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Forum Index : EV's : EV 5
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Trev Guru  Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The original prototype of Gordon's cell equalizers has now been boxed to protect it from water and dust. I have checked the individual cell voltages from time to time and they have always been within 0.01v, which means that at the peak of charging the difference would be similar to the figures posted before. 
Trev @ drivebynature.com |
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| bblocher Newbie  Joined: 04/10/2008 Location: United StatesPosts: 3 |
Hey Trev, Glad to see the EV is back up and running! Hey I just got the same BMS you have and was wondering if yours came with, or if you've found, any english documentation? :) The connection from the charger to the BMS is unclear and apparently I need to make that cable. Did yours come with this cable ready to go and if not what did you do here to figure out the pinout? Brian http://s2kev.blogspot.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
We are still testing the Relativities Equalizers. There has been some changes to increase the transfer rate and still some changes yet to test. We are getting much closer to a good product. The speed controller has been shifted again. The vertical position (terminals up) is a problem in rain. Water pools around terminals and current can flow directly across. It is kind of weired the vehicle driving itself. I guess a bit like cruise control, but in this case the only way off is the key switch or manual dissconect switch. The sitaution happened on the highway, so was left to drive, it maintained 90km/hr. If this happened in town, it could spell disaster. I stopped to dry the water off the speed controller, all was good again. The new postion is above where the 12v Thundersky batteries were. These batteries were shifted to the other side. The Thundersky batteries have now done over 20,000km. Speedo reading now 370746 minus the speedo reading when they were fitted 350153 = 20,593km. There is no noticable loss in capacity. I did a range test, mostly at 100km/hr and drove close on 100km with some spare capacity, so still capable of the original testing.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Some other changes A second Zivan NG3 charger (new model 17A) has been added. The outputs are paralleled. Both chargers together deliver 31A. I set the new charger to 155v (& current tapers off to 0A at that) while the other continues at 14A to 166v and then current tapers off as usual to 0A at 167v. This provides good charge time, but deliberately reduces the current at the end of charge. We have been testing a new vaccuum pump for the brake booster. This is the answer for all EV's. This pump is a cast iron rotary type pump, very fast vaccuum, top quality and much quieter. Sounds similar to an old electric aerial on a car. The downside, it is a little heavier.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Since fitting 2kW of solar on the roof (Jan 09), we have had power in the house, sheds and driving free. Every electricity bill has been in credit. 
Trev @ drivebynature.com |
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GWatPE Senior Member  Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Readers may not be fully aware, but I have developed the LiPo cell equalizer system that Trev mentioned in previous posts. I have some recorded data from a LiPo pack that I have been testing in an RE arrangement with Solar/wind/grid recharge and an inverter loading. This is a 7cell arrangement. I have some multi coloured graphs that show the battery cell voltages without and with equalizers during the last month of testing. These graphs depict cell voltages on an axis from 3.00V to 4.00V. This assists visual clarity of what is going on. These grapohs are a full days logging each. The first graph is 170909 and this shows the cell voltages prior to adding the equalizers[LHS of graph] and with the equalizers added[RHS graph]. This is during a normal discharge-charge etc period of battery operation. Note how quickly the cell voltages start to come together. This graph is pretty clear when the equalizers were connected. 
The next graph is on 300909 with equalizers in place. This covers a charging-discharging-charging sequence. There is approx 50mV difference between cells across this sequence. 
The next graph is after the equalizers have been disconnected for a period. It does not take long before the cells voltages separate again. 
The final graph is with the replacement of the equalizers. After a few hours, the voltages are brought closer together. The red vert line is where the equalizers were re-connected. It was not very clear before. 
