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

Sat Jan 13, 2018 10:42 am

No one said 100% safe. For those that think working on an ICE vehicle and an HV pack or line connection is a similar risk, well best of luck with those odds, HV techs have many hours of safety training and specialized tools over an ICE counterpart. Those that do not have enormous respect for HV systems are at high risk. There is also a reason the main contactor is located in the pack and the pack is sealed and isolated from the main cabin. Reliable, relatively safe and cheap don't really pan out in these cases but I can't wait to see the finished working projects posted here. I would challenge anyone to document ALL the hours and money spent. Time researching, planning, every bolt, wire, fastener, trip to the hardware store, looking into the trunk endlessly, etc. Adding up the cost of batteries and a few connectors is a bit of a cost pipe dream, it's not an RC car. Many people have actually documented every dollar spent on doing a project like this and it's always very telling, I would like to see that on one of these endeavors. Costs can include or exclude all the tools needed as well, don't forget your rubber cloves and coated tools:)
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mux
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Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Sat Jan 13, 2018 11:32 am

I'm a bit skeptical of the people calling out 'hours spent' on projects like these. Obviously it will never make sense financially if you consider this a commercial project with billable hours. The nice thing about hours you spend yourself is that they are truly free time (as long as you have free time). I don't consider this an expense, it's a hobby. It's fun! Well, for me. Can imagine it's terrifying for a lot of folks.

But, I do value other people's time. If I'm successful in making something decently safe and workable, I'll certainly document it for easy replication, if necessary with the help of other interested people. If it doesn't work out, well, I just spent a bunch of money on a fun side project and I'll reuse the batteries for something else.

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

Sat Jan 13, 2018 12:17 pm

mux wrote:I'm a bit skeptical of the people calling out 'hours spent' on projects like these. Obviously it will never make sense financially if you consider this a commercial project with billable hours. The nice thing about hours you spend yourself is that they are truly free time (as long as you have free time). I don't consider this an expense, it's a hobby. It's fun! Well, for me. Can imagine it's terrifying for a lot of folks.

But, I do value other people's time. If I'm successful in making something decently safe and workable, I'll certainly document it for easy replication, if necessary with the help of other interested people. If it doesn't work out, well, I just spent a bunch of money on a fun side project and I'll reuse the batteries for something else.


Even if you ignore the hours, comparing 2 things at similar price with brutally dissimilar effort to put together is something to think about.
I believe the fun part is the bms and vehicle integration, not the 4000 welds....


Any reason why the VW modules are a bad idea?

jkenny23
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Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Sat Jan 13, 2018 12:23 pm

mux wrote:I'm a bit skeptical of the people calling out 'hours spent' on projects like these. Obviously it will never make sense financially if you consider this a commercial project with billable hours. The nice thing about hours you spend yourself is that they are truly free time (as long as you have free time). I don't consider this an expense, it's a hobby. It's fun! Well, for me. Can imagine it's terrifying for a lot of folks.

But, I do value other people's time. If I'm successful in making something decently safe and workable, I'll certainly document it for easy replication, if necessary with the help of other interested people. If it doesn't work out, well, I just spent a bunch of money on a fun side project and I'll reuse the batteries for something else.


What is the voltage of those modules? If they're not an
even multiple of the Leaf pack they would still require taking apart and modifying.

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

Sat Jan 13, 2018 12:44 pm

RNM wrote:Even if you ignore the hours, comparing 2 things at similar price with brutally dissimilar effort to put together is something to think about.
I believe the fun part is the bms and vehicle integration, not the 4000 welds....

Any reason why the VW modules are a bad idea?


Aside from that I haven't stated anything about the VW hybrid modules...

Most importantly I won't be able to procure those VW modules here - at least not at the price you're able to get them. This goes for almost all modules - Tesla modules, IMiev modules, etc. , they're all either expensive or very hard to get compared to the US. And I'm not going to go the Jehugarcia route with recycled batteries or modules; that's even more work. New or bust. That also severely eases the speed at which I need to get my balancer in order; new cells, especially with 4+ in parallel, will be pretty much perfectly balanced for the first 50-100 cycles, so I can iron out any serious issues over like a year of use.

Re voltage of ready-made modules: most are 48V (12S), so that is perfectly compatible with the 96S pack in the Leaf.

Re chemistry: Leaf uses LMO (LiMn2O4), so really only LMO/IMR and LCO/ICR are acceptable chemistries to put in parallel with that. LiFePO4 is totally out of the question, as are non-lithium chemistries. NCR and other nickel/manganese/cobalt concoctions are probably maybe doable, but they have much more linear discharge curves so you'll get significant charge/discharge imbalance over the use of the pack.

As for 4k welds - it's not that bad! I do about two welds every 5 seconds, that's about two and a half hours worth of battery welding. Waaaaay less than all the other work. I figure the actual pack building can be done over a weekend. I've done way worse jobs like pack rebuilds with recycled tabs; now that I would not even start on this scale.

The real effort, work and the real stuff I'm anxious about is the stuff I don't know yet:
- Will I brick the car before I even start?
- Will I be able to actually splice cables on?
- Is there actually enough space somewhere to build on, in a sufficiently convenient shape?
- Can I get the contactor situation to work? I'll probably do this before even buying the batteries

After I have the RLY P/RLY V signals, they work reliably every time and I have a volume of air mapped out to put the pack in, all the work is done as far as I'm concerned. Welding and assembling the packs, doing the BMS, that stuff is all a formality to me. I've done that dozens of times already.

