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Wibla posted:That looks like prismatic cells. And they're not that big, glove for size right next to the case. For reference, big prismatic cells can go up to 300 Ah of size.
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Jun 9, 2023 13:49
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Is there a reason why you're not running two packs in parallel instead of modifying it to a 4s2p configuration for each pack? The BMS you're using? I did some research on this a few years back when I was playing around with the idea of making a battery for my electric truck (steel bodied golf cart) but went lead acid for ballast and time constraints. I didn't manage to find much on BMS other than for e bike conversions.
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Jun 9, 2023 15:51
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Joey Steel posted:It's a BMS reader address to each cell. Essentially a BMS is a giant voltmeter that has a huge series of probes that does a bunch of voltage readouts and just subtracts the voltage from the previous x number of cells to get individual voltages across individual battery cells. It helps balance the voltages across the whole pack by sending a potential though thatead that prevents/reduces any more current from flowing into the cell when individual cells fill faster than the whole pack, iirc. Every cell (in series) gets a BMS read. If you have 2 or more cells in parallel, you can treat it as one cell for the purpose of battery management.  I think the biggest one I've seen is around 5Ah and the these are much bigger than that or the 18650s or whatever some cars are using now so I was expecting to see more per module. Thought you mentioned it but I can't see it anywhere now, how much were the batteries? Feels like 10-15kWh could be enough for a fun project and also for something my parents could actually use around their small town 
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Jun 9, 2023 16:36
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mobby_6kl posted:Yeah makes sense but I'm generally familiar with lithium cells Hrm, do you think it'd work as an explanation for people not exactly familiar with it all? I spent 5.3k including shipping on the battery packs to get 48kWh of cells from batteryhookup.com, they have a constant 5% off for just using "DIY"
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Jun 9, 2023 19:19
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SpeedFreek posted:Is there a reason why you're not running two packs in parallel instead of modifying it to a 4s2p configuration for each pack? The BMS you're using? In short, because you need a LOT of external balancing hardware to avoid getting an "oops, gently caress, runaway thermal event" that destroys your batteries. I'm in favor of KISS for students. Orion BMS website has this: https://www.orionbms.com/manuals/pdf/parallel_strings.pdf scroll down to the "difficulties with parallel strings" and you'll get a really good rundown.
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Jun 9, 2023 19:21
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Gotta sort through these photos. We're going fast though.
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Jun 14, 2023 06:23
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Well, oops. Guess I fell behind a bit. Let's catch up:  Finally got those batteries removed and separated from their original boxes and we figured out a pretty good system to do it. Step 1 Angle grind the center of each busbar. Step 2 Gently persuade the busbars janky laser welds off the terminals Step 3 lift off plastic casing, which protected us from shorting anything while prying busbars. Step 5 Disassembly. Of course, this brings us to a new issue, we now have these bare top terminals and need to fit new busbars to them. Using a laser welder isn't going to cut it, since A) we don't have one, and B) We can't borrow one. So we figured on using Ye olde Stud welders with fancy CD welder. Which means we need a box of these guys:  Went with aluminum because of A) the galvanic effect of SS with aluminum and B) because I want to minimize resistivity within the pack because of good ol' heat =I2R. Since the current is based on our pushing of our pedal, we're stuck trying to optimize the resistance to keep the heat down. We'll also be using 2 part aluminum oxide layer stripper when we actually assemble the real busbars for the whole system. Every little bit adds up to significant savings over several hundred contact points. To do this right we need to rent a stud welder for a day of welding many, many studs in an extremely tedious manner. But we'll save that when we get all the batteries prepped out. We're using 1/2 our batteries to do a dry run with our BMS and motor for the sake of getting everything set up well and not try to be idiots and wire everything up while the batteries are in the car. That would be stupid. But let me take a moment to appreciate their manly little logo that only small businesses seem to enjoy:  Look at that fine specimen of manhood, what a stud. Anyway, So let's get back to the motor.  After heroic attempts to disassemble most of it, we were deemed 'ready' to call in our handy dandy family member of a student who happened to be a professional mechanic to pull the engine. Things... did not go as planned.  Action shot from the POV of the cherry picker before the whole mess. We discovered the ingenuity of the Jaguar engine designers this day.  