Calibike batt stats with CAv2.3

How long does it take to balance fully if it's really out of balance?

I'll leave it on for a few days then get some range stats, then if it's still messed up i'll work from the inside.
 
If individual cell groups ore out of balance you can use a single cell charger to bring them up. 2amps gotta quicker than 100ma.
otherDoc
 
If a pack manages to charge to full voltage yet has bad cells does that mean the bad cells still charge full but don't hold it very long?
 
when you use undefined terms like 'bad cell' it is hard to answer definitively.

if you can charge it up until each cell has fully charged, then you can discharge the pack into a dummy load through a wattmeter and monitor the individual cell voltages to determine which cell reaches the 2.0 V LVC first. the amount of charge delivered to the load in Ah defines the capacity of the pack. but it has to be fully charged first so you have to monitor the individual cell voltages while charging.

the total pack voltage is not relevant to this. it is cell level LVC that defines the capacity of the pack.
 
While the pack was charging i picked up the battery to cut into it ans see the bms, the charger started cutting off and on again.

The battery toggle switch was cutting the battery off when it shakes so i cut it off and twisted the wires together.....i don't know if that's completely what is giving me trouble, but i will charge it up and check the bms and cell voltage.
 
Electric Junk said:
While the pack was charging i picked up the battery to cut into it ans see the bms, the charger started cutting off and on again.

The battery toggle switch was cutting the battery off when it shakes so i cut it off and twisted the wires together.....i don't know if that's completely what is giving me trouble, but i will charge it up and check the bms and cell voltage.
Click to expand...

That could definitely be a problem. That doesn't explain why your pack goes dead on you only at the end of your rides though
 
My bms is identical to yours

can you just probe the positive and negative of individual cells in a pack? or will it short

Not sure if i'm doing this right but i started at the last bms bank and got 54.4 on my VM...then went down the line and subtracted the voltage from the previous and got 4.2 for all except 4.1 for 5 and 6
 
you don't have to take that pack apart to measure the cell voltages since they are present on the sense wire plug on the BMS. you have to peel up the hot melt glue to access the solder pads at the base of the sense wire plug legs.

when you measure them, measure adjacent pins to get the individual cell voltages and use the 20V DC scale and post up the values in .01V resolution.
 
that is about as balanced as it gets so now you can discharge it through a wattmeter that you have calibrated and measure the total charge delivered before the pack hits the LVC which i think is gonna be 2.5V on this BMS. but you can stop at 2.9V and know everything you need to know. it should be obvious which one is gonna go first by the time you get through 1/2 the discharge. the voltage drop on the lowest capacity cell will drop below the others by then. keep the discharge below 1.5-2A too.
 
I'm bench testing the bike on a trainer right now and i am seeing my watts up meter showing 0 watts and 0 amps until i get it up to about 8mph...i think there is something wrong with it also.....very crappy resolution unless over 3 amps.

Right now it's spinning away at a casual pace yet showing 0 amps and 0 watts but i'm guessing it's actually 2...when i think about it i made a bulb discharger a month ago and had 4 100 watt bulbs but when i load tested it, it only showed 40 watts total.

I have a whole mess of problems..h

As of right now every single bank is 3.65v at about half discharge...i shut it down for the night.
 
i found the Watts Up meters had the worst calibration of all the wattmeters and it cost the most. i prefer the G.T.Power Rc wattmeter and you can get two for the price of one watts up meter. they only record current and Ah when there is current flowing through them, and they are accurate.
 
Ok i put it on a lightbulb after the gng cut off @ 41.25....discharged on a 120w bulb for a few hours

3
3
3
2.84
2.85
3.05
3.02
3.03
3.05
3.06
3.02
3.03
2.95

38.9 bms cut off

I'm assuming the bms cut off when the cell bank hit 2.84.

Does this appear to be a healthy discharge?
 
dnmun said:
no, it woulda been at 2.5V when it cut out and rebounded to 2.84V. did you measure the Ah capacity?
Click to expand...



My watt meter fails to register at low amps so all my readings are incorrect leading to missing amp hours at the end of the discharge. I started to use it but after i realized the problem i stopped using it.

I have been telling rafe that my total capacity is 11ah, but that is false considering the Watts Up meter fails to register current under 2ah.

I was also told by rafe that the pack LVC is 37v....under a perfect discharge that would mean all banks hit 2.84 at the same time. 2.84x13 is exactly 37v

I don't think the low bulb current allowed discharge to 2.5
 
My bike cut out on me today. CA screen went blank. No power. Thought it was a loose connection but everything checked out. Put the battery on the charger it started charging. CA came on everything fine. Took charger off batt and nothing. No reading at all. The bms has an on/off switch which had to be in the on position to charge but now it starts to charge regardless.

I'm gonna try bypassing the bms and see if that works but if anybody has any other ideas please let me know.
 
Simple, i don't know if you saw but i posted earlier that the cheapo on off switch is suspect in my battery problems....i'm twisting the wires together now but plan on putting in a quality switch.

If it was on and i shook it then it would turn off, perhaps if it's off it could possibly be shaken back on.
 
Ok, so red balance lead came loose off batt. I resoldered now back in business. Need to secure bms to pack better so it doesn't move. This is a huge learning process. But I'm obsessed
I did call Rafe. The guy is very helpfull and always answers me back.
I think I'm almost ready to assemble my own pack.
 
That's really cool to see some actual stats. I have been riding my bike at least 20 miles every day with this battery and a 1000W rear wheel yescomusa kit, and it really gets the job done. My max speed on it is just over 32 mph, but I generally ride it around 20 mph so that I can extend the range a bit.

Note: I don't ride all 20 miles on one charge; I usually plug it in mid-day while I am between class and work.
 
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