KiwiEVs next project fast EV

[The Toecutter]

Im hope for 200 km combined highway city drive which I dont think is unrealistic

If you know how to keep the accelerator in check and do 80% of the trip under 90 kmh, and use various hypermiling techniques, its very possible. It's not what someone unacquainted with how to efficiently drive an EV is going to get their first time driving it, in the event that someone else drives it.

To aid you, you may want to check out Phil Knox's Toyota pickup and note its aerodynamic upgrades:

http://evworld.com/article.cfm?storyid=870

Why stop at 200 km range, when you could have 250, or even 300, on the same size battery pack... After all, Otto cycle engines tend to lose thermal efficiency as load decreases, decreasing the returns gained from reductions in drag coefficient/frontal area. The impact of aerodynamics is much more noticeable on the energy consumption of an EV due to an electric motor being efficient across the vast majority of its operating parameters, plus you don't have a lossy internal-combustion furnace to keep cooled and thus do not have to deal with the aerodynamic penalties associated with that if you choose not to by addressing it.

Ecomodder.com could show you a lot of info on this subject, as scores of vehicles there have modifications on them and there are even guides on how they were made.

The AC 51s are 144 volt

The AC 50s are 96 volt which Michael from EV west are running at 120 volt and giving just under 250 ft lb with 2 motors.

With 96V, you can go up to 650A, and get 120 lb-ft or so, so 250 lb-ft sounds about right. You'll lose high-rpm power, continuous power, and a little peak power though versus going with 144V/500A, but you're probably not concerned about that, as whether you use 144V/500A or 96V/650A, you're still going to be capable of 160+ kmh, and given that you would rather get the low end grunt, a logical choice.

I wish I could afford a set of twin AC50s for the GT6. Direct drive geared for ~170 mph top end with the 96V/650A setup for each would yield ~155 hp/245 lb-ft. In a sub 2,000 lb conversion, 0-60 mph would be in the mid-upper 4 second range... *drool* Better yet, a Tesla P85D drivetrain and a LoneStar pack would be lunacy.

As far as performance goes more focused on 0 to 60 times. I have a mate down hear who has the duel cab version with a warp 9 at 144 volts and 380 Amp limit on his controller and I have been with him and it does 0 to 60 in 9.2 seconds.
Btw his car weighs 1350 kg all up.

Is the 380A limit on the battery for that duel cab? I'd imagine the motor would require a bit more current in order to get the torque for that sort of 0-60 given that 144V*380A is 53720W, and 380A to the motor would only give a WarP 9 perhaps 100 lb-ft of torque. I could easily see 1,000A at the motor allowing that with its 250+ lb-ft, even if the power applied from the batteries is a meagre amount of around 55 kW.

http://evtv.me/2011/04/the-graphs-is-always-greener/

So the space cable is lighter not sure by what thou?

So I think 0 to 60 under 7 seconds is do able

But in the end it is just truck,

Cheers Kiwi

If you go with each AC50 getting 650A instead of 500A, it can be done, provided you get the traction needed.

Maybe you could do like a yankee redneck and paint it camoflauge and put a pair of truck nuts on it. :lol:

 

[kiwiev]

Thanks Toecutter

Great info bro especially the air drag on the Toyota truck, can you tell me at what speed drag really effects an EV?

Thanks in advance

Kiwi

 

[The Toecutter]

Thanks Toecutter

Great info bro especially the air drag on the Toyota truck, can you tell me at what speed drag really effects an EV?

Thanks in advance

Kiwi

At about 40 km/h in an automobile, air drag accounts for as much power to maintain cruising speed as all other losses combined, and its percentage only goes up from there.

However, when it comes to power needed for acceleration, mass is a bigger factor at virtually any speed, but if you're going to be doing a lot of careful steady-speed cruising to preserve your range, you definitely want to focus on aerodynamic drag reduction.

