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

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Thank you for your concern, but please answer the question :) This is the only problem that bothers me. If I transfer the current sensor, I can use no more than 24 kilowatt hours of energy, if I leave it in the same place - then I can use more energy, but I don’t know what pitfalls can be
 
Irling said:
Dear engineers, please help solve the problem. I connect an extra high voltage battery to my car (aze0 2014)
Where do I need to connect an extra battery? After the current sensor (it is installed in the middle) or do you need to transfer the current sensor? What problems will there be if I leave the current sensor in the middle and connect an additional battery at the battery output? Thanks



Which side of the main contactors have you circled? If that is the output, then you have bypassed the precharge resistor (white rectangular item in the middle) which limits the inrush current into the capacitors inside the motor inverter and the dc/dc converter during START. Plus you would have the system always energized and no way to disconnect the HV to turn the car OFF.

You need an additional set of contactors to provide ON/OFF/START control and isolation for the extra pack.

What is your plan for charging the extra pack?

Do you have a picture of the current sensor?
 
No one with limited experience should be touching an HV pack and I would warn anyone giving advice that they could be open for liability. More than one person has been killed working on a LEAF pack. It’s really crazy hearing people doing this that have no idea what they are doing. Is suppose if you live outside the US that makes it easier but some if the comments and advice here are really irresponsible at this stage.
 
EVDRIVER said:
No one with limited experience should be touching an HV pack and I would warn anyone giving advice that they could be open for liability. More than one person has been killed working on a LEAF pack.

Citation please.

Obviously, the pack is dangerous, but a little common sense and the right tools makes it not that bad of a job.

Plus, I believe people should be able to take risks in their life. This doesn't seem like an unacceptable one to me.
 
nlspace said:
Irling said:
Dear engineers, please help solve the problem. I connect an extra high voltage battery to my car (aze0 2014)
Where do I need to connect an extra battery? After the current sensor (it is installed in the middle) or do you need to transfer the current sensor? What problems will there be if I leave the current sensor in the middle and connect an additional battery at the battery output? Thanks



Which side of the main contactors have you circled? If that is the output, then you have bypassed the precharge resistor (white rectangular item in the middle) which limits the inrush current into the capacitors inside the motor inverter and the dc/dc converter during START. Plus you would have the system always energized and no way to disconnect the HV to turn the car OFF.

You need an additional set of contactors to provide ON/OFF/START control and isolation for the extra pack.

What is your plan for charging the extra pack?

Do you have a picture of the current sensor?

Thank you for your answer, I agree that, if there is common sense, this work can be safe. I want to connect them in front of power relays that connect the battery in ready mode. In the photo, I highlighted the contacts on which there is always voltage, these contacts are connected directly to the + and - of the battery . I decided to transfer the current sensor to one of these wires, and connect an additional battery in front of the current sensor, so I get the correct capacitance measurements from both batteries. To ensure correct mileage, I will update the module LBC/VCM software from Leaf 30 kwth firmware
 
EVDRIVER said:
No one with limited experience should be touching an HV pack and I would warn anyone giving advice that they could be open for liability. More than one person has been killed working on a LEAF pack. It’s really crazy hearing people doing this that have no idea what they are doing. Is suppose if you live outside the US that makes it easier but some if the comments and advice here are really irresponsible at this stage.

You are in a specialized forum, and the people who read it carry out any actions at your own risk. I understand your concerns, but you do not need to create a problem out of it, otherwise any technical forum will be useless :)
 
Irling said:
EVDRIVER said:
No one with limited experience should be touching an HV pack and I would warn anyone giving advice that they could be open for liability. More than one person has been killed working on a LEAF pack. It’s really crazy hearing people doing this that have no idea what they are doing. Is suppose if you live outside the US that makes it easier but some if the comments and advice here are really irresponsible at this stage.

You are in a specialized forum, and the people who read it carry out any actions at your own risk. I understand your concerns, but you do not need to create a problem out of it, otherwise any technical forum will be useless :)

Thank you for letting me know where I am, I just started posting here last week. Best of luck and buy some gloves and plasti dip.
 
