Battery voltage queries + others!

[westyorkylad]

Hello All

Having looked through the info on here for mechanical mods and watched a number of utube videos I have a few questions that I am hoping some of our more experianced forum users might be able to answer for me, as follows;

1) How will I know what the voltage drop is on any given battery when used in a mechanical mod?

2) How will I know when its time to change the battery on a mechanical mod?

3) When working out the amperage draw on a battery for a particular coil set up on a battery that has say a maximum draw of 35 amps what would be the safe amperage to work to, half that?

4) Watching videos on utube quite a lot of the people building coils fire them with a blow torch, is this just so that they can be easily bunched together, can this be done when firing on the mod before building the coil up with the wicking material instead?

5) Finally as a general rule of thumb does low ohms coils mean greater vapour production and higher ohms set up mean less vapour but more flavour?

Think thats about it at the minute guys and girls your help with this is very much appreciated.

[thatguy]

1. Vapour production will drop and vape will seem cooler
2. Once vapour production tails off and isn't hitting the spot anymore
3. Depends on the battery. A good quality battery should be absolutly fine at 75%, but 50% or less for batteries you don't know or trust. Sony, samsung, sanyo and panasonics are usually good to 75%
4. This anneals the wire to make it easier to form into a coil (i.e. removes the springiness of the wire)
5. Low ohms mean more vapour and more flavour as more liquid is vapourised, and also means a warmer vape, although the warmth of the vape is also affected by the size and shape of the coil.

[westyorkylad]

Mar 4, 2015 7:49:35 GMT thatguy said:

1. Vapour production will drop and vape will seem cooler
2. Once vapour production tails off and isn't hitting the spot anymore
3. Depends on the battery. A good quality battery should be absolutly fine at 75%, but 50% or less for batteries you don't know or trust. Sony, samsung, sanyo and panasonics are usually good to 75%
4. This anneals the wire to make it easier to form into a coil (i.e. removes the springiness of the wire)
5. Low ohms mean more vapour and more flavour as more liquid is vapourised, and also means a warmer vape, although the warmth of the vape is also affected by the size and shape of the coil.

Hi thatguy thanks for that - the only one that doesn't answer for me is the first if I had a 3.7v battery how would I know what the voltage drop would actually be so I could work out the high and low wattage whilst vaping i.e. the voltage being 3.7v when the battery is fully charged as opposed to when its nearing empty?

If sub ohm coils are much better for more vapour and more flavour, then why bother building coils over 1 ohm at all?

[GunJack]

Mar 4, 2015 11:45:41 GMT westyorkylad said:

Mar 4, 2015 7:49:35 GMT thatguy said:

1. Vapour production will drop and vape will seem cooler
2. Once vapour production tails off and isn't hitting the spot anymore
3. Depends on the battery. A good quality battery should be absolutly fine at 75%, but 50% or less for batteries you don't know or trust. Sony, samsung, sanyo and panasonics are usually good to 75%
4. This anneals the wire to make it easier to form into a coil (i.e. removes the springiness of the wire)
5. Low ohms mean more vapour and more flavour as more liquid is vapourised, and also means a warmer vape, although the warmth of the vape is also affected by the size and shape of the coil.

Hi thatguy thanks for that - the only one that doesn't answer for me is the first if I had a 3.7v battery how would I know what the voltage drop would actually be so I could work out the high and low wattage whilst vaping i.e. the voltage being 3.7v when the battery is fully charged as opposed to when its nearing empty?

If sub ohm coils are much better for more vapour and more flavour, then why bother building coils over 1 ohm at all?

thing is, a fully-charged battery should be more like 4.2 volts, not 3.7. Only way to check with a mech is a volt meter....

[markm]

The voltage drop is the resistance in the mods connections, so shouldn't be deducted from
The safe use calculations, it tells you how much of the power is going to the coil. Working
Out the safety is looking at how hard your battery is working, which will not be affected by
Voltage drop. Use 4.2v as that's what it will come off the charger at.

[westyorkylad]

Maybe Ive got the wrong end of the stick but the Ifest 18650 batteries I have are 2500's and say 3.7v on them? 35a current, so doesnt that mean that they are 3.7v batteries?

[Ripshod]

Welcome to the wonderful(ly confusing) world of batteries. If you haven't read it already:

allaboute-cigarettes.proboards.com/post/870306/thread

btw, that efest is actually only a 20Amp battery.

[DiscoDes]

Mar 4, 2015 12:36:38 GMT westyorkylad said:

Maybe Ive got the wrong end of the stick but the Ifest 18650 batteries I have are 2500's and say 3.7v on them? 35a current, so doesnt that mean that they are 3.7v batteries?

Have a look on Torchy's site HERE especially the discharge curves of the batteries. This varies from battery to battery and how hard you are making it work.

Invest in good quality batteries (and charger) and make sure it's up for the task you're using it for and you should be okay.
An up front investment will pay dividends in the long run.

[westyorkylad]

Mar 4, 2015 12:39:58 GMT Ripshod said:

Welcome to the wonderful(ly confusing) world of batteries. If you haven't read it already:

allaboute-cigarettes.proboards.com/post/870306/thread

btw, that efest is actually only a 20Amp battery.

Hi Ripshod

So why do they say 35 amp on them?

[DiscoDes]

35 A is the MAXIMUM BURST discharge rate for a SHORT period.

Here is a test of the very battery you are asking about LINK

NOTE what it says under the first table :-

"This is a very high current battery, but the 35A rating might be a bit optimistic."

[westyorkylad]

Mar 4, 2015 12:51:22 GMT DiscoDes said:

35 A is the MAXIMUM BURST discharge rate for a SHORT period.

Here is a test of the very battery you are asking about LINK

NOTE what it says under the first table :-

"This is a very high current battery, but the 35A rating might be a bit optimistic."

