Nice! Here's some more data from Endless-Sphere:jkenny23 wrote:Just thought I'd update with the discharge test results of the Boston Power Swing 5300 batteries I bought (just 4 samples from a US supplier on eBay) since they're the leading candidate for a small range extender pack:
They fare average, keeping 90.9% of the 4.2V discharge capacity, with a discharge characteristic similar to LCO, though from what I read it's a Li-Manganese battery (NMC?). Will be interested to see the 2C charge tests once I get my 10A battery tester in a couple weeks. A 96s2p pack built with these cells should have a capacity of ~3.2kWH usable.
Do you happen to know of any 18650s with a similar LMO chemistry/discharge curve? I'd like to bench test in my parallel cell setup to see the current sharing across the discharge/charge curve. I may just buy a real Leaf cell but at 64AH it's going to be a very long and very low C-rate testmux wrote:Note that if you want to make an extender with NMCs and mix them with the NCA-lite modern Leaf battery or LMO old Leaf battery, it needs to be a really large pack. As you can see, a significant amount of charge, even more than with NCA, is in the bottom end, so as the main battery discharges, the extender almost entirely takes over. NMCs are typically a bit lower rated (this one is rated for 0.7C charge/2.5C discharge) than NCA and LMO, so you either need to make sure never to use DCQC with an empty extender and to make the pack large enough that it can deliver your typical discharge current. If you make sure to drive the car gently, that means your minimum extender size is probably around 10kWh, so a 96S6P configuration.
But you do realize that for around the price of a new Leaf battery you are more than doubling the capacity! (39.5 + 24 = 63.5kWh!)alozzy wrote:That price makes the LEAF replacement pack deal offered by Nissan seem not so bad after all. Unless prices drop considerably, the DIY doesn't look to provide any savings, nor is there any warranty. Thanks for doing the leg work!