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I think you're misunderstanding some of the fundamentals. Charging current is limited by the voltage of the system. As the battery fills up, it can no longer take on additional charge at 14.1V. Here's a good website that explains how battery charging works, this website can teach you almost everything you could ever learn about batteries: Charging Information For Lead Acid Batteries – Battery University

The AGM batteries in the hybrid system aren't designed to cycle quickly like a typical starter battery. You really should only be running the inverter on the system when the car is in ready mode. If you want to run some tools temporarily without the car powered on, your best bet might be to look at some off-the-shelf Lithium battery solutions. Lead Acid is heavy and messy, and the hybrid isn't design to charge two LA batteries at the same time.

Hope this helps!
Thanks for both the advice and the source, I will certainly consider/check those.
 
Go over to priuschat.com. There is years of information over there about hybrid charging systems and their capabilities.

Many people run a 1000 watt true sine wave inverter with the car in ready mode. In fact Toyota has 1500 watt inverter as an option in the new Highlander hybrid, Rav4 prime and Senna.

You are right about charging voltage, I have no saying in that. What I don't understand is how charging current is limited when the DC-DC converter does supply around 1000W of power from that same line. (Internal resistance of the battery is almost negligible at 0.1-0.2C)


I just want to able to run some tools even when the car is not in ready mode and don't want to risk of draining the auxiliary battery since it would still result in me being not able to run the car :D
 
Question for those who name the new price of a car and say this is a risky idea: how, specifically. I am not saying it's risk free, but here are the realistic risks:

A. You might short the positive terminal to the chassis long enough to start a fire. Mitigation: use a battery connection with a fuse.

B. You might draw so much power for so long you overheat the 12v agm battery. Mitigation: the battery will vent gas when this happens. If the vent tube is connected, good. If this happens, you need another $200 battery.

C. You drain flat or cycle the 12v battery too much. Mitigation: buy another $200 battery.

D. You run the car in an enclosed garage. Mitigation: Darwin award.

What isn't a risk? The 12v supply in the vehicles inverter is NOT going to overload if you draw too much power. It will hit an internal limit on current and throttle the FETs. Nothing is going to happen to your 40k car unless you start a fire.
 
A) That's what cable insulation is for.
B) this shouldn't be an issue if you keep the car in ready mode. I've also never heard of a leadacid battery overheating from use like this (unless i'm misunderstanding you). The Rav4Hybrid has an issue where it will drain the entire battery overnight, it hasn't caused any additional problems yet!
C) same answer as B
D) yep! hahahaha

I've seen a lot of people talk about this on prius forums and no one has complained of any issues yet, thankfully they've tried it out so none of us have to screw up our cars trying it out first!

I want to know what Toyota uses for the 1500W inverter on the Rav4P when it comes out. It would be nice if it weren't too expensive/easy to install aftermarket.
 
A) That's what cable insulation is for.

I want to know what Toyota uses for the 1500W inverter on the Rav4P when it comes out. It would be nice if it weren't too expensive/easy to install aftermarket.
A is a problem as cables can chafe, etc. To be safe the fuse is mandatory.

Depends on how Toyota does this feature. If they tie into the 12v battery you might as well do the same with a $200 pure sine inverter. Connected directly to the battery with a fuse. If Toyota connects to the hv pack you have several problems. 350 volt dc input inverters are much more expensive, and it's not as easy or safe to aftermarket install one. You can do it, but you need to be a lot more careful, and to deenergize the system first by pulling the orange safety plug, and so on.
 
Is it likely that this is the 1500W inverter that the Toyota hybrids are using? If so then it seems to specify that it is connected to the high-capacity battery rather than the 12V battery that the 400W, 150W, and 100W DC-AC inverters are using.

1500W DC-AC Inverter
This Inverter delivers a maximum output of 1500W using the electrified vehicle's high-capacity battery. It enables electrical appliances that consume a large amount of power, such as microwave ovens, vacuum cleaners, and hairdryers to be used inside the vehicle, and can also be used as an emergency power source during disasters.
(Note: May not operate depending on the electrical appliances.)


Image
 
Is it likely that this is the 1500W inverter that the Toyota hybrids are using? If so then it seems to specify that it is connected to the high-capacity battery rather than the 12V battery that the 400W, 150W, and 100W DC-AC inverters are using.

1500W DC-AC Inverter
This Inverter delivers a maximum output of 1500W using the electrified vehicle's high-capacity battery. It enables electrical appliances that consume a large amount of power, such as microwave ovens, vacuum cleaners, and hairdryers to be used inside the vehicle, and can also be used as an emergency power source during disasters.
(Note: May not operate depending on the electrical appliances.)


