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Discussion Starter · #1 ·
Here is my list of when charge mode might be useful. Does anybody have more or disagree with using it for these purposes?
1. Charge while on highway on the way into a destination you know to have no charge capability but will need to make short trips.
2. Charge on the way into a camping destination where you will need battery power.
3. Charge while on highway before a fuel fill-up if you have a very long wilderness leg ahead and are worried about range.
4. Very low SOC on a trip with no charge station options (keep battery off low SOC for long duration).

The last one I find happens often on trips because I have good reason to use EV mode but don't want to leave the battery in a low SOC.
I don't use charge mode often but it is nice to have for a few situations.

Others? Comments?
 

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2021 RAV4 Prime SE Supersonic Red
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I feel that the only reason to use Charge Mode is when you have to (or want to) have enough of a charge at your destination to run in EV mode. So far, no cities in the US require vehicles to be EV only, but you'll be ready if they do. If you just want to have enough of a charge to run in EV at your destination, keep in mind that you will be using more gas than you would be by just using the hybrid system. Some posters have claimed that they have gotten better mileage by using Charge Mode while driving, but I'm not convinced. Using the hybrid system to charge the battery for EV mode will be at the best, equivalent to using the hybrid system directly and letting it decide when to charge the battery.

You don't need to be concerned about the car being left in a low SOC. The system is designed to operate between approximately 20% and 80% of the battery capacity. There is an advantage to not store the car for extended periods of time with a full charge, but the system will not let the SOC go so low that it hurts the battery.

The one scenario that intrigued me was using Charge Mode for camping. Instead of using Charge Mode while heading to your camping destination, can you run the car when it's parked there? It will charge just as well parked as it will while you are driving. Keep in mind though that you're only charging the HV battery and I assume that for camping you're going to use the 12V battery. It's rather small in capacity and will be depleted rather quickly. In addition, it will only be recharged while the car is in READY mode.
 

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Discussion Starter · #3 ·
Yeah, I thought about running the car at the campground but I hate when others make noise in the evening so if I plan to get there late I think charge mode would avoid having to make noise once parked.
 

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I feel that the only reason to use Charge Mode is when you have to (or want to) have enough of a charge at your destination to run in EV mode. So far, no cities in the US require vehicles to be EV only, but you'll be ready if they do. If you just want to have enough of a charge to run in EV at your destination, keep in mind that you will be using more gas than you would be by just using the hybrid system. Some posters have claimed that they have gotten better mileage by using Charge Mode while driving, but I'm not convinced. Using the hybrid system to charge the battery for EV mode will be at the best, equivalent to using the hybrid system directly and letting it decide when to charge the battery.

You don't need to be concerned about the car being left in a low SOC. The system is designed to operate between approximately 20% and 80% of the battery capacity. There is an advantage to not store the car for extended periods of time with a full charge, but the system will not let the SOC go so low that it hurts the battery.

The one scenario that intrigued me was using Charge Mode for camping. Instead of using Charge Mode while heading to your camping destination, can you run the car when it's parked there? It will charge just as well parked as it will while you are driving. Keep in mind though that you're only charging the HV battery and I assume that for camping you're going to use the 12V battery. It's rather small in capacity and will be depleted rather quickly. In addition, it will only be recharged while the car is in READY mode.
I thought the traction battery powered the 110v outlet, which is what I would use while camping. What does the 12v battery power when parked?
 

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Here is my list of when charge mode might be useful. Does anybody have more or disagree with using it for these purposes?
1. Charge while on highway on the way into a destination you know to have no charge capability but will need to make short trips.
2. Charge on the way into a camping destination where you will need battery power.
3. Charge while on highway before a fuel fill-up if you have a very long wilderness leg ahead and are worried about range.
4. Very low SOC on a trip with no charge station options (keep battery off low SOC for long duration).

The last one I find happens often on trips because I have good reason to use EV mode but don't want to leave the battery in a low SOC.
I don't use charge mode often but it is nice to have for a few situations.

Others? Comments?
IMO, only #2 seems useful to me. Regarding #1, might consider it, but don’t think I’d bother. #3. Since the vehicle can go>500 miles on HV, that would have to be a heck of a wilderness route (Alaska?) to worry about “saving” 40 miles of EV as insurance. I’d rather carry a 5 gallon gas can to give me 200 miles of additional range, plus a PLB and a SAT phone, Just don’t see the R4P as a wilderness vehicle, frankly.

I have “saved” my EV on a trip for puttering around a small, artsy town with all of the R4P windows and the moon roof open because it was so quiet and no exhaust. That was fun, but optional, not necessary.

Frankly, though, you don’t need anyone’s approval to drive your vehicle just the way you like it. If you think it’s important, do it, and enjoy.
 

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I thought the traction battery powered the 110v outlet, which is what I would use while camping. What does the 12v battery power when parked?
I don't know, I only have an SE with a 12V plug in the cargo area. I believe that there is a switch on the dashboard to turn the 120V inverter on and off. I would assume that it would be getting power from the 12V battery and the switch was to disconnect the inverter when it's not needed (to reduce losses). Is there a fuse for the inverter with the rest of the 12V fuses?
 

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I thought the traction battery powered the 110v outlet, which is what I would use while camping. What does the 12v battery power when parked?
Traction Battery powers everything.
The DC HV goes to a DC-DC converter... 300VDC to 12Vdc to the 12v small battery.
The inverter is used to make HVDC to HVAC for the motors, AC, Heat Pump, etc...

I think the inverter sends AC power to the 120 outlet as well....

