Wow, Itâ€™s been a long time since Iâ€™ve had something to update on here. Iâ€™ve done pretty much nothing to the motorcycle in 6 months. Iâ€™ve been busy, Iâ€™ve moved, and most of February and March was spent with friends who moved and had birthdays. The guys helping me with the fabrication have been slammed as well. Now that that is all over, Iâ€™ve hunkered down and decided to get serious!
I didnâ€™t like the fact that my battery test setup didnâ€™t cut out automatically at a set voltage and temperature to protect the battery, so I bought a CBA-II and a temperature sensor to help automate the test. I increased my discharge current ability, but now I can just walk away. So far the tests look good and I love the graphs from the CBA so far. It gives me all the information automatically (Ah, Watts, temperature, voltage). I want to set up â€œBurst Modeâ€ on the CC400/CBA setup so I can alternate between 2 currents with 2 associated durations. For instance, set the CBA to 5A, and set the CC400 to alternate between 15A continuous and 75A for short bursts. This will allow me to check that the cell can discharge at 2C continuous and 8C bursts. From that, I can look at my CBA output and get the voltage at 2C and 8C and calculate IR for each cell. Its gonna take a while, but hopefully I can catalog all of the batteries. I better get to work, thereâ€™s 160 cells to test!
Another big thing to announce that Iâ€™ve found some help on the mechanical side. A guy at work who goes to ITT has 2 classmates that wanted to do an EV project for their senior project. I talked with them a bit and theyâ€™ve decided to use my project as their final project. Theyâ€™re mechanical engineering students and wanted something real world, not just a drawing of something. Iâ€™ll do the electrical, and help with ideas on the mechanical, but for the most part, that is their project. Iâ€™ll be working with Aston and Bryan on getting the bike finished by June 4th, when they have to present. We wonâ€™t have the bike street legal, but itâ€™l be drivable. I can work on the lights/paint after its done.
I also decided to sell my AC15 and Curtis 1238-7501 (AKA AC18) combo. Why? well, I decided to buy an AC20 off a friend of mine. Itâ€™l fit in the same motor mount, but itâ€™l stick out 1.5â€³ more. I sold my AC18 to a fellow board member on ELMoto, so I know itâ€™l have a good home.
So this week, I removed the old motor and shipped it, and readied the chassis for the AC20 motor. Aston and Bryan came over and we made foam mockups of all of the batteries (160 of them) in groups of 55, 55, 25 and 25 to fit in the chassis. We think we can get everything in without cramming everything in. At this point it looks like those groupings will get us the 160 without any issues. Weâ€™ll probably go with steel for a battery box and make it somewhat easy to remove out of the top of the frame. We measured and everything looks like itâ€™l fit. Iâ€™ll have some photos and drawings soon.
So this weekend, Iâ€™ll probably fit the motor in the bike and get some of the Headway batteries tested on my discharger. Iâ€™ll throw them on a single cell charger for a bit to charge them up, let them rest for 24 hours or so, and then do a burst mode discharge to ensure they can do 80A (8c) and estimate their IR. I want to catalogue the cells by barcode so I have a â€œfileâ€ for each cell. This will prove useful in matching as well as future use. I may decide to measure these cells again at a later date, so I have some real world data on % capacity loss after XX cycles.
Anyway, thats it for now. Hopefully we finish by June without any hiccups.
frodus wrote:definately a slow build eh?
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