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Forum Index : EV's : EV 5
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Trev Guru  Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Some changes to the EV. New motor, same as the old one, but with a shaft out the front to fit the airconditioning. The airconditioning pump does not show any variation in the amp draw of the motor. Nothing wrong with old motor, used for testing on Foxcon aircraft test rig. If anyone wants to buy it let me know. After removing old motor, found that he spline from the centre of the clutch plate was almost all worn out. It had rusted slightly too, so was extremely hard to get off. A new flex coupling was cast and machined out of Manganese Bronze. The part that fits the spline of the geabox shaft is clamped with 2 bolts through the sides. The part on the motor has a bolt in the end of the shaft. The only movement now is on the red washers, easily replaced. This is the same design as the coupling that we make for Foxcon, the connection between Subaru EA81 motor and reduction drive box on their aircraft. The power steering will be changed to a small 12v unit.  
 
 
Edited this motor was fitted with speedo reading 347555 Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Power steering is now complete and works very well. Runs on 12v. Amp draw is 15A going up to 50A as required when turning. Super quite. Highly recommended for any power steering needs. 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Had done some driving in town to see what range may be possible with the Pwersonic AGM batteries, at town speed and driving conditions. I did not drive continuously until batteries were empty, but in approx. 50km I had used less than half the power according to the Curtis fuel guage. I think it is safe to assume that 120km or so should be acheivable. There is no sign of power or capacity loss with these Powersonic batteries, but the new set of Thundersky Lithium batteries have arrived, so the Pwersonic batteries will now take on a different role.... wind and solar power. The 2 dirty ones (outer corners away from the wall) were the ones in the back box. 768kg out. Speedo reading was 350153 minus original speedo reading of 340092 = total distance driven of 10,061km minus the couple of weeks with the first set of lithium 635km = 9426km. Not bad at all, with no sign of slowing down yet. 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Time to make the changes needed to accomaodate the new set of Thundersky Lithium Batteries. The back part of the battery box was cut off and the height of the box raised. This was all glassed over and flow coated again. The steel mountings on the chassis was cut out and lowered, one at a time to be able to measure the new height. The new steel rails are welded in, same as before. The bolts that hold down the box have also been changed to 8 x countersunk M10, 12.9 grade high tensile. The bolts themselves have more holding power than the 6 others that I used to have, and now with less than half the weight, but have used more bolts as I now don't have big flat washers. 342kg in. It has been discovered that the Thundersky recommended BMS does not equalize the cells, but Thundersky still maintain their recommendation. We are using & testing this BMS for now. The speedo reading for the change of batteries 350153. Photo taken at 350208  
 
 
 
