Lipo battery pak problem 24V 20AH

[JOSE PINTO]

Good, once again I come seeking help for my 24 pak v lipo 20A.
the problem is the duration of the battery charge. do one load after 3km and I am already out of power, has swapped the BMS but soon finds that the problem was not in there because nothing has changed. in covers with our friend Kim, this one gave me the strength to post here my big problem, I'll post some pictures and I'm waiting avossa precious help, since now I apologize for my bad English.



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these figures are after a charge, the led on charger never reaches 100% and loads in 30 minutes. The charger has been tested and has no problem
Ouvir

 

[Hillhater]

3.17 v per cell is not charged ! ..infact it is well discharged ! .. Lipo should be 4+ v charged
What cells are they
What charger are you using ?

 

[dnmun]

measure voltage on each cell, then put it on the charger and measure voltage on the cells until it reaches full charge. they should all reach 3.6V at least.

 

[texaspyro]

Those look like LiFePO cells (3.2V nominal, 3.65V max), not LiPo cells (3.7V nominal, 4.1V max).

 

[AussieJester]

Yes they are definitely Lifep04 they came with his cyclone kit...

KiM

 

[dogman dan]

Quite possibly some very undercharged cells and the pack way out of balance. Unfortunately, a few actually dead cells is also possible.

One thing I've learned to look at first, is the connector to the charger. One flaky, intermittent connection there and the pack is not actually getting charged. Then start looking at each cell with a voltmeter. Using a cell phone charger to bring low cells up one by one, the pack can be fixed if it is simply out of balance.

 

[JOSE PINTO]

3.17 v per cell is not charged ! ..infact it is well discharged ! .. Lipo should be 4+ v charged
What cells are they
What charger are you using ?

Good, my apologies, I have to rectify the batteries are actually LiFe PO4. By mistake I wrote lipo. I bought this set in tw cyclone, known to our Paco who abandoned me when I complained the anomalies of the kit, we could only sell a BMS most saying that there was the problem. photo submission charger supplied with the pak, where they can check the voltage. I thank all the friends that atensão arrow to give this my problem

 

[dnmun]

1st, measure each cell voltage, list them

2nd, plug in the charger and measure voltage when fully charged, on each cell, list them

3rd, remove charger and watch to see which cells drop off fastest.

4th, do capacity test, charge up and then discharge battery into a fixed load like a resistance heater. discharge through a watts up or turnigy wattmeter so you can keep track of total discharge.

while discharging the pack, measure each cell voltage as the pack is drained, and stop when the voltage on ANY individual cell reaches 2.1V. record the total watthours discharged to that point. record the Ah on the wattmeter.

since the low cell would be damaged by further discharges, place it on a single cell charger long enuff to put sufficient charge back into that low cell to allow you to continue discharging the pack, and record which of the cells next drops to 2.1V, then repeat by charging up that cell and continuing the discharge until you can tell which cells are limited in their capacity, then you can decide what to do next about that pack. they are PSI cells and may still be ok.

 

[JOSE PINTO]

1st, measure each cell voltage, list them

Thank you for the help, although some difficulty in seeing in full, as the friend should understand, even with the help of google translator says the Portuguese thing contrary to English and sometimes not easy to understand. Anyway your help is precious. If I may just want to ask a further question. my charger has five LED signaling 30% 50% 85% 100% when I put him in charge Pak begins in the third% and goes up to 85% when 85% is in the notice that the charger begins to operate Inpulse by fractions of a few seconds running continuously without reaching the level of 100%. Also I have done the test load to the charger making a pak sealed gel batteries and the load reached the level 100% wrong to conclude that the loader does not have any problem. Just one more question that I liked your answer.! to measure the individual voltage of each battery pak has to be disconnected from the whole set? (Remove all the boring of the series of batteries)

 

[Samba]

You can measure the voltage of each cell while they are still connected.

 

[TylerDurden]

You can measure the voltage of each cell while they are still connected.

You sure about that...? the pack looks to be 2p8s.

 

[Samba]

You're right it is 2p. If you measure it as connected the paralleled pairs will be measured as a pair not individually.

If a pair is way out of norm, then both the cells in that pair would have odd readings if you did measure them individually.

If one cell is bad then that pair will show low voltage or very low capacity. Then you would want to disconnect them to see if its one bad cell or 2 weak cells.