map40home
Posts: 18
Joined: Sat Oct 26, 2019 11:41 am
Delivery Date: 26 Oct 2019
Leaf Number: 009238

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Nov 14, 2019 5:54 pm

jkenny23 wrote:
Thu Nov 14, 2019 12:59 pm
map40home wrote:
Thu Nov 14, 2019 12:04 pm

Thanks for the answer. I want one. If I understand correctly, I just need:
1) Batteries to produce 384V nominal (for me, 8 sets of 48V nominal LifoPo4 with their own BMS, in series)
2) Connection to the power cables out of the battery to parallel the new pack (with a nice reseteable fuse in the middle for safety)
3) Relays to connect/disconnect the extender so there is no damage to the resistor in case you turn off the car and the extender is still connected. (By the way, is it possible that you could sell us the wiring diagram for those relays?)
4) CAN in the middle attack board

Am I missing something?

Once again, thanks Mux, looking forward for you to share with us your knowledge.
I really don't advise using LiFePO4 with an extender unless you expect your extender battery to be able to handle the full charging and discharging current (120A charging, 280A discharging). LiFePO4 is such a vastly different chemistry than LMO that I foresee a lot of problems trying to parallel the 2, not even getting into the different charging profile and termination characteristic.

What kind of resettable fuse have you found that can interrupt 400VDC at 300A? I would be interested in such a part.

I can provide the wiring diagram for the contactors, it will basically be identical to the ones already in the car main battery, sharing the same control lines also. If you're new to EVs, you need to use things called contactors which are specially designed to stop DC arcs and have a much higher rating than a typical AC relay, which can get away with less since there's a zero crossing in the waveform.
Got it, thanks. What batteries do you recommend?
I could use the wiring diagram if you have it handy
I’ll see if I get you the part number for the resettable fuse. If I recall, it was 250 amps

map40home
Posts: 18
Joined: Sat Oct 26, 2019 11:41 am
Delivery Date: 26 Oct 2019
Leaf Number: 009238

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Nov 14, 2019 5:56 pm

Irling wrote:
Thu Nov 14, 2019 5:22 pm
map40home wrote:
Thu Nov 14, 2019 12:04 pm
1) Batteries to produce 384V nominal (for me, 8 sets of 48V nominal LifoPo4 with their own BMS, in series)

You need to use 114 elements. However, if you plan to install an additional battery in AZEO, then you will encounter the same problem as me. First, the COX will increase to 103% (if the second battery is connected correctly, transfer the current sensor), you will receive 285 energy GID for work. As soon as your battery is discharged to approximately 5 GIDs, you will get a turtle despite the fact that the voltage of your battery is still high and half of the energy reserve is left. This is the main problem that needs to be addressed ..
I thought the Mux solution circumvents this limitation. I suppose that for the Mux device to work correctly, the second battery must be connected after the current sensor, it needs to be checked.
I was assuming that the Mux device would address the turtle mode. As far as the battery, what do you recommend?

Irling
Posts: 23
Joined: Tue Jul 16, 2019 10:38 pm
Delivery Date: 17 Jul 2019

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Nov 14, 2019 6:09 pm

map40home wrote:
Thu Nov 14, 2019 5:56 pm
Irling wrote:
Thu Nov 14, 2019 5:22 pm
map40home wrote:
Thu Nov 14, 2019 12:04 pm
1) Batteries to produce 384V nominal (for me, 8 sets of 48V nominal LifoPo4 with their own BMS, in series)