Trev @ drivebynature.com |
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| BjBlaster Regular Member  Joined: 04/04/2008 Location: AustraliaPosts: 55 |
Hey Trev, I was wondering where you got that pump from? I'm converting a '94 camry that has p/s and this looks like a great idea! Check out my projects here in: Bj's Shed |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Bj, I have sent you a private email. Had a look at your website, looks like you have been having lots of fun. Good luck with your camry project. Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Couple of months ago I changed the speed controller to above the motor, in more air flow. The reason, behind the left headlight is very little air flow. In the summer the speed controller had cut back because of excess heat. But, on top of the motor, it has proved to be not as good as I thought. So I will shift it again, when I can find some time. The other reason is, I wanted the space for the Zivan NG3 charger. I could not put the charger above the motor because it is not sealed against water ingress. Here in the front corner is ok for it. I have driven in rain, and has not been a problem. Now there is no power in the rear box.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Gordon [GWatPE] has made an equalizer for 4 x Thundersky cells. Thanks heaps Gordon. I changed the AGM lead acid 12v for 4 cells x 90ah Thundersky Lithium in my EV. Cell voltage balancing is a significant problem with lithium batteries. Overvoltage and undervoltage of LFP cells can cause damage, or cells can just stop working, (even fire in other lithium chemistries). LFP are deemed to be fire safe, but still the voltage boundaries must be observed. I have seen individual cells in a battery pack with up to 0.5/0.6V variation between cells during charging. This is not good. When one or more cells have a higher voltage than the others, the chances of reaching an overvolt situation with these cells is greater. In my main pack I have to watch the end of every charge and manually switch of the charger when the high volt cells reach there maximum voltage. The Thundersky BMS is helpful by monitoring and signalling an alarm when overvolt occurs (I set to 4.1v/cell, max is 4.25v), but does not equalize the cells. The Thundersky BMS also has external alarm outputs which could be connected to automatically shut down the charger, but still does not address the problem of reduced overall capacity of the pack. While some cells are full, the others are not. I have tested Gordon's equalizer here and it works extremely well. It is connected to the battery cells only. I don't know exactly how it works, but it makes the cell voltages become equal. It seems to equalize the cells at all times. It has a high voltage warning LED, but the charger could not reach the high volt warning. It has a low volt warning at 12.4v (12.4v/4cells = 3.1v) and another low volt warning at 11.2v (11.2v/4cells = 2.8v). It is not like other BMS. It is not dependant on a charger. It does not have charge current bypass at a particular voltage on any cells. It does not burn off (wasted as heat) any power as other BMS units do. As already said I have seen 0.5/0.6v differences in these 4 cells while under charge. These recordings are when I first connected Gordon's cell equaliser to the battery and covers the first charge. 1) Using CTEK charger, soft start, amps ramp up over a few seconds to 23.8A. Cell 1 - 3.40v cell 2 - 3.41v cell 3 - 3.43V cell 4 - 3.41v 2) After a few minutes current still at 23.8A. Cell 1 - 3.42v cell 2 - 3.42v cell 3 - 3.42V cell 4 - 3.41v 3) 20 minutes later, charger at 23.8A Cell 1 - 3.43v cell 2 - 3.43v cell 3 - 3.43V cell 4 - 3.43v 4) As the cells were near full the voltage seperated some, the charger had gradually cut back the current to 1 amp. Cell 1 - 3.56v cell 2 - 3.83v cell 3 - 3.42V cell 4 - 3.59v 5) 1hr later, still charging 1 amp Cell 1 - 3.58v cell 2 - 3.80v cell 3 - 3.43V cell 4 - 3.60v 6) 2 hrs later, still charging 1 amp Cell 1 - 3.64v cell 2 - 3.72v cell 3 - 3.43V cell 4 - 3.61v 7) Charger was manually switched off for the night. The next morning the cell voltages were Cell 1 - 3.33v cell 2 - 3.34v cell 3 - 3.33V cell 4 - 3.33v 8) Charger switched on again, charge at 24A. After a few minutes Cell 1 - 3.43v cell 2 - 3.44v cell 3 - 3.43V cell 4 - 3.43v 9) Charger current automatically cutting back, charge at 6 amps Cell 1 - 3.66v cell 2 - 3.78v cell 3 - 3.50V cell 4 - 3.65v 10) Charger current automatically cut back to 0 amps. After some time the voltages are Cell 1 - 3.35v cell 2 - 3.35v cell 3 - 3.35V cell 4 - 3.35v This was just too good to be true, but no joke thats the numbers measured. The next was to see what happens under discharge. And then another recharge. I am tired of typing, I will try to copy my hand notes.  
 