I thought the traction battery powered the 110v outlet, which is what I would use while camping. What does the 12v battery power when parked?
The DC Traction battery powers the Inverter/converter.
The inverter/converter takes the 355 V DC and Makes AC Volts for the motors, heat pump, AC compressor, and assume the 120 Volt outlet also.
The 12 volt battery is very small, and will only power accessories for a short amount of time, It will discharge rather quickly...
If your in READY mode, the DC-DC convertor will charge the 12 volt battery. The DC-DC convertor takes the 355 Volt DC Battery down to 14.5 volts to charge the Small Battery only when the Ready mode is on .... ( It also charges the 12 volt battery during Traction battery charging as well )
 

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I have an SE so I can't test it. Can the 120V inverter in the cargo area run when the car is in ACC mode or only when it is in READY mode? While it is true that when disconnected from an external source all power comes from the HV traction battery, that battery is isolated from the rest of the car until it is in READY mode. Seems that a majority of 120V inverters run off of 12V, and it may be the same in the RAV4 Prime. If so, then the car will have to be in READY mode for the DC to DC converter to send power from the HV to the 12V auxiliary battery to keep it charged. Shouldn't be a problem while camping, but if the SOC goes too low, the ICE will fire up which @Salmoh wanted to avoid.
 

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The only other idea for using charge mode that would be useful is under all 3 of these conditions:

It's cold out
The R4P has less than 80% charge
You've just started the car, and want it to warm up as quickly as possible

(The increased fuel to charge the battery will warm up the engine faster)
 

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2021 Rav4 Prime XSE Pro Audio/Dynamic Nav/Weather Packages Build date: June 2021
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Others? Comments?
I use Charge Mode to force the ICE to stay on for short drives between 5 and 10 miles or so one way at city speeds, during very cold snaps, so that the entire block heats up the quickest versus using HV mode where downhills and stops will typically turn the ICE off. We do this for two reasons: 1, to get the HVAC system being able to output decent heat the quickest; and 2, because we never let the ICE come on unless we plan to warm the engine up fully, and I mean fully. For trips less than 5m in icy temps we skip HVAC because it will not get to temp anyway when the entire ducting in the car is sub freezing over that short a time period. We use steering wheel and seat heaters and a good down parka to keep us toasty in these situations. Also, we only use CM only on the flat, or on the downhill, since it really does work harder, plus when going uphills the car stays in HV mode anyway in our classic CM use scenario of those short drives in icey temps.

I see no reason to ever charge the Traction Battery for long trips w/ no charging station access--the ICE takes care fully of the car's energy needs so I see no need to charge the battery in this scenario.
 

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Discussion Starter · #12 ·
Also, we only use CM only on the flat, or on the downhill, since it really does work harder, plus when going uphills the car stays in HV mode anyway in our classic CM use scenario of those short drives in icey temps.
Interesting. We often drive 13 miles up a pass to visit relatives and sometimes use this trip to make sure we periodically use the ICE (maybe once every 2-3 weeks). I prefer to drive up the pass in EV then return in HV to warm up the ICE but not put much pressure on it. On the way back the ICE gets switched off in places. It sounds like this might be a good application of charge mode to keep it running until we get all the way home.
 

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Discussion Starter · #13 ·
As I take more trips in our R4P I have found two primary reasons to use CHARGE MODE:

1. To bring the State Of Charge up to a reasonable level (for battery longevity) when we arrive at a destination at zero charge and find we have no good charge options. I am no expert but I believe dropping down to minimum SOC on a trip and then driving around in HV alone at a low SOC for an extended period would be detrimental to battery life.
2. To keep the ICE running when I want to make sure it gets warmed up and used once in awhile.
 

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To get the fuel system in use to prevent petrol going bad / lubricator the system with it never in use if using EV for weeks on end. Otherwise I’ll use it sparingly just because, reasons.
 

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1. To bring the State Of Charge up to a reasonable level (for battery longevity) when we arrive at a destination at zero charge and find we have no good charge options. I am no expert but I believe dropping down to minimum SOC on a trip and then driving around in HV alone at a low SOC for an extended period would be detrimental to battery life.
Not a good reason. A minimum SoC is maintained by the car for this very reason. If your battery gauge is between the blue and green, then it’s fine. If you’re parking the R4P for a very long time, then yes, bring it up to 50%. Otherwise, there’s one less reason to ever use charge mode.

I used it once the day I got the car to try it out, and will likely never use it again. There’s just no good reason to in the U.S. The engine runs until it is warm, its cheaper and more efficient to plug in for charging, and we have no EV-only zones in the country (yet). I just don’t buy any of the reasons some think it’s a necessary mode.
 

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I just don’t buy any of the reasons some think it’s a necessary mode.
I agree it's hardly 'necessary' but I use it on rare occasion to get the ICE to stay on so that not only the coolant but a better part of the block gets really warmed up, which during wintertime here can take quite a while. A goal I have is to never 'short-cycle' the ICE for various reasons, mostly theoretical, and also it may get the heating working better/quicker than allowing the ICE to cycle off. When I do use it I am mindful to only use it when on the flat or on a downgrade as the ICE sounds like it's really working hard if I climb hills or accelerate in Charge Hold mode. I wonder if being in Charge Mode Hold does any better with charging than braking when for example being on a very long significant descent on a freeway. I also make it a point to use the ICE once a week for a shorter drive, again enough to fully warm up the block. During the warm months time to fully hot is much quicker and there is no need to enhance cabin heating.
 
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