# EV Idea using MR2 or Celica, AC or DC.



## Manntis (May 22, 2008)

I talked at length with DeltaQ about ganging chargers in just that way - they said it was highly possible using their products but as delivery date neared they backpedaled. However, I've heard of others doing so.

have you considered Lithium Ion batteries? Substantial weight savings, right there, though they do cost a fair amount more. 

The RX-7 I converted started life at circa 1,139kg (approx. 2,512lbs) and after conversion was 1,363kg (approx. 3,006lbs) using 98 LiIon cells @ 3.2V each with an AC55/DMOC445 combo. 

In my case, I was able to remove 191kg (approx. 420lbs) OEM weight by no longer carrying around the following: gasoline (Gasoline = 737.22 kg/m3, full tank 63 litres); Fuel tank & mounting hardware; 13B engine core (including water pump); Flywheel; Starter; Alternator, Mazda 70 amp; Oil cooler; Radiator; Evaporator; AC pump; Intake Manifold, air box, and air flow sensor; Coolant (9.46 litres); Oil (5.68 litres); Distributor assembly and ignition wires; Exhaust manifold, catalytic converters, exhaust piping, and muffler; Brackets & hoses; Clutch and clutch hydraulics 

That said, the particular LiIon cells used were crap and are being replaced.


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## saab96 (Mar 19, 2008)

Manntis said:


> That said, the particular LiIon cells used were crap and are being replaced.


I think we're all waiting to hear news of a reliable lithium supplier.


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## Manntis (May 22, 2008)

saab96 said:


> I think we're all waiting to hear news of a reliable lithium supplier.


I'm in talks with Lithium Technology Corporation ( http://www.lithiumtech.com ) about their cells - has anyone experienced anything especially positive or negative about the cells or LTC's shipping & customer support?


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## maiku (Jun 1, 2008)

i've done a few more calculations and it seems that AC 312V does provide, on average, more range.
I've looked at a ton of battery choices and used some estimated values
put it in the range formula

range[km]=250 x capacity[kWh] / (mass[kg]^0.6) 
-or-
range[miles]=250 x capacity[kWh] / (mass[lbs]^0.6)

and got average of 80km (50 miles)
so I guess weight does play a pretty big factor, nearly all of the battery types exceeded the GVW. 


When choosing the DC 144V motor type, and using 12V batteries, the average range is about half, as expected.
However, I looked at a few Trojan 12V deep cycles like the 4D-AGM and 8D AGM, and surprisinging, the 4D (115lbs) with 165Ah managed 70km (44miles) with only 12 batteries, and only 180lbs over GVW, which is very much doable. 
Unfortunately, it looks like it costs $300+ per battery, but being that i only would need 12, it's not that bad of a price, and I could live with 70km. 


Everything still up in the air
still worried about the charge time though


and I'm not against Lithium, it's just that i'm limited to roughly 20k.
the car is 5k (safe number). That leaves 15k. Unless I play around with a DC for roughly 5K for parts, leaving 10K for actual lithium batteries, then it might be possible


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## Manntis (May 22, 2008)

question on that formula... is that assuming a ratio of kWh/mile at .51 (1.95 miles / kWh)?


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## maiku (Jun 1, 2008)

i'm not really sure, i just found it on the forums

i know of the 0.3 kW/mile assumption as well

in any case, it's a fairly good indicator of the approx range


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## adric22 (Jan 17, 2008)

I thought heavily about doing an MR2 as well, but my wife insisted the vehicle have at least 4 seats. I think it is an excellent car for conversion, however, I hate to be the one to break it to you. I do not believe it is possible to get anywhere near 100 miles out of the thing on conventional lead batteries. You'd have to go with NiMh or LiFePo4. However, I still reserve doubts about getting 100 miles reliably on those. I'm sure you could get 80.


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## maiku (Jun 1, 2008)

it looks like i'll be fairly limited to range, no matter what motor I go with if I stick with lead-acid.

Why are people going with the Zilla and their 1000A rating if the Warp9 and other DC's can't draw that much amperage? 

And can someone offer some input regarding charging over 30kWh of batteries on a 115V input? I'd like to avoid changing over the garage to 230V if possible, but to charge that much power overnight doens't seem feasible


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## VDubber (Jun 2, 2008)

maiku said:


> And can someone offer some input regarding charging over 30kWh of batteries on a 115V input? I'd like to avoid changing over the garage to 230V if possible, but to charge that much power overnight doens't seem feasible


If you already have a contactor to break the pack in half when the car is off like some suggest, then using two 156V chargers should be fairly straightforward. Just make sure to use two different 20A circuits. Seems like a 220V plug might be simpler to manage then getting two 110V outlets on different circuits, though. Aren't most clothes driers 220V?


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## maiku (Jun 1, 2008)

looks like the russco SC 30-120 chargers work up to 170V. So 156V @ 17.5A which would charge 15kWh in about 6 hours, so that is totally doable.

I'm sure 220V is doable, it's just that i'd like to have the option of using 120V for oppotunity charging.
However, since most household 120V outlets are limited in amps, the chargers may trigger the circuit breaker if I don't have two seperate circuits


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## VDubber (Jun 2, 2008)

Well, the russco chargers let you dial the max AC current used:

"Safety features include an on/off toggle circuit breaker with ground fault circuit interrupt protection, power-on indicator, AC line circuit breaker protection, DC fused output, *electronically regulated AC line current limit*, soft-start up, overtemp protection, and fan cooling. A high power factor with low crest factor lowers AC line peak current while increasing line current duty cycle, reducing AC line heating and lowering radio/TV interference."

So you could dial them both down to a 7-10A AC limit and plug the pair into a standard outlet. *But ask the manufacture before setting them up this way*, as they would be sharing a common neutral AC line. Breaking the pack down the middle as well as at the top (before controller) might be needed to keep the chargers from shorting out if they do not have fully isolated outputs. Note that you need the boost transformer to run them above 120, as well.


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## maiku (Jun 1, 2008)

spoke to russ at russco

he said as long as I isolate the two packs seperately to each charger, there shouldn't be a problem charging from one outlet.
however, the chargers would draw about 48A on a 120V, so unless I have a 60A or higher socket, i'd have to use two seperate circuits, or limit the total current to keep the breaker from going.

very much doable


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## maiku (Jun 1, 2008)

So, due to funding reasons, i'm likely going to do a DC system, and hopefully when costs come down, I can still get the extended range from lithiums.
It's not worth it to me for the price hike for AC just for regen, and maybe slightly better performance. 

I'll probably try for a 144V using a Warp9 (or Warp 11 if i'm so inclined) and either:
12 x 12V Trojan 4D-AGM 
165Ah
115 lbs
23760 Wh 
est. range: 45 miles (70km)

or 
24 x 6V Trojan 6V-AGM
200Ah
65lbs
28800 Wh 
est range: 51 miles (82km)

the 6V will really increase the weight of the car, but i think the chassis can manage, and since they're AGM, i'll get a bit better accel.


but if I wanted to switch to a 156V system, would the curtis controller handle it?
it's rated only to 144V, so i'm not sure if it could output the extra 12V required


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