run your home.

http://www.priups.com/

For your needs, the simplest way is to buy a 1000 Watt inverter, hook it up to the 12V battery in the back and leave the hybrid system running. This is not the most efficient means to create 120V as you are taking high voltage from the Hybrid battery, knocking it down to 12V, then pumping it back up to 120V AC. Too many conversions however, the 1000W inverter would be a very inexpensive device to buy and it would be the least invasive.

Don't go anything above 1000 watts though as the DC - DC converter can only put out 1200 Watts and you lose some energy in the conversion.

 

I did some more research on the PRIUPS site and found that you can buy an inverter that will take the high voltage DC and convert it to 3500 watts of A/C power (240V even!) Here is a link to it:

http://solar.sharpusa.com/files/sol_dow ... ter_SS.pdf

This could be an interesting way to use the Prius as an emergency power source or as a power source on a job site or when camping. Just keep the car in Ready mode and you'll be good to go!

 

The sharp inverter is designed for grid tied solar electric systems. It does not work as stand alone 120 volt AC power source. But is designed to interconnect with the power grid. It takes the DC power converts it to AC power. This causes the electric meter on the side of your house to run backwards.

 

From what I read of the specs (not on their site but on the PRIUPS site), there is a way to use it as a stand alone inverter. The problem is that it needs power to get started. I don't know if it needs 110 or 220 but if it only needs a 110 source, a small inverter should do the trick and then once it's running, I believe it will be self sustaining.

The PRIUPS site is pretty interesting about drawing power off of the Prius.

 

Whatever you decide to do, I wouldn't recommend running a 1000 W inverter off the Prius 12 V battery. It isn't designed for that kind of current draw, and it would shorten its' life - a lot. You could add a second battery, say an Optima, paralleled to the existing battery using a "battery isolator" (available from motor home places). You would have to securly tie it down. You wouldn't want a 30 - 40 lb battery flying around inside your car in case of accident.

 

David.. I didn't suggest using the 12V battey to power the inverter. It would be discharged too quickly. My instructions are to leave the hybrid system in Ready mode. The DC - DC converter will provide all the power needed from the hybrid battery and the ICE will start and stop to keep the hybrid battery charged.

The 12V battery should do nothing more than providing a buffer which it currently does now when your A/C fan goes on high, you turn on the rear defrost, lock or unlock the doors, etc.

 

"From what I read of the specs (not on their site but on the PRIUPS site), there is a way to use [the Sharp inverter] it as a stand alone inverter. The problem is that it needs power to get started. I don't know if it needs 110 or 220 but if it only needs a 110 source, a small inverter should do the trick and then once it's running, I believe it will be self sustaining."

The Sharp inverter can be used in a current-drive mode only, and is NOT suitable for this application. It's a pity, really, because it is ideal in most other respects. The PriUPS project uses a big computer room UPS to turn the hybrid battery into 115/230VAC. If the site is giving the impression that the Sharp will do the job, please let me know exactly where it says that and I'll fix it.

1000W is about the limit that can be taken from the 12V system. If you need that as a peak current, e.g., for starting motors, and the average drain is considerably less, an ordinary, cheap inverter should be fine. But if you need 1000W average and more on peaks, it's unlikely that the Prius can handle it and you'll have to look into tapping the HV battery.

Richard
http://www.PriUPS.com

 

On your site, you specify that you can have a 3kW UPS in the trunk as a stand alone for $200+. Since the DC to DC converter cannot supply that kind of current, it would have to be an inverter that can handle the high voltages of the HV battery.

That inverter was the only one I could find on your website (as a direct link) so I made the assumption that was the one needed.

Please clarify where I can get a 3kW inverter for the stand alone unit that I would be able to use in the event of a power failure.

I currently use a Honda Inverter Generator as they are the cleanest and quietest I could find and we tend to lose power here frequently.

 

adding an inverter

For loads exceeding 1000 watts, you are in Richard Factor's world; PriUPS.

For anything less, it is quite straightforward to add an inverter with short and thick wires in the vicinity of the 12 volt battery. There have been several such installations and a few web site descriptions. One of those is on Bob Wilson's Prius web site, I believe.

AFAIK all have used modified sine wave inverters for this, even though pure sine wave would do better with inductive loads. $400 is probably the minimum price for pure sine wave; modified 1/4 of that.

As mentioned the car must be in 'ready' mode to draw high current from the 12 v system.

What I always inject into these discussions is a caution to add your own 'sacrificial' fuse, prior to the Prius 125 amp main fuse. If you lose the latter, the car does not run until a somewhat complicated replacement. Not one that you would want to do on the side of a road.

