Levenkay
Well-known member
Apologies if I'm posting to the wrong forum..
There's been quite a bit of discussion about new retrofit batteries, seemingly with the underlying assumption that as long as the battery module is mechanically easy to swap, current LEAF owners stand a good chance of upgraded battery transplants becoming available somewhere down the line. I like to cherish that hope myself, but I wonder about the extent to which the current LEAF's firmware is prepared for a battery technology upgrade.
I've never tinkered with lithium batteries at any scale, but I get the impression that the LEAF's battery management firmware is quite tightly bound and tuned to the present battery technology. If you replaced the current pack with one that used a slightly different chemistry and had a couple dozen millivolts more cell voltage, would the battery management adapt? Or would it try to stop charging according to builtin assumptions of the old pack's characteristics, and wind up with only a 30% charge or something?
Of course, Nissan can produce a new tightly-tuned battery management firmware version, and simply require it to be installed along with the battery swap. But the truly cool thing to do would be to devise a general battery model with enough parameters to describe any foreseeable possible replacement battery, and then either build a high-level interface into the battery packs themselves (so that they'd have a controller that can answer general questions like, "How full are you?"), or at least provide an electronically readable "battery description/calibration" dataset, much like the little I2C modules that have been going into dynamic RAM modules for many years now. Your home PC may have started out feeding 2.2V into its RAM modules and running them with one set of interface timings, but when you replace those modules with fancier ones, your system automatically knows to drop the supply down to 1.83V (or whatever), with different clocking, because it was able to read those specifications electronically from the new modules themselves! A very worthy characteristic to bestow on battery modules, I think.
It would allow 3rd parties a much easier design target to hit, and allow aftermarket battery modules. Not that the LEAF is all that ideal as a sports car, but it might be fun to take advantage of newer battery technology in the other direction: Instead of packing another 50 miles' range into the same space, it might be fun to put in a pack with half the capacity, but only one quarter the weight! And it would be cool to be able to change back & forth
There's been quite a bit of discussion about new retrofit batteries, seemingly with the underlying assumption that as long as the battery module is mechanically easy to swap, current LEAF owners stand a good chance of upgraded battery transplants becoming available somewhere down the line. I like to cherish that hope myself, but I wonder about the extent to which the current LEAF's firmware is prepared for a battery technology upgrade.
I've never tinkered with lithium batteries at any scale, but I get the impression that the LEAF's battery management firmware is quite tightly bound and tuned to the present battery technology. If you replaced the current pack with one that used a slightly different chemistry and had a couple dozen millivolts more cell voltage, would the battery management adapt? Or would it try to stop charging according to builtin assumptions of the old pack's characteristics, and wind up with only a 30% charge or something?
Of course, Nissan can produce a new tightly-tuned battery management firmware version, and simply require it to be installed along with the battery swap. But the truly cool thing to do would be to devise a general battery model with enough parameters to describe any foreseeable possible replacement battery, and then either build a high-level interface into the battery packs themselves (so that they'd have a controller that can answer general questions like, "How full are you?"), or at least provide an electronically readable "battery description/calibration" dataset, much like the little I2C modules that have been going into dynamic RAM modules for many years now. Your home PC may have started out feeding 2.2V into its RAM modules and running them with one set of interface timings, but when you replace those modules with fancier ones, your system automatically knows to drop the supply down to 1.83V (or whatever), with different clocking, because it was able to read those specifications electronically from the new modules themselves! A very worthy characteristic to bestow on battery modules, I think.
It would allow 3rd parties a much easier design target to hit, and allow aftermarket battery modules. Not that the LEAF is all that ideal as a sports car, but it might be fun to take advantage of newer battery technology in the other direction: Instead of packing another 50 miles' range into the same space, it might be fun to put in a pack with half the capacity, but only one quarter the weight! And it would be cool to be able to change back & forth
