Dani

Re: Additional pack

Sat Apr 23, 2016 2:49 am

Thanks for the reference Aerowhatt.

Dani

Re: Additional pack

Sat Apr 23, 2016 2:33 pm

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
Posts: 161
Joined: Tue Jan 07, 2014 12:17 pm

Re: Additional pack

Fri Apr 29, 2016 4:06 pm

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/suzu ... m/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-mi ... -box-74903

jsantala
Posts: 296
Joined: Fri Sep 12, 2014 9:32 pm
Location: Finland
Contact: Website

Re: Additional pack

Sat Apr 30, 2016 6:52 am

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.
kWsaki.com / EVs: Nissan Leaf 2012, Citroën Xsara 1997 (conv. 81V & 8" Series DC) and Kawasaki GPX750R 1987 (conv. 87V & ME1003 PMDC) / Used to have a Citroën C-Zero 2011

Aerowhatt
Gold Member
Posts: 442
Joined: Wed Jan 28, 2015 1:52 pm

Re: Additional pack

Sat Apr 30, 2016 5:19 pm

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
(July) 2014 cool silver ES, acquired new 4/2015 (40.9ah at ~34K miles)
(Aug) 2014 Labrador Black Pearl ES, acquired new 3/2016 (39.7ah at ~20k miles)

Dani

Re: Additional pack

Fri May 13, 2016 3:38 pm

178km SoC 33% with 2 packs on first trial. More details 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
Posts: 1210
Joined: Thu Jan 15, 2015 7:25 pm
Location: Phoenix

Re: Additional pack

Fri Nov 04, 2016 5:30 pm

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

http://eauto.si/metron-shop/?product=el ... e-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 product[i]on 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?
2012 iMIEV ES
2014 Chevy Volt

Return to “Batteries and Battery Management”