 

There's also the question of how much current the DC-DC converter could actually handle. It is probably about 80A on average, with peaks possible up to 100A. There's a 100A fuseable link on the converter side.

 

That's a little scary.... If the converter maxed out at 80A, then a 100A fusible link would probably be safe as the battery would put out the remaining juice needed during surges. You could limit the load to around 800 Watts and probably be OK. However, if the converter can hit that 100A then it alone could blow that fusible link during a surge.

Even if you used a smaller inverter (let's say a 750W) there is still a chance of a high surge and that could blow that link.

I wonder if it is designed to blow quickly or if it could handle the 100A draw for brief periods without blowing.

 

Depending where you tap. It is confusing how they have the power distributed according to the wiring diagram.

The battery has a 120A fusable link, this is clear.
But some loads go directly to the converter through their own fuses, and some loads are on the battery side of the 100A fuse. It seems that the 100A link is probably there to protect the converter from the battery should the battery terminals be shorted (say by the battery itself), which may not blow the 120A link.

Don't forget, no matter what current load we determine the converter to be able to handle, whether 80A or 100A, the car itself has a load on it. Remember, the car is in READY for the converter to be available.

Wow, that JBL amp has a 30A fuse dedicated to it.

 

That's a great point. I hadn't factored in how much the car alone will be using. I guess it makes sense to shut off as much as possible.

 

Hmm, this reminds me, I should pack my 300W inverter and extension cords for tomorrow.
My friend is selling his house, and has been fixing it up some so it has a better chance of selling. He already moved out, and the electricity is supposed to be shut off any day. I realize my inverter won't handle a vacuum cleaner or rug cleaner that we might need to use, but we may need a few lamps here and there, even if we are going to work in the daylight.

 

One of my favorite items I use when house hunting is a "Pocket Generator" by a company called Victor. It is a small gel cell 12V battery and a 50 watt inverter. The entire package is about a 5" cube and weighs about 5 lbs. I carry that and a 13 watt flourescent light and I have never had the battery die and it's great for looking in homes with the electricity off or in basements, attics and sheds when lighting is not good enough.

 

"On your site, you specify that you can have a 3kW UPS in the trunk as a stand alone for $200+. Since the DC to DC converter cannot supply that kind of current, it would have to be an inverter that can handle the high voltages of the HV battery. ... Please clarify where I can get a 3kW inverter for the stand alone unit that I would be able to use in the event of a power failure."

My answer to "where can you get" is usually "eBay." The smaller inverters, greater than 1kW but less than 10kW typically will NOT run right off the hybrid battery, but need anywhere between 24VDC and 180VDC depending on make and model. For my trunk-mounted units, I've found the Compaq/HP XR1500 and XR3000 units to be useful, which work on 48VDC or 110VDC respectively. This means that you need a separate power supply to step down the hybrid battery to the battery voltages used by the inverters. Of course this results in a (minor) loss of efficiency and makes getting the hardware that much more complicated.

The XR inverters typically are cheap (<$100), especially if the batteries are bad. Since you don't need the batteries and they are most of the shipping weight this is the way to go. Of course, there's some risk to buying on eBay, but I've been very lucky so far.

For info on using these inverters, see:
http://www.priups.com/misc/bonus-15mar06.htm

As far as stepping down the hybrid battery to the right voltages, that's another story, also covered at that link.

Richard

 

Big inverter on the 12 volt bus

I preceeded the 1000 watt inverter with a 100 amp ANL fuse, until reading up on specifications, such as may be seen at:

http://www.bussmann.com/library/bifs/2024.PDF

At present I am using a 60 amp ANL fuse and even that might not be 'sacrificial' enough. Cause who knows how fast the Prius fuse will pop?

On 2001 Prius, I tapped into the +12 v line quite near the battery. A neater way to to this would involve fused distribution blocks as used by the thumping car audio folks. BTW the rear of the center console is a good place to install a 110 vac socket. They are available in nearly-matching gray. May be possible to do the same in the new model Prius?

As far as the Prius' DC/DC converter maximum output, Bob Wilson loaded it (2003 Prius) up rather heavily via a modified sine wave inverter, and observed its output voltage to drop. He was 'pulling the tiger's tail' there, in my opinion. But as the amps went up, the volts went down, and the watts stayed right around 1000.

At some point, the Prius 12 volt battery may help out on load peaks. Not a subject area that I know much about, but one could stack the deck in their favor by replacing with a larger battery. More amp hours and less internal resistance. Lee Hart found this one:

http://www.surpluscenter.com/item.asp?U ... em=11-3096

This puts about 20 lb weight penalty in the Prius (not counting the added inverter), so may not be the best thing to take along for an mpg competition. But neither is the rear seat, for that matter...

edit: remember, your warranty is not my problem

DAS