Electric DeLorean

[RamblinDMC]

I'll be 21 in July, I guess that makes us some of the youngest DeLorean owners here on DMCTalk.
Congrats on the progress of your DMC EV project!

These modules are fairly long (about 39 inches), so I don't think they could fit on the sides running parallel to the length of the car. And I don't think they'd fit above the motors - they're actually going to be fairly tall because there will be two stacked on top of each other.



22, unfortunately. That's why it's so difficult.



I think that might be a slightly different/older model. Here's what they're going to be putting in:
http://www.evwest.com/catalog/produc...lkc63b12pmnb77

[Bitsyncmaster]

So it looks like your battery packs still loose about 25% capacity after 500 charge/discharge cycles. So if your range was 200 miles a charge (like the Tesla) you would expect to need replacing the battery packs around 100,000 miles.

I'm still waiting for better battery packs to ever see the EV cars starting to replace gas engines cars.

[DrJeff]

I've looked at those EVWest "Tesla" modules before - but I have yet to find any evidence that they actually come from a Tesla. The larger Tesla battery modules (large flat modules) are from the Model S and X - and are the current standard modules from Tesla. Best case the EVWest modules are from a Roadster (but I also can't find any Roadster battery modules that look like these - not many Roadsters out there, so unsure where a good supply of batteries would come from).

I'm wondering if these are "Tesla-like" batteries in that they are composed of 18650s, but not batteries that actually lived in a Tesla vehicle. Also all true Tesla batteries are going to be used (most likely from a salvaged vehicle). This company (AutoBahn) - also in San Diego - dismantles cars and lists these (or has listed these modules on eBay) - note the same text and specs as the EVWest modules.

I would do a little more digging - there are only really two critical components to an EV - the motor/controller and the batteries.

Jeff

[Chris4099]

So it looks like your battery packs still loose about 25% capacity after 500 charge/discharge cycles. So if your range was 200 miles a charge (like the Tesla) you would expect to need replacing the battery packs around 100,000 miles.

How are you coming to this conclusion? The web site linked to says after 100,000 miles, they should lose about 15% capacity. Assuming his D ends up with an initial 140 mile range, that means after 100,000 miles, he'll have about 119 miles of range. That's still more then pretty much any new non-Tesla EV and very usable. Remember most driving (particularly with the longer range batteries), have much shorter charge/discharge cycles which don't hurt capacity nearly as much. Average US driver does about 40 miles a day which is just a fraction of a full charge/discharge.

These modules are fairly long (about 39 inches), so I don't think they could fit on the sides running parallel to the length of the car. And I don't think they'd fit above the motors - they're actually going to be fairly tall because there will be two stacked on top of each other.

I see. I was picturing the newer modules in the S/X which aren't as long. I can see how those modules would be difficult to put in the back and how you are able to put so many in the passenger compartment. I think those are the modules used in the Mercedes, Smart and Toyota EVs where Tesla provided the battery/motor system.

[DrJeff]

...I think those are the modules used in the Mercedes, Smart and Toyota EVs where Tesla provided the battery/motor system.

Here's a dimensions diagram for the modules. Listed as "Smart Tesla Module 2015".

Some interesting discussion in the comments attached to this article. Look at the comments starting with David Murray's question about Tesla and Smart.

Additional information here (search for Tesla).

[Bitsyncmaster]

How are you coming to this conclusion? The web site linked to says after 100,000 miles, they should lose about 15% capacity. Assuming his D ends up with an initial 140 mile range, that means after 100,000 miles, he'll have about 119 miles of range. That's still more then pretty much any new non-Tesla EV and very usable. Remember most driving (particularly with the longer range batteries), have much shorter charge/discharge cycles which don't hurt capacity nearly as much. Average US driver does about 40 miles a day which is just a fraction of a full charge/discharge.

Look at the data sheet of the battery. It has a graph of battery capacity with charge cycle numbers.

[Chris4099]

Look at the data sheet of the battery. It has a graph of battery capacity with charge cycle numbers.

OK, so you are assuming those with 200 mile EVs drive from 100% to 0% (of usable charge) before recharging. You also assume that once it's lost that 20%, it has to be replaced. Neither of these are common in normal EV use. I just wanted to point this out in case somebody thought the batteries actually have to be replaced after 100k miles. Most EVs will be able to use their original battery pack long after 100k miles. This is accomplished by the fact EVs usually don't let you fully charge to 100% and discharge to 0% (this decreases capacity drop by several magnitudes). Also most drivers charge the car at home while they sleep, which prevents the car from getting heavily discharged in the first place. In my case, after over 42k miles so far, I've only done a near full charge cycle a handful of times due to road trips and have approximately 5% capacity loss. I think age will be a greater factor in capacity loss then mileage. Even then, I have to lose close to 25% before it becomes a problem for some road trips and >60% daily driving (this is with my 200 mile Tesla with 60kWh battery pack).

[Bitsyncmaster]

OK, so you are assuming those with 200 mile EVs drive from 100% to 0% (of usable charge) before recharging. You also assume that once it's lost that 20%, it has to be replaced. Neither of these are common in normal EV use. I just wanted to point this out in case somebody thought the batteries actually have to be replaced after 100k miles. Most EVs will be able to use their original battery pack long after 100k miles. This is accomplished by the fact EVs usually don't let you fully charge to 100% and discharge to 0% (this decreases capacity drop by several magnitudes). Also most drivers charge the car at home while they sleep, which prevents the car from getting heavily discharged in the first place. In my case, after over 42k miles so far, I've only done a near full charge cycle a handful of times due to road trips and have approximately 5% capacity loss. I think age will be a greater factor in capacity loss then mileage. Even then, I have to lose close to 25% before it becomes a problem for some road trips and >60% daily driving (this is with my 200 mile Tesla with 60kWh battery pack).

Your correct the batteries will last a lot longer if you don't depend on that max range. And it's a good question as to what state of charge will loose how much capacity. Maybe if you never let the batteries get below 50% there is no degrading. Maybe also the degrading gets less and less after that 500 "charge" number. I've never seen charts go above that number.

[Chris4099]

Ya, most battery manufacturers seem to list battery life ending once it reaches 80% capacity. I guess that's considered a standard in that industry even though it doesn't necessary mean it's useless in most applications. Also, most charts I've seen do show the most degradation happening early on with the rate decreasing over later cycles. That's why I think age will be a bigger factor with the battery life on EVs. Temperature is also a very large factor into life span. But with active cooling, most of that can be managed. Leafs are the most popular EV that lack this which is why they seem to have more of a capacity loss issue in hotter climates versus cooler ones.

To get back on track of this thread, I'm looking forward to seeing how EV West does cooling on the batteries. I'm wondering if they involve the AC compressor or just a more passive system with the coolant going to the radiator only. I may have to bug Mario for a visit the next time I'm in the bay area.

[mr_maxime]

Out of curiosity, how many battery packs could have been able to fit where the transmission is?