Prius as backup generator with midnight classic as voltage converter possible?

[travissand]

I played with the U-set mode and I don't like it. I set the mppt sweep interval to 0 so it'll only do a sweep the first time it turns on. I set the sweep parameters to stay within 3% of voltage open circuit. The problem is as the Prius battery drains down it's voltage beyond the 3% the classic will simply switch to rest mode and stop helping. When this happens since there's no load anymore on the Prius battery the voltage rises a bit and then when the classic sees that it's back within range it turns back on and initiates another sweep so it finds the best mppt from that new sweep point and starts pulling the correct amount of power out of the Prius again. Then the Prius battery voltage starts to drop and the cycle repeats itself.

If I stood there and push the enter button to force a sweep every few seconds it works pretty good.

so I went back to the sweep interval adjustment and it's only adjustable in 1 minute increments. so the lowest increment of sweeping every one minute is not often enough to avoid the problem. also with the one minute sweep interval it's annoying because the kids will turn on the microwave in the house and the classic is resting so all the power comes from the house batteries. Then the batteries charge rapidly after the classic turns itself back on at some point and does a new MPP sweep. This is just needlessly cycling the house batteries.

I like the wind setting better because it never does a sweep and you can set the cut in voltage so it will also never draw the Prius battery down below what you specify.

[travissand]

I'm almost thinking since batteries are so dang expensive it might be a good idea to use a supercapacitor bank in the place of the house batteries (or a small but high amperage ability house battery bank) and leave the Prius on indefinitely. During the daytime most of power will come from the sun and every once in awhile maybe the Prius will give a boost. Then at night all the power would come from the Prius instead of draining the house batteries. Sure then you're paying for gasoline but that might be cheaper than paying for a new large house battery Bank every 5 to 10 years.

It's all quite complicated and thinking with a large enough lithium house battery Bank the Prius / generator wouldn't be needed at all and there'd be no complicating anything. That's looking like an attractive option even though it's expensive.

[travissand]

After messing around with the wind graph settings & maximum amp limit in the charge menu I still have the resting cycling problem. Since this is never a problem in the absorb phase of charging I'm thinking I'd like to have two classics that way I'm capable of pulling 4000 Watts out of the Prius and It will be less likely to enter into the bulk phase. Keep in mind that when it's in the absorb phase it's not really at the true absorb voltage recommended by the house battery manufacturer. I have turned it down to about float voltage because the batteries are already full and I'm not trying to charge them at this point I'm just trying to let the power pass from the Prius through the classic to the inverter to power the house without draining the house batteries.

[travissand]

I want to focus the Prius on charging the batteries and I’d like to use a Classic 250 to do this. It seems simple and efficient. I’ll order the 250 and start to collect some smaller items needed. Thanks for the code reader / app recommendation.

I talked to classics tech support today I think it was Doug he's not too interested in supporting unapproved uses but helped me none the less.

One issue I'm having is if the battery voltage and the absorber voltage set point are far from each other the classic will switch to bulk and then classic will go to rest and cycle back to bulk and then rest repeatedly. If I lower the amp limit very low it doesn't happen but that defeats the purpose. I'm not done experimenting with the wind setting but next I'll try the U-set mode and see if that gets rid of the irritation.

one thing that helped a little is tying the wires from the classic directly to the house batteries instead of the bus bar where the inverter is also connected.

[Ampster]

Glad to see some 15 year old Prius's providing some value. I found a wrecked Nissan Leaf and harvested the batteries for backup. I am grid tied so I don't need the generation capability.

[Carmat76]

I want to focus the Prius on charging the batteries and I’d like to use a Classic 250 to do this. It seems simple and efficient. I’ll order the 250 and start to collect some smaller items needed. Thanks for the code reader / app recommendation.

[travissand]

The other aspect of your two choices are efficiency. Which way is more efficient? My method it's probably more efficient because I know the classics efficiency is very very good. My method is definitely more efficient if your goal is to charge your lead acid batteries.

Think about all the inefficiencies of using the DC from the Prius going through an AC inverter and then into your Schneider and then converting back to DC again to charge those batteries.

With the UPS option However once the batteries have reached your desired state of charge and the AC power it's producing is basically going straight to the house through the contactor relay in the Schneider the Snyder will go to sleep saving you power while its internal DC charger floats your batteries efficiently. so then from that point on the efficiency ratings are all dependent on the ratings of the UPS inverter itself which I believe we're about the same as the Schneider anyway.

I'm probably overthinking this anyway but if efficiency was the goal you could do both. Just use the midnite only when you're trying to charge the house batteries and use the UPS inverter AC power output to go through the Schneider to the house but disable the DC charging in the Schneider's menu. Then you have the best of both worlds. and if you want the best of all three worlds figure out a way to automate the whole thing.

