Ive read about folks using the car with an inverter to power apliances during blackouts, im not interested in warranty issues just a few facts on operation, I dont own one but am curious. Does the 12v lead battery start the motor, Does the traction battery tell the motor when to start because it is low. If a load is on the 12v lead battery does the traction battery keep it charged when motor is off Why have a 12 v lead battery Can a 1000w inverter be used safely but only pulling 500 watts Is cooling components an issue in winter or summer if not driving. The Auto starts when ON if traction battery is low, and motor shut off. Can power, kwh produced be monitored- recorded by the car if generating for an inverter. Do many use the car for emergency power Can it be done safely by someone with experiance with generators, transfer panels and AC power What are logical drawbacks and limitations
This seems to be a highly optimized solution - thank you.
My inverter (true sine wave) has an inrush thermistor, but I'll add your suggested RF toroids.
When drawing more than a kW I don't see the voltage drop that you reported. It could be internal resistance because conversion to 18650 Li-ion cells affects both energy-density and energy-flow. Thoughts? (my car is an '04)
My inverter is heat-sunk onto a thick (0.5") Al plate, battered into a shape such that it attaches to the car's sheet metal at several points and becomes a heat pipe. It stays pretty cool for short-term use, but I added a 12V computer fan to keep air moving over the outer finned case. It vents into the car with no problems, but I've been thinking of running the air to the outside. If I make the system more automated like yours, heat may become an issue. What do you think?
Also, as I understand your diagram, the traction battery charges the 12V circuit when the 'ignition' is ON, and you've added an automatic switch to the 'ignition' circuit. Can you provide details of that circuit?
We just bought a 2.5kW gas generator for backup purposes, so the Prius solution is less important. I may restore the original battery, freeing up the Li-ion pack for other uses.
I use the toroids to block higher frequencies from feeding back into the
12 VDC bus. I didn't want inverter noise to feed back into any of the ECUs. The inverter vendors advises against toroids but they are there to protect the $10,000 car, not the $100 inverter. So far, I've had no problems.
Did you rig up a separate LiON pack as an energy storage buffer? Do you have a skematic and/or photos somewhere?
I've racked my brains to figure out an affordable, power isolation approach. Sure I can put in a 100A diode so current flows one-way but there would be a 1.2 VDC forward voltage drop, 120 W.
The only way that makes sense would be a power MOSFET with a current sense amplifier for the gate. This would provide a fractional forward voltage drop. Properly designed, it could limit maximum current draw from the car and thus protect the fusable link. But there lies the path of madness.
The next thought is to build a switching power supply with ultra-capacitors as the energy buffer. The advantage is no battery chemistry risks. But once I start that path, when do I stop?
In my case, I lower the hinged panel to access the inverter. This puts it in one of the prefered mounting orientations. The unit already has an internal fan and it is thermally protected. Since I still need to run the power into the house, I simply keep the trunk cracked open and any heat easily escapes.
Not quite. I modified my inverter to provide a remote ON/OFF switch. This allows me to use the inverter when traveling to provide 110 VAC for laptops or other light duty devices.
It is very important that the vehicle be ON and in "READY" when using the inverter. The 12 VDC battery does not have enough power to run long and you need to let the Prius engine cycle as needed to maintain traction voltage. So my remote switch is powered by the cigarette lighter circuit. This circuit is only on when the car is in "READY."
Only because I'm leary of LiON batteries due to their notorious temperature sensitivity and constant current charge-discharge characteristics. I'd probably replace them with NiMH if only because NiMH are less finicky and don't have a reputation for self-destruct. But it sounds like a clever approach to handling surge loads.
Well, there is the olde generator voltage regulator approach: a relay with a current bucking coil added. You would have to wind your own bucking coil (which is no easy thing with compact relay designs) and it is not a perfect zero-crossover switcher, but it does offer essentially no forward voltage drop. Maybe a more modern approach would involve a relay driven by a current sensing driver.
This thread stimulated me to pull the system apart (before the game). Tomorrow I'll put the original battery back in the car. The Li-ion pack simply replaced it, but it will return to its role powering a scooter. For my purposes, the original lead-acid battery will handle the load.
btw, pin 2 of the leftmost connector of the block under the steering wheel is always-ON, and sufficed for light loads and a small inverter until I got carried away.
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