Problem with 36V 15Ah LifePo4 pack not charging completely

dnmun said:
don't cut the battery pack open, just cut the plastic sleeve that is on the BMS lengthwise on the backside from one end to the other in the middle so you can fold it back over the BMS later.

that BMS is the same as the hi current signalab without the leds. you measure the first cell voltage between B- spot and the first pin on the sense wire plug, where the pins are soldered to the BMS. put the black probe on one pin and the red probe on the next higher pin, measure to .01V using the 20V scale and post them up so we can tell you what to do next.
Click to expand...

I'm going to wait a few days before I decide whether or not to cut into it, btw there is no obvious bulge or anything on any of the surfaces of this brick...if there had been I would already be there.
The brick is in fact gaining almost .1v after a nights charging.

wj
 
2 Queations:

Are you metering the charger with it plugged into the battery pack, or are you metering the charger when it has no load aka not plugged in to the battery?

What options do you have with sunthing? Are they going to give you a refund for a bad battery? Or anything else, like a discount?

:D
 
I guess one loose sense wire to the bms. X-ray vision. Or give me a razor blade. Remember nobody sends a battery pack back to china. Sunthing tech support ? Not like a Ping hua ?
 
e-beach said:
2 Queations:

Are you metering the charger with it plugged into the battery pack, or are you metering the charger when it has no load aka not plugged in to the battery?

What options do you have with sunthing? Are they going to give you a refund for a bad battery? Or anything else, like a discount?

:D
Click to expand...
measuring with charger disconnected from battery
I haven't broached that subject as yet...too many people say to charge for a week and watch the load, sun thing said to charge for several days.
I'll give it a bit of time before I cut into it, if need be.

wj
 
999zip999 said:
I guess one loose sense wire to the bms. X-ray vision. Or give me a razor blade. Remember nobody sends a battery pack back to china. Sunthing tech support ? Not like a Ping hua ?
Click to expand...

I don't know what to guess.
wj
 
Not guessing either....the batteries need to be metered. Sorry, but no two ways about that if you want to know if the pack is good, bad or repairable.
 
If you have put it on the charger for 4 plus hr. the charger light came on and no differents. plus the charger is at a higher voltage output then the battery. You will need to cut the end or side with the bluge or where the BMS is to check the each group of cells. Should be 3 - 5ah cells togethere ( equals one cell ) for 15ah for one of 16 series cells for 48volts. If you can feel the bms with all the wires these is where you need access. To check cell voltage or voltage of each cell. Should charge to 44-45 volt fresh off the charger. Be very careful as all cells look dead, but as dead as a rattle snake. So all have voltage and all add up to more voltage as 44 volts.
 
12 fet lyens controller. 40 amps one? If so, that's an excellent way to drive a 15 ah 2c lifepo4 pack into a severe unbalance.

Since you did not buy that thing from Sunthing, you can kiss any kind of refund or CS goodbye from him. It's between you and the actual seller now.

You may as well expose the bms now, it's not like you have any kind of warranty here. That would allow you to see if all the wires to the bms have current, or got disconnected. With a small light bulb, you could hurry up the balancing manually.
 
dogman said:
12 fet lyens controller. 40 amps one? If so, that's an excellent way to drive a 15 ah 2c lifepo4 pack into a severe unbalance.
Click to expand...

yes the 40 AMP one, I have the 3 speed switch. Can I program to some value that will lower the potential high A draw when using the lifpo brick? and then switch to speed 3 or 4 when I use the Li ion batteries?


wj
 
dogman said:
12 fet lyens controller. 40 amps one? If so, that's an excellent way to drive a 15 ah 2c lifepo4 pack into a severe unbalance.

Since you did not buy that thing from Sunthing, you can kiss any kind of refund or CS goodbye from him. It's between you and the actual seller now.

