Learned more Rivian Gen 2 tech updates / differences to Gen 1

[HaveBlue]

Lead acid batteries have survived in the elements under the hood for the last 100 years though some BMWs also placed them under the rear seat and the bottom cushion would need to come up for access. Hydrogen gas venting is needed in these scenarios.

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[hammick]

Lead acid batteries have survived in the elements under the hood for the last 100 years though some BMWs also placed them under the rear seat and the bottom cushion would need to come up for access. Hydrogen gas venting is needed in these scenarios.

Haven't had a Beemer for many years but I'd be shocked if they aren't using AGM batteries these days. AGM's are lead acid but don't need to be vented. BMW always tried to get close to 50/50 weight distribution hence the battery placement.

 

[HaveBlue]

Our bmw and Audi have them in the trunk but they are old models, lead acid and a vent. AGM batteries still have pressure relief valves in case something goes wrong. Venting is per the manufacturer even on those.

 

[CrazyOne]

Except how do you get to it if it has a catastrophic short and the truck is locked? Jump process won't work. Break window?

Yes, break a window and Pay Rivian $4K to fix it. It was an actual quote from Rivian.

 

[C12farmer]

Hopefully the 12V battery issues have all been fixed in Gen 2. If my understanding is correct, the Gen2 now has a "float" charger always connected from the HV battery to the 12V system. So basically all the low power drain when the vehicle is off is always feeding off the main HV. I actually think this DC-DC 12V can output quite a bit of power before the 12V battery needs to supplement. It'd be interesting to see the specs on the new 12V DC converter.

The Gen 1 12V charger system was basically a contactor that opened/closed to charge up the 12V when it drained down a certain amount. That system had many more points of failure and also cycles the 12V battery way more. Gen 1 also has a lot more vampire drain which puts further stress and cycles on the 12V battery. I think Rivian has made a lot of progress to optimize the 12V system behavior compared to early days.

I'd still rather have the battery in some other location other than under the seat.

 

[NY_Rob]

^ to me, it looks like in the diagram above, Rivian is simply providing an easy to reach access point for float charging via an external charger like an NOCO float charger. This way you don't have to go disconnecting battery cables in order to connect a float charger with ring terminal connectors.

 

[mkhuffman]

^ to me, it looks like in the diagram above, Rivian is simply providing an easy to reach access point for float charging via an external charger like an NOCO float charger. This way you don't have to go disconnecting battery cables in order to connect a float charger with ring terminal connectors.

This is exactly what I was going to say. They are not telling us about a back-end system that is used to keep the 12V circuit active, they are telling us how to connect an external battery charger to maintain the battery when needed.

The ability to connect a float charger without opening the hood or unlocking the car is awesome, IMO. People are building their own connections do to that, and with Gen2, you don't have to build your own solution anymore. Awesome!

 

[usofrob]

This is exactly what I was going to say. They are not telling us about a back-end system that is used to keep the 12V circuit active, they are telling us how to connect an external battery charger to maintain the battery when needed.

The ability to connect a float charger without opening the hood or unlocking the car is awesome, IMO. People are building their own connections do to that, and with Gen2, you don't have to build your own solution anymore. Awesome!

I agree, they seem to be indicating that you can float charge the gen2 battery. It's not clear from the diagram if you can use the rear tow hitch cables or not. They point to the positive terminal under the hood, but not a reliable negative.

Also, I believe what C12farmer said above is also true about having a direct HV-DC to 12V-DC charger for the battery, but maybe it doesn't do float charging. So, having terminal access can allow you to use a float charger and avoid nearly any HV battery drain.

Before you put a float charger on, we'd want to know what type of battery is in there, because the protocols can be different, particularly for Li-Ion.

 

[C12farmer]

I agree, they seem to be indicating that you can float charge the gen2 battery. It's not clear from the diagram if you can use the rear tow hitch cables or not. They point to the positive terminal under the hood, but not a reliable negative.

Also, I believe what C12farmer said above is also true about having a direct HV-DC to 12V-DC charger for the battery, but maybe it doesn't do float charging. So, having terminal access can allow you to use a float charger and avoid nearly any HV battery drain.

Before you put a float charger on, we'd want to know what type of battery is in there, because the protocols can be different, particularly for Li-Ion.

I was lazy and didn’t actually watch the video until now. Looks like their meaning of float charger is from an external source to that access point behind the frunk. In any case, it’s still be neat if Rivian gave more info on how they fixed up the 12V system. I know it’s been a pain point for many Gen 1 owners.

After watching this video, I’m amazed at all the changes that have been made. I really hope it results in the insurance companies reducing the premiums for Gen2. Right now they’re all getting lumped together.

 

[JeremyP]

I have a gen 2 R1S so I decided to investigate the 12v relocation. There is a panel under the front of the passenger seat that easily pops off to see a little bit of the 12v battery (green in the picture). The negative battery cable connects to the body under that panel as well. I also checked out the jump point under the hood, so I think my plan of having a jump box under the hood as well as having the tools to open the hood is still valid.

 

[kenyee]

I have a gen 2 R1S so I decided to investigate the 12v relocation. There is a panel under the front of the passenger seat that easily pops off to see a little bit of the 12v battery (green in the picture).

Looks like it's confirmed you have to remove the entire seat to replace the battery?

 

[JeremyP]

Looks like it's confirmed you have to remove the entire seat to replace the battery?

Yes almost certainly. Hopefully with the changes discussed earlier it lasts much longer.

 

[SoCal Rob]

The non-over-engineered solution would be just to provide a backup physical key.

I was at the L.A. Auto Show today and noticed that Hyundai has solved this problem with door handles like the Rivian’s. You can see the unobtrusive lock cylinder for the driver’s door behind the handle.

 

[Steve A.]

I was at the L.A. Auto Show today and noticed that Hyundai has solved this problem with door handles like the Rivian’s. You can see the unobtrusive lock cylinder for the driver’s door behind the handle.

Well, I think every other ICEV solves it a long time ago. ?

 

[SoCal Rob]

Well, I think every other ICEV solves it a long time ago. ?

True, but…

Rivian designers clearly don’t want a keyhole showing and I’ve never seen ICE cars from a long time ago which have this style of door handle.

Seriously, the exact problem which Rivian was seemingly unable to solve was, in fact, solved by Hyundai Kia. Of course, it wouldn’t be the first time Rivian dug their heels in when it comes to resisting existing solutions.

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