You need to use 114 elements. However, if you plan to install an additional battery in AZEO, then you will encounter the same problem as me. First, the COX will increase to 103% (if the second battery is connected correctly, transfer the current sensor), you will receive 285 energy GID for work. As soon as your battery is discharged to approximately 5 GIDs, you will get a turtle despite the fact that the voltage of your battery is still high and half of the energy reserve is left. This is the main problem that needs to be addressed ..
I thought the Mux solution circumvents this limitation. I suppose that for the Mux device to work correctly, the second battery must be connected after the current sensor, it needs to be checked.
I was assuming that the Mux device would address the turtle mode. As far as the battery, what do you recommend?
Use LiNMC battery elements (3.65V., for example LG Chem 60ah Chevrolet bolt)
We are waiting for a response from Mux, what will happen to his device when the LBS spends all 285 GIDs

jkenny23
Posts: 97
Joined: Sat Aug 19, 2017 12:49 pm
Delivery Date: 19 Sep 2017
Leaf Number: 009318

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Nov 14, 2019 7:24 pm

map40home wrote:
Thu Nov 14, 2019 5:54 pm
jkenny23 wrote:
Thu Nov 14, 2019 12:59 pm
map40home wrote:
Thu Nov 14, 2019 12:04 pm

Thanks for the answer. I want one. If I understand correctly, I just need:
1) Batteries to produce 384V nominal (for me, 8 sets of 48V nominal LifoPo4 with their own BMS, in series)
2) Connection to the power cables out of the battery to parallel the new pack (with a nice reseteable fuse in the middle for safety)
3) Relays to connect/disconnect the extender so there is no damage to the resistor in case you turn off the car and the extender is still connected. (By the way, is it possible that you could sell us the wiring diagram for those relays?)
4) CAN in the middle attack board

Am I missing something?

Once again, thanks Mux, looking forward for you to share with us your knowledge.
I really don't advise using LiFePO4 with an extender unless you expect your extender battery to be able to handle the full charging and discharging current (120A charging, 280A discharging). LiFePO4 is such a vastly different chemistry than LMO that I foresee a lot of problems trying to parallel the 2, not even getting into the different charging profile and termination characteristic.

What kind of resettable fuse have you found that can interrupt 400VDC at 300A? I would be interested in such a part.

I can provide the wiring diagram for the contactors, it will basically be identical to the ones already in the car main battery, sharing the same control lines also. If you're new to EVs, you need to use things called contactors which are specially designed to stop DC arcs and have a much higher rating than a typical AC relay, which can get away with less since there's a zero crossing in the waveform.
Got it, thanks. What batteries do you recommend?
I could use the wiring diagram if you have it handy
I’ll see if I get you the part number for the resettable fuse. If I recall, it was 250 amps
I mentioned previously, but batteries from a plug-in hybrid make a good candidate for the high drain/high rate charging that the Leaf experiences. Examples are Hyundai Sonata PHEV (what I am using), Chevy Volt, Ford Energi PHEV, etc.

mux
Posts: 233
Joined: Sat Jan 13, 2018 3:52 am
Delivery Date: 13 Oct 2011
Leaf Number: 6177

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Thu Nov 14, 2019 11:50 pm

map40home wrote:
Thu Nov 14, 2019 5:56 pm
Irling wrote:
Thu Nov 14, 2019 5:22 pm
map40home wrote:
Thu Nov 14, 2019 12:04 pm
1) Batteries to produce 384V nominal (for me, 8 sets of 48V nominal LifoPo4 with their own BMS, in series)

You need to use 114 elements. However, if you plan to install an additional battery in AZEO, then you will encounter the same problem as me. First, the COX will increase to 103% (if the second battery is connected correctly, transfer the current sensor), you will receive 285 energy GID for work. As soon as your battery is discharged to approximately 5 GIDs, you will get a turtle despite the fact that the voltage of your battery is still high and half of the energy reserve is left. This is the main problem that needs to be addressed ..
I thought the Mux solution circumvents this limitation. I suppose that for the Mux device to work correctly, the second battery must be connected after the current sensor, it needs to be checked.
I was assuming that the Mux device would address the turtle mode. As far as the battery, what do you recommend?
We cannot currently address this type of turtle mode. It's technically possible with some work, but this is not something we've made so far. The big issue is that it's not a straight 'add main and extender battery capacity'-calculation. You have to actually interrogate the battery to make sure it's not overdischarging (or overcharging), essentially completely replacing the discharge and charge algorithms, something that may be quite dangerous if done improperly.