 

[kiwiev]

That makes sense in the Sonic driving around at 40 kph it uses bugger all juice and I can do 10 km on less that 3% of the battery.

Thanks mate

 

[The Toecutter]

That makes sense in the Sonic driving around at 40 kph it uses bugger all juice and I can do 10 km on less that 3% of the battery.

Thanks mate

This is why I keep saying that you need to build a streamliner body for that Sonic. No kit that I know of will give you this, you will need to build it from scratch, with the goal of reducing drag as much as possible(keeping in mind stability requirements, ect) and the design oriented towards that purpose.

Imagine that instead of 10 km at 40 kph consuming only 3% of your juice, you can increase your speed to 100 kph for the same 3% consumption for the same 10 km distance.

How much more practical would the car be as a result? How much more expensive would it cost?

If you do an analysis, you will more likely than not find that per mile of added range, it's vastly less expensive to cut required consumption than it is to add more batteries. We're talking a few hundred dollars of materials and a few months of work for what will amount to perhaps up to a doubling of usable range, by turning your Sonic into a streamliner.

 

[kiwiev]

Thanks mate

One day it will be a good project

On another note what would or is better horse power or torque the HPEV 35 x 2 96 volt has awesome torque and would this be better for the Toyota being heavier and a gearbox ?

See attached graph.


Cheers Kiwi

 

[The Toecutter]

Thanks mate

One day it will be a good project

On another note what would or is better horse power or torque the HPEV 35 x 2 96 volt has awesome torque and would this be better for the Toyota being heavier and a gearbox ?

See attached graph.


Cheers Kiwi

What is "better" depends on what you want out of the design.

I am assuming 0-100 kph acceleration is more important to you than top speed, in which case I'd go with a twin 96V/650A setup. However, if I wanted to do 200+ kph, twin motors at 144V/500A would be a better fit due to higher peak and continuous power both achieved at higher rpm, but low-end acceleration under 50 kph would be significantly slower.

 

[kiwiev]

That's what I thought too

Got the old girl on the road registration done, they sit nice and flat on the road and go round corners reasonable well.

I couldn't help myself and put lighter wheels and better tires on


Cheers Kiwi

 

[Cowardlyduck]

Looking great mate.

That thing should rip with some electrons pushing it along.

Cheers

 

[Lurkin]

remove a few leaf springs for more low... heh heh heh

 

[kiwiev]

remove a few leaf springs for more low... heh heh heh

Great minds think a like just ordered 3" drop blocks for the rear

Cheers Kiwi

 

[Cowardlyduck]

You might wanna leave some spring in the rear if your gonna load it up with 100's of KG of batteries though?

 

[kiwiev]

You might wanna leave some spring in the rear if your gonna load it up with 100's of KG of batteries though?

The thought was to run a set of air bags with a pump so I can raise and lower great for that nice dirt road I live on

I also put a spray tank on the other day and fulled it with 240 litre of water the back dropped 2" .

Hopefully the aussie dollar will keep climbing CD it will make those 18650 cells looked better btw do you know how many cycles you can get?

Cheers Kiwi

 

[Cowardlyduck]

Hopefully the aussie dollar will keep climbing CD it will make those 18650 cells looked better btw do you know how many cycles you can get?

Cheers Kiwi

Yeah, I'm getting might itchy to jump soon with the way the AUD is at the moment.
Depending on the chemistry, and depth of discharge, but they are often 'rated' at 500+ cycles with some saying up to 1000 cycles. Really I would say a minimum of 300 cycles if fully discharged every time, and double that if less than 3/4 discharged each time.

Cheers

 

[kiwiev]

So I'm going to take Toecutter great advise lower the ute and stream line underneath.

I wish the 18650 cells had more cycles

I like the pouch cells

14Ah, 3.7V, 3.5C
2.3L * 0.5W * 7.4H in
60 * 12 * 190 mm
9.7 oz / 275 g
Bestgo Power Pouch Cell
EV Li-NCM Lithium Pouch Battery
Model: BP-LN-14AP

I need 640 cells which weighs 175 Kg and good for 1000 cycles they are about USD $ 18.50 each


What do you think ???