Image
Yeah that's got to be it. Notice the orange plug. 1500w is disappointing, however - clearly the battery can supply immensely more power than that and Toyota could have put a bigger inverter. You can DIY and get basically the same feature for a few hundred bucks yourself. You lose efficiency with the DC - DC conversion to 12v, maybe 5-10 percent but whatever.
 
I’m rather impressed by the utility of the 1500W outlet given how little they seem to be touting the feature. I’m thinking of power tools in the field, tailgating appliances, portable PA systems, a flat screen TV, as well as emergency backup power for household appliances. As part of the 2020 Highlander Hybrid Limited/Platinum trim, it offers the functionality of about a $1000 portable generator rather than the $5000 variety. Apparently, the usage of the 1500W outlet is limited to 1 hr unless the vehicle is locked but, presumably, an extension cord can be run out of an open window.

Edit: The newly announced 2021 F-150 Hybrid will come with a 2.4kw AC inverter upgradable to 7.2kw inverter in the bed. That’s some manly power, there.
 
Yeah that's got to be it. Notice the orange plug. 1500w is disappointing, however - clearly the battery can supply immensely more power than that and Toyota could have put a bigger inverter. You can DIY and get basically the same feature for a few hundred bucks yourself. You lose efficiency with the DC - DC conversion to 12v, maybe 5-10 percent but whatever.
DC to DC converters on these toyota hybrids only have been used up to 1000W, not 1500W. I wonder what the OEM/aftermarket kits for a 1500W DC to AC converter will cost. If the price is too high, then I think I can live with a 1000W on my future R4P.

Knowing me, I'll likely end up with the 1000W DIY converter with an install similar to OP, haha. While 1500W would be nice and cleaner, as I think about it... I would only use the extra wattage for heating applications likely, and we already have gas stoves. Butane is super cheap and fairly easy to find at stores.
 
Hybrids may have been capped at 1000W inverter, but the new 2021 Rav4 Prime has an optional 1500W inverter (must buy weather, Audio, and Premium packages). As per Toyota newsroom; Get the First-Ever 2021 RAV4 Prime Starting at Under $40K MSRP - Toyota USA Newsroom

Weather with Audio and Premium Package (+$5,760)
  • Weather and Audio package plus:
    • AC (6.6kW) Enhanced Charger
    • Digital Rearview Mirror
    • 120V/1500W AC power outlet in cargo area
    • And much more
 
There was a company, Converdant, I think, that used to do the high-voltage mod to connect to the Prius hybrid battery and then you had an external inverter that looked like a PC tower. I think it was well over $1000 plus $500 for the battery connection mod and would risk voiding your hybrid system and battery warranty. Not surprisingly, they don’t do those anymore. Especially, now that the warranty goes to 10yr/150K miles.

There is a lot more interest in backup generators among ordinary folks, these days. PG&E just pleaded guilty to something like 80 counts of manslaughter related to the wind-fueled California fires which probably ensures that above a certain wind speed (45 mph gusts or something) power companies are going to be implementing regular blackouts to reduce fire risk. Most people are stocking up a lot more in their refrigerators and freezers, these days, due to sheltering-in which makes any outage more than inconvenient. Even if you have a portable backup generator, having another one that travels with your vehicle seems very worthwhile at certain times.
 
Toyota was testing a kit in Japan to connect the three phase HV battery to a home. They are also doing something similar with the Mirai.


Now Ford will be offering a 240 volt connection in the F150. Now it wont be as efficient as using a Toyota hybrid as running the Ford V-6 or V-8 will be costly to make power long term, but for a tradesman to weld or similar, it will work great.

I think there are several benefits to using a Toyota hybrid to make power. They provide a plan B if your generator fails and for car camping. If you depend on a Hybrid as your sole generator, you don't have to worry about storing lots of fuel as you always start out with a fresh full tank in the ca,r and you don't need to exercise and maintain a generator as you drive the and maintain the car.

I see my neighbors construction generators sit in their garage. I suspect more than half wort work when needed. Generators require maintenance and proper fuel storage.


I’m rather impressed by the utility of the 1500W outlet given how little they seem to be touting the feature. I’m thinking of power tools in the field, tailgating appliances, portable PA systems, a flat screen TV, as well as emergency backup power for household appliances. As part of the 2020 Highlander Hybrid Limited/Platinum trim, it offers the functionality of about a $1000 portable generator rather than the $5000 variety. Apparently, the usage of the 1500W outlet is limited to 1 hr unless the vehicle is locked but, presumably, an extension cord can be run out of an open window.