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

Sat Jan 13, 2018 2:28 pm

The fact that we must struggle with trying to integrate more batteries into our Leaf cars because Nissan won't permit the swapping of 30kWh packs into 24kWh cars with extreme degradation is frustrating. Even if it isn't financially the most economical solution, they should permit it if someone is so inclined to do so... :evil: Sigh, oh well.
Pulled the trigger on going EV on 10/2016 with a 2012 Leaf, and a Tesla Model 3 reservation expected to receive in June 2018.

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

Sat Jan 13, 2018 10:11 pm

Durandal wrote:The fact that we must struggle with trying to integrate more batteries into our Leaf cars because Nissan won't permit the swapping of 30kWh packs into 24kWh cars with extreme degradation is frustrating. Even if it isn't financially the most economical solution, they should permit it if someone is so inclined to do so... :evil: Sigh, oh well.


I'd find a way to fork over $6,000 if I could put a 40kWh battery in my 24kWh leaf instead of trying to do it myself.

On that thought I've always wondered what a Leaf's BMS would do if you changed out the 'ol 24kWh cells for 30kWh or 40kWh (or 60kWh) cells.
2013 SL 50,000 miles.
12 bars until 44,300 miles on June 2, 2017. :D
11 bars current. :)
The Nissan Leaf is the fourth best long distance car for highway driving. >>Best Long Distance Cars<<

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

Sun Jan 14, 2018 6:42 am

Well, I've had a bit of a look around the car, and even though this is probably all well-known information to modders, I just had to see it for myself:

- The wires leading from the charger to the battery, i.e. the ones that are 'easily' accessible from the boot in a '11-'12 Leaf, are way too thin to splice in a traction battery. Hard to see from the outside how thick the insulation would be, but it's maybe 6-8AWG.
- There is literally nothing between the steel trunk floor and the plastic underfairing. It's an ocean of space ready to be populated by lots of 18650s

This means I will have to somehow get this car jacked up, remove the underside of the entire car and do the Leaf XPack-splice. Not looking forward to that.

Can anybody confirm to me that it is 100% safe to uncouple the 12V battery, remove the traction battery service coupling and start work on the splice? Do I need to remove any DTCs afterwards (i.e. do I need to buy leafspy pro now?)

Does anybody by chance have the part number for the traction battery data connector? I wonder if it's possible to make this a non-destructive splice. I definitely need those signals.

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

Sun Jan 14, 2018 9:21 am

No the wires at the charger are not adequate and even if they were it’s the wrong place to connect. Personally I would not wast an hour of time adding capacity to a LEAF unless you are doing it inside the existing pack with a larger OEM pack. In the end buying a different ev is a better option of find a wrecked LEAF with a bigger pack. As a an improvement to the car this probably takes second place to the push trailer so many people wanted to do. Much easier, safer and better to try and leverage a pack from a salvage car.
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mux
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Re: Extra Battery, How to Integrate with 24kWh Traction Battery?

Sun Jan 14, 2018 12:14 pm

I keep seeing that comment, but I'm not quite sure how that could be construed as safer or easier in any way. Again, for me it is entirely not an option; we don't have salvageable batteries in Europe. This is either illegal or exceedingly hard to come by, as salvage cars require their hazardous components to be properly recycled.

But then still - a trailer is just a massive hassle. I don't have anywhere to put the car, let alone a trailer. It's extra air drag, it's pretty hard to interface (you'd have to build a whole secondary interface controller instead of just tapping the existing signals), you have to make a flexible super high current cable that actually conducts a couple dozen kW from the trailer to the car, and the whole thing has to be less than the allowable towing weight (maximum allowable combination weight is 1965kg in the Netherlands, the battery unit is about 300, so that leaves bupkis for the frame, wheels and the rest).

Sounds to me like a much bigger engineering challenge tbh.

And the same goes for doing anything inside the main battery. Opening it up means chiseling through the gasket material, doing whatever you need to do inside, and then closing it again. Fail to properly weatherseal it and boom, the car goes up in flames. We have a precedent for this. Regardless; the resale value and insurability of such a vehicle would be disastrous.

So it seems to me that really, if you want this to be safe, insurance-proof, within the design limits of the car and as minimally intrusive to normal usage as possible, there are very few avenues to go.

Of course, just buying a car with more effective range is the obvious, off-the-shelf solution. But where's the fun in that. Also, in my case and around where I live, it's not really a cheap solution. The cheapest comparable second hand car with ~40kWh capacity is more than twice the cost (~€22000 vs €9000). I know this is different in the USA, but that's just the cards I'm dealt. For at least another 2 years, I will not be able to afford (or well, willing to pay for) a car with significantly more range. That's fine, we bought the Leaf because it was sufficient, but I'm a tinkerer at heart and adding range to cars seems to be all the rage right now with only few success stories, so it seems like a nice challenge right up my alley.

And also; it's just a crying shame that these cars that have frames and electronics that will easily last another 10 years or more should be discarded or used for less than their original intent just because of shitty batteries. But that's obviously a topic touching on the consumable nature of cars in general.

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