ebikes.ca Ezee hub motor kit with LiFePO4 4.5 years on.

This is my first post in about 4 years.

I bought a ebikes.ca Ezee kit around about August 2010 and installed it into a Kona smoke (all chromoly).

Rode it regularly for a year and a half then got a job in South Otago NZ, (wet, windy and cold) and lived literally next door to the school I taught at.

The poor bike sat in a drafty wet 100 year old garage for three years. Took it out about 3 times a year for about 3-5km rides at a time. If that.

Long story short, I have moved to a warmer city and am looking at commuting 5km each way to school. The Kona is now rusty, too small for me and will be replaced with a TBA internal hub commuter style bike.

The ebikes LiFePO4 battery pack still seems good but as I have only just now ordered that CA I don't really know how much juice the battery can still hold. I used to get 25km a charge, so 10km should still be doable for a while. No issues in the two times I've ridden in so far.

Any idea how long it will be before a gently used ebikes LiFePO4 pack gives up the ghost?


PS I normally wouldn't bother with ebikes for a flattish 5km, but since I have the kit already I may as well use it. Maybe longer commutes are in the future.

i have some lifepo4 pouches in my pack that are almost 10 years old i think. usually you can restore most of the capacity of the battery by forcing it back into balance and then allow the BMS to keep it balanced after that. it should still have 90% capacity.

Kiriakos GR, again thanks for your wisdom,we are all grateful.

It really depends a lot on how much charge was on them when they say idle. the cold would have been good for them, however. Lithium last longer when stored cold.

If they were stored at around 40% of charge and cold enough, then retaining >80% of their original capacity isn't unreasonable. If they ever sat for long periods of time unused at full charge, or at no charge, then you may be down around 50%, and/or they may suffer from voltage sag under load more than previous. But they may still suit your needs.

Well they still get me the ~10km return, but the voltage seems a bit more saggy. I pedal a bit harder to get up the hills.

I'll hook up the CA when it arrives and report here.

if you wish to restore the battery to a balanced state it requires a little effort. you will have to open the battery to access the BMS so you can measure the cell voltages to see how far outa balance it is. the cycle analyst will not tell you that.

Yea as dnmun is saying to do what you are asking you need to find the voltage of each cell in your battery.

He is the best at leading someone thru that process so you would be smart to follow this opportunity.

GL

Re the lifespan, if you had said " the bike sat in a hot dry 40c garage for three years" We wouldn't need a fortune teller to guess about it's condition.

But since it was stored reasonably cool, no reason to think the battery is toast yet. But it is reasonable to assume it could be badly out of balance now.

If stored fully charged, then it's quite possible that they are pretty degraded from that. But that doesn't mean they might not be usable, especially once balanced up good.

As I understand it the BMS is a balancing type, but I suppose that is designed more to keep a currently balanced pack in order than fix a badly balanced pack correct?

I am currently flat out with my position at the new school, jobs around the new house, and other bits and pieces. If I get some spare time I will take the boat out fishing.
As long as running the battery unbalanced won't kill it I'm content, at least until the next term break when I will have some tinkering time.

But if anyone can point me to threads on balancing old batteries I'd appreciate it. Otherwise I'll look myself, I can Google fu as well as the next guy.

wish you good luck with mr google fu. let us know if you find out how to do it.

I once dealt with an older unbalanced lifepo4 pack. The best way was to connect a moderate load of less than what the charger puts out (a series of automotive light bulbs will do the job) that forces the charger to stay on all the time, and wait a couple days till the pack gets perfectly balance charged.

I balance my RC packs manually all the time. If you can identify which cell is high, causing the charger to stop, you can discharge that cell faster than the bms would. with a 12v turn signal light bulb.

So while the charger is trying to balance it, identify high cells, and help the bms lower those cells with the bulb. Works great when the problem is one high cell.

If the problem is just one or two much lower cells, then briefly apply a single cell 3.5v power supply to it. Easy if you have an RC charger around. You do have a 4-5v supply around I bet, a phone charger. But careful with those, you can overcharge a cell easy.

If you aren't going fishing for a long time, just plug in the charger for a week or two. Eventually, if the bms is working, it will bring up the low cells. But it might take weeks. You may never get the capacity you had again, but no reason you can't still use the battery as long as you don't have any completely ruined cells in there.

Using old stuff, it can be really good to at some point make the effort to add wires to each cell, with jst plugs on them. This allows you to watch the voltage of every cell in the pack as you use it, or charge it. Helps you know which cells are the problem ones. Not worth the effort yet, but if the pack wakes up and seems to work ok, its at an age where closer watching of it's voltages is nice to have.

Nice to have on a new pack too, but not until the warranty is over of course. No opening the pack and voiding that for no reason.

Thanks Dogman. That made a lot of sense. I teach Maths and a bit of Physics, so probably should have figured that out by myself. Can also get access to school power supplies as well I'm sure.