Cheers Kiwi

 

[Cowardlyduck]

You've gotta take cycle counts with a truckload of salt.
The cycles I mentioned about are based on real world usage, not coming from the vendor trying to sell you their product.

My Stealth Fighter battery (LifeP04) when purchased was rated at 1000 cycles. I'm at about 550 cycles now. More than 50% of those were less than 65% depth of discharge. I now only see about 70% of original capacity if I take it real easy and less than that if I pull lots of amps. The number of cycles are supposed to be the number of times you can charge and still get 80%+ of original capacity. Well so much for that.

The point is, plenty of 18650 cells will also advertise 1000+ cycles just like those Bestgo pouch cells, but in real world usage it depends on how hard you use them. I'm pretty sure the current 18650 cells are also a derivative of the Li-NCM chemistry also, so the only real difference between them is one is pouch format vs the other is a round cell.

The only real advantages to a pouch cell format is the per cell capacity meaning you can use fewer total cells and have fewer total connections.
The drawbacks compared to 18650's are many however being;
- More total weight (lower Kwh per KG)
- More cost per Kwh
- Higher risk of fire
- Cell puffing

This is why I don't intend to use Hobby King packs again. My HK Zippy Compact cells have all puffed quite badly now at around 300 cycles now with the outer cells (1 and 6) on each pack all producing less capacity as a result.

Cheers

 

[kiwiev]

You've gotta take cycle counts with a truckload of salt.
The cycles I mentioned about are based on real world usage, not coming from the vendor trying to sell you their product.

My Stealth Fighter battery (LifeP04) when purchased was rated at 1000 cycles. I'm at about 550 cycles now. More than 50% of those were less than 65% depth of discharge. I now only see about 70% of original capacity if I take it real easy and less than that if I pull lots of amps. The number of cycles are supposed to be the number of times you can charge and still get 80%+ of original capacity. Well so much for that.

The point is, plenty of 18650 cells will also advertise 1000+ cycles just like those Bestgo pouch cells, but in real world usage it depends on how hard you use them. I'm pretty sure the current 18650 cells are also a derivative of the Li-NCM chemistry also, so the only real difference between them is one is pouch format vs the other is a round cell.

The only real advantages to a pouch cell format is the per cell capacity meaning you can use fewer total cells and have fewer total connections.
The drawbacks compared to 18650's are many however being;
- More total weight (lower Kwh per KG)
- More cost per Kwh
- Higher risk of fire
- Cell puffing

This is why I don't intend to use Hobby King packs again. My HK Zippy Compact cells have all puffed quite badly now at around 300 cycles now with the outer cells (1 and 6) on each pack all producing less capacity as a result.

Cheers

Thanks CD

The prismatic cells that Andrew is using in his Hilux are 5 years old and have 1600 plus cycles to varying degrees but hold reasonable charge.

So it still looks like the 18650 are the go, I need to put the ute on the hoist and measure the room underneath 50 cells in arrow at 900mm is a bit long plus room for the buzz bar out the end, I do like the KISS principle of just running 2 rows of a 50 x 18650 cells and 1 buzz bar down the middle.

So mate can I get a cell that puts out more C rating or will I have to run 4 rows of cells with 2 buzz bars at 25 cells a row? would be a big heat shrink to fit over that :?

I guess there are Pros and Cons and coin $$$ to every option.

I'm going to work on setting up a tilting rear tub system to access the battery boxes too, plan is to get all parts together and fabricated then spend a week and do the conversion

Also are you just going to bottom balance only? and rely on the charger to top off? or BMS? and what sort of charger are you thinking?

Cheers Kiwi

 

[Cowardlyduck]

Wow! 1600 cycles is impressive. I would be interested to know what the typical DoD was. I think you could see similar with the 18650's if the majority of cycles were less than 50% DoD.