You may as well expose the bms now, it's not like you have any kind of warranty here. That would allow you to see if all the wires to the bms have current, or got disconnected. With a small light bulb, you could hurry up the balancing manually.
Click to expand...

sunthing28 was not very helpful. Only asked to cycle the battery more times and said max voltage will rise. Gave him charger output voltage and also said it was fine.
 
It quit raining so I went for a ride to check out my ‘bricks’ capacity today.
Previously the battery would measure @ 39.4 hooc and I could ride @ 4.25 miles (not wot but with pedal assist and part throttle) before I would hit LVC and the battery would measure @ 25.4V.
Today, after the battery was connected to the charger for @ 48hours:
hooc the reading was 40.1V, I rode 12.5 miles and since that was my ride of the day, I did not hit LVC.
The measured V after the ride was 36.4V.
The lifepo brick is back on the charger, can’t wait to see what tomorrow brings.
wj
 
Do not drain the battery that far. Light discharge and back on the charger. Then light discharge. Then back on the charger. Get the battery charged and balance.
 
wymjymn said:
It quit raining so I went for a ride to check out my ‘bricks’ capacity today.
Previously the battery would measure @ 39.4 hooc and I could ride @ 4.25 miles (not wot but with pedal assist and part throttle) before I would hit LVC and the battery would measure @ 25.4V.
Today, after the battery was connected to the charger for @ 48hours:
hooc the reading was 40.1V, I rode 12.5 miles and since that was my ride of the day, I did not hit LVC.
The measured V after the ride was 36.4V.
The lifepo brick is back on the charger, can’t wait to see what tomorrow brings.
wj
Click to expand...

Much better than day 1! lol.
 
Definitely don't zoom off from stop signs in the highest speed switch setting. At least give it half throttle for the first 30 feet or so.

Wot cruising at 36v shouldn't be that bad though. Assuming you aren't going much more than 25 mph, that cruising wattage won't be much more than 1000w even in the wind. No wind, more like 600w. The big controller can't hurt when the motor will not pull more than 1000w.

For sure, you took a not balanced pack, and hammered it into even less balance on that first ride. Never take it off the charger, unless you are riding would be best. The big controller's amp spikes will keep on hammering that pack into unbalance.

Get a wattmeter, and try to ride so you don't pull more than 15 amps much.
 
Todays update:
Monday hooc 39.9v 12.5 mile ride ending with 37.4v
Tuesday hooc 40.0v 12.5 mile ride ending with 37.6v
Wednesday hooc 40.2 12.5 mile ride ending with 38v
I found that if I disconnect the charger from the pack and unplug the charger from the wall…wait for thirty minutes and connect everything that I will get @ 30 seconds of charging. If I don’t disconnect everything mentioned the charger will not go into a charge mode. I did this disconnect reconnect 6 times this morning and raised the hooc voltage from 39.9 to 40.2.
Whatever……………….
I’ve sourced some li ion cells for my frame pack and will be rebuilding it this month so the lifepo4 brick is not as important as it once was to me. I assume that I hurt it with my immediate usage and possibly the subsequent usage…..from what everyone here has explained. That is unfortunate, I thank you for the information.


wj
 
<quote>For sure, you took a not balanced pack, and hammered it into even less balance on that first ride.</quote>

My take is that my actions hurt it...don't know how others would read that.

If offering information on the whole rather than the individual components isn't information...............

the information I received on the whole did help me, I didn't feel obliged to cut and measure and certainly don't now that I'm getting better performance
wj
 
it was a slow process but several days ago the battery took a higher charge. I'm done measuring unless an issue arises.

lifepo4.jpg


wj
 
wymjymn said:
it was a slow process but several days ago the battery took a higher charge. I'm done measuring unless an issue arises.

lifepo4.jpg


wj
Click to expand...

hrrm.. looks like it sprung back to life! Sunthing says it should reach 44V. You've surpassed 44V. That's as good as it gets!
 
Nuke zero you most likely bought a lifepo4 that was mass produced years ago in china and sat on a shelf slowly discharging. You should ask for your money back or a replacement. Leave sunthing negative feedback for the garbage he sold you.
 
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