The equalizers still have at least 11 more months of testing, but the prelininary findings on the 90Ah pack show typical expected results. The system works all of the time and is not a shunt regulator type. The requirements of an EV are more extreme and this area is being worked on. Gordon. become more energy aware |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Trev, not much discussion happening, maybe stunned disbelief, or readers are waiting for the commercial release, or are not fully aware of the significance of maintaining equal cell voltages with LiPo batteries. Gordon. become more energy aware |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Gordon, Thanks for the graphs. This is so much easier to read than all my numbers. You have done an excellent job with the monitoring and an excellent job with the Equalizers. They are keeping the cells in order quite well. Why the significance? For the readers, it is the upper and lower voltage limits. The cells are able to be out of balance (voltage difference between cells), but the further apart the voltages are, the less capacity is available. In an extreme case, if one cell voltage is at 4.25v (upper limit) and one cell voltage is at 2.5v (lower limit), then the battery pack cannot be charged or discharged without either cell sustaining damage. Hence the reason for Active Balancing, to keep all cells tracking together. Maximum charging pack voltage or Minimum discharging pack voltage can then be set with confidence that one (or more) cells will not be outside their limits. If there is any one waiting for the commercial release, please email your interest. Also for the readers, in the graphs above from Gordon, the cell voltage display window (black area) is 3v at the bottom and 4v at the top of the window. Trev @ drivebynature.com |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Gordon, your contributions are noted with interest, as always. I was aware about the LiPo cell balancing requirement (there is a commercial product available I was told when I inquired about these cells some years ago) but as these batteries are way outside my price range the interest remains academic. I am still curious how the balancing is actually done but suppose its your intellectual property you may not wish to publish here. Klaus |
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| GWatPE Senior Member Joined: 01/09/2006 Location: AustraliaPosts: 2127 |
Hi Tinker, There are a bag full of shunt type cell maximum voltage limiting regulators[equalizers] available for LiPo batteries. My experience is that these are not the real solution. The method of equalizing has significant IP. Anyone interested in the units tested here, should follow up with emails to Trev. Gordon. become more energy aware |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The EV Hilux is a good work horse. It has had lots of things strapped on the back. Carry bars for long lengths have been in the plans for a while now. Every time I change vehicles I have to make my carry bars. This is the first set of bars I have made in aluminium, tig welded. With plans of a new wind turbine, I had to get these made to carry the long pipe for the tower. But more sooner, I need to do some shed renovations - lengths of timber for internal walls and who knows what else.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
VK4AYQ (Bob),(just posted in EV 4). Have you done a cost per 100klm including the cost of the Lipo batteries and associated equipment needed to keep it all working as this would give a fair comparison with other fuels. I have had no cost of electricty for around a year now. The only running cost would be the batteries, which would not be the total cost of batteries, because I could deduct the cost of electricity I use in the house and sheds. My electricity bill has always been in credit, which could also be deducted off the battery cost. I look at it this way. A lot of people go an buy a $30,000 car and still put fuel in it. And.... As explained in a much earlier posting, to gain true comparison costs, you need to factor in 1. service's 2. tuneup's 3. spark plugs and leads 4. radiator and hose repairs 5. oil and filter changes 6. exhaust repairs 8. air filter changes 9. fuel injectors and pump issues 10. alternator repairs 11. any other that I have forgotten Electric cars are virtually maintainance free, which means no cost. But... to answer your question. EV Hilux's Thundersky Lithium batteries have now done 376574 - 350153 = 26,421km. My minimum daily commute is 86km. I have not kept a record of cycles, but take 26,421km / 86km = 307 cycles. Some of my trips are 100-110km so the number of cycles would be a little less than 307 cycles. I have not seen any noticeable reduction in capacity. It is expected that a lot of cycles are possible. The factory claim 2000+ for these. The new chemistry, they claim 3000+ cycles at the same purchase price. As for cost. 200ah x 45 cells x $1.80/ah = $16,200. $16,200 / 2000 cycles = $8.10 per cycles / 86km = $0.09 cents per km. I did work out in an earlier post that electricity from off peak is less than $2 per 100km. $2 / 100km = $0.02 cents per km. Add that to the battery cost makes it $0.11 cents per km. Petrol alone is like 10 litres/100km x $1.30 (here in Mackay) = $13/100km = $0.13 cents per km. I would love to see some real comparison with all maintainance costs included to keep a petrol vehicle running. I have no idea of real costs because I have always done my own maintainance. Cost to me is not that important. My health is worth everything. 