The only cells that will put out more C ratings than the 3500mah Sanyo's, Samsungs and LG's are all lower capacity.
The next best options I know of would be the LG HG2 or Samsung 30Q, putting out 20A and 15A continuous respectively.
Both these cells are only 3000mah however, so your loosing a good 15% capacity for the same number of cells. To still hit 41Kwh you would need to get and weld an extra 480 total cells and put 115 in each parallel group...or just stick with 100 paralleled and accept 35Kwh capacity.
The other factor is they are more expensive, compared to the 3500mah cells...see here for a rough difference.
http://ru.nkon.nl/rechargeable/18650-size.html

I would recommend just sticking with the 3500mah cells and if you need more current capability, just add more parralelled cells. It will cost you less overall and you will get extra capacity/range also. There is also a discussion going on right now about how much peak current these cells can really handle:
https://endless-sphere.com/forums/v...sid=c4107abd69cdee3bf6cc573f0d626da9#p1164651
I don't know heaps, but I would say it's fine to peak to about 15A per cell without issue. That gives you 1500A to play with.

I'm already setup with a couple of bulk chargers that I intend to use. I periodically balance after charging roughly once a week or 2 usually. Up to you if you want to do this for the car, but given the number of cells you are dealing with, you may want something a bit more automated.

Cheers

 

[oatnet]

My Stealth Fighter battery (LifeP04) when purchased was rated at 1000 cycles. I'm at about 550 cycles now. More than 50% of those were less than 65% depth of discharge.

In battery ratings, cycle is not actually the number of times you discharge/charge the cell, but equivalent to using 100% capacity of the cell. If you only use 1/3 the cell on each discharge/recharge, it would take (3) of those usages to count as one cycle.

In addition, the cycle rating depends on a certain level of discharge - the cell might get 1,000 cycles when tested a 3c, but half of that at 6c, 150 cycles at 9c - it all depends on chemistry, and the c rating/AH should be sized to the duty cycle.. The rating is also until the cell yields 80% of capacity, so at 70% your pack is considered "failed" even though it has plenty of utility. You might have something else going on, like an out-of-balance cell that stops discharge early.

18650's come in a wide range of chemistries, keep in mind that the high-discharge Samsung 30q is only rated for 150 cycles IiRC. A car-size pack of 18650's would mean a lot of points of failure in a high-vibration application; I know tesla pulls it off in clean-room conditions, but I don't think I could home-build an equivalent pack that would be as reliable.

I saw Okashira quoting international shipping on his factory A123 modules which do 30c, and it seemed pretty reasonable.

-JD

EDIT: this is the post I was talking about, mentioning shipping a pair of 28s3p a123 modules, don't think cost to AU would be much different. https://endless-sphere.com/forums/viewtopic.php?f=9&t=75710

We just got a quote for overseas shipping. We can ship two modules (168 cells) for about $370 USD to New Zealand. You will have to pick up at port.

At $1,400US per good module, that is cheaper than I paid for abused modules from China.

Each 106lb (50kg) module is 102.2v off the charger, 60ah, and capable of 30c/1,800a. a123 has a nice flat discharge curve so you don't lose a lot of voltage as the battery empties out, and super low resistance so there is much less sag and less waste heat generated. 2,000-3,000 cycles ARE realistic with a123, and you can take a full 58.5ah from it, 20% DOD is already factored into the rating.

Because it is pre-assembled, all you have to do is bolt your controller's power cables to it. The modules also have mounting holes so you can bolt them down, making install easier. IMO they are the best and simplest solution out there for DIY Automotive EV's.

I see from Galderdi's posts our Chevy Volt is the Holden Volt out there? These a123 packs are on the Chevy Spark (EV version) so I wonder if you have an equivalent "Holden Spark" model over there, so you could get some modules from a wrecking yard.

