# Hyundai Conversion



## TheSGC (Nov 15, 2007)

Your batteries need to be broken in. I have driven my EV about a 100 miles and have about 20 cycles on my EV, and the pack still isn't broken in. I have been told that it needs 40-50 cycles before full performance can be achieved. For comparison, I have a 96 volt system using 12 volt 125 Ah batteries and have a range of about 15 Miles currently. The cold weather has been brutal on the batteries, as well as me playing with the Kelly Controller settings. I am expecting a 20 mile range on my next run (with improved Kelly settings) and possibly more once I have more cycles on the batteries.


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## Technologic (Jul 20, 2008)

engineer_Bill said:


> That should leave me with a range of 40 miles at 45 MPH. My actual measured range is 18 Miles, or less than half of what I expected. Am I missing something? Did I get some bad batteries? Any sugestions would be good as doubling my battery pack is not a good option.


How did you calculate the 40mile range?

Also Have you calculated what the IR of the batteries is... and what the Peukart effect really would be drawing 250-280amps?

What's the battery temp as well while driving.


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## Guest (Mar 6, 2009)

engineer_Bill said:


> I just finished converting a Hyundai accent. I used 12 - 200AH 6 volt golf cart batteries, a Kelly controller, and a Sep-ex forklift motor. I have only driven it a few charge and discharge cycles, but I was expecting to get a little longer range. At 45MPH I draw 150AMPs at speed 250-280 AMPS during accelleration. Which a little math 72 volts * 150Amps gives 10KW/HR. Even with the Puekart effect the batteries should give 135AH at 72 volts which is 9700KW. That should leave me with a range of 40 miles at 45 MPH. My actual measured range is 18 Miles, or less than half of what I expected. Am I missing something? Did I get some bad batteries? Any sugestions would be good as doubling my battery pack is not a good option.


I'd say your equations are missing some things. Sounds about right real world distance in cold weather with only 72 volts. Actually I think you are doing quite well. I am slowly gaining more distance each charge cycle. Performance is about the same but distance is growing. Got photos of your car? What motor? What are your Kelly settings? Your set up for SepEx is different than mine. 

Pete : )


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## CPLTECH (Sep 14, 2007)

I hear some speak of the “Peukert effect” but never paid much attention to what was said since I got around OK for where I wanted to go, plus had confidence in the big USBatt 145’s (250AH). I had a Link 10 meter but now just received a Link 20 upgrade today and was reading the manual about Peukert. What a revelation! On both those 2 models, it has a feature that gives the AH used and a led display of how “full” the batteries are. On a regular, 4 times a week 28 mile trip I used ~90AH, but just about the time I made it home the led display turned red meaning the pack was dropping below 40% full at that point when it changed to red. So, on the one hand the light bar said I used 150AH (60% of 250AH) but the digital readout says 90AH. The manufacturer warns of this discrepancy & blames it on the “Peukert effect”, which is exceeding the amperage of the 20 hour rate (your 200 and my 250AH battery). The manual also has a chart that says if you discharge the battery in 1 hr vs. 20 hr, you will get only 47% of its original capacity. WOW!!! To view the manual, go to: http://www.xantrex.com/web/id/76/docserve.aspx
In the past I would tell people that I never let the batteries fall below 50%, thus increasing cycle life, but now I need to revise that figure to more like 60% discharge on that trip.

Hope this sheds some light on your situation, sure enlightened me.

94 S10, 120V, 9”ADC


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## madderscience (Jun 28, 2008)

engineer_Bill said:


> Which a little math 72 volts * 150Amps gives 10KW/HR.


You need to figure battery capacity by multiplying usable AH times battery voltage, NOT by multiplying battery voltage times amp draw at some speed.

With Flooded lead, it is a common estimate to use about 1/2 of the rated capacity of the batteries as your usable capacity. This back-of-the-envelope calculation would factor in peukert. You might further de-rate that capacity if it is extremely cold. You could add some battery box insulation to reduce the cold weather driving effects.

so in your case, 72V * 100AH == 7.2KwH usable. So if your car is getting 200wh/mile, then you could go a maximum of 35 miles or so. If your car gets 400wh/mile then you would be at about 18 miles. It is fairly likely you are someplace between these two numbers, most small car EV conversions are.

Does your motor get hot while driving? If it is a small forklift motor it might be underpowered and inefficient. If it is a sepex motor, do you have the right type of controller for it? a standard series wound motor controller might drive it, but it might not work properly. What type of tires do you have and how well inflated are they? Do the brakes drag at all? Are there any other chassis issues that might be reducing range? bad alignment, worn suspension bushings, etc? A few little details that we commonly ignore in our gas cars (even though they cost us range there, too) can make a huge difference in the range of an EV.

Also, are you using "good" batteries (US battery, Interstate, Trojan) or something like wal-mart batteries? You get what you pay for with batteries. The store brand ones work but typically have higher peukert values (shorter range) and will last for fewer cycles.

Based on your assertion of 150A at steady state cruise at 45mph I suspect you could improve efficiency somewhere, independently of the battery capacity issue. That is 10KW to maintain 45mph (assuming level ground, etc). My MR2 needs about 8KW to do the 45mph, and about 6.5KW to do 40mph, and it is a much heavier car (I have almost double the battery weight vs. you). I have done almost everything I can (LRR tires, alignment, brakes, etc) to reduce rolling resistance. 

Since you have a sepex motor, you can do regenerative braking. This will help you a bit if you have a lot of stop and go or if you ride the brakes going down any hills. Find yourself a 72V golf cart motor controller that is designed for a sepex motor that includes regen capability (assuming the kelly doesn't already).

Good Luck.


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## Guest (Mar 6, 2009)

Kelly has regen for their sepex controllers. Set it up and use it. Keep the settings low at first to be sure it is working fine. Make sure you have a heat sink installed along with a cooling fan. Same for the motor. A good cooling fan will go a long way to keeping everything alive. It won't be a hot rod. Accelerate within the motor limits. Don't hot rod your little motor. 

Pete : )


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## engineer_Bill (Jun 24, 2008)

Thanks, I do have regen capability, but it is currently on the lowest setting. I also have field weakening, also on lowest setting. The motor and batteries are warm when running, but still cool enough for my hand. I am accelerating at full throttle to keep up with traffic, that is a factor. I'll keep driving small trips, and tweaking and see how it works out.


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## Guest (Mar 6, 2009)

engineer_Bill said:


> Thanks, I do have regen capability, but it is currently on the lowest setting. I also have field weakening, also on lowest setting. The motor and batteries are warm when running, but still cool enough for my hand. I am accelerating at full throttle to keep up with traffic, that is a factor. I'll keep driving small trips, and tweaking and see how it works out.


Do you have cooling on your motor? Controller? You will need them no matter how much tweaking of your settings. 

Pete : )


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## DIYguy (Sep 18, 2008)

I'm thinking the same way as Technologic on this one... Low voltage = higher current = more severe peukerts effect. I just lean more and more to higher voltage all the time. I know it drives up some cost...but the system will run with lower current the higher you go on voltage.


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