Additional pack

[databeestje]

I think the Tesla Powerwall has most of the required battery bits inside, for things like voltage and temperature, etc.

It's a 150VDC battery effectively, so a simple 2kW DC/DC converter should be all you need to feed into the battery. Perhaps you could also add a DC/DC charger the other way around when traction battery voltage rises to > 350 Vdc and then proceed to charge the battery at about 2kW using the onboard charger and a DC/DC converter in series.

It's not impossible.

 

[databeestje]

Well color me surprised, something called a bi-directional DC/DC converter actually exists. They have models with CAN bus and all.

For example the Brusa BSC614-24 allows for stepping down from the traction pack to a 24 Volt pack and up from the 24 Volt to the traction pack. http://www.brusa.eu/en/products/converter/auxiliary-dcdc-400-v/bsc614-24-v.html

With 2.8kW of power available that's a decent amount for a extension pack. If one would program the pack to charge from the traction battery at 270 Volts (75%) it would still piggy bag a few kW when fast charging when the main pack starts to level out.

If the step down activates when the pack goes below 325 Volts (0.9) you would still have a bit of buffer for regen. A 24 Volt battery and just 2.8kW isn't a awful amount of current, and the wires needn't be terribly thick. For comparison, the heater is 5kW and has a fairly mild wire thickness because of the high voltage.

I think Brusa could quite easily adapt a existing bi-directional DC/DC converter specifically for this purpose.

 

[PV1]

I was thrown off a bit by your voltages, but then I remembered that the 80-cell pack runs a lower voltage. Can this unit handle 360 volts (full charge voltage of the 88-cell pack)?

 

[databeestje]

Yes, the Brusa allows upto 450 Volts for the traction pack.

 

[Phximiev]

Another range extender company, tho I haven't heard of these folks:

http://insideevs.com/nomadic-power-ceo/

 

[jray3]

Since related threads have been quiet for a year, I'll add a 'suitcase pack' discovery on here. A startup in Seattle is nearing release of their 9.9 to 50 hp electric outboard boat motors for planing hulls, powered by a 6 kWh 350V 'suitcase pack' of 18650 cells packed in a phase-change wax for a cool combo of waterproofing and thermal management.
Depending on final specs and pricing, these portable packs could be good as double-duty i-MiEV range extenders.
Their website is lacking, but the staff is pedigreed and I have it on intel that the product is nearly ready for release.
http://www.purewatercraft.com/about/

 

[DonDakin]

This thread discusses pack removal and there is a link a few posts down to an online document from mitsubishi for removing the pack.

http://myimiev.com/forum/viewtopic.php?f=10&t=1323

Don....

 

[PV1]

A converter or DC-DC charger would be required with that Pure Watercraft battery to drop the voltage from 350 volts nominal to 325.6 volts nominal, but yes, it would make a great range-extender as 18650 cells can be quite energy-dense.

 

[Anonymous]

So I've got a recovered pack from a wrecked ev. Same volts and same amount of cells. I understand the BMS and contactor is onboard the pack.
Anybody who can clarify if the pack on its pack-frame fits in the back of the car on top of the folded rear seats?
Or any suggestions and experiences of how to make this work safely?

Any ideas of how to wire up the BMS and contactor (and other electronics on the pack if needed) on the 2nd pack when lying in the back of the car?

Thanks.

 

[Aerowhatt]

Your best bet would be to start out by reading all posts by siai47

Aerowhatt

 

[Anonymous]

Thanks for the reference Aerowhatt.

 

[Anonymous]

I'm reading cell balancing is one of the main challenges when having a second pack so I wonder about how to handle this.

BMS of 2nd pack:
1. Since I've got a fully equipt extra pack how can I activate its OEM BMS so it continues to balance the cells when used and charged?

2. Is it possible to simple provide the BMS of the 2nd batterypack with 12V (i.e. in parallel to the existing pack) and then it'll selfregulate as a stand alone pack?

3. What would it take to connect the OBD socket to the stand-alone BMS to still have an option to connect an OBDLink and monitor the status using Canion and EvBatMon?