Trev @ drivebynature.com |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Trev Thanks for the details it is very good from a cost per Klm point of view, I have been looking at a EV project for the last two years as I did one 30 years ago and was realy happy with that. My problem is that I would need a range of 250 / 300 klm to make it a viable project {from home to bris run abit and back} and it looks like that untill the battery capacity improves a bit I am just out of range I to have health problems due to poison and find unleaded petrol a real issue fumes before and after combustion I did send you a book on what is helping me it may help you to. I might have to go the hybrid route again untill battery development catches up, looking at a van type project as the flat roof lends itself to a few panels to pick up a bit of energy when parked and it is high enough to keep the panels out of sight of rif raf. I have several 48 volt 200 amp generators I was thinking of using for the initial trial and go to a proper motor later on, the first one I built had a 15 KW fork lift motor in it and it outperformed the origional motor. Thanks again for the info you have got me fired up again. All the best Bob Foolin Around |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
We have now passed the 30,000km mark with the Thundersky Lithium batteries. 380454 - 350153 = 30301km. I was skeptical that I would reach the same range at 100km/hr as lately it has felt like it has lost some capacity. But today I made the range test, driving the same road as I had done before. I achieved the same range as when they were new. The speedo trip meter stuck as it was turning over the 100km, about 2km from home, so I did 202km. Used 21.9kw.  
Trev @ drivebynature.com |
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| VK4AYQ Guru Joined: 02/12/2009 Location: AustraliaPosts: 2539 |
Hi Karl Thanks for the update it is very encouraging All the best Bob Foolin Around |
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| brucedownunder2 Guru Joined: 14/09/2005 Location: AustraliaPosts: 1548 |
Hi Trev , nice update on the ev,thanks. whats the rego like compared with a petrol engine ,,same cost?. ok, for your 30000 km how does the overall cost work out and how does the running cost work out -.Second one is important, because if you were to sell the car you prob would get most of the construction costs back ,,so the running costs could be the big saver here. Hope you and the family came though the storms ok.. Bruce Bushboy |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Bruce Rego is cheaper. It is blue plated as LV1 (which is electric) and registered under the code of ‘electric, steam & something else’(can’t remember). I have not paid an electricity bill since fitting the 2kw of solar. There is no other running cost apart from batteries wearing out. Expected costing is back a few postings. But here is another way to look at it. Battery cost is $1.80/ah x 45 cells x 200ah = $16,200 $16,200 / 30,000km = $0.54 cents /km, but they are not dead yet. In fact as just tested, still performing very well. I am still yet to see a petrol/deisel running cost which includes all services and spare parts charges. Bruce, I have posted cyclone posting Trev @ drivebynature.com |
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| turbotrana Newbie Joined: 14/05/2010 Location: Posts: 3 |
Trev! Gordon! Anymore info on the LiPo cell equalizers. Price? Availability? ETA? Who's excited, I am. But more info required so that I can get my LiPo starter batteries made. BTW I am thinking of using LifeBatt batteries that have a voltage of 3.3 and charge at 3.65. Will this work or will that .1 volt difference between Thundersky bats 3.2v be important. |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Turbotrana, I have just been veiwing the data that Gordon has recorded on the latest equalizer design. We have learned a lot about the behaviour of Lithium cells with Gordon's data logging. I am extremely grateful to Gordon for doing the testing and experiments with further improvements to the cell equalizers. Gordon has made more improvements than I have fingers (& I have not lost any fingers yet). This latest round of testing has shown good results. Yes these cell equalizers will work on other lithium cell brands. May I ask why LifeBatt?? Thundersky are good. Trev @ drivebynature.com |
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| turbotrana Newbie Joined: 14/05/2010 Location: Posts: 3 |
Lifebatt because of battery size. Whilst 8 10ah 40123 will have a footprint of roughly 12cm x 16cm and have the power to start a car, a 40a/h Thundersky (which I believe is the smallest made) will be a little harder to fit in the proposed location. Nevertheless Thundersky prismatic style is not out of the question as its a slightly easier battery to mount when it comes to welding up brackets, but a squeezy fit. Availabilty is another issue as neither seem like a stocked item and have to be ordered but I will deal with this when I get the BMS decided. I am hoping to have one of Gordons BMS on my Perth doorstep late August ready to go when I come back from holiday. What do ya reckon . Possible |
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