999zip999
100 TW
I didn't see anchor nuts on the frame for a rack.
Taking a chance on Alibaba (K Power battery)
- Thread starter dogman dan
- Start date
I finally got to ride my battery with a Mac 10T and CAV3.
I rode for 25 miles at around 15 mph, and I did another 20 miles at wide-open throttle - which was in the 25-28 mph range. No pedaling. After 45 miles, the voltage was around 44 when under power, and 46 when at rest.
The Mac motor started to stutter, and everything shut down. Turning the key off and then on would reset it and allow my CAV3 to come back up, but if I rode under power, it would shut down again.
It seems that either my Infineon controller has the LVC set to around 44 because I pulled the battery output and using a multimeter, got 48.2, so the battery was still supplying power, or the battery BMS is tripping and cutting current, but still letting 48.2 volts through to read on the multimeter.
I am not sure how BMS work, but after tripping, is it possible to measure voltage on the battery output? Or would it be totally zero volts? Paul from Em3ev thinks that maybe the battery has a weak cell group that is tripping the BMS early.
As for the battery capacity - I accidentally reset the CAV3 mid-ride when I was changing some settings, but from my memory, I believe the LVC cut off at around 18.5 Ah / 820 Wh. That is pretty promising, especially since it was still at 44 volts.
I will try it again tomorrow.
I rode for 25 miles at around 15 mph, and I did another 20 miles at wide-open throttle - which was in the 25-28 mph range. No pedaling. After 45 miles, the voltage was around 44 when under power, and 46 when at rest.
The Mac motor started to stutter, and everything shut down. Turning the key off and then on would reset it and allow my CAV3 to come back up, but if I rode under power, it would shut down again.
It seems that either my Infineon controller has the LVC set to around 44 because I pulled the battery output and using a multimeter, got 48.2, so the battery was still supplying power, or the battery BMS is tripping and cutting current, but still letting 48.2 volts through to read on the multimeter.
I am not sure how BMS work, but after tripping, is it possible to measure voltage on the battery output? Or would it be totally zero volts? Paul from Em3ev thinks that maybe the battery has a weak cell group that is tripping the BMS early.
As for the battery capacity - I accidentally reset the CAV3 mid-ride when I was changing some settings, but from my memory, I believe the LVC cut off at around 18.5 Ah / 820 Wh. That is pretty promising, especially since it was still at 44 volts.
I will try it again tomorrow.
999zip999
100 TW
Don't do that. First get a couple of light cycles leaving it on the charger hours after the light comes on. Please do not run to lvc and unbalance your battery. Or by hammering and lugging up a long hill. You will be trying to kill a new battery. Best to leave something in the battery as unplugging a bms and resetting for more miles is a No No. And unlearn that trick. Or you may be crying.
Just use it 10ah12ah and charge it. Enjoy it. You don't need to be a beta tester. As your tests may not go as planned or demand.
Just use it 10ah12ah and charge it. Enjoy it. You don't need to be a beta tester. As your tests may not go as planned or demand.
Ok, for the future I will do that. When I posted that though - I was not sure if the BMS was even tripping. I thought it was the motor controller because the CA was showing 44 volts. Now I know it is the battery BMS and the voltage was dipping under load at the end of the capacity.
I did leave it on the charger all night, and ran it today mostly at full throttle (25-28 MPH, averaging 19.6) until it cut off.
Here are the results:
My question is - should I be unhappy that this "20Ah" battery got a true 17.3Ah? Or is that pretty typical to not make the rated capacity? When you buy batteries for 2x and 3x the price of this, do they typically make their rated capacity as indicated with a CA, or not really?
I guess I got a true 17Ah / 820Wh battery for $407 delivered.
I did leave it on the charger all night, and ran it today mostly at full throttle (25-28 MPH, averaging 19.6) until it cut off.
Here are the results:
My question is - should I be unhappy that this "20Ah" battery got a true 17.3Ah? Or is that pretty typical to not make the rated capacity? When you buy batteries for 2x and 3x the price of this, do they typically make their rated capacity as indicated with a CA, or not really?
I guess I got a true 17Ah / 820Wh battery for $407 delivered.