Not quite exact but certainly fixes the problem of voltage extremes. Note in the first charge where Gordon's equalizer had only begun to equalize, the maximum difference of 0.41v. Note in the 2nd charge the maximum difference of 0.10v. It is now being considered for a short production run. It can be used on any number of cells. Simply overlap each unit by 1, 2, or 3 cells to match any number of cells in a pack. Edited too many times, hand notes! I win eventually. 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Gordon's Equalizer has been used daily now for 3 1/2 weeks. The batteries are charged at night and everytime I have checked in the morning, the cell voltages have been exactly the same or at most only 0.01 out. Here is the voltages of charging after a normal days discharge.  
I checked them again in the morning and the cell voltages were all exactly the same at 3.35v. The batch of new equlizers should arrive soon. They are smaller and only take 6mA or so instead of the 14mA or so for this prototype, and still have the same transfer capacity. Trev @ drivebynature.com |
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| bblocher Newbie  Joined: 04/10/2008 Location: United StatesPosts: 3 |
I've been following your conversion for a couple months now. Great work. I'm going to be coming on my battery purchase for my EV and was wondering what your overall thoughts are on the TS batteries at this point. What Ah rating and cell count are you using? How many miles are you getting per charge and how many cycles have you went through so far? Any issues, dead cells on arrival or after some usage, etc, etc. Any info you can provide is appreciated. Thanks Brian http://s2kev.blogspot.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Brian, Thundersky batteries are excellent. The only thing is to have them equalize effectively. I will talk more about this issue in the coming days/weeks. I am using 45 cells (144v nominal) at 200ah. I have done 140km driving at 80km/hr. The only other full discharge was some at 100km/hr (approx 40km), some at town speed of 60km/hr (approx 70km) and drove home at 90km/hr (approx. 40km) Total something like 150km. The speedo reading now is 355403. The Thundersky batteries were fitted at 350153. Distance travelled so far is 5250km. Number of cycles, not really sure but could be something like 50-60 cycles. We have not had any dead cells at all. I sell these batteries and have not had any customer complaint yet. These batteries are excellent batteries. But they do need to be balanced. With each cycle the cells get further and further out of balance. As said above I am currently using the Thundersky recommended BMS, but it has been found that it does not equalize the cells. So my main pack has not had any equalizing at all. More on this later. I am sure these batteries will give you value for your dollar. Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
The equalizing issue is a big one. To be told that the Thundersky recommended BMS (Battery Management System) was the best there is, is simply not true. However, I do give a big thankyou to Thundersky for clarifying that this BMS does not equalize the cells. To cut back a charge current or switch off the charger (Thundersky Charger) altogether when a cell reaches its maximum voltage does not allow the full potential of these batteries. Don’t get me wrong, this BMS is a great Battery Monitoring System. It does have a lot to offer for a monitoring system, however the low and high voltage alarms are not consistant. With no equalizing, each cycle the cells become more and more out of balance. When I first fitted the TS-200ah cells the difference was around 0.3-0.4v between the highest and the lowest cell in the pack of 45 cells. Over time this difference has become more outstanding. At times, for some unknown reason they appear to be equalling. After a while I started to photograph the screen. The dates on the screens are wrong, but I think I have them in order. Here you can see the red writing at the bottom of the screen, sometimes but not at other times, which is over voltage alarm. I set this over voltage alarm to 4.1v. The charger was manually switched off whenever a high voltage was reached. Very annoying every morning keeping a check on the battery charging. The kWh reading is also wrong, don’t take any notice of that, I have not calibrated it properly yet. In each screen, the differences are 0.71v, and increased to 0.77v, then decreased 0.75v, 0.73v, 0.69v, 0.66v, but then started to increase again, 0.77v, and 0.83v.  
 
 
 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Here are a few screen shots after charging, after the voltages have settled. The date is still wrong, but take note of the time on the screen. There is no equalizing.  
 