[travissand]

If you used the UPS inverter option and your house was consuming less than its Max rating your Schneider will essentially go to sleep and stop consuming that phantom draw of 70watts. The problem that I had though was when there was a large demand suddenly from the house the Snyder would take a second to wake up and help out. Even if it was already helping when the surge hit. I'm not sure if mine was slow to respond because it was defective or if they're all like this.

[SunEagle]

I wrote a lengthy reply and pretty much don't purchase the midnight yet. My reply is unapproved I'm not sure if it's pending approval or why it's unapproved but I'll work on getting it through

I approved your post. It was held up due to the multiple web links in it. All is good.

[Ampster]

Glad to see some 15 year old Prius's providing some value.

[travissand]

Wow... this thread is so timely! I live in Ontario Canada outside of Ottawa on 50 acres. We are off grid with a 48v lead acid bank charged by the sun when it shines through 2 Classic 200’s. My Conext SW4048 does the job of powering my house. I’ve played around with various generators. Some I could auto start with my Schneider AGS. I am receiving a 2004 Prius today purchased to be our new generator ($700CAD sweet deal I think). The Midnite Classic 250 Buck at discount price is in my shopping cart from last night. I’m not much more than a novice tech-wise but I knew this was possible. Can I get a bit of hand holding on this going forward? I guess I need to pull the trigger on the Classic 250. Again... sweet timing and thanks for the posts!!!

Sure. Most likely you've made an excellent choice. Does your Prius have any of the high-voltage battery problems like so many do?

First first thing you need to do is buy a Bluetooth code reader for the Prius. I read a great deal of info on which reader to get and I eventually stumbled on a thread that talked about it. I think it was at priuschat. Com but pretty much I decided to get the $10 code reader and it has the right microchips to read every battery cell in the Prius. https://www.amazon.com/dp/B011NSX27A..._2lEoEbXMQ9NCR

Then then purchase the doctor Prius app. I believe they have one for the iPhone as well but I think there was some limitations there like Bluetooth or Wi-Fi doesn't work with the iPhone version. If you're using an Android it all works fine. Trust me you'll love the ability to see an app designed just for the Prius information about power in vs. Out and cell voltage. It also has the ability to read all the battery codes that other apps seem to miss. And you can clear the battery codes which so far I have to do every time I turn on my Prius as a generator. https://play.google.com/store/apps/d...om.nexcell.app
there's plenty of tutorial videos on how to access the high voltage battery contactor terminals.

I'm not sure where the best place to hook up to the Prius is yet but right now I have it hooked up underneath the small metal cover on the driver side right next to the high-voltage battery. I have it hooked to the driver side of the contactor which is the side that doesn't have any high voltage when the Prius is off. I need to poke around the Prius UPS threads that already cover so much of attaching an actual inverter to the high-voltage battery. Maybe they know where the best place to hook up is without throwing codes.

Your off-grid and you have lead acid batteries you probably already know it's bad to leave them at a low state of charge. There's two methods you have to choose from and both methods will give you the ability to charge your batteries / power your house intelligently. I'm split between recommending you use my method vs hooking a UPS inverter directly to the Prius high voltage battery instead. In the classics menu you can very quickly and easily change its output voltage so whenever you need to start the Prius as a generator you'll be able to make the decision on whether or not to charge the batteries or simply hold them at their current state of charge. It's too bad you are midnight is a 200 because if it were a 250 you would already have what you needed.

I have a Schneider connex 4024 so I'm probably familiar with your 4048. Your inverter I assume is the newer type that will loadshare so you could actually get a UPS inverter and run it's 240 volt output to your Snyder inverters input breaker. You have the AGS which enables load sharing so your inverter will actually help the inverter in the Prius if your house is drawing more than it's rated for. and then of course when you're not using more than it's rated for your inverter will use that extra incoming AC power from the Prius to charge the house batteries up to the amperage you program.

Your AGS is probably capable of hardwiring directly to the start button of the Prius and might be able to automatically turn on both the Prius UPS inverter and the Prius as required but it would take some brain power that I have not yet exercised. Schneider has Advanced communications abilities as well that might be able to communicate to an UPS inverter to command it on and off.

[Carmat76]

Wow... this thread is so timely! I live in Ontario Canada outside of Ottawa on 50 acres. We are off grid with a 48v lead acid bank charged by the sun when it shines through 2 Classic 200’s. My Conext SW4048 does the job of powering my house. I’ve played around with various generators. Some I could auto start with my Schneider AGS. I am receiving a 2004 Prius today purchased to be our new generator ($700CAD sweet deal I think). The Midnite Classic 250 Buck at discount price is in my shopping cart from last night. I’m not much more than a novice tech-wise but I knew this was possible. Can I get a bit of hand holding on this going forward? I guess I need to pull the trigger on the Classic 250. Again... sweet timing and thanks for the posts!!!

