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  #91  
Old 06-10-2012, 09:43 PM
TigerNut TigerNut is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

Quote:
Originally Posted by PeterH View Post
Ok, new test results.

I changed to a 2.1K resister. Didn't have a 2.2K available. But that is certainly close enough and I understand the need to reduce the load current on the sensor, so good move.

With the new resister in place:

1. I tried connecting the resister between the TACH and SGND terminals. I had to change the scope settings to get a signal at all, but it was a positive going signal, but at only .5 mV. A very low signal and at that degree of sensitivity, it is a very noisy signal.

2. I went back to the TACH to S12V terminals. I'm back to the same before except the new signal voltage level is around .55 V with a negative going pulse, back to zero.

I wonder if there is a fairly simple circuit that could be designed to grab the .55 V negative going signal, invert it to a positive going signal and amplify it to perhaps +5V.

Thoughts?

Thanks,
Pete
Hey Pete,
I messed up the first time I did the math and edited my post to reflect that... it may be that your circuit is not pulling enough current to get the output to go 'high'. With the S12V current limit at 100mA as per Tesseract's note, you could safely try going for 20 to 30 mA... that would mean a 470 or 390 ohm load resistance.

Based on your previous result that may still only get you a couple volts of signal... but if you have those resistance values available then it's worth trying. If you don't then you can parallel two or three 1k's.
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  #92  
Old 06-11-2012, 05:22 AM
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Tesseract Tesseract is online now
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Default Re: 1991 Geo Tracker 2WD Conversion

I got a reply from Kostov and they confirm that this is what happens if the sensor is too far away from the sensing targets. So, time to pull everything apart, I'm afraid.
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  #93  
Old 06-11-2012, 08:24 AM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

Just for giggles I tried a 470 ohm resister. It increased the positive voltage to .8 v. Wanted to try that before I started the disassembly job.

My biggest fear of this effort was pulling the adapter from the motor shaft. However, looking back at my pics this morning, I noticed that (of course!) I have the pressure plate mounting screws to use with a gear puller. Meaning, removing the adapter shouldn't be the near-impossible task I thought it would be.

I was anticipating this... so much so, I even bought a transmission jack last week. Hoping I can pull the motor and trans out as one piece, from beneath the EV. Otherwise, the disassembly job becomes much larger due to all of the wiring for the bms.

I believe I'll be sending the Soliton back for minor repairs in the next day or so. That gives me time to deal with the sensor adjustment.

Still hoping to have this back together and on the road by the 4th of July.

Thanks,
Pete
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  #94  
Old 07-05-2012, 01:58 PM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

July 5, 2012 Update.

BMS is still not working. Drove to town today to make the top board in for repairs. I accidently connected cells out of order and it takes only a second to burn out one of the cell monitoring circuits on the centralized mini BMS. Hopefully the bad one can be bypassed and I can use the board. Otherwise, it is another $250 to replace it.

Decided to go 'BMS Free' for a few days. Charged the pack up to 'full' and loaded up my son for a test drive into town. It went very well. Took a back road all the way in and didn't have to go over 40 mph. I'm drawing less than 100 amps at 40 to 45 mpgs on the level.

First stop was the local scrap yard to have it weighed. Turns out to weigh 2640 pounds. More than I expected but very reasonable.

Drew 150 amps at 55 mph on the way home. We took the highway for a few miles. At the end of that run, the 'check engine' light was flashing. I suspect the soliton was reaching 65 degrees C and throwing an alarm. It didn't seem to limit me in any way, but I did slow down and take my time for the final 4 miles home.

More to follow.
Pete
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  #95  
Old 07-05-2012, 09:27 PM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

I fired off an email to Evnetics tech support about my check-engine light. Had a response almost immediately. Turns out that I still had the soliton set to expect a tach signal. Without the tach signal the controller will throw an error every time. So quick fix to this bit of "operator error".
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  #96  
Old 07-09-2012, 08:52 PM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

July 9, 2012. 200 miles on my EV.

My local EV parts vendor did a house-call on Saturday. After a few hours he decided the mini-BMS master board was defective and had to go back.

