Beginners guide to batteries

Nealh

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The timing might be what the chargers discharge timing is set to, 2hrs.
 

paintboy

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What current are you discharging at? Is it a single cell?
Just found the setting for the safety charge which makes sense as it's for 120 minutes. So my cell is discharging for 2hours max.
If I disable that somehow would the cell have a chance to discharge more than the 700 I'm getting?
It's all experience!
 

vfr400

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Jun 12, 2011
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If you were discharging for 2 hours at 1A, you would see 2000mAh at bottom right, so you must be misunderstanding something.

The reason it stops at 2 hours is because that's the default safety setting. Download an instruction manual, so that you know how to work the charger.
 

paintboy

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If you were discharging for 2 hours at 1A, you would see 2000mAh at bottom right, so you must be misunderstanding something.

The reason it stops at 2 hours is because that's the default safety setting. Download an instruction manual, so that you know how to work the charger.
[/QUOTE. I ll see how to take the timer off and see if I get anywhere near 1500mah . A learning curve
 

soundwave

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soundwave

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i doubt it will make any difference but you will need to turn it of to test bigger capacity cells.

DSC_0558.JPG
 

soundwave

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you must be discharging the cells at 0,5A for it to take that long but if you turn the amps up it takes less time but you will get the same result.

this is the cell in the pic
 

paintboy

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Nov 14, 2020
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you must be discharging the cells at 0,5A for it to take that long but if you turn the amps up it takes less time but you will get the same result.

this is the cell in the pic
Hi, ethe cells are discharging to around 950mah now. Still crap but now the timers off they go down to 3.1v instead of 3.5. Question is when I get cells of approximately 3000 mah what sort of difference is acceptable when making parallel connection?
Eg. I've got a cell of 929, 956 and 1021. If these were together is there too much of a gap. I ll do it anyway and note the results, just wanted an opinion
 

vfr400

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Those cells won't work on an ebike. If the nominal capacity is 1500mAh, they're completely shagged if you get anything less than 1200mAh. Only use new cells in an ebike battery, otherwise you'll be building your battery twice.
 

sjpt

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Those cells won't work on an ebike. If the nominal capacity is 1500mAh, they're completely shagged if you get anything less than 1200mAh. Only use new cells in an ebike battery, otherwise you'll be building your battery twice.
Certainly true. But if you aren't yet practiced at building batteries that may be no bad thing. Make your mistakes on the first one that is going to be rubbish anyway, and the build the one you are going to use correctly.
 

Nealh

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Hi, ethe cells are discharging to around 950mah now. Still crap but now the timers off they go down to 3.1v instead of 3.5. Question is when I get cells of approximately 3000 mah what sort of difference is acceptable when making parallel connection?
Eg. I've got a cell of 929, 956 and 1021. If these were together is there too much of a gap. I ll do it anyway and note the results, just wanted an opinion
A part from there shagged, the mah rating of any battery is the lowest cell rating. Although the average mah is 968, 929 is the rating as one can't get more out of them once the lowest one reaches it's discharge target.
 
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paintboy

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Certainly true. But if you aren't yet practiced at building batteries that may be no bad thing. Make your mistakes on the first one that is going to be rubbish anyway, and the build the one you are going to use correctly.
Hurrah, someone who realises I m practicing on **** cells!
 

Nealh

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We know you are practising because you said so in #1 .
 

paintboy

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Nov 14, 2020
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We know you are practising because you said so in #1 .
New question in my quest for knowledge.
I discharged 5 cells and the average was 1015. Only 30 mah between highest and lowest.
So put them together as 5p cell. Charged it and discharged it and only got 3717 mah.
Just the cells being crap, or charger getting bored?
 

Nealh

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What voltage were the 5 cells discharged to before connecting to 5P ?
 

soundwave

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May 23, 2015
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2.99 is to low id not go lower than 3.2v as the voltage falls off a cliff going any lower.

when you put 5 cells as 1 pack it is as only as good as the weakest cell voltage wise so some cells might have a bit more left in them but only on there own.

so when 1 cell in the pack reaches cut of voltage it will stop discharging the hole pack.

like it only takes 1 cell in a pack of 40 to go bad and the bms stops charging the pack
 

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