This won't work. We tried, the LBC doesn't like it and you're going to get fatal DTCs all the time.
 
mux said:
This won't work. We tried, the LBC doesn't like it and you're going to get fatal DTCs all the time.

Therefore, I am waiting for your decision :) What exactly won't work? Move the current sensor to its extreme position?
 
It would help to see a picture or know what type of current sensor is being used.

If you could make a parallel shunt path to bypass the current sensor, then it might only see half of the current and allow longer operation before reaching the A-hr limits.
 
You'll either sit before the current sensor and cause the BMS to throw balancing/end of charge errors as well as not properly accounting for capacity (because the LBC is limited to 24kWh nominal capacity internally - and you can't flash the 30kWh firmware without re-pairing, and the pairing key does not work across battery types), or you'll sit after the current sensor and get current mismatch errors as well as not being able to account for the extra capacity at all.

Plus, your secondary battery pack will need its own BMS that works together with the car.

I built a company around all of this, it took me a year to get basic functionality to work consistently. Given the expertise or lack thereof you've displayed so far, I'd also highly recommend either not going through with this project or committing much more time to figuring out all of this yourself and learning from it in little steps.
 
mux said:
You'll either sit before the current sensor and cause the BMS to throw balancing/end of charge errors as well as not properly accounting for capacity (because the LBC is limited to 24kWh nominal capacity internally - and you can't flash the 30kWh firmware without re-pairing, and the pairing key does not work across battery types), or you'll sit after the current sensor and get current mismatch errors as well as not being able to account for the extra capacity at all.

Plus, your secondary battery pack will need its own BMS that works together with the car.

I built a company around all of this, it took me a year to get basic functionality to work consistently. Given the expertise or lack thereof you've displayed so far, I'd also highly recommend either not going through with this project or committing much more time to figuring out all of this yourself and learning from it in little steps.

Excellent advice.
 
mux said:
You'll either sit before the current sensor and cause the BMS to throw balancing/end of charge errors as well as not properly accounting for capacity (because the LBC is limited to 24kWh nominal capacity internally - and you can't flash the 30kWh firmware without re-pairing, and the pairing key does not work across battery types), or you'll sit after the current sensor and get current mismatch errors as well as not being able to account for the extra capacity at all.

Plus, your secondary battery pack will need its own BMS that works together with the car.

I built a company around all of this, it took me a year to get basic functionality to work consistently. Given the expertise or lack thereof you've displayed so far, I'd also highly recommend either not going through with this project or committing much more time to figuring out all of this yourself and learning from it in little steps.

Thank you very much for your response. Yesterday I used an additional current sensor, which I installed on the last element of the battery (positive wire). For the experiment, I will make three wires, one common, and the other two will be connected before the current sensor and after the sensor. Thus, I was able to choose a better option for me. Firmware from 30 kW is already used in some cars in our city, it works well, the mileage forecast has increased, however, if the main and additional batteries have an energy reserve of more than 30 kilowatt hours, then problems may occur. 3 bms 32S can be used to balance the extra battery https://item.taobao.com/item.htm?spm=a312a.7700824.w4002-16866903036.34.3a3276ec8iSS0R&id=546044502892 but yesterday I used the second LBS module from the Leaf, connected in BMS only mode. This works well to display the voltage level of each element, however there is no balancing and protection function. If your technical solution allows you to use an additional module for balancing, and can also issue a control signal to interrupt the power circuit - this will be a breakthrough :) Sorry for my bad english

4e1bd949fe17.jpg
 
mux said:
Not really, still trying to get a bunch of pre-mass production boards out to my friends and co-devvers in the community. Things are going slower than I'd like.

