Going to buy the MCPX-BL

[5hane]

This is probably a daft question:

As an example, is 3.7v the same as 3.70v? Or is 3.70v 0.63v more than 3.7v?

I only ask because I don't I don't want to be doing all this stuff if I don't fully understand everything im doing.
Further: today I wanted to fully charge 5 x 1s lipos at the same time but the levels nearly all read differently: 3.74 / 3.76 / 3.80 / 3.82 / 3.82, but I honestly don't know if that meens they are all safely within 0.2v / 2v (whichever it is) of each other. From how I look at it they aren't, and yet a month or so ago I had put each one in to the same storage charge state.
Or perhaps they are charged enough already to fly my heli right now, then after they run down they can finally all be charged together (parallel).

Is there a bloody idiots guide to lipo batteries?

Thanks

[Peteski]

This is probably a daft question:
As an example, is 3.7v the same as 3.70v? Or is 3.70v 0.63v more than 3.7v?

Of course 3.7 =3.70 No idea where you are getting 0.63v from. Is it a trick question?

[Peteski]

Or perhaps they are charged enough already to fly my heli right now, then after they run down they can finally all be charged together (parallel).

No they need to be at 4.2v to fly your helicopter. Just fully charge them all in parallel before you fly.

[5hane]

Of course 3.7 =3.70 No idea where you are getting 0.63v from. Is it a trick question?

Because im obviously a complete div that should have paid more attention at school. No word of a lie this charging business hurts my brain.
Isn't 70 minus 63 = 7? (3.70 - .63 = 3.7). I'm almost scared to ask lol

I know most of you probably think I just need to get on with it, but with all this talk of the dangers of lipo's, I swear I'll burn my home down unless I get a clue.

A few people said that it shouldn't be more than a .2v / 0.2v (if there's a difference) difference between batteries when parallel charging, so looking at the state of mine, the gaps are larger than that unless don't understand how to read what I see.

[Peteski]

Because im obviously a complete div that should have paid more attention at school. No word of a lie this charging business hurts my brain.
Isn't 70 minus 63 = 7? (3.70 - .63 = 3.7). I'm almost scared to ask lol

No it doesn't work like that with decimal places. 3.70 - 0.63 = 3.07 i.e 70-63 = 7 (not 70)
3.7 = 3.70 = 3.7000000000000 it doesn't matter how many zeros you stick on the end!

[myxiplx]

Because im obviously a complete div that should have paid more attention at school. No word of a lie this charging business hurts my brain.
Isn't 70 minus 63 = 7? (3.70 - .63 = 3.7). I'm almost scared to ask lol

I know most of you probably think I just need to get on with it, but with all this talk of the dangers of lipo's, I swear I'll burn my home down unless I get a clue.

A few people said that it shouldn't be more than a .2v / 0.2v (if there's a difference) difference between batteries when parallel charging, so looking at the state of mine, the gaps are larger than that unless don't understand how to read what I see.

In your equation above you're confusing 3.70 with 3.07:
3.7 - 0.63 = 3.07

When it comes to 3.70, that's the same as 3.7.
3.7 = 3.70

But 3.70 is a higher than 3.07. It's 0.63 higher.

Hope that makes sense :-)

[Peteski]

A few people said that it shouldn't be more than a .2v / 0.2v (if there's a difference) difference between batteries when parallel charging, so looking at the state of mine, the gaps are larger than that unless don't understand how to read what I see.

The difference in voltage is less than 0.1v, so don't worry about it too much. 3.82v - 3.74v = 0.08v

[myxiplx]

today I wanted to fully charge 5 x 1s lipos at the same time but the levels nearly all read differently: 3.74 / 3.76 / 3.80 / 3.82 / 3.82, but I honestly don't know if that meens they are all safely within 0.2v / 2v (whichever it is) of each other.

As a general rule, if they're within 0.1V of each other they're fine, and I'll happily connect them together if they're a fair bit further apart than that. All of the voltages you listed would be fine, that 0.1V gap would mean that anything between 3.74V and 3.84V is ok to connect together.

