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#31
06-27-2012, 12:20 PM
 frodus Senior Member Join Date: Apr 2008 Location: Portland, OR Posts: 3,185
Re: Hpevs ac50

So you know voltage, but between those two points (before you removed it), how much current is flowing? Measuring time and voltage only gives a little bit.... usually there's little, if any actual Wh being put into the battery at it's upper voltage.
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#32
06-27-2012, 09:25 PM
 tomofreno Senior Member Join Date: Mar 2009 Posts: 1,958
Re: Hpevs ac50

Yeah, it turns out that LogView had time in x minutes, y seconds. Excel just appended y to x leaving out any units. I just assumed it was giving time in seconds, until I went back and checked my data sheet for that charge session and saw I added 110 Ah. No way it added that in 3314 seconds, less than one hour!

So the time is much longer than I showed in the plot and the current during the exponential part of the curve is much smaller due to the charger tapering back after hitting the limit voltage. I do not have a data log of the current, so cannot say how many Ah charge were added during that time. I made the mistaken assumption that since it came out to 3 Ah with the incorrect time scale, it must have not cut back current until very close to the end. That is why I chose this curve. I have other charge curves like this, but they all have the same problem, I don't know the current during the exponential part of the charge curve since the charger is significantly cutting back current by then.

I have individually charged cells with a power supply at constant current and measured the time, and from that can say that there is typically less than 1 Ah from 3.450V to 3.600V. Not data logging, just me with a timer, so no graph. I've posted that a number of times here over the last couple years. I think the stored Wh is exaggerated because the input R of a cell is increasing rapidly in that exponential part of the curve, so the product of Ah and the cell voltage is not a good measure of Wh added to the cell - more of that energy is being dissipated as heat in this part of the curve. Energy moves the car, but Ah is much more straight-forward.

Edit: collected new data and reported it here: http://www.diyelectriccar.com/forums...1&postcount=62

Last edited by tomofreno; 05-05-2013 at 09:52 AM. Reason: update
#33
06-28-2012, 05:42 AM
 JRP3 Senior Member Join Date: Mar 2008 Location: Central New York Posts: 7,625
Re: Hpevs ac50

Jack Rickard has done a number of charge graphs for CALB and TS cells if anyone is motivated to look through his blog archive. Not it
#34
06-28-2012, 08:21 AM
 tomofreno Senior Member Join Date: Mar 2009 Posts: 1,958
Re: Hpevs ac50

Quote:
 Originally Posted by JRP3 Jack Rickard has done a number of charge graphs for CALB and TS cells if anyone is motivated to look through his blog archive. Not it
Scroll down, click on graph to enlarge. It is at 75A though so quite different voltages than you would see at more typical 10-20A.

Last edited by tomofreno; 06-28-2012 at 08:24 AM.
#35
06-28-2012, 12:05 PM
 HPEVS Member Join Date: Jun 2012 Location: Ontario, CA Posts: 84
Re: Hpevs ac50

Hi All,

Not to change the subject, but, we had a meeting this morning about building a dual siamese motor, like in the Jetta. This would have two of the AC35 stators and rotors, on a common shaft, in a single housing. I want to get some feedback and see if you think there would be interest out there for it. Preliminary power would be 190 Ft lbs of torque, 130 HP running on 144 volts. Base speed will be around 4500 RPM, so its going to pull to pretty high RPMs. What do you think? To those DIY veterans, how do we get the word out on DIY about this?

Thanks,
Brian
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HPEVS
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#36
06-28-2012, 03:36 PM
 JRP3 Senior Member Join Date: Mar 2008 Location: Central New York Posts: 7,625
Re: Hpevs ac50

If you could provide a general price point for the system we could start a poll in the motor section about interest in such a setup. Weight and length would be good to know as well, it might be hard to fit in some setups if it's too long. I assume this would use two of the new 500 amp controllers.
#37
06-28-2012, 04:25 PM
 HPEVS Member Join Date: Jun 2012 Location: Ontario, CA Posts: 84
Re: Hpevs ac50

Quote:
 Originally Posted by JRP3 If you could provide a general price point for the system we could start a poll in the motor section about interest in such a setup. Weight and length would be good to know as well, it might be hard to fit in some setups if it's too long. I assume this would use two of the new 500 amp controllers.

We should have an outline drawing in a few days. I think it will be 20" long though. Weight around 150 pounds. Retail price point for the whole system should be around \$9000.00.

It can use the new 144 volt 500 amp, 96 volt 650 amp or 72 volt 550 amp.
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HPEVS
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#38
06-28-2012, 05:12 PM
 JRP3 Senior Member Join Date: Mar 2008 Location: Central New York Posts: 7,625
Re: Hpevs ac50

#39
07-03-2012, 12:44 PM
 major Senior Member Join Date: Apr 2008 Location: Ohio, USA Posts: 5,244
Re: Hpevs ac50

Quote:
 Originally Posted by HPEVS Hi All, We are just getting going on DIY. My main goal here is to help with tech support and fill in the gaps in the information/disinformation out there.
Hi Brian,

Please tell me the OV trip point for the 1238-6501. Spec sheet says 48 to 80 Volts. Since I can build pack to a bit higher, just wondering

Thanks,

major
#40
07-03-2012, 03:48 PM
 Ivansgarage Senior Member Join Date: Sep 2011 Location: Tucson AZ Posts: 194
Re: Hpevs ac50

Quote:
 Originally Posted by major Hi Brian, Please tell me the OV trip point for the 1238-6501. Spec sheet says 48 to 80 Volts. Since I can build pack to a bit higher, just wondering Thanks, major
Hey Major see post 23 24 i ask the same thing
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