Not letting that stop me from using my EV. I have one cell that is weaker than the others and it reaches 3.65 volts before the others do. So when I charge, I monitor the number of amp hours added to the pack and when it reaches what is near full, I start to monitor that one cell manually. The moment it hits 3.65 V I stop the charge. I have the JDL404 set to read 48 Ah when full and the charge is finished. With my 130 Ah pack, that means I'm using only the top half of the available capacity. That gets me to town, a few miles of running around, and home again with 10 or 12 Ah left over. Perfect!

Meanwhile, I'm loving driving my EV! I take the back roads to town so I don't have to go over 45 mph. I tried using the highway the other day and after about 10 minutes at 55 mph, with a line of traffic behind me, I turned off onto my side road just as the Soliton started to signal an error of some sort. Guess I could actually check the web interface, but I'm just assuming it was an over-temp situation. When I opened the hood the Soliton was very warm. I could put my hand on it, but not for long. I've ordered a pump, some 70 degree C tubing and a radiator/tank combo from FrozenCPU.com to put together a cooling system for the Soliton. Once that is in place and working, I'll try the highway again. By then my brushes will be set.

So far, I haven't pulled more than 200 amps from the main pack and normally I'm pulling under 100 amps.

Going to trailer the EV to the local EV Club meeting tomorrow. I'll try to grab a good pic of the finished exterior. I'm still putting the interor back together. Those cheapo pressed board interior panels have to go. Considering going with 1/8 th inch think aluminum panels. I have enough left over to do that... just need to take the time with the plasma cutter and a file to finish it up.

Also considering going to a smaller Aux battery and relocating my DC/DC converter so I have room for the Soliton cooling system and the passenger compartment water heater. But with the weather hitting highs of 90+ F, I'm in no rush to worry about cabin heating. :-)

Pete
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  #97  
Old 07-11-2012, 08:46 AM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

Trailered my EV to the club meeting last night. Since it was the only auto EV there, it got a good going over by those at the meeting. Seems there is a charity car show on Sunday that the club thinks I should attend. They have an EV category that I can 'compete' in... thinking I might be the only conversion there.

Having my 2 inch lift kit installed on Monday along with new ball joints and an alignent. Since I've NO idea how many miles are on the rig and since the ball joints are likely to be under greater stress with the lift kit in place, it makes sense to have them switched out will they are installing the lift kit. I could do it, but who wants to spend the weekend surrounded by parts when I could be out driving! I'll post some pics after the car show on Sunday.

Seems I'm providing neighborhood entertainment again. My wife runs a coffee shop and heard this morning, that several of the neighbors were discussing my project last night.

Thanks,
Pete
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  #98  
Old 07-23-2012, 12:59 PM
PeterH PeterH is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

July 23, 2012. Just over 500 miles on my EV now. Here is what the "finished" project looks like with the new 2 inch lift kit installed. Going for slightly taller tires later today.

Over the weekend I added the Soliton cooling system and that makes a HUGE difference in the temp after a long highway drive. Highly recommended!






Also just got a new trailer hitch for this EV. I have a small trailer that is perfect for hauling loads of firewood down out of the mountains. With my new cooler, driving up there won't be a problem. Only 11 miles away and mostly flat roads with some short, low grades to climb.

My BMS is still not working. We still don't know why all the cells show green indications but it still sounds the audible alarm when 12 VDC is applied. :-(

Almost time to turn to working further on the interior. Need carpeting and some door panel work. The transmission sure is noisy in 5th gear! Might need to get that rebuilt this winter.

Thanks,
Pete
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  #99  
Old 07-23-2012, 01:34 PM
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Default Re: 1991 Geo Tracker 2WD Conversion

I like that little radiator with the filler plug on top - is it a surplus item of unknown provenance or something that can be bought off-the-shelf?
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  #100  
Old 07-23-2012, 03:10 PM
Yukon_Shane Yukon_Shane is offline
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Default Re: 1991 Geo Tracker 2WD Conversion

That's a good lookin' machine Pete. Well done.

I clearly have to do some more work if I'm going to keep up with you
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