Ok, you got me there, but I doubt you'd build an eBike flow battery! =) On Sun, Oct 5, 2025 at 5:05 PM Cor van de Water via EV <[email protected]> wrote:
> Phil, > I agree with what you said, except that there is a chemistry with WAY > higher energy density than Li ion. Both in energy per volume and energy per > weight, though the latter is lower, because the main electrode is made of > Iron. > Power density is much lower and besides that, the cells need air and > electrolyte pumped, so it is not an easy self contained battery like Li > ion, but the company I joined recently, Form energy, develops utility sized > Iron-air batteries. > With about 4 times higher energy than comparable Li containers. That was > one of the reasons I joined Form energy (short: Fe) instead of Tesla. We > need different battery technologies. > Cor. > > On Sun, Oct 5, 2025, 4:33 PM (-Phil-) via EV <[email protected]> wrote: > > > You also will not find any other chemistry that can equal the energy > > density of ternary lithium. LFP is probably close enough for an eBike > and > > relatively safe, though when charging below 0°C (32°F), the charge > current > > must be reduced to 0.1C, if below -10°C (14°F) it must be reduced to > 0.05C, > > and below about 18°C (0°F), you should not charge at all. They will > > continue to discharge ok, but with reduced performance. But I can't see > > anyone wanting to ride an eBike at those temperatures! Just charge > your > > packs inside where it's warmer and you'll be good to go. > > > > You can buy pre-made LFP packs in eBike voltage ranges with built-in BMS > on > > Aliexpress. > > > > On Sun, Oct 5, 2025 at 4:15 PM Cor van de Water via EV < > [email protected]> > > wrote: > > > > > For deep freezing performance, there are the flooded NiCd cells, only > > 1.2V > > > per cell, but well liked for snowblowing ElecTraks, original service > life > > > is typically aircraft starter batteries. Model nr varies, often > referred > > to > > > as BB600. Quite a weight for eBike, so maybe look for standard round > NiCd > > > or NiMH batteries. > > > Note that many battery types cannot stand cold when discharged and in > > > particular Li cells essentially become worthless when charged at very > low > > > temps, they essentially block all the passages where ions move inside > the > > > cell, quickly dropping the capacity to store energy. > > > Cor. > > > > > > On Sun, Oct 5, 2025, 4:00 PM t ray via EV <[email protected]> wrote: > > > > > > > I'd like to buy or build an eBike. Problems include our local > > > > deep-freezing winters, and the combustible lithium batteries. I have > > no > > > > desire to build a soil-covered bunker (doghouse) in the back yard > > where I > > > > can store and charge lithium batteries safely. > > > > So far, the best I know is the LiFePo chemistry, but the commercial > > > > products are not the equal of lithium batteries. I keep seeing > > "better, > > > > faster" options in development, but somehow, never this year. > > > > Does anybody know a source for batteries of near-equal or better > > > > performance than lithium? Since I don't need very many, I am willing > > to > > > > look at more expensive options if they can do the job here. > > > > Thanks. > > > > -------------- next part -------------- > > > > An HTML attachment was scrubbed... > > > > URL: < > > > > > > > > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251005/6b5e0fa2/attachment.htm > > > > > > > > > _______________________________________________ > > > > Address messages to [email protected] > > > > No other addresses in TO and CC fields > > > > HELP: http://www.evdl.org/help/ > > > > > > > > > > > -------------- next part -------------- > > > An HTML attachment was scrubbed... > > > URL: < > > > > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251005/1f311ec8/attachment.htm > > > > > > > _______________________________________________ > > > Address messages to [email protected] > > > No other addresses in TO and CC fields > > > HELP: http://www.evdl.org/help/ > > > > > > > > -------------- next part -------------- > > An HTML attachment was scrubbed... > > URL: < > > > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251005/f08434ea/attachment.htm > > > > > _______________________________________________ > > Address messages to [email protected] > > No other addresses in TO and CC fields > > HELP: http://www.evdl.org/help/ > > > > > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: < > http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251005/9b7f07da/attachment.htm > > > _______________________________________________ > Address messages to [email protected] > No other addresses in TO and CC fields > HELP: http://www.evdl.org/help/ > > -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20251005/40a95abf/attachment.htm> _______________________________________________ Address messages to [email protected] No other addresses in TO and CC fields HELP: http://www.evdl.org/help/
