thedarlington wrote:this info is out there and spread out all over, so here's a dedicated "BMS free zone"thread specifically for this, when starting out BMS can easily be the biggest pain to understand, most don't even have a brand and each have obscure specs making them hard to compare, and then many very easily fail, often the most frequent failure point to a non working ebike. Its easily the shadiest part to ebikes with little details and then trying to compare them... so instead here's a thread to those of us who preffer a more purist simpler solution, yes you do need to watch #'s a bit more closely but it's also more rewarding to know exactly whats going on with your ebike, sorta like manual vs automatic.
rule of thumb>>> [#Series * Voltage] & [#Parallel * mil AMP hours] = total Battery Volt & mAmphrs ... LIFEPO4 @ 3.3v, & LIPO @ 3.7v
Which chemistry do you mean when you say "LiPo"? LiFePO4 is LiPo, so is LiCoO2, so is LiMnO2, so is LiMnCoO2, so is LiNiMnO2, in fact ALL lithium ion cells are lithium polymer................
thedarlington wrote:some options for you are:
LIPO - - simple and robust batteries, small and lightweight battery packs which are not as delicate voltagewise as lifepo4, many cheap low voltage alarms ($1) set to go, but more expensive and dont last as long, works out to about double lifepo4 cost? (citation needed) manual balancing (is it needed for lipo?)
Dangerous assumption here, as every LiPo chemistry is different, and LiFePO4 is just one of the many LiPo chemistries. When determining voltage characteristics, safety etc then you need to be specific about the cell chemistry.
Here is a brief run down on the various types of LiPo cells and the relevant voltages, etc:
LiCoO2 - Commonly used for RC type LiPo packs, 3.7V nominal, 4.2V maximum, no lower than 3V on deep discharge (preferably no lower than 3.5 to 3.6V for best life).
LiMnO4 - Not that common, nominal voltage 4V, maximum about 4.5V, low energy density when compared to LiCoO2
LiNiO2 - high energy density, nominal voltage 3.5V, maximum about 4V, no lower than 3V on deep discharge
LiFePO4 - medium energy density, potentially the safest current LiPo chemistry, 3.3V nominal, 3.65V to 3.7V maximum, no lower than 2.7V on deep discharge
LiCo1/3Ni1/3Mn1/3O2 - higher energy density than LiCoO2, 3.6V nominal, maximum about 4V, no lower than about 3V on deep discharge
LiNiMnO2 - very high energy density, not yet commonly available, 4.2V nominal, maximum and minimum not known
Please ask questions on the forum, rather than by PM, as it helps others and you'll get a better range of answers.