 

[Cowardlyduck]

oatnet, I agree 100% with what you said and you basically said what I was trying to say anyway.

Yeah, the number of cycles is based on 100% capacity, but nobody actually measures that, so in general you expect at a minimum the rated cycle number to be reachable in normal (non 100% DoD) usage.

Those A123 modules sound simple, but they are not really much cheaper compared to 18650's from Tumich.

Kiwiev would need at least 6 modules to get the same Ah, however the nominal voltage is 26V lower, so total Kwh with 6 modules would only be 32Kwh. For 6 modules it would end up costing 11534 Aud at today's exchange rates, assuming the shipping of $370 would not change for 6 modules.

I'm all for simplicity, but if Kiwiev wants the best bang for buck performance, regardless of effort, I still think 18650's are the go. Plenty of us have successfully made large and reliable 2-3Kwh (some 4-5Kwh and larger) 18650 packs for our E-Bikes, scooters and motorbikes. It's just matter scaling that up...which is what Tesla did, successfully. It just takes careful planning, thinking outside the box, and taking your time and I'm sure it can be done.

On the other hand, the A123 modules do sound like an easier option, so it really comes down to effort.

Cheers

 

[kiwiev]

remove a few leaf springs for more low... heh heh heh

Got the 3" lowering blocks today

Here are some pics

Cheers Kiwi

 

[kiwiev]

Also managed to slip by the local rubbish tip and weight the ute 1340 Kg with 3/4 tank of fuel bike racks in tub and some helmets so I think 1300Kg should be about right

Cheers Kiwi

 

[kiwiev]

oatnet, I agree 100% with what you said and you basically said what I was trying to say anyway.

Yeah, the number of cycles is based on 100% capacity, but nobody actually measures that, so in general you expect at a minimum the rated cycle number to be reachable in normal (non 100% DoD) usage.

Those A123 modules sound simple, but they are not really much cheaper compared to 18650's from Tumich.

Kiwiev would need at least 6 modules to get the same Ah, however the nominal voltage is 26V lower, so total Kwh with 6 modules would only be 32Kwh. For 6 modules it would end up costing 11534 Aud at today's exchange rates, assuming the shipping of $370 would not change for 6 modules.

I'm all for simplicity, but if Kiwiev wants the best bang for buck performance, regardless of effort, I still think 18650's are the go. Plenty of us have successfully made large and reliable 2-3Kwh (some 4-5Kwh and larger) 18650 packs for our E-Bikes, scooters and motorbikes. It's just matter scaling that up...which is what Tesla did, successfully. It just takes careful planning, thinking outside the box, and taking your time and I'm sure it can be done.

On the other hand, the A123 modules do sound like an easier option, so it really comes down to effort.

Cheers

So whats the $$$ for the 18650s at todays rate mate

BTW looking forward to Sunday should be a great ride up the Thredbo valley trail go-pros at the ready

Cheers Kiwi

 

[Cowardlyduck]

So whats the $$$ for the 18650s at todays rate mate

Well yeah, with today's AUD jump it will be even better....we should make a move soon.
Assuming no change in the prices I was quoted 3 months ago (2.99 per cell of Samsung 35E's), and we ordered 4000 cells between us, it would be $15743 AUD before shipping and PP fee's. I'm after 300 cells, so about $900 of that would be mine.

BTW looking forward to Sunday should be a great ride up the Thredbo valley trail go-pros at the ready

Yeah me too...although I'm really not sure if my sad battery will cope...I might have to use the target range feature of my Adaptto and go a bit slower to ensure we make it.

Cheers

 

[kiwiev]

[/quote]
Yeah me too...although I'm really not sure if my sad battery will cope...I might have to use the target range feature of my Adaptto and go a bit slower to ensure we make it.

Cheers[/quote]

The Weekends are busy so we will be doing push bike speed, worst case we can just go up as far as your mid-point on your pack then turn around 8)


Cheers Kiwi