Edit: The newly announced 2021 F-150 Hybrid will come with a 2.4kw AC inverter upgradable to 7.2kw inverter in the bed. That’s some manly power, there.
There was a company, Converdant, I think, that used to do the high-voltage mod to connect to the Prius hybrid battery and then you had an external inverter that looked like a PC tower. I think it was well over $1000 plus $500 for the battery connection mod and would risk voiding your hybrid system and battery warranty. Not surprisingly, they don’t do those anymore. Especially, now that the warranty goes to 10yr/150K miles.

There is a lot more interest in backup generators among ordinary folks, these days. PG&E just pleaded guilty to something like 80 counts of manslaughter related to the wind-fueled California fires which probably ensures that above a certain wind speed (45 mph gusts or something) power companies are going to be implementing regular blackouts to reduce fire risk. Most people are stocking up a lot more in their refrigerators and freezers, these days, due to sheltering-in which makes any outage more than inconvenient. Even if you have a portable backup generator, having another one that travels with your vehicle seems very worthwhile at certain times.
 
I’ve had my 2020 Hybrid for a couple months now and I’ve read some conflicting information about how the battery system works. This thread has cleared some things up (and discussed the exact use case I’m interested in), but I want to be absolutely sure. This is my understanding; please let me know if I’m wrong:
We have a high voltage/hybrid/traction battery (let’s call it the hybrid battery) and a 12 V AGM battery. With the car OFF (or in ACC mode?), you pull power from just the small AGM battery, which will drain fairly quickly and is not a good idea. With the car ON (“ready” mode), you still pull from the AGM battery but the hybrid battery actively keeps it charged through a DC-DC converter, and the combustion engine kicks on as needed to charge the hybrid battery when it gets below some threshold. Is my assessment correct?
 
Yes, that should be correct. I think it also charges in ACC mode, but I'd have to check, there are some notes about this in the owners manuals. The 12v battery won't charge if the car is in neutral, even if the car is "on"
 
I’ve had my 2020 Hybrid for a couple months now and I’ve read some conflicting information about how the battery system works. This thread has cleared some things up (and discussed the exact use case I’m interested in), but I want to be absolutely sure. This is my understanding; please let me know if I’m wrong:
We have a high voltage/hybrid/traction battery (let’s call it the hybrid battery) and a 12 V AGM battery. With the car OFF (or in ACC mode?), you pull power from just the small AGM battery, which will drain fairly quickly and is not a good idea. With the car ON (“ready” mode), you still pull from the AGM battery but the hybrid battery actively keeps it charged through a DC-DC converter, and the combustion engine kicks on as needed to charge the hybrid battery when it gets below some threshold. Is my assessment correct?
you are correct. And technically, with the car in ready mode, you'll never truly be pulling from the AGM battery unless you have a spike in your electrical load as the DC-DC converter in the car will run at around 14 volts (which prevents any power coming from the battery directly). The spike in electrical loads is why you want to mount the system directly to the battery.

Also, the car needs to be in ready mode (this will initiate the HV battery and engine to run when appropriate). ACC modes on cars are designed to only run off of the 12v battery, so you will not be able to charge at the same time.

(I don't own a Rav4... just a future Prime owner who's done a lot of reading in prius forums on how this inverter hack works, lol. I also have a technical background.)
 
Does anyone know for sure the power limit for the DC-DC converter, or are we just speculating that it’s the same as the Prius (i.e. ~1000 W)? I’m about to pull the trigger on my inverter setup, and I’ll spring for the 1500 W model if I can actually utilize that much power, but I’d rather save some money/space and go for the 1000 W model if I’m bottlenecked to 1000 at the DC-DC anyway.
 
Does anyone know for sure the power limit for the DC-DC converter, or are we just speculating that it’s the same as the Prius (i.e. ~1000 W)? I’m about to pull the trigger on my inverter setup, and I’ll spring for the 1500 W model if I can actually utilize that much power, but I’d rather save some money/space and go for the 1000 W model if I’m bottlenecked to 1000 at the DC-DC anyway.
what size is the fuse?
 
I assume you mean from the DC-DC to the 12 V. Good point; I’m not sure. But I suppose if I can find it or someone here knows the size, a safe bet might be (3/4)x(12 V)x(fuse_amps) as the power limit
Correct! and yep, that's a solid safe bet. If I remember correctly from watching one of those weber videos, the fuse on the prius is 120 amps, so using that rule gives you exactly 1000W.
 
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