Hi Mux, how are you? Is your device available for order?
I plugged in a second battery, however the turtle appears after 24 kilowatts of energy has been consumed

4d38d06e270a.jpg
 
Hi Mux. Any chance we can buy yet (US customers)? Just the boards and the instructions. I would be willing to sign you off any liability (If I didn't die when I had my V8 town car running for 2 years with my home made hydrogen cell, 400V are not going to kill me😁).
Me personally, I am not interested in all the bells and whistles. Just how to design and connect the extender pack and the CAN. I can live with the GOM being a little off, or some alarms in the dash. I am not interested in selling it, just using it. I love standing by the big lifted trucks here in Florida that look at you like a roach and leave them behind crying because they can't take off as fast as my leaf. The problem is that if I do that twice, the goes half my battery...😀
I'm sure we can get some batteries here that can work for the extender concept (we had no e-golfs here until this year).
 
map40home said:
Hi Mux. Any chance we can buy yet (US customers)? Just the boards and the instructions. I would be willing to sign you off any liability (If I didn't die when I had my V8 town car running for 2 years with my home made hydrogen cell, 400V are not going to kill me😁).
Me personally, I am not interested in all the bells and whistles. Just how to design and connect the extender pack and the CAN. I can live with the GOM being a little off, or some alarms in the dash. I am not interested in selling it, just using it. I love standing by the big lifted trucks here in Florida that look at you like a roach and leave them behind crying because they can't take off as fast as my leaf. The problem is that if I do that twice, the goes half my battery...😀
I'm sure we can get some batteries here that can work for the extender concept (we had no e-golfs here until this year).

Seconded, been waiting eagerly for the electronics. I'm sure Mux will finish it just as quick without us pestering him though ;)

I'd be happy to help with battery selection/testing for the community, I've already had some experience with this (see my testing several pages back, probably easier just to search my posts), if you want to stay in the safe operating envelope of the car's charging/discharging rates, you'll need some pretty high drain cells, which is why I went with the PHEV cells, it's a lower energy density, but can accept much higher charge and discharge because it's only a 9.8kWH nominal pack that needs to put out (or accept from regen) 20-30kW to/from the motor.
 
Maybe the Mux solution doesn’t work too well, because the whole problem is hidden in the LBC Module. For AZEO, this module has a maximum capacity of 285 Gids., We can correct any readings on the dashboard, however if the battery has a capacity of more than 285 gids, there will still be a turtle. Correct me if I am wrong
 
My solution only works for batteries that have a separate BMS and are switched in parallel to the main battery on the HV bus. It is HIGHLY discouraged for a multitude of reasons to either replace the main cells with a different chemistry or to parallel them inside the main battery. Different battery = different BMS.

My boards are ordered in bulk, they should arrive *somewhere* this month, after which I'll be happy to sell them to anyone.
 
mux said:
My solution only works for batteries that have a separate BMS and are switched in parallel to the main battery on the HV bus. It is HIGHLY discouraged for a multitude of reasons to either replace the main cells with a different chemistry or to parallel them inside the main battery. Different battery = different BMS.

My boards are ordered in bulk, they should arrive *somewhere* this month, after which I'll be happy to sell them to anyone.

if the second battery does not have bms, and one bms is used for two batteries, this will not work correctly?
what happens when bms 24kwh aseo counts 285 Gids?
 
You run into multiple issues.

If parallelling each cell individually, the BMS will likely have too little balancing current available in the long term. The BMS in the Leaf uses table look-up for determining SOH, internal resistance, allowable charge and discharge rate, etc., which is chemistry-specific and really even cell-specific. Parallelling cells together with potentially different chemistries will make this useless and will possibly cause the battery to determine the wrong SOH, SOC and allowable current at different times.

Parallelling the entire pack together means one pack will not have cell-level balancing and monitoring. This will cause fire and death. You can't have a BMS-less pack.

If the Leaf's BMS were designed a little bit better, the first approach could actually work fine, but it's got the 285 GID maximum as well as monotonic degradation memory (meaning a battery can never get 'better', only 'worse' according to the BMS), which makes it hard to properly gauge capacity and SOC witht he existing BMS. This can't really be solved with a CAN MITM workaround.
 
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