[Mike90250]

I hope you are leaving your garage door open, so you dont poison yourself when the Prius starts up to charge it's battery. Or are you running the power cord from the car outside, under the closed garage door ?

Awesome you got it working with your battery & inverter

[travissand]

This is working so freaking beautifully. I played with the wind curve charts and pretty much I have it cut in at 196v at a low wattage (185w) output and then as the voltage rises to 203v its output is set to put out 2347w. Which is 46 volts * 51 amps. And then on up to 249 volts I have its output set ridiculously high because it forces you to go 1 amp higher for every step and it forces you to use all 16 steps. But in the charging limits I have the output limit at 55 amps so I assumed it would never go over that anyway.

Now the strange thing is I've never seen the output go over 50 amps into the inverter at house battery voltage which is 46.3 volts * 50 amps =2315w. I'm not quite sure why this is but dang I'm impressed regardless. The classic gets warm but not near as hot as I thought it would considering the huge conversion it's doing and relating it to my past experience with high incoming voltages on the classic 150 making a lot of heat. Remember though I'm only pulling over 2,000 Watts out of the Prius occasionally to run the microwave or something so maybe if I kept the microwave running for hours heat in the classic would build.

I went outside and had a panic attack when I couldn't hear my Honda generator echoing off my neighbor's house. Realizing that I don't need to run that damn thing anymore it stinks. now I'm hearing all kinds of sounds I normally can't hear over the noise of my own generator like my distant neighbors generator sputtering as it runs out of gas LOL.

I watch the Prius high voltage battery drop its voltage as its engine demanded power from it to start up. As soon as the voltage drops below my cut in the midnight stops taking power from the Prius so that way there's more for engine cranking. Using the wind curve chart is definitely the way to go. I know the curve is kind of backwards because it's built for a windmill. With windmills you take higher amperage out the higher the voltage but when you're pulling power out of a battery the voltage drops as you take more amperage so it's kind of backwards but it works.

When I initially start up the Prius it throws a high voltage battery code. I have the classics input connected to the Prius on the side of the contactor that has no voltage when the Prius is off. There's a small spark when I hook it up because the midnight is providing 37 volts to the Prius. I think the small voltage feeding into the Prius is what's causing the code.

Now the next project is to hook up an adreno or raspberry pi to turn the Prius off and save the 300 watts that the Prius requires while it's in standby waiting to start its engine. The program would monitor the battery voltage and turn the key on when the battery voltage got low enough to warrant starting up the engine to recharge again. I predict on one gallon of fuel I'll be able to get a run time of 14 hours with this modification. Right now according to what I've read from other people I'll be using 2 gallons for 16 hours of run time which is the same as my Honda eu2000. During the 16 hours the classic will be outputting 325 Watts on average. Not bad for a generator that's capable of tremendous surge capacity! it's the Best of both worlds. The fuel economy of a 400 watt generator with the ability to pull out over 2000w when you need it.

And after that project I'd like to use some lithium titanate batteries in the Prius because they have such awesome C ratings and four times the cycle count rating of lithium iron phosphate. Or maybe supercapacitors but I would need so many. I'm just wondering how much life I'll get out of the stock nickel metal hydrides that are in there now. The thing already has 200,000 miles you know.

No more stinky generator no more weekly oil changes no more neighbors mad at the noise. No more tiny fuel tank. No more overloading the generator and browning out everything with the internet rebooting and kids screaming bloody murder.

For the past few hours my Prius has been silently keeping our house going and I am wishing I had done this a long time ago. Now with my new lithium batteries on the way soon I won't even need to run the Prius or any generator at night.

Everybody who's truly off grid should do this if they don't have a large enough lithium Bank. Heck I'm thinking the cost per kilowatt-hour might be so low that off-grid people could simply have this generator setup with no solar panels and just a real basic small battery Bank and quality inverter. The gasoline bill would likely be low enough for them to save some money up for a large amount of quality panels and lithium batteries. The cost per kilowatt-hour is probably about $0.50 which is the same as what the Hawaiian Electric company charges. And if your consumption is low and the adreno mod works that might be $0.30 per kilowatt hour.

[travissand]

It's working! I had to use the classic local app on my laptop and program the wind curve through the network. Then I walked over to the classic and viewed the curve and I could actually see it at that point despite the screen irregularities.

I never tried the U set % mode.

I'm trying to understand the amperage on the wind curve. Midnight's YouTube video on the subject says that the amperage you choose is the max amperage available to export to the battery at that voltage but it was going up to the maximum amperage output that I had set in the regular charging menu despite a lower amperage setting at that voltage in the wind curve chart. I'm not quite sure cuz I'm a little bit mind boggled by all this so I'll study it more thoroughly but it's working!... Oh and did I tell you it's working!