Went ahead and did the dual charger upgrade on the 2015 85D myself (thoughts)

[toaplan]

So I asked around to see if one needed the toolbox in order to install another charger (MCU2 2015). People said yeah you need it in order to configure it as a slave, but no one knew if you can just install a preconfigured slave and have it reconfigure itself to support the dual chargers. This would mean one would need to buy a 1 day Toolbox pass for $150.

Took about 6 hours to install this because I was triple checking everything. I am glad to report that MCU2 reconfigures itself so you don't need the Toolbox in order to set it for dual chargers. You do have to set it in service mode and flush the coolant/check the temps which all passed. I took it to a charging place and was charging at 48 amps, so I think we're good to go. Hopefully this helps some people.


And for the ever important question, how much did this cost?

$200 for the charger (had the grounding cable and the HV terminator on it, bought it from Donuts on ebay..and luckily it was the same REV as my Master, so that's cool)
$75 for the two molex cables (cause no one was selling them under $60 each, I ordered them from Canada...didn't want to bother going through Tesla)
$20 Coolant

And how much did Tesla want? Close to $3000, nope lol.


That's it. If you have the tools, you are good to go. I appreciate all the help that was on this forum since I was refering to it and the manual many many times to make sure I wasn't doing anything stupid.

 

[islandbayy]

Dual Chargers are amazing! Strong proponent of them back in the day. Not as useful these days as they once were before we had so many superchargers, however, still worth it. I can't believe how Tesla has gone backwards in AC charging speeds. Being able to fully charge my 90D in just 3 1/2 hrs at home is insane! Only 1 1/2 hours longer for a full charge than the supercharger!

 

[Krash]

+1 for modding old cars to higher OEM spec AC charging rates.

Although the new external connectors are 48A, my 2017 S was one of the last to come with the optional internal factory 72A.Although you shouldn’t need more than 40A for overnight (unless you don’t sleep much.) I can’t tell you how happy I’ve been the dozen times I ended up at a 72A V1 destination charger.

What AC charging rate did you have before? 40A?

I thought that 2015 85Ds came with single 40A or dual 80A chargers. So I assume when you say you tested at 48A, you mean that you upgraded internally to 80A, but when you tested it, the external charger (or circuit) was limited to 48A.

I know this kit wouldn’t fit your car, as it is for more recent models, but I’m curious as to how the parts differ from what you did.

 

[toaplan]

+1 for modding old cars to higher OEM spec DC charging rates.

Although the new chargers are 48A, my 2017 S was one of the last to come with factory 72A and I can’t tell you how happy I’ve been when I end up at a 72A V1 destination charger.

What DC charging rate did you have before?

I'll be honest, the only reason I installed this is just in case I go on a trip and there are no superchargers at the hotel or any near by. I use superchargers 99% of the time (free charging go) and only have a mobile charger at home Mine was limited to 40 amps before I changed this (duh), I think it was something like 8 hours to charge at 40 amps. I don't know the specific charging rate.

Well the 85D either came with a single or a double. When I was installing it, this is what it looked like:

 

[el-guapin]

Nice MOD.. THNX 4 sharing!

 

[toaplan]

I thought that 2015 85Ds came with single 40A or dual 80A chargers. So I assume when you say you tested at 48A, you mean that you upgraded internally to 80A, but when you tested it, the external charger (or circuit) was limited to 48A.

I know this kit wouldn’t fit your car, as it is for more recent models, but I’m curious as to how the parts differ from what you did.

Yup, that's what I meant, sorry.

As for the difference between these...it seems that's only one charger (72) while the one here is GEN2, not 3 and there are 2 chargers (40 + 40)

 

[brainhouston]

Do u have a screenshot of what u changed in service mode?
Cause in mcu1 there's nothing for charger, so must be mcu2 only option

 

[toaplan]

Do u have a screenshot of what u changed in service mode?
Cause in mcu1 there's nothing for charger, so must be mcu2 only option

Oh sorry, I wanted to edit that and put "You go into service mode and do all the coolant/thermal tests". It auto configs itself, so this is just after you install it to even out the coolant.