 
Trev @ drivebynature.com |
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| bblocher Newbie Joined: 04/10/2008 Location: United StatesPosts: 3 |
Did you originally charge each individual cell before assembling the pack? Do you have a charger that can do just one cell if you did want to balance these manually later? I'm trying to figure out how I'd rebalance them myself if I went with a simular setup. Brian http://s2kev.blogspot.com |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Brian, I think Trev is at work, so I will add a bit. These EV LiPo cells are 200Ah each, and there are 45 cells. If you spent 1 hour to manually equalize each cell, if that was possible, then you can work out how many days, this would take. You would probably need a second battery, or take the vehicle OFF the road, while you did it. Trev can elaborate some more if this is really possible. Gordon. become more energy aware |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
bblocher, No I did not charge each individual cell and no I do not have a charger for charging individual cells. Manual equalizing is possible by burning off voltage from the higher cell. This is how most BMS work. Wasted power. Manually, I imagine it would be very time consuming and you would still have to watch the end of every charge as I have done now for quite some time. Even worse if you have no volt meters to know if you go over volt. Outside the boundaries the cells will die. Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
Here I believe is the answer. I received the new equalizers from Gordon. The circuits are smaller than the original prototype. A potting box was made and all the circuits were sealed to protect from dust, water and vibration. The circuit fits in the thicker part of the potting, leaving the thinner wings able to be drilled for mounting. The name given to this equalizer is Relativities and is engraved in the original pattern. It is a Lithium type battery cell voltage equalizer. I wanted to mount them with the name up as shown in the first few pics but because the LED indicators are on the other side it makes more sense to have them on the top. The 2 LED’s are directly under the white circle area seen on the side where the wires come out. One LED is to indicate the circuit is on and working, the other is to indicate high or low voltages. This same side also has the plug connector for a lead wire to have a LED in the vehicle cabin to indicate these high and low voltages. Red wall plugs are a very good fit in the gaps between cells (200ah) so these were screwed on and simply pushed into the gaps between cells. These equalizers are made to equalize 4 cells, but in larger battery packs they are overlapped. I have 15 equalizers to cover the 45 cells in this pack, each equalizer is overlapped by one cell except the equalizer on the most negative of the pack is overlapped by 2 cells. All wires must be used for the equalizer to function. These equalizers are very voltage sensitive, so much care must be taken in connecting. The battery cells must be connected in series and these connections cannot be broken. The wires must be connected in the correct order or they burn out. To best facilitate this all individual wires need to have there own screw down point. Push on connectors are not acceptable, as one poor connection with vibration over time will lead to burn out. All connected and all working.  
 
 
 
 
 
Trev @ drivebynature.com |
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| chenyj01 Newbie Joined: 19/11/2008 Location: United StatesPosts: 1 |
Trev, Is this Gordon's Equalizer commercially available? If yes, where can we buy it? |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Hi Trev, I like to comment on your very neat installation and pass on a tip that may help with the long term reliability of the battery connections. I see you use plain copper bus bar type links. These might want to be tinned once you are past the experimenting stage. One of my jobs in the past involved making switch boards with lots of heavy gauge copper bus bars. They were always tinned at the connection area. Having seen how quickly plain copper can go green with moisture present, the tinning was well worth the effort. If you have never tinned before, get the thickest resin cored solder wire you can find, a non synthetic rag and a propane torch. Heat the busbar end with the torch, testing frequently with the solder as you don't want it too hot. Once the solder flows freely cover the contact area and, very quickly, wipe it off with the rag. You have a neatly tinned contact area on both sides now. It does help to wear some heat resistant gloves for this job  Klaus |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 640 |
We are back in business again. The Curtis speed controller burnt out and so the Hilux has been parked. The new speed controller arrived today and has been fitted up front with heat sinking, something that should have been done a long time ago. Curtis say that heat was the main contributing factor for the premature failure. They say that if the speed controller cuts back at all, then more heatsinking is needed. In all locations, I have had this heat related cut back, at least twice that I remember, cut right out. With a little time the speed controller cooled enough to drive again. But this time when it burnt out, it did not cut out, it went full throttle, proving necessity of the battery shut down switching. Curtis think that it should be ok now. Time will tell. Appologies to all those looking for data on the Relativities cell equalizers (from Gordon). I hope to have some data soon, now we are driving again, that is, able to charge and discharge again. Chenyj01, these will be available from me soon, at this stage they will be priced at $140 each. Tinker, thanks for the advice.  
 
Trev @ drivebynature.com |
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