Hi DiscoDes

Thanks for the link, looked at that and whilst it says that 35a is the max discharge current - it doesn't say anything about the max prolonged discharge current so where would you get that figure from if its not listed with all the technical specifications?

It has at least answered my question about voltage drop which apears to be from around 4.2v to 3.5v until the battery begins to become exhausted of charge.

To say that the information surrounding these batteries is confusing is a slight understatement I think, the battery clearly says on it 35a and 3.7v, but what I am basically being told is that its neither!

So who can come up with a figure for the prolonged max amp discharge that I need to use in working out the min resistance of my proposed coils then?

[DiscoDes]

Mar 4, 2015 13:03:27 GMT westyorkylad said:

Mar 4, 2015 12:51:22 GMT DiscoDes said:

35 A is the MAXIMUM BURST discharge rate for a SHORT period.

Here is a test of the very battery you are asking about LINK

NOTE what it says under the first table :-

"This is a very high current battery, but the 35A rating might be a bit optimistic."

Hi DiscoDes

Thanks for the link, looked at that and whilst it says that 35a is the max discharge current - it doesn't say anything about the max prolonged discharge current so where would you get that figure from if its not listed with all the technical specifications?

It has at least answered my question about voltage drop which apears to be from around 4.2v to 3.5v until the battery begins to become exhausted of charge.

To say that the information surrounding these batteries is confusing is a slight understatement I think, the battery clearly says on it 35a and 3.7v, but what I am basically being told is that its neither!

So who can come up with a figure for the prolonged max amp discharge that I need to use in working out the min resistance of my proposed coils then?

It is VERY confusing ???

OK, well I have just received 2 of these very batteries in the post (I had built up some credit with a vendor) and at the moment am using them in a mechanical Mod 69 Clone with a Aspire Atlantis Tank with a 0.5 ohm coil and it is vaping away nicely.

So with a quick (and dirty) bit of Ohms law I'm running at 4.2v (you always assume the maximum voltage even though the voltage does not stay at this) and 0.5 ohms so my current draw is 4.2 divided by 0.5 which means I am running at 8.4 Amps maximum. As the "normal" running current is 20A or these batteries this gives me plenty of "head room" with this set up. I don't want to stress my batteries and 0.5 ohm is a good coil resistance for me so I personally like to run at 50% of the battery current capacity. So I could go down to 0.4 ohms and be just a touch over 10 A (10.4) with these batteries, I also have some Sony VTC 4's which will run at a higher current.

If you really want to run much lower than this you really need to be running 2 18650's in parallel otherwise your running time will not be very long and this open ANOTHER can of worms!

[Ripshod]

Mar 4, 2015 13:03:27 GMT westyorkylad said:

To say that the information surrounding these batteries is confusing is a slight understatement I think, the battery clearly says on it 35a and 3.7v, but what I am basically being told is that its neither!

3.7V is halfway between the highest and lowest usable voltage limits seen with these batteries - it's the middle ground per se. The same with NiMH batteries - they come off the charger at ~1.55Volts, when the lable says 1.2Volts. Similarly a 12Volt car battery is considered 'fully' charged at 13.8Volts, and flat at 10.8Volts.

The confusion re the Current rating comes from a relabler wanting to get more than a 20Amp battery is worth, so lable it as 35Amp and get more dollars, and more sales. Pure greed westyorkylad

[westyorkylad]

Mar 4, 2015 13:18:00 GMT DiscoDes said:

Mar 4, 2015 13:03:27 GMT westyorkylad said:

Hi DiscoDes

Thanks for the link, looked at that and whilst it says that 35a is the max discharge current - it doesn't say anything about the max prolonged discharge current so where would you get that figure from if its not listed with all the technical specifications?

It has at least answered my question about voltage drop which apears to be from around 4.2v to 3.5v until the battery begins to become exhausted of charge.

To say that the information surrounding these batteries is confusing is a slight understatement I think, the battery clearly says on it 35a and 3.7v, but what I am basically being told is that its neither!

So who can come up with a figure for the prolonged max amp discharge that I need to use in working out the min resistance of my proposed coils then?

It is VERY confusing ???

OK, well I have just received 2 of these very batteries in the post (I had built up some credit with a vendor) and at the moment am using them in a mechanical Mod 69 Clone with a Aspire Atlantis Tank with a 0.5 ohm coil and it is vaping away nicely.

So with a quick (and dirty) bit of Ohms law I'm running at 4.2v (you always assume the maximum voltage even though the voltage does not stay at this) and 0.5 ohms so my current draw is 4.2 divided by 0.5 which means I am running at 8.4 Amps maximum. As the "normal" running current is 20A or these batteries this gives me plenty of "head room" with this set up. I don't want to stress my batteries and 0.5 ohm is a good coil resistance for me so I personally like to run at 50% of the battery current capacity. So I could go down to 0.4 ohms and be just a touch over 10 A (10.4) with these batteries, I also have some Sony VTC 4's which will run at a higher current.

If you really want to run much lower than this you really need to be running 2 18650's in parallel otherwise your running time will not be very long and this open ANOTHER can of worms!



Ok thanks I get that no problem - how do you know its a 20a battery that is the only part I am struggling with?

[Ripshod]

Originally they removed the wrapper and it had the same unique markings as an LG battery

Further testing confirmed it.

These batteries: ripshodfm.co.uk/files/public-docs/LGHE2.pdf
See item 2.7 Max. Discharge Current

The main thing this forum is concerned with is that everybody enjoys their vape SAFELY! So we pool our knowledge.