# which one for an EV project? Mazda 323F, Honda CRX or Nissan NX ?



## frodus (Apr 12, 2008)

get the lightest car you can, but also look at suspension, because lead is heavy. Get manual.

That motor (not engine) looks great. It's made by Advanced DC and should be a great motor for a car like that. Don't go too high of a voltage, it's a 36V motor.

60miles and lead batteries might be hard to do though... consider reducing range or getting lithium.


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## huseyinozsut (Feb 15, 2012)

Producer company says that it can safely be used between 36V and 120V. They say it is possible for 144V also. In its specs it writes 36-120V. For example with 200AH lead batteries 120V at total, what milage should I expect? Considering a city usage?


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## Yabert (Feb 7, 2010)

120v 200Ah is 24000 wh of energy.

A small car need around 225 wh/miles at city speed in good conditions
24000 / 225 = 106 miles or more realistically 85 miles at 80% DOD.


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## dladd (Jun 1, 2011)

Yabert said:


> 120v 200Ah is 24000 wh of energy.
> 
> A small car need around 225 wh/miles at city speed in good conditions
> 24000 / 225 = 106 miles or more realistically 85 miles at 80% DOD.


something is incorrect here. I don't think a 120v lead powered car will go 85 miles/charge. More like 30-40 on a good day, right? Just based on my observations and readings, not calculations.


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## MN Driver (Sep 29, 2009)

Lead-acid has the peukert effect which takes away almost half the available capacity at a decent discharge rate and you aren't supposed to use more than half of that if you want them to last for a two or three years if you are really lucky and gentle with them.


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## Yabert (Feb 7, 2010)

dladd said:


> something is incorrect here.


Absolutely! I missed a word: Lead...
Calcul is good for lithium.


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## frodus (Apr 12, 2008)

Good luck fitting 10 200Ah lead acid batteries in a car that small..... you would absolutely have to upgrade and tune the suspension.

Consider lithium.


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## huseyinozsut (Feb 15, 2012)

So for deep cycle batterries the situation is same? Or gel batteries? I have cheap access to these kind of batteries. The place I live is very close to industrial area. So there are Lots of forklift batteries and Also i can find some golf kart batteries. Are they also bad?


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## frodus (Apr 12, 2008)

ANY kind of lead will make the car too heavy. That is the limitation. Doesn't matter if it's SLA, Flooded lead acid, AGM or Gel. 

Look up the weight of 10 200Ah lead batteries. Lets say 150lbs each, that's 1500lbs before you even add the weight of motor, cables, controller, charger, passengers, battery mounting, transmission adapter.

With 24kwh of lead batteries in your car, you're talking about adding a few thousand lbs of lead into a car that was never meant to hold it. Your suspension will need to be upgraded, your handling will be compromised, you'll bottom out over bumps and it WILL accelerate like a turd.

With the range and speed you need, Lead acid is not a great choice. Look into lithium. If that is too expensive, them reduce your range and speed requirements.


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## huseyinozsut (Feb 15, 2012)

My calculations were 600kg (1330lbs) for batteries and 1600kg (3500-3550lbs) for total weight. After making the conversion my plan is to switch to lithium batteries as soon as possible. But I have both budget and import legislation problems. So I can get lithium batteries in one year time. 

One last question: My plan is to use 30-40 or 60 ah batteries in series and parralel. When I start to buy lithium batteries, is it possible to use them parrelel with leads? For example on one buying I can get 40ah 120V lithium batteries, and I can get rid of 40ah 120V worth of lead batteries. Is using them parralel possible without harming one of them? If it is possible, after converting the car, in one year, all the batteries can be lithium in my car.


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## huseyinozsut (Feb 15, 2012)

Sorry for my older post. As I see, using lead with lifepo4 together is not feasable.

Because of budget problems, if I can't find a lead something like for free, I'll be buying 40ah thundersky at first. Then I'll add some more 40ah thundersky's, until I reach 60 miles of range at city speed at moderate traffic. (Here traffic is not moderate; but people drive like crazy! Full throttle and then lots of lots of braking... Stupids...)

Now I'll start to search regen; because I will need the max milage from that 40ah, without harming it. The bad news: I live uphill, which means, when I go downhill my batteries will already be full... When I'm returning home, I'll be climbing up with empty cells... 

I have also performance questions... To get the most performance out of the 23KW 120V motor, what should be my controller's power and what should be the continous discharge Ampere of the battery? I ask this because when I want to have fun, I don't mind about the milage...


