[Scotty274]

So to start with, I am working off the EVWest assumption that a large car will use 300Wh/Mile, converting that number to Metric, I come to around 187Wh/kilometre

So the wife's daily commute is around the 180 kilometre mark, which means that she should use around the 33,660Wh to do that trip, or 33.66kWh

Anyway, I have a 24kWh LEAF sitting here, and it's just not enough. However, there's bulk room in the Volkswagen, and it had me wondering, as the packs are all modular, can I just....find another wrecked LEAF and use it's batteries too? I'd probably easily be able to find the room for a further 24kWh in the Jetta, so 48kWh would be mint. It would give her a mathematical range of 235km which is more than enough to get her to work and back.

So yeah, can I just...add more batteries and get it rolling? Maybe run 2xLEAF BMS's and have the charger have some form of switchover, so charge BMS bank A to 100% and then switch over and charge BMS Bank B to 100%?

That way we can also only charge one bank if we only need one bank, and we can switch between the banks when not driving long distances so we can even out the wear on the banks.

 

[kennybobby]

This would be a good question for Daniel, he is an expert on Leaf packs.

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[Tremelune]

The answer is yes, just add more. If the voltage is higher than your components can handle at full charge, you can parallel them. Be aware that you're talking about ~800lb of weight...Likely 500lb over stock when all is said and done. That may impede your ability to carry passengers/luggage without overloading the chassis/suspension. I dunno.

Thunderstruck's BMS system has modular satellites, each one responsible for 24 cells. You can just buy as many of those as you need (though I'm sure there's some absolute limit).

I gotta mention, perhaps an EV conversion is not the best use case for what I would call a massive commute...A motor in front and back with 420ftlb of total torque would be rather fun, though...Does your wife want to rely on a home-built contraption to get to work predictably and reliably, somewhat far from home...?

I don't mean to be negative, but if you want to succeed, you'll want to be sure the juice is worth the squeeze...What are your goals with this project?

 

[ishiwgao]

can I just....find another wrecked LEAF and use it's batteries too?

...

have the charger have some form of switchover, so charge BMS bank A to 100% and then switch over and charge BMS Bank B to 100%?

That way we can also only charge one bank if we only need one bank, and we can switch between the banks when not driving long distances so we can even out the wear on the banks.

If you're gonna go with 2 packs, why stick with the old 24kWh LEAF pack?

I understand the setup is probably easier since you've done it once. However, the cells have very low density compared to the newer LEAF packs, and even much lower when comparing to a wrecked Tesla Model S module or something.

Price is higher for the Tesla module that's for sure, but you get what you pay for. Great energy, low weight

 

[Tremelune]

I'm not sure there's a slam-dunk there. Tesla packs are for sure more dense, but the later Leaf packs seem to just be...more modules. The 30kW packs have heat-based degradation similar to the early 24kW packs. The Leaf batteries to get are the ones from a 24kW pack, April 2013 build date onwards. 2015+ model year packs are even better. I don't know much about the 40kW or 60kW packs, 'cause the bang-for-buck isn't there yet (as these cars are quite recent).

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Some napkin numbers:

Tesla S module - 27x11.5x3.5" (18L), 5.3kWh, 23v, 55lb
96Wh/lb, 294Wh/L, 0.42v/lb, 1.3V/L

Leaf module - 303x223x55mm (3.7L), 0.5kWh, 7.5V, 8lb.
63Wh/lb, 135Wh/L, 0.92V/lb, 2.0V/L

 

[brian_]

Tesla packs are for sure more dense, but the later Leaf packs seem to just be...more modules...

Leaf module - 303x223x55mm (3.7L), 0.5kWh, 7.5V, 8lb.
63Wh/lb, 135Wh/L, 0.92V/lb, 2.0V/L

What do you mean? All of the original-style Leaf packs (everything before the 62 kWh Leaf Plus/e+) have the same number (48) of the same size (2S2P, same dimensions as shown above) of modules; that's 24 kWh, 30 kWh, and 40 kWh... all in the same volume and configuration.

The 62 kWh pack does use a larger volume of differently-proportioned cells in three different heights of modules. Since it is not 55% larger in volume than the 40 kWh pack, it has some combination of more compact packing of cells into the pack case and higher energy density (by volume) of cells.

 

[Tremelune]

Shit, you're right. That's great for me for future upgrades!

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[Scotty274]

I gotta mention, perhaps an EV conversion is not the best use case for what I would call a massive commute...A motor in front and back with 420ftlb of total torque would be rather fun, though...Does your wife want to rely on a home-built contraption to get to work predictably and reliably, somewhat far from home...?

I don't mean to be negative, but if you want to succeed, you'll want to be sure the juice is worth the squeeze...What are your goals with this project?