HV wiring:
1. Where do you suggest best to connect the additional pack for a permanent wiring and with the option to disconnect the 2nd pack, i.e. using HV connectors.

2. Intending to place the 2nd pack on the back seat and rear footwells I wonder how best to route the HV cables from the 2nd pack to the point of connection. Any suggestions for a permanent install?

2nd onboard charger:
1. Do you have any experience as to whether its possible to parallel a 2nd AC charger and get more than the 3.3kW which is current rate?
2. Any way to adjust the MUT value of the charger to a higher charge-set which Siai47 has been mentioning?

Securing 2nd pack:
1. Anybody with experience in how to secure a 2nd pack placed in the rear footwell and on backseats?

Thanks.

 

[pbui19]

apparently the Power Box is available for purchase, albeit steeply at $1800, and for a lousy meager 1500-watt

http://global.rakuten.com/en/store/suzukimotors/item/tuph004/

sure would love to get my hands one one to see how it turns on the DC relay, tried to look at the manual unsuccessfully. May be the it has to be in Ready mode to get the 12vdc.

https://carmanuals2.com/mitsubishi/i-miev-2015-miev-power-box-74903

 

[jsantala]

Regarding the original BMS, you'd need to fake all the appropriate CAN signals to and from the rest of the car. So I wouldn't hold my breath on getting it to work. Balancing only happens at the very end of the charge as far as I know. Not during use. You could also try bottom balancing the second pack and not use a BMS for balancing. These types of cells are prone to combust if they are over-discharged and the charged, so voltage monitoring on the cell level is a must in any case.

 

[Aerowhatt]

This pack may be different but I doubt it. The boards over each group of cells have a power sync built in for each cell. So that when the cell reaches a certain voltage some power is shunted to the power sync (usually a resistor). So that cell will charge slower or not at all while others in the string that are lagging are still getting charged. End result is cell balancing. It makes no sense whatsoever to remove this function from autonomy for each cell handled by the board attached to it. So a very low amperage charge at the end of charging will balance such a pack. The value of or ability of the shunts to dump power to heat is good to know to avoid any overcharging. Charge at the rate that they can shunt or less and no worries.

The BMS is far more complex and centralized on the discharge end protection. That, one would likely not be able to integrate a second pack into cooperating with existing systems. So keeping the cells balanced would be simple. Preventing a lower capacity cell from being damaged by under voltage towards the end of discharge is far more difficult. Generally one would have to figure out how to monitor the BMS outputs and for a low cell situation have a logic circuit open the extra packs contactor that connects it to the rest of the car to prevent damage to it once a cell gets out of line on the bottom end of the discharge cycle.

Aerowhatt

 

[Anonymous]

178km SoC 33% with 2 packs on first trial. More details http://www.myimiev.com/forum/viewtopic.php?f=23&t=3074&p=27634#p27634.

In same weather and driving conditions 240km range seams realistic. Just city driving and trafic would make 260km possible on a single charge.

Interesting how I stopped worrying about range issues when driving with two packs. Seeing the battery gauge barely moving was of course a nice calming support.

The wonder was at this point how much time it would take to reach the turtle.

 

[Phximiev]

This company is advertising a 8 kWh extra pack for our vehicles:

http://eauto.si/metron-shop/?product=electric-range-extender

Interestingly, it also uses a DC/DC converter, which boosts the extender battery from 60V to 360V. I'd like to get one of those converters..

€ 7,978.80 :shock:

In my trip planning gyrations, I looked at some of the older posts on adding a pack and clicked on this site. It appeared to be closed so I sent emails to Metron:

They responded:

“Unfortunatelly we are not producing BREX for iMiev any more We might restart next year, price will be around 7000 EUR without VAT for 8 kWh battery. We have sold 3 pcs, problem is that producton of suitable DCDC converters has stopped in China. We need DCDC converter from 48 V DC to 370 V DC with 3 kW power”

It would seem that a rental pack, like the portable rental Chademo charger would be useful for use on trips.

And bundled with a trailer?