Generator to charge R1T when extra range needed

[ajdelange]

There is a very good reason if you don't have an engine hoist and I don't. Thus a supplemental battery pack is of no practical use to me.

The other things to consider are that Li ion batteries are expensive. Most of the time this thing you paid 6 grand for will be sitting around doing nothing. And, unless the architecture of the supplemental pack is at the same voltage as the vehicle's battery you will have to go through the voltage upconversion process which loses energy (miles) and can be slow.

I do carry a 1 kW battery pack in the Tesla when on long road trips and that would put 3 or 4 miles into the car in an emergency but it would take an hour to do so. Thus it's not there as an "electric Jerry can" but is used to run the fridge over night.

Now none of this is to say that a 50 kWh battery based DC fast charger (and I believe there are some made) wouldn't be great for road side service. Obviously it would be more or less permanently installed in the service truck, could be recharged on the truck and would be used frequently enough to justify its cost. And it would be able to recharge the imprudent stranded motorist enough to get to a charging station in reasonable time.

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[bsaik]

The Generac should be fine. Let's say you dial the charge rate back to 7 kW to not fully load the generator. You should be able to charge 7000/480 = 14.6 miles per hour. There should be no need to "modify" the generator. If it is newer there will be a terminal marked as ground and instructions as to how to connect that to the generator's neutral. If these are not there this can be done inside the plug on a custom adapter (short extension cord) easily put together. This may be necessary anyway but at this point we don't know what "adapters" will come with the Rivian portable charger.

For maximum safety a ground rod should be driven and wired to the ground teminal (generator frame).

I’ve tested this with my 7kw generator and a Tesla model Y For a few minutes. The Tesla mobile adapter was plugged straight into the generator. The car takes a charge but I did notice some surging. The Y will start taking charge at 5-6 kW for about a minute or so and then it pauses and drops to 1 kw before ramping back up. This makes the generator throttle up and down to match the power draw. So it kinda works but I’m assuming the power is not clean enough to sustain a good even charge.

 

[ajdelange]

If the car notices anything out of the ordinary the first thing it does is drop the charge rate. I suspect your generator does not have the world's best voltage regulation. Try lowering the car's charging rate to 10 amps (2.4 kW) and then plug into the generator. It may be more stable. Then bring the charge rate up gradually to find the max rate at which car and generator are happy.

 

[bsaik]

If the car notices anything out of the ordinary the first thing it does is drop the charge rate. I suspect your generator does not have the world's best voltage regulation. Try lowering the car's charging rate to 10 amps (2.4 kW) and then plug into the generator. It may be more stable. Then bring the charge rate up gradually to find the max rate at which car and generator are happy.

Yep!

 

[Sean]

There is a very good reason if you don't have an engine hoist and I don't. Thus a supplemental battery pack is of no practical use to me.

The other things to consider are that Li ion batteries are expensive. Most of the time this thing you paid 6 grand for will be sitting around doing nothing. And, unless the architecture of the supplemental pack is at the same voltage as the vehicle's battery you will have to go through the voltage upconversion process which loses energy (miles) and can be slow.

I do carry a 1 kW battery pack in the Tesla when on long road trips and that would put 3 or 4 miles into the car in an emergency but it would take an hour to do so. Thus it's not there as an "electric Jerry can" but is used to run the fridge over night.

Now none of this is to say that a 50 kWh battery based DC fast charger (and I believe there are some made) wouldn't be great for road side service. Obviously it would be more or less permanently installed in the service truck, could be recharged on the truck and would be used frequently enough to justify its cost. And it would be able to recharge the imprudent stranded motorist enough to get to a charging station in reasonable time.

It's all up in the air but what I heard was more of a rental model for the supplement pack. To be installed and removed at a service center. Not practical for most use cases but I'm sure many would be interested for getting to more remote locations.

 

[ajdelange]

Yep!

Does that mean you tried it and it worked? Always curious as to how such experiments go.

