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Forum Index : EV's : EV 7
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Trev Guru  Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Time to have a battery change in the EV Hilux. Started 25 June 2013 and first drive was around the 15 July 2013. The original lithium pack is not dead yet but has been borderline for my daily round trip distance for a while. Everyday dropping the voltage very low, the battery pack is not going to last very long. It was really one cell in particular that was limiting the range, it showed a much higher internal resistance, but was also smaller in capacity. Another cell, one that had not shown any issues, on a longer trip, died from being discharged too low. It was time to change before I killed them all. I want this pack on my house wind and solar system. Distance of original lithium pack is 437956 – 350153 = 87803 km. Cost calculated at $1.80/ah retail at the time of purchase. $16200 / 87803 km = approx. $0.18c per km. Cost calculated at current retail of $1.40/ah. $12600 / 87803 km = $0.14c per km Current price of unleaded petrol is $1.57/litre. As a 2.7litre petrol Hilux, used 10 litres per 100km. That approx. $0.157c per km, then you have to add the other costs of oil changes, filters and so on. 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The new pack is bigger, much bigger. Compare……….. Old pack originally was 45 cells x 3.2v = 144v x 200ah = 28800 Whrs or 28.8kWhrs Later lost one and added 8 more to make it 52 cells x 3.2v = 166.4v x 200ah = 33280 Whrs or 33.28 kWhrs New pack 52 cells x 3.2v = 166.4 x 260ah = 43264 Whrs or 43.264 kWhrs Taking data from http://www.thebackshed.com/forum/forum_posts.asp?TID=902&PN= 3&TPN=2 , this new pack should give 116km / 25kWhrs (3 kWhrs spare) x 40 kWhrs (3 kWhrs spare) = 186 km driving at 100km/hr. I don’t intend to be making any range testing, I am sure that every deep discharge some cycles are lost. Cost of the new pack at current retail $1.40/ah x 260ah x 52 cells = $18928 Here are some pictures of the new alloy battery box. It has been changed to alloy so that the box can still be sealed, keeping out dust, water and mud, but is a massive heat sink, letting out any heat generated. So far the highest temperature I have seen is 26 degrees C. The box is made from 3mm alloy checker plate. The hydraulic pan brake I used did not have a deep throat so some sections had to be bent by hand with steel clamped near the bend lines. The box was made up in 4 sections and TIG welded together. Apologies for the poor quality pictures.  
 
 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Having an alloy box meant that more framing had to be fitted for support. The alloy would dent with the battery weight on bumpy roads. The original round pipe across the chassis was replaced, taking out the old battery box cross rail. More box tubing welded in, 2 RHS under each row of cells. The cells are also clamped down to these RHS rails through the alloy box.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Pictures of fitting the batteries. All are handled one at a time. Cells are clamped together using 6mm stainless steel threaded rod, 3 on each side. The font of the box is used as one end plate and the back end plate 3mm alloy checker plate with the top and bottom 10mm folded for stiffening. The centre end plate, is one plate, right across both centre rows of cells. So cells are clamped to the front of the box and down through the steel rails underneath. The cells cannot move.  
 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The Zivan chargers were used to charge the cell and then a bundle of 3.7v chargers moved across the pack bringing each cell up to 3.7v. While they were charging, I set about connecting the BMS (monitoring) wires. Some teething problems with the BMS. Some wire connections mucked the whole system and took me ages to trace through it all and get it working. The BMS wires were wrapped up with poly spiral tubing to make it all neat.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The Relativities and 14.8v chargers were then fitted. I persevered with this system testing for a few weeks. It is hopeless. With the few 14.8v chargers I had in the old pack, they seemed to work well. But across the whole pack, they don't seem to work well. I have put in a double layer of Relativities now. 8 cell Relativities across the entire pack, except the last one is a 4 cell Relativities. There is no overlap. The second layer start with a 4 cell Relativities and the rest are 8 cell Relativities. This way every cell is covered twice and one layer can transfer between groups of the other layer. I will see how this goes over the next week or so. I have left the Zivan charger on, holding pack voltage and assisted the Relativities by balancing manually. Currently the highest cell is 3.54v and the lowest is 3.45v. I am charging the pack to 182v which divides equally at 3.5v per cell.  