Also, with these small 1S batteries the risk is much lower as they can't put out anywhere near the current levels of the large packs. A big 5000mAh 6S battery can start a car or weld its wires together. A small 300mAh 1S pack is much less dangerous.

[5hane]

As a general rule, if they're within 0.1V of each other they're fine, and I'll happily connect them together if they're a fair bit further apart than that. All of the voltages you listed would be fine, that 0.1V gap would mean that anything between 3.74V and 3.84V is ok to connect together.

Also, with these small 1S batteries the risk is much lower as they can't put out anywhere near the current levels of the large packs. A big 5000mAh 6S battery can start a car or weld its wires together. A small 300mAh 1S pack is much less dangerous.

Thank you for the explanation. I've just this used a calculator and got that 0.1v result you just gave, so perhaps all I have to do is keep a calculator handy at all times!

[Peteski]

so perhaps all I have to do is keep a calculator handy at all times!

Seriously you should! The calculator will stop you getting confused with decimal points etc as you clearly have.

[tourerjim]

Thank you for the explanation. I've just this used a calculator and got that 0.1v result you just gave, so perhaps all I have to do is keep a calculator handy at all times!

No worries mate, question of lipos is very common on here, your gain more experience as goes.

[feathering]

Thank you for the explanation. I've just this used a calculator and got that 0.1v result you just gave, so perhaps all I have to do is keep a calculator handy at all times!

Not directly related to charging but here is an explanation as to why 3.7 represent the same number as 3.70.

Let us draw something that resembles a ruler. Draw a segment (line) and mark the left end with 0 and the right end with 1. Then split the segment into 10 smaller segments, drawing ticks and labelling each tick as 0.1, 0.2,..., 0.9. Now take the first segment (the one from 0 to 0.1) and further split it into 10 smaller segments. Mark each of the smaller ticks as 0.01, 0.02,..., 0.09. Note that by the time you get to 0.09 and move to the next tick that next tick would already have been marked as 0.1. But you were on 0.09 and after 0.09 comes 0.10. Therefore, 0.10 coincides with 0.1. That is, 0.1=0.10. If you keep doing this you will see that after 0.69 comes 0.70 which coincides with 0.7. So again 0.7=0.70. This is so because you are looking at proportions and splitting the original line into 10 segments and moving 7 segments down the line is the same as splitting the line into 100 segments and moving 70 segments down the line.

The manufacturer of your charger decided to split things into 100 ticks so to go from 3.00 to 4.00 you would have moved 100 ticks.

[Peteski]

It's always going to be hard to understand any of this stuff if you are struggling that much with numbers! I know that sounds a bit harsh, but I think it's unrealistic to understand the ins and outs of lipo charging if you are struggling to understand decimal numbers. Maybe a course in fundamental maths would help as a starting point and would be very useful in general life too.

[5hane]

Not directly related to charging but here is an explanation as to why 3.7 represent the same number as 3.70.

Let us draw something that resembles a ruler. Draw a segment (line) and mark the left end with 0 and the right end with 1. Then split the segment into 10 smaller segments, drawing ticks and labelling each tick as 0.1, 0.2,..., 0.9. Now take the first segment (the one from 0 to 0.1) and further split it into 10 smaller segments. Mark each of the smaller ticks as 0.01, 0.02,..., 0.09. Note that by the time you get to 0.09 and move to the next tick that next tick would already have been marked as 0.1. But you were on 0.09 and after 0.09 comes 0.10. Therefore, 0.10 coincides with 0.1. That is, 0.1=0.10. If you keep doing this you will see that after 0.69 comes 0.70 which coincides with 0.7. So again 0.7=0.70. This is so because you are looking at proportions and splitting the original line into 10 segments and moving 7 segments down the line is the same as splitting the line into 100 segments and moving 70 segments down the line.

The manufacturer of your charger decided to split things into 100 ticks so to go from 3.00 to 4.00 you would have moved 100 ticks.

Thanks for the detailed explanation. I need to read through that a few more times until it sinks in more

[tomatwalden]

https://www.mathsisfun.com/decimals.html