 

[PastyPilgrim]

What's the landscape like for portable, diesel/gas generators? If you need to bring an emergency charge source (i.e. if going truly off grid), I'd think a few gallons of gas would be the way to go. Anything compact that can readily convert fuel to EV juice?

I know Juicebox is already a brand of EV chargers but that'd be such a good name for a purpose-built, emergency generator for EVs.

 

[crashmtb]

It's all up in the air but what I heard was more of a rental model for the supplement pack. To be installed and removed at a service center. Not practical for most use cases but I'm sure many would be interested for getting to more remote locations.

Yes. Like the battery swap programs which exist for things like scooters in SE Asia.

if I could rent one for a long trip where charging is an issue, I.e. driving to a remote provincial park in the subarctic(an actual use case for me), and have it put in by the Rivian service centre or their mobile service, that would be ideal. It would make no sense to own such an occasional use, expensive extra.

 

[kneebuster]

While Rivian has the patent for an aux battery in the bed, the main reason I don't think we'll see one any time soon is there is no provision for plugging it in to the main pack, at least nothing that's been shown or talked about. Not gonna want to run long charging cable to the front port while driving.

 

[crashmtb]

While Rivian has the patent for an aux battery in the bed, the main reason I don't think we'll see one any time soon is there is no provision for plugging it in to the main pack, at least nothing that's been shown or talked about. Not gonna want to run long charging cable to the front port while driving.

A hole saw and a few pluggers-in and it’s off to the races!

but for serious, it will be interesting if they do anything with this concept in a future model.

 

[Eeyore]

They patent so that others have to pay them to use the rights, or force others to not make them. They don't patent with the intent of making it themselves potentially.

The whole patent thing is just a way for many companies to monetize intellectual property. They don't have to actually use the patents themselves to make things. They just want to collect the licensing revenue.

 

[jjwolf120]

The other things to consider are that Li ion batteries are expensive. Most of the time this thing you paid 6 grand for will be sitting around doing nothing.

If the supplimental battery pack could be added to your home battery system when not in use, it might be worthwhile. But that's a big if.

 

[ajdelange]

While Rivian has the patent for an aux battery in the bed, the main reason I don't think we'll see one any time soon is there is no provision for plugging it in to the main pack, at least nothing that's been shown or talked about. Not gonna want to run long charging cable to the front port while driving.

It has to tie directly to the main battery dc bus for sure but in addition to that it has to also tie into the BMS (or have its own which interfaces with the main BMS) and it also has to interface withe the cooling system.

 

[ajdelange]

They patent so that others have to pay them to use the rights, or force others to not make them. They don't patent with the intent of making it themselves potentially.

The whole patent thing is just a way for many companies to monetize intellectual property. They don't have to actually use the patents themselves to make things. They just want to collect the licensing revenue.

There's even another aspect to it which was a new one on me that might be applicable here. This is evidently called the "bubble gum card" patent. The company who holds some of these can trade them with another company that holds one they want to use. Tesla lets them use their laser windshield wiper implementation if they let Tesla use their electric jerry can.

 

[ajdelange]

If the supplimental battery pack could be added to your home battery system when not in use, it might be worthwhile. But that's a big if.

I think I mentioned the 1 kW Jackery pack I carry for the fridge in the car. It actually gets used for other things more than I thought it would. It is, IMO, easier to grab that thing than it is to find, untangle and then recoil an extension cord for a lot of jobs. If I want to use my laptop outside for the better part of a day I'll use that.

I'm doing a solar garage - no grid connection. I have a 6 kWh Yeti pack running the whole building while I wait (and wait and wait) for Powerwalls. It gets charged via an extension cord from the house at 150 W but can run lights, garage door openers, tools, the heaters (propane) and even heat pumps (briefly). At the moment it's wired into the main panel. I'll probably work out some sort of transfer switch for it when the job does finally get completed but it will stay in the system (as backup to the backup). I never take it in the car. Too heavy.

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