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## frodus (Apr 12, 2008)

40Ah batteries are WAY WAY too small for a car. They're good for ~120A continuous. You'll be using more than that. Even if you keep adding them to the car, those first batteries are going to get completely worn. Especially using a series wound motor.

Just save up and do the pack all at once. It's better in the long run.


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## huseyinozsut (Feb 15, 2012)

Then maybe 90AH or 100AH? Then I can buy 40-60ah to get to 60-70 miles of range ? My plan is to have 130-160ah battery at total in one year. When I do that, can I get the maximum out of the motor I chose? And what should be my controller's power to get the max. out of the motor?


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## frodus (Apr 12, 2008)

Use matching Ah, matching chemistry and just do it all at once. There is no "good" way to buy a small pack and continuously add onto it. If you start with larger batteries and add smaller ones, the old ones will be stressed more before the addition of new ones. Then, when you add smaller ones, the cell internal resistances may not match that of larger batteries and you'll have issues with current sharing. 

Also, the current from each battery may not be balanced. Just because it's a 40Ah battery doesn't mean you can current limit it in a pack where it's paralleled. The controller tells the pack how much current goes to the motor. By putting 100Ah and 40Ah in parallel, nothing is telling that 40Ah how much current to give, and nothing is telling the 100Ah what to give, the controller only tells the pack what to give.

Again, just save and do it all at once. You're introducing a lot of variables by doing a pack piecewise.


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## huseyinozsut (Feb 15, 2012)

frodus said:


> Use matching Ah, matching chemistry and just do it all at once. There is no "good" way to buy a small pack and continuously add onto it. If you start with larger batteries and add smaller ones, the old ones will be stressed more before the addition of new ones. Then, when you add smaller ones, the cell internal resistances may not match that of larger batteries and you'll have issues with current sharing.
> 
> Also, the current from each battery may not be balanced. Just because it's a 40Ah battery doesn't mean you can current limit it in a pack where it's paralleled. The controller tells the pack how much current goes to the motor. By putting 100Ah and 40Ah in parallel, nothing is telling that 40Ah how much current to give, and nothing is telling the 100Ah what to give, the controller only tells the pack what to give.
> 
> Again, just save and do it all at once. You're introducing a lot of variables by doing a pack piecewise.


AHA! So thats why I rarely see a pack on back, a pack on front type systems! Thank you! For years I was working on hi-end sound systems on several cars. Generaly for Sound Quality setups. Even if amplifiers need much less energy, running 5 meters of 0 AWG high quality cable was not allways the solution. Having battery as close as possible to amplifiers was one of the convenient solutions... So I was thinking one group of batteries in the hood, one group of battery in the trunk. By this I thought controller would not have any problem in using the full power of the batteries... But this time, the pack which is closer to the controller would be used much more... Which means reduced life... There were double power in amplifiers for these issues! (like some double monoblock amps) . I just need a double power in controller! 

Anyway... Then my plan can be like this:
I can buy the first bulk, just to be able to make my tests during installation. The installation and test process will not be under 6 months. Near end of the conversion I will buy the second bulk, same AH batteries. And start to use the car on ragular basis like that. 

I guess to have 60 miles range, I need around 140-160 AH batteries? And for getting the max out of the motor I found, what should be the power of the controller? And what should I expect in terms of performance at max power usage? 

Also I will have A/C, heating problems... In all over Turkey, we see all kinds of weather. The place I live can get up to 38C at summers and can get as low as -15C (a few days. Mostly around 0) at winters. Also lots of rain and some snow. Generally sunny though. First I will try seat heater/coolers. But it won't be enough I think... I also want the power steering working. Maybe I can use a 2kw motor for both Power steering and AC. I need to insulate and heat the batteries for cold; but I need to cool them for summer. Heating is easy; because while doing that car will be getting charged. So consuming some electrycity won't be a problem. But cooling will be problem. I hope some fans will be okay...

I also need to talk with our apartment residents about getting a line from the apartment's service line... Which means I will need an electric counter, to calculate what I consumed from apartment's service line, and pay it... (Our flat is at the fourth floor, if I get a line through our flat, it would look really bad! And it is dangerous!)


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## drgrieve (Apr 14, 2011)

huseyinozsut said:


> I guess to have 60 miles range, I need around 140-160 AH batteries?


For range calculation, it's not the ah of the battery but the kwH of you pack.

For example 250 wh/mile * 60 miles * 1.2 DOD = 18 kwH.

Then depending on your voltage will determine the ah target. 