Their great answer to "how do we fix our engines that constantly burn oil like it was made by a drunken Irishman whose idea of tolerance is to NOT spit on protestants during lent" was to apparently shove the biggest oil pan they can get in there to just have a nice reserve of oil to burn between oil changes. Clever, but annoying as all hell to deal with.  Despite taking the steering rack off the mounts, shoving and cursing we got stuck here. So hey, if you can't beat them.  Drop 'em.  And now we can take it away, tear it down further and give it to Teddy, our Jaguar man.  Yeah buddy! Though wow, that bitch needs a power washing. Other bits from the week include  Popping out the gas canisters. Jaguar XJ6's had two, one on each side of the trunk. Makes me wonder why they didn't go up like a Ford Pinto, but hey, they don't have a reputation for lighting on fire on a whim, so I guess it worked. Except... why two tanks? Couldn't they just put one in there and call it a day, instead of needing to have a complicated pumping systems just to access the two tanks? Weird. We also are getting the upholstery out as well, for restoring and repairing the leather.     And starting to polish out our body to see what bits need fixing. drat thing is changing colors. And a rundown of the 12V system. We gotta fix the rear passenger side window and the sunroof, but that's it. I'm honestly surprised. Joey Steel fucked around with this message at 05:42 on Jun 18, 2023 |
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Jun 18, 2023 05:36
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And on the note of our Side Quest We took a junkyard battery pack, charged up all the cells, did the same for Teddy's battery pack and waited a day to see which ones would self-discharge below 7V. After that, we sorted the good from the bad and made this:  Which then went into:  And now we got the car throwing a big "Warning Hybrid system Error". Which we tried to test out with our ODB2 meter reader and got a clean bill of health. With a little bit of internet reading and swearing we discovered that we need this guy to read anything on the hybrid side of the Prius. https://www.amazon.com/dp/B0977HJB42?psc=1&ref=ppx_yo2ov_dt_b_product_details To actually reset the system so it will accept the "new" battery. Apparently Toyota didn't want people doing this stuff in their garages or something. Like 270V nominal is dangerous or something.
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Jun 18, 2023 05:46
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And one more fun thing: I have this thread in the cycle asylum, but here's some exciting progress on my student's motorcycle build: https://www.youtube.com/watch?v=K6sdF7F1N6s We're in the home stretch of getting him a 16 Hp electric motorcycle with a 6.5 kWh battery pack. about 80-100 miles of range and able to do highway speeds. Total cost of build, sub 2k. Joey Steel fucked around with this message at 05:58 on Jun 18, 2023 |
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Jun 18, 2023 05:48
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So, feedback question, should I post the cad files and design documents when we get there? We're really close to that point. I could possibly make a bit of a step by step guide for this I think, if somebody here might want to do a conversion as well? Especially since you could do this with a fair number of other jaguar IRS cars, like from the 1960s to the 1980s or so. It's a bit of extra effort, but not unreasonably so.
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Jun 20, 2023 03:55
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Joey Steel posted:So, feedback question, should I post the cad files and design documents when we get there? We're really close to that point. I could possibly make a bit of a step by step guide for this I think, if somebody here might want to do a conversion as well? Especially since you could do this with a fair number of other jaguar IRS cars, like from the 1960s to the 1980s or so. Make a GitHub repo, it will be easier to manage.
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Jun 20, 2023 06:10
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Joey Steel posted:So, feedback question, should I post the cad files and design documents when we get there? We're really close to that point. I could possibly make a bit of a step by step guide for this I think, if somebody here might want to do a conversion as well? Especially since you could do this with a fair number of other jaguar IRS cars, like from the 1960s to the 1980s or so. I don't know how many people will try to EV-swap Jaaaags but if it's not too much effort I'm sure it'd be interesting and maybe specific parts could be useful in all sorts of projects
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Jun 20, 2023 10:40
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SlowBloke posted:Make a GitHub repo, it will be easier to manage. This.
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Jun 20, 2023 16:28
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Havent forgotten this. Just getting the github amd 3d scans off the school's system.
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Jul 2, 2023 04:29
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Did the patient not make it off the table?
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Aug 9, 2023 17:05
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ThirstyBuck posted:Did the patient not make it off the table? Oh we are still working on it, I just need to get off my rear end to update this thread. Short story, we had to do a redesign of out motor due to structural issues in the rear, but we are well on out way to getting it up and running.
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Aug 10, 2023 13:59
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