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

[Carmat76]

I appreciate your advice. I’ll order the Classic 250. If I can direct charge at 2000 watts or a bit more I’ll be quite happy!

[Carmat76]

Crazy idea time lol forgive me in advance... what if I just bring Prius 12vdc into my battery bank. I’ll branch off with 4 pairs and charge 4-12v sections simultaneously.

[Ampster]

Crazy idea time lol forgive me in advance... what if I just bring Prius 12vdc into my battery bank. I’ll branch off with 4 pairs and charge 4-12v sections simultaneously.

Do you know how the Prius charges that 12 volt battery and the capacity of that charging. Is it an alternator off the motor or a DC to DC converter from the high voltage pack?
Most likely, unless you have some way of disconnecting the series connections between the batteries you will get a short circuit if you were to connect your branch connector without isolating the batteries or the branch charging cable.

[Carmat76]

I picked up a Schauer JAC1548H for $50 and thought I’d play around with the Prius 12vdc option while I wait for the Classic 250. It’s a golf cart 15A 48v charger. I found out my modified sine wave 12v inverter (2000watt) will not run that charger properly. Maybe it’s ok but that inverter seems to be flickering the charger power and switching it on / off rapidly. Thought I’d shut it down before I let the smoke out The charger is fine when plugged into my generator 120v outlet.

[travissand]

Crazy idea time lol forgive me in advance... what if I just bring Prius 12vdc into my battery bank. I’ll branch off with 4 pairs and charge 4-12v sections simultaneously.

The short answer is no don't do that.

It's Possible but not worth it unless you're in the middle of a zombie apocalypse.

You would have to disconnect the series string of 48 volts and put them all in parallel to charge them this way. You can't hook them up both ways at the same time it will short-circuit and the cables will be glowing red and melting battery terminals. And you must be careful the resistance isn't too low for the Prius to handle. People have reported pulling a thousand Watts out of the 12 volt system successfully for a few hours at a time. That sounds hard on it to me.

I'm just worried that if your battery bank is too large it'll try and pull more than a thousand Watts out. My AGM battery Bank Love's charging at amperages higher than it's rated for. There's a few ways for me to throttle the amperage. One way is I could lower the absorb voltage which you can't do with the way you're planning. And the other way is to go into the charge controllers menu and set the maximum amperage allowed into the battery. Which is another thing you can't do the way you are planning.
If your battery bank is too large and thirsty for the Prius 12-volt system you would need to put an inline resistor of a huge amperage ability and I'm not sure the math on what size you would need but it's possible.
So basically no you can't do that. Rewiring your battery Bank every time you want to charge at night would be a pain in the butt. Because then of course you would have to use a 12 volt inverter to power the house so you'd have to hook that up to or do some very very expensive complicated huge amperage switches around with heavy gauge stiff wires all over the place.

[travissand]

In your inverters manual chapter 1 page 12 talks about AC coupling.

Your inverter is it's capable of AC coupling kind of like what I spoke of earlier about the unregulated backfeeding incoming AC / generator power through the inverter and charging the batteries with it. Except the Schneider does it more intelligently then the example I spoke of earlier. The Snyder can shift its AC frequency in a sort of attempt to communicate with the other device. If the other device is capable of responding correctly to the shift it will reduce its output. A lot of grid-tie inverters are capable of this behavior.
For us Schneider inverter owners this would be most useful if we decided we needed more solar panels but didn't want to buy charge controllers for them. We could use grid-tie inverters which are notoriously inexpensive. We could tie their output directly to the output of the Snyder they will play nice, the Schneider can intelligently manage the power and even use it to charge the batteries. and it can do all that without even needing to pass that power through its AC input breaker where you would normally hook up your generator.

Manuel also says if you're doing this do not hook up a generator. But it seems to me like it would be fine as long as the generator never ran during the daylight hours.

[Carmat76]

Back to my interim experiment with charging 48v batteries with the Schauer 15A charger... the charger will not work unless I’m plugged into my SW4048 Schneider inverter output. I have tested three other inverters, all new, including a pure sine. These small units connected to a 12v batter will not run the charger. Any ideas / explanation s for me? Thanks!

[travissand]

Back to my interim experiment with charging 48v batteries with the Schauer 15A charger... the charger will not work unless I’m plugged into my SW4048 Schneider inverter output. I have tested three other inverters, all new, including a pure sine. These small units connected to a 12v batter will not run the charger. Any ideas / explanation s for me? Thanks!

