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

[TomT]

And wait, and wait, and wait...

Or just wait for the 60 kw battery.

[Brenthasty]

Underneath the trunk and between the diffuser is room for quite a bit more of a battery

[Atkam]

Hello!

For several months as I work on the project "additional battery in parallel with the main in my nissan leaf y2012.
Planned additional battery 22p96s 18650 -15-20kwh - aprox 120kg.

I read the forum and Nissan documentation and examines the contributions of members to the Forum (turbo3, gerygid ... - my respect). Recently, however, I found on youtube a similar project:

https://www.youtube.com/watch?v=1ooEgQ3ZxnM

It is interesting that it has already taken the test and according to the internal resistance (use 2p96s) of the load got about 50A main battery; 3,6A of extra batteries.

Watch the video.
aprox: main 60Ah, extra 5Ah... 60:5 ==50:3.6 divided current according impendanceand capacity. Leaf not detect small additional current, the question is what is happend in case additional 50Ah??

However, it is still a long way, especially when taking into account the security and toughness integration.
As some one wrote on the forum: not be easy do it, but I find technical and skilful a challenge for Leisure...

Atkam


my first post

[collink]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf. It has been driven around for months thereafter. I can't say that there are never any problems but they're rare and clear with a power cycle. The car used to get perhaps 55 miles per charge but now I can just barely squeeze out 85 miles if I really run it dead. However, my integration was a bit more involved than the average hobbyist project. The Leaf BMS is smart enough to do many checks before it'll enable anything and that makes it tough.

1. I'm connected in line with the big power wires coming out of the main pack.
2. I have my own contactor to trigger my pack in
3. I've tapped the power wires going to the main pack's contactors so I know when they're closed
4. I'm reading CANbus from both the Leaf BMS and a BMS on the add-on 12kw pack
5. You have to close your contactor only once the main system has precharged and closed for driving.
6. You must open your contactor immediately if the main pack opens
7. You can't close until the voltages measured on both sides are almost the same. Sometimes this delays linking the packs until driving for a while or charging for a while.

Basically, it is computer controlled and uses a contactor. If you don't cooperate that way then the BMS will scream at you and you go nowhere. I wouldn't say that such a project is super easy but I can vouch for it being possible. You absolutely cannot have voltage from your pack getting to the motor controller or other HV components until the Leaf is ready. Otherwise, the car will slap you and it'll be hard to clear the errors. My system is fully automatic now but it took a lot of work and experimentation to get there.

[TimLee]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf. ...

Wow

Separate charger for the 12 kWh add on pack?

[collink]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf. ...

Wow

Separate charger for the 12 kWh add on pack?

No, I integrated the add-on pack such that the car ends up using it both for charge and discharge without knowing the extra pack is there... most of the time. Sometimes it generates an isolation fault or something. But, the error it generates clears with a power cycle so when it happens we just turn off the car for a bit and turn it back on. I'd have no patience for needing to charge the add-on pack separately. The fact that I'm spoofing out the car unfortunately means that it also doesn't really properly take the add-on pack into consideration when doing distance calculations. It somewhat does as it figures out that the car isn't drawing the main pack down as fast as it thought it would but the distance calculations get really funky - it'll drop 5 miles in range in 2 miles then stay steady for 5 miles, then drop 1 mile for each mile, then drop a bunch, then level out again. It's really confused. I thought about spoofing signals to the gauges but that seems like too much work for little benefit. I'm just happy to be able to reliably drive 75 to 80 miles in a 2012 Leaf.

[DaveEV]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf.

This is really cool - do you have any pics or documentation of your setup?

[TimLee]

... No, I integrated the add-on pack such that the car ends up using it both for charge and discharge without knowing the extra pack is there... most of the time. ...

I somehow thought charging might cause issues.
But in both cases the two packs are in parallel.
And charging stops based on voltage.
So if one pack is more depleted current will flow into the weaker pack.

And in discharge Turtle is based on voltage too.
But pack disconnect always appears to occur at 4 Gids.
Is there any risk of over discharging the 12 kWh pack if it is weaker?
Or does its BMS independently protect and disconnect it?

[RNM]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf.

This is really cool - do you have any pics or documentation of your setup?

I'm really interested in knowing what chemistry have you used. All 18650 i know don't "fit" the leaf pack very well in terms of SOC vs voltage...

[bmartin]

I've done it successfully. I added 12kwh worth of batteries in the "trunk" area of a 2012 Leaf. It has been driven around for months thereafter. I can't say that there are never any problems but they're rare and clear with a power cycle. The car used to get perhaps 55 miles per charge but now I can just barely squeeze out 85 miles if I really run it dead. However, my integration was a bit more involved than the average hobbyist project. The Leaf BMS is smart enough to do many checks before it'll enable anything and that makes it tough.

1. I'm connected in line with the big power wires coming out of the main pack.
2. I have my own contactor to trigger my pack in
3. I've tapped the power wires going to the main pack's contactors so I know when they're closed
4. I'm reading CANbus from both the Leaf BMS and a BMS on the add-on 12kw pack
5. You have to close your contactor only once the main system has precharged and closed for driving.
6. You must open your contactor immediately if the main pack opens
7. You can't close until the voltages measured on both sides are almost the same. Sometimes this delays linking the packs until driving for a while or charging for a while.

Basically, it is computer controlled and uses a contactor. If you don't cooperate that way then the BMS will scream at you and you go nowhere. I wouldn't say that such a project is super easy but I can vouch for it being possible. You absolutely cannot have voltage from your pack getting to the motor controller or other HV components until the Leaf is ready. Otherwise, the car will slap you and it'll be hard to clear the errors. My system is fully automatic now but it took a lot of work and experimentation to get there.

I want to do this to my 2012 leaf as well. Could you provide a parts list of what you used?
You programmed your own interface to the CANbus? I tried writing an Android app to read the CAN bus, but I wasn't able to get the protocol right, only a bunch of OK messages.

I would love to learn from the resources you used, I've tried looking for documentation but can't find much.

This technology is absolutely amazing.