999zip999
100 TW
24 hours on the charger so bms can balance the pack.
LIfepo4 36v 15ah 4 years later 10 mile range.
- Thread starter Blueshift
- Start date
e-beach
10 MW
Unless after 24 hours the pack is still unbalanced. Then leave it for 48 hours and check it again. Or....do what Dogman said....let it charge for some hours, ride it around the block a few times and then let it charge and balance for a few hours and do it again until the pack is balanced.
Blueshift
100 W
Its about hour 17 on the charger. No blinking bms yet, eleven solid leds and one off. Will continue to let it balance.
Thanks everyone for the advice.
So it speeds up the process by discharging a bit by doing a couple laps around the block?
Maybe Ill give that a try.
Thanks everyone for the advice.
So it speeds up the process by discharging a bit by doing a couple laps around the block?
Maybe Ill give that a try.
Peter.bp
10 W
My bike battery is 8 years old (LFP 16S/10Ah), passed over 20000km. I noticed that every year I have to keep it on charger over three days in order to get out at least 85% of its' original capacity.
My advice is to keep it on the charger even for a week if you don't want to open it and balance manually.
Sometimes the SOC can differ between cells over 50%...
If after a week it doesn't balance, then you may have a problem.
With 70mA balancing current you can balance only for 1.68Ah/day.
When ageing, LFP cells (LiIon too) differ in self discharge rate, this is why is good advice to keep them once per year long enough on charger (to let them to balance).
I am lazy enough that I don't want to dismantle and open battery box, at least as long as I have over 85% of designed capacity.
I am in worse situation as I cannot see any leds as the box is closed and sealed.
Update: I use bike around 4-5 months per year and it stays in the garage over winter. I never bothered to charge or discharge battery when I store it for winter.
My advice is to keep it on the charger even for a week if you don't want to open it and balance manually.
Sometimes the SOC can differ between cells over 50%...
If after a week it doesn't balance, then you may have a problem.
With 70mA balancing current you can balance only for 1.68Ah/day.
When ageing, LFP cells (LiIon too) differ in self discharge rate, this is why is good advice to keep them once per year long enough on charger (to let them to balance).
I am lazy enough that I don't want to dismantle and open battery box, at least as long as I have over 85% of designed capacity.
I am in worse situation as I cannot see any leds as the box is closed and sealed.
Update: I use bike around 4-5 months per year and it stays in the garage over winter. I never bothered to charge or discharge battery when I store it for winter.
Blueshift
100 W
Update: Finally, the last LED came on. All LEDs are solid now. Thanks guys for all the advice. Anything else I should watch out for?
Should I take the charger off now?
Should I take the charger off now?
Blueshift
100 W
So I tried removing the charger and the last led to go solid that required a long time to balance, only stays solid for less than a minute.
Does this indicate anything?
Does this indicate anything?
e-beach
10 MW
Probably indicates less then full voltage to that cell. Could be the cell, could be the bms bleeding down. Did you ever measure the voltages of each cell individually? If not this is the time. If you are satisfied that the pack is as balanced as it can get.......
Start with your meter set to 20v (do not meter the whole pack with the meter set to 20v) and place the black probe of your meter to the thin black balance wire on the bms, then put the red probe to the white wire next to the black wire. Read the voltage and write it down like this:
1: x.xx
Then put the black probe to the white wire that is next to the black wire and move the red probe to the next white wire. Read the voltage and write it down. keep moving the probes to the next sets of wires and write the voltage down until you have tested all the cells.
Post them here on ES.
Start with your meter set to 20v (do not meter the whole pack with the meter set to 20v) and place the black probe of your meter to the thin black balance wire on the bms, then put the red probe to the white wire next to the black wire. Read the voltage and write it down like this:
1: x.xx
Then put the black probe to the white wire that is next to the black wire and move the red probe to the next white wire. Read the voltage and write it down. keep moving the probes to the next sets of wires and write the voltage down until you have tested all the cells.
Post them here on ES.
Peter.bp
10 W
Leave it on the charger for at least two hours after you got al leds lit.Blueshift said:
Usually you don't have to do this often, once per year is quite enough, for normal charging you can disconnect the battery as soon as you got all leds lit, even before that...
999zip999
100 TW
What motor controller combination are you using do you write a lot of Long Hills do you help with pedal assist ? I asking it's use history.
Blueshift
100 W
999zip999 said:
I am not sure what motor controller it is but it came with my 500w-750w DD hub from Amped bikes (which doesn't exist anymore). I Pedal any large hills i have which isn't that many, mostly one bridge. I try to keep the bike greater than 8mph as I know i will draw more amps and it will become taxing for the system. I also try to start with leg power as that draws more current throttling from standing still. If I am at a decent speed, say 14-20mph i usually use throttle only. Sometimes, if i am uncertain how much more battery I have, i will pedal and lower the throttle.
As far as use goes, I have taken long breaks not using the bike upwards of 3-4 months, but when i do use it, I use it every day and almost always partially discharge. I would estimate that i leave usually at least 20 percent capacity in there. I.E. 20 percent before it cuts off when i ride. Id say its normally though I would probably discharge it to about 50 percent. Somtimes I charge it 2 times or 3 times a day. But those charges are from shallow discharging typically so charging > than 50 percent capacity.
Ive run the battery to the cutoff 2 or 3 times in its entire lifespan.
I have left the charger on for long periods over a week sometimes. I have also not balanced for a long period of time. I usually leave the battery fully charged when not in use though sometimes i remember to store it with about 80percent charge. I have left the bms ribbon connected for longer a couple of months without balancing. ( which I heard can drain a couple of the cells)
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