First I thought maybe it was a modified sine wave vs. Pure sine wave problem but If it really is a pure sine wave inverter your hooking to the 12 volt battery. And what I mean is it's a quality unit not a fake. Then the problem must be not enough amperage voltage available to the inverter from the 12 volt system. This could be because of a improperly crimped / bad connection or the wire gauge between the battery and the inverter is too small.

I also have a 48 volt golf cart charger and I've noticed if I measure its inrush surge like when it first starts charging its much larger then its first charge rate. Maybe this surge is too much for your inverters rating?

Another thing is your chargers power factor might be bad. So perhaps it's only consuming 900 watts from the inverter but in fact there's 1500 watts moving through the wire back and forth. Kind of like I'll take 1500 watts and then I'll give 600 back and you can give it back to me on the next wave. the inverter is only required to produce 900 watts but because of the chargers bad power factor it's forced to handle 1500. My iota chargers work like this. It's very frustrating because it overloads my 2000 watt Honda inverter generator even though I'm only charging at 1200 watts. My golf cart charger has a very good power factor and I don't have that problem at all other than its initial search which my Honda generator handles no problem.

[Mike90250]

Most battery chargers have terrible power factor. That doubles the wattage of inverter needed to power it. I would not expect any mod sine inverter to be able to power it.

[travissand]

These small units connected to a 12v batter will not run the charger. Any ideas / explanation s for me? Thanks!

Call the manufacturer of your charger and ask them about the power factor. I couldn't find the specs for power factor their spec sheet.
800-899-VOLT (8658)

[Carmat76]

That’s a big help guys... likely explanation for why my inverters are struggling. I will call Monday. Im looking forward to getting the Classic 250

[travissand]

The prius consumes 0.98 gallons for 16 hours of use.

The Honda eu2000i is 2 gallons for 16 hours of use.

Probably 390w average output. Which comes out to 31 kilowatt hours.

That's that 6.2 kilowatt hours per gallon.

And at $3.50 a gallon that's $0.56 per kilowatt-hour which is only $0.06 more than the electric company charges here.

These these numbers are just roundabout educated guessing for now, so nothing scientific yet. I would expect the true numbers to be not more than 20% different give or take. but I can tell you I've been burning 2 gallons every night consistently in the Honda for many many months. Now that I've been running the Prius instead for those 16 hours for the last 5 days I've only been able to fit 5 gallons in when I filled it up. and yes I did shake the whole car around it and make sure it was actually full. If you don't know they have bladders inside the tanks that interfere with filling sometimes.
I do normally consume 500 watts continuously until about 2 a.m. and then my consumption probably drops to around 250 w average until 8 a.m. when the sun hits the panels and the the solar takes over. At this point no one's around to shut off the Honda sometimes until it runs out of gas around 9 or 10 a.m. So we've been shutting off the Prius at some point normally between 10 and 11 a.m. because we forget it's on cuz you can't hear it.

One thing worth mentioning is when the Honda generator is running it is actually powering the house directly. There is no charger plugged into the Honda. I chose to do it that way because if I plug in the charger instead the Honda won't last through an 8 hour sleep cycle without running out of fuel and gets overloaded very easily because of all of the extra losses involved with an inverter generator changing its own DC output to its AC output and then the charger changing it back to DC for the house inverter to change it back to AC again. Using the charger with the generator leads me to a 30% reduction in fuel economy.
I do sometimes use the charger instead but only when I know the loads are going to be light and I don't want to deal with the automatic transfer switch and the start-up surge on the refrigerator interrupting my internet.

[Carmat76]

It’s working... probably not efficiently but the Prius ICE is cycling and I’m charging my 48v bank at a constant 15A.

9A160FF5-DDE4-4C01-9ECA-ACB35C291852.jpeg

[travissand]

It’s working... probably not efficiently but the Prius ICE is cycling and I’m charging my 48v bank at a constant 15A.

9A160FF5-DDE4-4C01-9ECA-ACB35C291852.jpeg

even with the inefficiencies I bet it's still a better use of your gasoline then running a normal generator

[Carmat76]

You’re probably right. What app do you use to watch fuel consumption? I am using Dr. Prius to watch the hybrid battery but I’m wondering about the other details now.