999zip999
100 TW
You forgot to break in your battery and fully balance. STOP doing lvc test. STOP DOING LVC TEST. Some need to hear it three times they say. Go leave on the charger. Start by getting a good balance on your battery. Step one.
That also means don't go the steepest hill and go up and down till things shut off. Ok say ok.
That also means don't go the steepest hill and go up and down till things shut off. Ok say ok.
999zip999
100 TW
You have a 10p14s or 140 cells getting to know each other and balance or learning to play nice. Remember Dogman got it because it was cheap. Plus this is not the first time Dan has broken new battery ground for others.
Plus a review thread. Thanks
P.s. spinning magnets said 9p13s or 119 cells. Playing nice.
Plus a review thread. Thanks
P.s. spinning magnets said 9p13s or 119 cells. Playing nice.
markz
100 TW
Most likely that battery was over-hyped in the stats department. They are like politicians, they like to lie!
999zip999
100 TW
My ford focus gets 29mpg not 32mpg.
Give one test in two weeks or more.
Hell I have A123 20ah cells they give 18ah, but 200amps per cell.
Give one test in two weeks or more.
Hell I have A123 20ah cells they give 18ah, but 200amps per cell.
I forget what my Ford Focus gets.
dogman_dan and I don't have the same cells. I supposedly have some sort of unspecified Samsung cells.
His made 17.8Ah and mine made 17.3.
Maybe I can make more if I ran slower, but I won't know, because I agreed to not hit the LVC again. Besides, I plan to start Pedlecing so I will probably never be able to run out of power.
My charger is taking maybe over eight hours to charge. I have a Kill-a-watt on it now.
dogman_dan and I don't have the same cells. I supposedly have some sort of unspecified Samsung cells.
His made 17.8Ah and mine made 17.3.
Maybe I can make more if I ran slower, but I won't know, because I agreed to not hit the LVC again. Besides, I plan to start Pedlecing so I will probably never be able to run out of power.
My charger is taking maybe over eight hours to charge. I have a Kill-a-watt on it now.
999zip999
100 TW
Pedal first is the biggest battery saver over time.
markz
100 TW
300W manual power!
dogman dan
1 PW
The price I paid, I'm mighty happy mine seems able to put out almost 18ah.
It's possible you were hitting a 44v lvc on your controller. I was for the last mile. I just kept going slower and slower, to get that last .5ah out of it. Slow enough to go till the bms finally shut off the display for good.
Since the weeds are now 6-8 feet tall along most paved roads lately, I have not done any more long distance riding on the K power battery. Next up when the mowers get done, ride it very slow, and see if capacity gets better if I do a long slow ride on flat ground. On that ride where I got almost 18 ah, I did climb a pretty big hill. About 2000 vertical feet big.
It's possible you were hitting a 44v lvc on your controller. I was for the last mile. I just kept going slower and slower, to get that last .5ah out of it. Slow enough to go till the bms finally shut off the display for good.
Since the weeds are now 6-8 feet tall along most paved roads lately, I have not done any more long distance riding on the K power battery. Next up when the mowers get done, ride it very slow, and see if capacity gets better if I do a long slow ride on flat ground. On that ride where I got almost 18 ah, I did climb a pretty big hill. About 2000 vertical feet big.
Paul says that I have no 44v LVC on my controller, and even if the LVC in the controller were tripped, it would not have shut off my CA. Only the battery's LVC can make the CA go black.
Actually if you look at my CA readouts, it seems like the pack dipped to 27.4 on the vMin display.
Actually if you look at my CA readouts, it seems like the pack dipped to 27.4 on the vMin display.
dogman dan
1 PW
Sorry I did not look so close at your CA screens, and kudos for showing them. Yeah, my cutouts were not making the CA screen go black, or make my kit display go black. That's how I knew the bms had not tripped yet on my ride. But as my voltage dipped below 44v under load, the controller was shutting off then going back on.
In any case, I really was thinking in terms of having a fat 15 ah battery when I made my purchase. I was thrilled when mine passed 17 ah. Especially after I stupidly ordered the pack with no name cells.
