xb-700li - Battery Life? Anyone seeing a decrease in range....
I have owned my xb-700li for 18 months and my range appears to be decreasing after putting a little over 3000 miles on it. Has anyone else ridden more miles than that? And if so has your range decreased? Are you seeing decrease in full charge voltage?
I'd check cell voltages UNDER LOAD at the end of a fairly long ride. I'd bet that one or more cells is out of synch. You will at least have hard data to give to the vendor...
How many recharge cycles has the pack had?
Lithium Iron Phosphate batteries are 'better' than lithium manganese oxide (LiMn2O4, which is what I assume you mean - I don't believe there is such a thing as a lithium iron manganese oxide cell which is what LIFEMNO4 would be), largely in the sense that they can't catch fire. On most other measures they are worse (energy density, power density). But that not catching fire thing is important. And yes they do have much better cycle-life.
Here's a useful comparison summary:
That lists 500 cycles as the lifetime for managnese based cells.
Did you check the AIR PRESSURE of your TIRES recently?? It is VERY important for good range!--Low pressure shortens range!!
I'm on the sidelines on this one, since I've got lead in my XB600. However, a series of cells lives and dies on the individual cells in the pack. That means, in practice, a BMS system for cells that cannot withstand an "average" charge over the years.
What kind of BMS does the XB700 have? Are they just "hoping" that all the cells will remain synched?
I'm not clear which battery type you have in your machine. Is it stock or did you buy it separately and if so from where? You said you had 'LiFEMNO4' batts, which I can only find mention of in some obscure research papers.
I don't have your particular machine either so don't know much about it. Ah, I see from http://www.x-tremescooters.com/electric_bicycles/xb700li/xb700li.html that models built before 2010 have 'LiMn' packs, whilst newer ones have 'LiPO4'. You need to provide this sort of info if you want people to help, not expect them to look it up on the internet themselves for your benefit. What sort of battery-management is provided on the bike?
The link I provided earlier sugests that Lithium Manganese (actually Lithium Managnese Oxide or LiMn2O4) packs have a 500 cycle life so your seeing noticeable capacity reduction at this point seems in line with that.
If you read up on endless sphere you will find endless information on the details of battery management. If you look inside the pack to find out which actual cells were used it might help people advise on their expected lifetime.
Here's a page saying that both colbalt-based and managanese based chemistries have increasing internal resistance over time (resulting in increased voltage drop under high load) and will be poorly after 2-3 years.
Not storing at high charge levels seems to be the main way to extend lifetime of lithium-ion cells, but of course that isn't usually very practical.
Bottom line: assuming I have the right chemistry, then yes, you've had a reasonable life from them and they are probably now on the way out. A Lithium-iron phospate replacement will be bigger/heavier for the same capacity but _should_ last at least 4 times as long (if protected with a suitable BMS to prevent differential cell charging and over-discharge/undercharging).
Just wanted to comment on my scooter, I bought a XB700Li around march of 2010, it has the newer batteries in it. Rode it about 60 hard miles a week and not always charged right after riding sometimes after a few days of riding. Lost job, brought bike to my home and let it set for a month with battery charged. Got it back out recently and still getting 35-45 miles from a charge. I love it, it saved my life when not having a drivers license.
On another note, sold the bike today to a nice older woman. She rode around all day and loves it. Unfortunately, they just called and said they plugged it in after riding and it started to smoke. I think they plugged the charger cord only directly into the bike's charging port, this is the only way I can imagine that it would smoke when plugged in. They will return the bike tomorrow and I will access the damage for them and see if I can fix it. I am sure that this is not the first time someone has done this, anyone else fry the controller by plugging directly into the charging port from the AC wall socket, if so, PM me and leave some details if you can.
Oooh, that's heartbreaking. It is basically criminal to use a standard 110V AC plug type for a 48V DC supply. There was a case in England where the same thing happened. The same plug style is a more standard service plug in England.