 
 
 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Here is a picture taken on Friday (2 days ago). I have bought myself a 2 post car hoist. It was an offer too good to say no. The ute needs a wash too. 
Trev @ drivebynature.com |
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Downwind Guru Joined: 09/09/2009 Location: AustraliaPosts: 2333 |
Trev, I was hoping the old cells were going for scrap and i might have got a good deal on them. 
Nice work you done on the ally fabrication, im not sure if i understood correctly with one battery end terminated to the ally box (Gnd i guess) if so i would warn against it due to corrosion of different metals at the connection, ally is bad for this and you will get resistance over time. The Relativities work well on maintaing cell balance once the pack is stabilized within a few 100mV difference, but can take some time to bring the cells into balance, and im guessing is why you have doubled them up. Perhaps you might need to ask to trial some of the later cell balancer design thats still under testing  as they appear to have a much faster equlization time.
Pete. Sometimes it just works |
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| praxidice Newbie  Joined: 18/07/2013 Location: AustraliaPosts: 18 |
Your figures are particularly interesting when compared with the prices I've been getting in respect of a Prius plug-in / lithium polymer battery conversion. Apparently the plug-in conversion provides the ability to completely over-ride the factory computer which would normally start the petrol motor at speeds over 40k or whatever. I can't recall details of battery capacity however I have been assured by several different supposedly professional conversion businesses that $15000 will pay for installation of both the plug-in bits & sufficient batteries for 200k EV only range at 75 - 80k. Obviously I'll need to go back to them and check how many batteries are involved, but presumably its something less than you have in the Hilux. I'm guessing that the weight of a Prius is probably comparable to the Hilux, aerodynamics are certainly better, and the AC motor should improve efficiency a bit, consequently less battery capacity should return something like the same range as you are getting from the Hilux at same speed. According to Prius cab operators in both Brisbane & Cairns, the original Prius batteries are holding up extremely well, with the early Brisbane Prius cabs getting close to the end of their 6 year service life & still on original battery after 700 - 800,000km. I would have thought the charge / discharge cycles would have killed the batteries well before that. Any comments would be greatly appreciated. |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
Here you are Pete, The old lithium pack is now fitted to my wind and solar system. http://www.thebackshed.com/forum/forum_posts.asp?TID=6010&PN =1&TPN=1 I had contemplated putting them up for sale but really they are too good to give away yet. Pete, the Relativities in the plastic bubble wrap are new ones, just a few weeks ago. And no, there are no GND terminations. The main pack voltage is floating, it cannot be connected to the chassis or body of the vehicle. praxidice - I wreckon the Prius cabs on 700-800,000km are driving on petrol, not batteries. Trev @ drivebynature.com |
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| praxidice Newbie Joined: 18/07/2013 Location: AustraliaPosts: 18 |
t A Prius won't show any signs of life unless both the main & accessory batteries are in good working condition. The petrol motor apparently starts off the traction battery & the accessory battery is only used to run airconditioning, instrumentation etc. Furthermore, I've been in a few high-mileage Prius cabs and can verify that they all ran on battery power until road speed exceeded the normal 40kmh, at which speed the petrol engine started up. Toyota Australia advised there have only been three Prius battery replacements in Australia. My conclusion for what its worth is that the batteries don't get heavily discharged and that results in the extremely long life. |
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| tomqu7 Senior Member  Joined: 09/11/2012 Location: AustraliaPosts: 168 |
i need to get a fast charger in melbourne i have a substation and industrial power supply does anyone know who i could consult top something in hong kong will make any bttery config u like from lithium batteries i believe there re gel batterys out |
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| tomqu7 Senior Member Joined: 09/11/2012 Location: AustraliaPosts: 168 |
what is weight of 100 batteries |
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| isochronic Guru Joined: 21/01/2012 Location: AustraliaPosts: 689 |