No way in hell I dreamed it would put out a full 20 ah. But I would have loved it to see 19.25 ah. Maybe it will without climbing a mountain.
In any case, I really was thinking in terms of having a fat 15 ah battery when I made my purchase. I was thrilled when mine passed 17 ah. Especially after I stupidly ordered the pack with no name cells.
No way in hell I dreamed it would put out a full 20 ah. But I would have loved it to see 19.25 ah. Maybe it will without climbing a mountain.
999zip999
100 TW
Why go up hill we all life is easier going down hill with the wind at your back. Many variables on the road. Getting full AH is rare.
dogman dan
1 PW
Usually I go up that particular hill to find out things. Will a motor overheat, etc. View is nice too, and on the top it's cooler than the valley. Higher than Denver on top. It's a nice 14 mile round trip from my driveway to the top of San Augustine pass.
Paul thinks that my battery LVC is probably tripping at a higher-than-normal voltage because I may have a weak call group, and says that the vMin is not that meaningful a readout on the CA. That would mean that there are most likely other batteries from this company which would get more Ah just by ending up with more better cells.
But it is ok. If I pedal, I only draw 8.7 Wh per mile, which at 820 actual Wh, gives me a real-world 94 mile range. Two days ago, I rode about 18 miles, and yesterday I rode about 50 - and I can still go up to another 26 miles before charging it (though I will charge it after my next 18 mile ride to the gym to not come too close to the LVC).
But it is ok. If I pedal, I only draw 8.7 Wh per mile, which at 820 actual Wh, gives me a real-world 94 mile range. Two days ago, I rode about 18 miles, and yesterday I rode about 50 - and I can still go up to another 26 miles before charging it (though I will charge it after my next 18 mile ride to the gym to not come too close to the LVC).
999zip999
100 TW
What ? Still doing lvc tests ? Charge it as often as you can for your new battery. Yes more time on charger, after each short ride to help balance the New battery. Keep it simple and put it on the charger so the bms can balance your New battery. Quit doing LVC tests. Charge and leave on charger. Clue. That is your clue.
This is the way to add AH. Your way will decrease AH.
This is the way to add AH. Your way will decrease AH.
anoNY42
10 W
rsilvers said:
From my reading of the conventional wisdom, this would not harm your battery. Batteries have ratings at full discharge/charge cycles (eg. 1000 cycles for LiFePo or something like that). But that only holds if you completely discharge and then charge 1000 times. If you were to, say, discharge only to 50%, then charge it back up, the battery should technically last something like 2000 of those half-cycles (if rated for 1000 full cycles).
That said, I have looked for but never found any research that actually tests this.
dogman dan
1 PW
At 2 cycles, It's hard to believe he really got a full, balanced charge. I don't think he ruined a cell, but he might have some less than great cells in the pack, as I have in mine. They might need more balancing to dish out another half ah.
I have little hope that he'll get a huge amount more, after a really full balance charge. Charging to 54.6v, and not dropping more than .2v or so after a few hours off the charger would indicate the battery is as full as it can get. If it drops more, try putting it back on the charger again. Repeat till it holds the charge, if it can.
As it ages, as full as it can get will be noticeably less than 56.4v. Some cells will start to slightly self discharge when the charger is taken away. But it should still drop, then hold at some number. That becomes the new number to look for, to know you got balanced.
I have little hope that he'll get a huge amount more, after a really full balance charge. Charging to 54.6v, and not dropping more than .2v or so after a few hours off the charger would indicate the battery is as full as it can get. If it drops more, try putting it back on the charger again. Repeat till it holds the charge, if it can.
As it ages, as full as it can get will be noticeably less than 56.4v. Some cells will start to slightly self discharge when the charger is taken away. But it should still drop, then hold at some number. That becomes the new number to look for, to know you got balanced.
My charger is 2 amps, which seems stupid low for this battery size. I just ordered a 6 amp charger for $37.90 delivered. It should allow me to charge in 3 hours. Even an 8 amp would be less than 0.5C. I can keep it in the bike’s bag. I can still use the 2 amp charger if I am in no hurry, but I doubt 6 amps will hurt it as it is only about 0.3C.
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