Irling
Posts: 23
Joined: Tue Jul 16, 2019 10:38 pm
Delivery Date: 17 Jul 2019

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Mon Nov 18, 2019 12:21 am

mux wrote:
Thu Nov 14, 2019 11:50 pm

We cannot currently address this type of turtle mode. It's technically possible with some work, but this is not something we've made so far. The big issue is that it's not a straight 'add main and extender battery capacity'-calculation. You have to actually interrogate the battery to make sure it's not overdischarging (or overcharging), essentially completely replacing the discharge and charge algorithms, something that may be quite dangerous if done improperly.
Do you planning to develop a technical solution to the turtle problem after the 285 gids in the azeo? Is it possible to develop alternative BMS firmware?

mux
Posts: 233
Joined: Sat Jan 13, 2018 3:52 am
Delivery Date: 13 Oct 2011
Leaf Number: 6177

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Mon Nov 18, 2019 12:35 am

We're not making any solutions for the behind-the-current-sensor-extenders or direct cell swaps. But it's not too hard to code it yourself. We're still in the process of open sourcing the boards, so it's something you can likely do yourself pretty soon.

map40home
Posts: 18
Joined: Sat Oct 26, 2019 11:41 am
Delivery Date: 26 Oct 2019
Leaf Number: 009238

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Nov 20, 2019 10:02 am

OK Mux, I just bought a used Leaf battery (I decided that the best chimestry to use would be the same that I already have). I just need one of your boards. We are ready to burn electricity!!!!!!

jkenny23
Posts: 97
Joined: Sat Aug 19, 2017 12:49 pm
Delivery Date: 19 Sep 2017
Leaf Number: 009318

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Nov 20, 2019 11:48 am

@map40home, I thought it was better to just share the information here in case anyone else wants it (it's all publicly available knowledge anyways, but I put it together for my own reference):

You want to use 3 contactors with your extender pack; 2 need to be full current capable, I recommend Tyco Gigavac EV200 which you can buy for a very reasonable price from EVWEST for the main contactor pair (negative and positive): https://www.evwest.com/catalog/product_ ... cts_id=387
And you can use the smaller LEV100 for the pre-charge contactor (positive only): https://www.evwest.com/catalog/product_ ... cts_id=388

The main LEAF VCM has 3 control lines that control the 3 contactors in the pack, labeled RLY N, RLY P, and PRE CHG:
Image

The pre-charge resistor is 30 ohm, 40W. I would suggest to use the same value and rating in the extender pack.
Image

So you want to intercept the 3 control signals from the BCM (behind the glovebox), run those signals to the trunk area, then buffer, and use these buffered signals to control the contactors for your extender pack in exactly the same manner as the main pack, as Mux has mentioned in this video:
https://youtu.be/k3jaGtkyxvA?t=524

The only change I would make is to add an AND gate between the signals coming from the BCM to your contactors, to allow your own E-stop/limit signal to kill your pack connection in case things go bad (e.g. over temp, cell under/over voltage, etc.), from the BMS you are using in the extender pack.

map40home
Posts: 18
Joined: Sat Oct 26, 2019 11:41 am
Delivery Date: 26 Oct 2019
Leaf Number: 009238

Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Wed Nov 20, 2019 1:31 pm

jkenny23 wrote:
Wed Nov 20, 2019 11:48 am
@map40home, I thought it was better to just share the information here in case anyone else wants it (it's all publicly available knowledge anyways, but I put it together for my own reference):
THANK YOU! It is greatly appreciated! I got a fully assembled Leaf 24KW battery comming, and I am planning to get this hooked up and running as soon as I get everything. Eventually I will get the Mux board and get the right GOM.
Once again, Thnaks!

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