I suspect a lot of batteries are damaged by the charging method taking the electrode voltage too high. Some chargers are nothing more than a transformer and diode, after the cell has charged the charging voltage goes way over spec. If the recharge causes 1% damage to the active material each recharge, it is almost undetectable but obviously the damage accumulates. I kept an old lithium mobile between 10 and 80% charged, instead of a 100 % charge, and it was still going strong after 6 or 7 years. (Caveat : lead acid types would sulphate up / reform by zapping etc) |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
tomqu7 I have one, make me an offer, email me DrivebyNature@gmail.com http://www.thebackshed.com/basiclynatural/ViewItem.asp?CL1=1 7&CL2=53&CL3=NA&id=52 What size? You can look up the details in the manufacturers website http://en.winston-battery.com/ Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The commercial batch of Relativities have a problem. In the pictures I posted on the 11 August 2013, you can see that some Relativities are wrapped in plastic. These are from the commercial batch we had made. They have a natural voltage difference averageing around 200mv, which means when the pack is charged to what should be an average of 3.7v per cell, the lowest could be 3.67v and the highest could be 3.87v. This is not good enough. It will be while before we have a solution. Meanwhile, I have removed them all. I have now changed the brushes in the WarP 11 motor. The motor was fitted 384870 and the speedo reading now is 444158. That is 59,288km driven on the original set of brushes. They won't do much more. I don't want to run the risk of running out somewhere, or, damaging the motor. Some have worn differently, and are different length than others.  
 
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
I have also changed the 12v auxilary battery to a new 100ah block. One of the chargers input cable fell out and I didn't find it until the cell was zero volts. It charged up againand I used it for a while until the input cable fell out again. Flat again, but this time it did not want to take any more charge. The cell that had been split, melted the crack back together with a soldering iron, was still running charm. It stil carried enough capacity for my driving needs. The new battery is kept full with a 14.8v charger used as DC DC. An older prototype Relativities keeps the cells equal.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The testing of Relativities double layer (posted back on 11 August 2013) did not work. In a very short time the cell voltages were pulled out of balance. It was discovered that they had a fault. It was later found that one of the key components were substituted for a different component and so they did not work. They had to go back to be changed. We now have them back, and tested on my test setup. All looked good, so set about potting.  
 
 
I then fitted a double layer to my EV Hilux again. They were fitted Friday afternoon 7/2/14.  
After leaving for a few days (weekend) with the Zivan charger switched on and holding pack voltage, the cells reached 3.52v on the top and 3.48v on the bottom by Sunday 9/2/14 afternoon at 6.20pm (18.20 on the screen). 
The most separation is at the top end of charge and so I have pictures of the screen at this point. 2 days later 11/2/14 the cells have separated some. The next day 12/2/14 they are separated some more. The next day 13/2/14 separated more again.  
The next day I got the photo at pack voltage 182v, showing a greater separation in cell voltage. Just over an hour later you can see voltage difference is closer. Pack voltage is still the same. If the pack could be left long enough it would get them much closer. 6.20am is when I am off to work (teaching).  
The next day, 15/2/14, at peak pack voltage 3.50am it was 3.63v -3.46v (170mv). By 6.15pm (18.15 on the screen) Relativities had brought the voltages back to 3.58v -3.46v (120mv). As you can see, the large pack does not balance very quick. The number in brackets to the right of the cell voltage is the cell number, so cell 1 is the highest and cell 20/19 is the lowest. The power from cell 1 has to go through several Relativities to get to cell 19 or 20. Relativities is holding them though, every morning the cells have been around the 170mv different. They are not separating any more.  
Trev @ drivebynature.com |
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| Trev Guru Joined: 15/07/2006 Location: AustraliaPosts: 639 |
The results of a single Relativities on my Solar light are far more impressive. You can check out the results here http://www.thebackshed.com/forum/forum_posts.asp?TID=6322&PN =1&TPN=1 Link only provided for Relativites. Please do not create discusion on solar lights in my EV thread. Trev @ drivebynature.com |
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| electrondady1 Senior Member Joined: 12/02/2009 Location: CanadaPosts: 208 |
i can't find a good explanation of what these relatives things do and how can you explain or point to a good source |
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