Well it's not like she's that far from home, as it's 90km each way, so it's not far to go get her with a trailer if I need to.

I'm not sure why you would call that a massive commute, it's like...an hour and a half drive down the highway.

Price is higher for the Tesla module that's for sure, but you get what you pay for. Great energy, low weight

Very very high for Tesla packs in Australia, unless I'm importing them....and then it's not much cheaper than buying them locally. Very low supply on Tesla stuff here, very high demand.

And for those that are saying why use Leaf packs, I have them already in my wreck, and if I already have one system, it would probably be easier to integrate more of the same system.

 

[brian_]

Well it's not like she's that far from home, as it's 90km each way, so it's not far to go get her with a trailer if I need to.

I'm not sure why you would call that a massive commute, it's like...an hour and a half drive down the highway.

The vast majority of the world doesn't travel anywhere close to 90 km each way for their commute. The average car (electric or not) in North America only travels about 55 km (or 33 miles) per day, total. 90 km isn't a major journey, but it is very long for a regular commute.

 

[Scotty274]

The vast majority of the world doesn't travel anywhere close to 90 km each way for their commute. The average car (electric or not) in North America only travels about 55 km (or 33 miles) per day, total. 90 km isn't a major journey, but it is very long for a regular commute.

Fair enough, the average here is around 25,000km per year.

That equates to around 480km a week, which is 96km a day for a 5 day work week, or 68km a day if you drive it every day.

I think in our household it's pretty balanced, as I do 30km a day, and the wife does 180, so for a 2 car family, we basically have an average allocation of around 82km a day, each, I only use 30 of that, giving my wife an extra 52km for the average, putting her at 134km, meaning as a household, her usage is only 46km more than the average.

Plus it makes more sense to do her car as the savings there will be far greater than doing my car.

For me doing 30km a day, at 12l/100km and fuel price of $1.14/l for Diesel, that means my daily commute costs around $4.104 or $20.52 for 5 days driving.

Her car runs around the 8l/100km, but as she uses Premium at $1.22/l that's around the 14.4l/day or $17.568/day in running costs for her. So weekly that's $87.84 or $175.68 per fortnight.

So financially, that's around $4,567.68 in savings in her car if we make that the electric one, or only $1,067.04 if I convert my car.

Sure I'd save more on the rego on my car with it going electric, around $600 per year or $400 per year on hers, but also once I factor in Servicing costs on her car, hers is done every 20,000km versus mine at 15,000km, I need 0.52 services per year, ergo, 1 service per year, as I hit time before distance normally. Whereas her car doing 2.34 services per year means I save $600 in servicing on her car, versus only $300 in servicing on my car.

So at $6,400 for the cost of parts for the conversion in the wrecked eNV200, plus around $2,000 in engineering and maybe $2,500 in miscellaneous parts, I'll be at around the $10,900 on the conversion, maybe add another $2,000-3,000 for extra batteries, I'll be looking at the $14,000 mark, which at $4,567.68 in fuel savings, $400 a year in Rego, and $600 in servicing, for a total saving of $5,567.68/year, I'll be looking at an ROI of 2.51 years

I suppose though that in somewhere like North America, a lot of things are closer together, each city is closer than another city in America, each town is closer. For me, the nearest (big) town to me is 35km one way, that the "City" of Ipswich, which is an "Outer Suburb" of Brisbane, and Ipswich to Brisbane is 45km.

For us there are some things we just can't get locally, oftentimes needing to drive across town, 50-60km just to get to a singular store in town that has it. There's not chains like in America where each minor outlying city of a big one has a franchise, we just don't have the population density to support that kind of retail.

This is also why when you get a job here, you may be driving much further to actually get to work. I like numbers, and I think purely as a numbers game, it makes more sense to spend the extra money to make the wifes car the electric one over my 4x4, as that will give me the most savings long term.

 

[brian_]

I suppose though that in somewhere like North America, a lot of things are closer together, each city is closer than another city in America, each town is closer. For me, the nearest (big) town to me is 35km one way, that the "City" of Ipswich, which is an "Outer Suburb" of Brisbane, and Ipswich to Brisbane is 45km.

Only an Australian could suggest that! Yes, population is more dense in many areas here, but it is around major cities anywhere. My situation is somewhat similar to yours, and from my nearest major city to the next one of similar size is 300 km... but we just don't commute hours across the empty prairie to another major city to work. In some major Canadian cities housing prices force people to commute longer distances, but most people manage to live in the same city where they work - as they apparently do in Australia as well (given the 25,000 km/yr average use) - so 90 km each way, every working day, is much further than most people drive.

Yes, converting the vehicle using the most energy makes some sense, but it is a long-range application by the standards of DIY conversions. Nothing wrong with that... just watch out for recommendations which make assumptions of a shorter required range.