18 kWh / 147.2V (46 cells) = ~80ah



huseyinozsut said:


> But cooling will be problem. I hope some fans will be okay...


I haven't heard of anyone fan cooling the batteries - no need I guess. Would be interested if you find anyone that has. I can get 42C days where I live.


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## huseyinozsut (Feb 15, 2012)

drgrieve said:


> For range calculation, it's not the ah of the battery but the kwH of you pack.
> 
> For example 250 wh/mile * 60 miles * 1.2 DOD = 18 kwH.
> 
> ...


I thought if I insulate the cells for cold and if I don't want to remove insulation every summer, I would need fans to remove the heat; because the insulation protects the batteries from cold, will work vice-versa in hot weather. It will prevent the batteries to get moderately cool air. I can remove insulation and remount every 6 months. But here in springs, we can have huge day/night differences also. 23C in the morning can be 0 at night... In two days snow may come, but the day after it can get back to 20+C...  Funny; but true! So I need an EV, which is optimised for all weather drive, all at the same time...  If you think that insulated cells won't be problem at summer, it is good to hear! Or I can demount it for 3.5-4 months of summer time...

Also accroding to your milage calculation 18000/147.2 = 122 not 80 ? Then in 120V I need 150ah batteries to get 60 miles range... Does this includes accessories like brake, power steering and lights? Or not?


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## frodus (Apr 12, 2008)

People use front/rear packs because they split the pack in the middle of the series string, but they all match. 

Also, I'd add some fudge factor. If you calc 80Ah, maybe do 100Ah and a couple more cells in series (48 is a good number for finding chargers and monitoring/management systems if you decide to use one). Batteries aren't 100% efficient (though they're close), and you also might want to have a DC-DC converter for 12V loads. Always design a little over what you need.

These batteries should not get hot if you use them within their continuous ratings. If you're constantly stressing them, they'll get warm.

His calcs are just an estimate of 250wh/mile for a smaller car. Your range will vary a bit, and it's hard to calc exactly (but possible). There are a ton of factors. 250 is a good estimate, but I'd go larger batteries. His calc of 80Ah was off, 18k/147 = 122Ah, so maybe get some 130Ah or more batteries depending on what you can find. I think 130 is the closest to what is available for larger prismatics.

Just take your time and get the motor/controller/DC-DC figured out and get it mounted and maybe a small pack of 130Ah batteries (maybe 24) to get it moving along and add the other 24 later. Just make sure your controller can work at 72V and 144V (i'm using those voltages as a loose term because normally we just kind of talk about things in multiples of 12V, even though it's actually more, cause its easier to talk to others about).


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## huseyinozsut (Feb 15, 2012)

Oh I totally missed that! It is true that if I can find a controller that can work within 72-144V, then I can buy 150ah 24 batteries at first, see that my car actually works then another 24...  I totally forgot that! Thank you!

I may want to use a big service battery for accessories. I may want to run an 150*2 SQ amplifier and some good quality speakers. If seat heater-cooler won't be enough, I would also need A/C and Heater working. I'm thinking about a 200 ah 12V lithium battery for that also. I'm thinking that a 1.5kw motor can work with both power steering and A/C, hardly; but can do the trick. 2kw would be much better. I can make a simple board that will prevent my DC-DC charger to charge my service battery untill it gets to %70 DOD. By this, I can use service battery approximately for 45 minutes without charging it. (%70 DOD: 140ah. AC: 1500kwh/12V = 125Ah. I still have 15amp left, then I will be able to use the battery for about 45 mins. without charging, while A/C is on. Not charging means, not reducing my range. And I can choose a dc-dc converter a little more powerfull then what accecories consume without heater and A/C. So when my board opens DC-DC Charger, it will close Heater and A/C. By this, I won't let A/C to reduce my range.

Also I can make a remote control to open A/C or heater when the car is parked at home and Charging. By this I can cool the car while charging (cooling/heating the car is the most energy consuming part. Keeping it cool-warm is not that hard). And I can use less energy for cooling or heating while not charging.


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## MN Driver (Sep 29, 2009)

I'm not too aware of the power requirements of an automotive air conditioning system but are you sure that you can run an A/C compressor off of a 2kw motor?


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## huseyinozsut (Feb 15, 2012)

I don't think that it is enough; but I plan to reduce the power of the A/C with some new chiller or so. With that 1.5-2kw of power can be enough, will reduce the power of the a/c; but with help of seat cooler, it should be enough... First I'll give the seat cooler a try though.


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