Multiple onboard chargers

[TonyWilliams]

Ya, if you could add range, that would probably be first. The problem, of course, is there is no way you'll add 100 miles for $15k.

Today, I chatted with the guys building a portable CHAdeMO charger about putting a port on the Rav4. I think that will be "relatively" cheap and straight forward, but a lot of development.

Adding a second or third 10kW Tesla charger has not been overlooked. The chargers are about $3600 each. We need to read the CAN messages for this, but essentially, we will just slave them together.

 

[Ampster]

Ya, if you could add range, that would probably be first. The problem, of course, is there is no way you'll add 100 miles for $15k.
......

Yes I think you are correct. I initially figured you could get 100 miles of range on 30kWhrs. I have seen LiFePo batteries for as low as $0.35 per watt so I figured $0.50per watt for batteries, battery boxes, additional charger and cable.

The problem with my initial math was that in order to get 30kWhr of usable battery Tesla probable uses a pack with a total capacity of 50kWhr and at $0.50 per watt it would cost $25,000 for that amount of extra power. It would take up the entire space behind the back seats at least 12" high and still not have the Thermal management that the Tesla pack has.

 

[TonyWilliams]

And, with all the added weight, it wouldn't add 100 miles!!!

 

[Brandy]

After reading this thread it seems to me for the amount of money one would have to spend it would be more cost effective to use the money as a deposit on a Model X.

 

[Ampster]

Yes, and an additional 70 miles of range only costs $10,000 extra.

 

[fooljoe]

Tony, have you looked into these guys and their 12kw charger? They also have an intriguing EVSE offering.

 

[ehelmholtz]

Is there direct access to the battery?

 

[TonyWilliams]

Is there direct access to the battery?

Of course... that's how the current onboard charger does it.

 

[solarjackpv]

Is there any way to add a dual charger option like this one from tesla.

http://shop.teslamotors.com/products/2nd-onboard-charger

 

[cwerdna]

Even if there were, would you have an access to an 80 amp EVSE (assuming you wanted to charge at full speed) and room for a 100 amp breaker?

 

[TonyWilliams]

You use two separate J1772 plugs, for 30 amps at 208 volt * 2 = 12.48kW

For single 80 amp charging, a simple adaptor would work for:

80 amps @ 240 volts = 19.2kW
80 amps @ 208 volts = 16.6kW

 

[solarjackpv]

When i go to the bay area i have to stop for three hours in patterson and well if i had two chargers i could utilize an empty chargepoint j1774 plug and double my charging speed.
I know it's not affordable but can it be done?

 

[fooljoe]

Several Leaf drivers have added extra chargers to their cars to do precisely this - I assume we could do the same.

 

[banshee08]

I think Tony's DC fast charger mod that he is developing is a better option than a second charger. A true 50kwh dc fast charge can easily get the Rav4 EV to 80% in about 40mins.

 

[fooljoe]

No reason you can't do both!

As far as which is better, I suppose that just depends on what situations you find yourself in. If you've got a lot of available Chademo chargers around, of course that's better. But if instead you have many unused J1772's around, you might get more use out of having 2+ chargers on board.

Actually, this has gotten me thinking - it's really the 2 J1772 inlets that provide the value more so than having multiple chargers, since most public charging stations only use about 60% of the capacity of our 10kw onboard chargers anyway.

One could construct a relatively simple and inexpensive device with 2 J1772 inlets and a NEMA 14-50 plug that you could plug a 40a EVSE like the Jesla into so you could suck a bit more power out of public charging stations, assuming the stations you encounter don't have out-of-phase conductors. In this way you could at least step up from the typical 6kw public charging station to something like 8kw (~200V @ 40a instead of 30a.)

If you included a transformer you could even get the full 10kw going, and wouldn't have to worry about the possibility of out of phase charging stations, but of course then the device becomes much more heavy and expensive.

 

[TonyWilliams]

No reason you can't do both!

As far as which is better, I suppose that just depends on what situations you find yourself in. If you've got a lot of available Chademo chargers around, of course that's better. But if instead you have many unused J1772's around, you might get more use out of having 2+ chargers on board.

Actually, this has gotten me thinking - it's really the 2 J1772 inlets that provide the value more so than having multiple chargers, since most public charging stations only use about 60% of the capacity of our 10kw onboard chargers anyway.

One could construct a relatively simple and inexpensive device with 2 J1772 inlets and a NEMA 14-50 plug that you could plug a 40a EVSE like the Jesla into so you could suck a bit more power out of public charging stations, assuming the stations you encounter don't have out-of-phase conductors. In this way you could at least step up from the typical 6kw public charging station to something like 8kw (~200V @ 40a instead of 30a.)

If you included a transformer you could even get the full 10kw going, and wouldn't have to worry about the possibility of out of phase charging stations, but of course then the device becomes much more heavy and expensive.

Yep.

 

[JasonA]

Several Leaf drivers have added extra chargers to their cars to do precisely this - I assume we could do the same.

I'm already working on a plan to do this. Ofcourse since we don't have the fancy CAN integration like we did on the Leaf side, it'll have to be a manual/Auto control thingy through the Brusa but I did that in the early stages before the CAN stuff.

But I won't say that CAN isn't in the process..

And I've got 2 shinny new Brusa's waiting to do something!!

17kw would be a nice thing to have!

 

[valerun]

Several Leaf drivers have added extra chargers to their cars to do precisely this - I assume we could do the same.

I'm already working on a plan to do this. Ofcourse since we don't have the fancy CAN integration like we did on the Leaf side, it'll have to be a manual/Auto control thingy through the Brusa but I did that in the early stages before the CAN stuff.

But I won't say that CAN isn't in the process..

And I've got 2 shinny new Brusa's waiting to do something!!

17kw would be a nice thing to have!

Jason strikes again! ;-))

BTW what is the easiest way to [electrically] access RAV4 battery?

 

[TonyWilliams]

If you're asking about DC connections, just use the same ones that the current onboard charger uses. Easy.

If you mean control wise, you'll have to figure out the CAN bus like several of us are doing. I have acquired a second Rav4 EV devoted solely to this research for the JdeMO project plus adding AC powered onboard chargers (and controlling them) and finally fixing the GOM to give a rated mileage output.

That means 41.8kWh of usable energy will display 142 miles on the dash GOM when 3.4 miles per kWh of economy is selected.

 

[JasonA]

It's about taping into the pack like we did on the Leaf side.. Keep it clean, neat and simple(so it can be taken off quick and easy!) and make the integration part as simple as possible.

It's good that we have multiple people working from different aspects and angles on this! I totally agree on the multiple charger scenario/dual J-plug integration! This was my vision on my Leaf since I didn't have DCQC and an open spot sitting there. 1 Brusa wasn't enough but 2 with the 2nd hooked up in AUTO mode is AWESOME!

83% of the time (yes, that's an accurate# as of last Dec).. everytime I was charging.... there was always an extra J-plug hanging within reach but I was unable to use it. Another 3.3kw is nice!

I foresee the Rav in a perfect world with a CHAdeMO mod and very minimum 1 LC Brusa or hopefully a Val isolated badboy special.

There's just tooooo much power out there in the wild going to waste!