Battery safety.

[xibxang]

I am pretty good with technical stuff, but I will be honest, the P=IV stuff just isn't clicking for me yet. I have read it all several times over but for some reason when it comes to the practical application of it, the logical progression just escapes me and I feel like I am reading it for the first time all over again. I have read a huge amount on battery safety and I am confident my set up is safe, but generally I am pretty good with numbers and I am struggling, I hate to think how someone crap with numbers would cope. It is always better to ask that to risk it, so you can expect a few similar questions from me as I get to grips with mechs.

And I absolutely believe that there is no such thing as a stupid question. Sorry if I gave the impression that I think that newbie questions are a no-no. I'm a newbie myself!

What I'm referring to is raising the awareness of resources like online Ohm's law calculators. We don't all have to be fluent in mathematics which is why these calculators should be linked out of the wazoo for people to refer to. Sure, we should always have patience for anyone who wants to gain knowledge in any given field but we should equally be encouraging people to empower themselves at the same time.

 

[Diche]

And I absolutely believe that there is no such thing as a stupid question. Sorry if I gave the impression that I think that newbie questions are a no-no. I'm a newbie myself!

What I'm referring to is raising the awareness of resources like online Ohm's law calculators. We don't all have to be fluent in mathematics which is why these calculators should be linked out of the wazoo for people to refer to. Sure, we should always have patience for anyone who wants to gain knowledge in any given field but we should equally be encouraging people to empower themselves at the same time.

The calculators are a useful tool, but until I really understand the way this stuff works they will still be a bit gobbledegooky to me. A four year old can tap in numbers and get it to spit out a result, but I won't feel comfortable and confident in the result until I really understand this stuff. It feels a bit daft really because all the other areas have pretty much clicked straight away. I will keep reading every post on the subject until something goes bing! Though I must admit it doesn't help that they can't even use the right letters of the blasted alphabet lol.

 

[Jonshaw78]

I am still learning this stuff but I'm not going to let it stop me vaping, I aint building mega low resistance coils anyway, and I'm sticking with the Sny VTC4. I will get this ohms law eventually...

 

[SublimeSparo]

I find it easiest to use V=IR, reaaranged to I=V/R to find your current draw in Amps

Then to find power in watts i use P=(V^2)/R as it saves working out your amps each time.

 

[xibxang]

The calculators are a useful tool, but until I really understand the way this stuff works they will still be a bit gobbledegooky to me. A four year old can tap in numbers and get it to spit out a result, but I won't feel comfortable and confident in the result until I really understand this stuff. It feels a bit daft really because all the other areas have pretty much clicked straight away. I will keep reading every post on the subject until something goes bing! Though I must admit it doesn't help that they can't even use the right letters of the blasted alphabet lol.

OK, so in layman's terms you need to know:

• The safe amp draw limit for the batteries you're using. If you're unsure, tell us here in this thread what make and model they are and someone can look it up for you and report back.
• This is the important bit. Measure the resistance of your coils then feed it into V=IR to find out how many amps they would draw from a battery. This means you'd shuffle this formula to I = V/R. So say for instance you'd made a coil that measures at 0.8 ohms. That's the "R" part. Keep that number in your head. For the "V" bit, you always assume that your batteries will be fully charged. The number is always 4.2. So, I = 4.2/0.8. The result is 5.25 amps. That's the "I" part.
• So, now you know that your 0.8 ohm coil will pull 5.25 amps out of your battery when it's fully charged.
• Most batteries are rated at between 10 and 30 amps but this can vary depending on what you bought. 5.25 amps is pretty safe at this range so you're good to go. The lower your resistance goes though, the more amps you'll pull and you need to be comfortable with that number when you put it against your battery's draw limit. There comes a point when your coil resistance gets down to 0.2 ohms and under, and you need to blend knowledge with experience and a wee bit of bravery to come up with a decision.

Hope that helps. Sincere apologies if I'm teaching your granny to suck eggs.

 

[Diche]

OK, so in layman's terms you need to know:

• The safe amp draw limit for the batteries you're using. If you're unsure, tell us here in this thread what make and model they are and someone can look it up for you and report back.
• This is the important bit. Measure the resistance of your coils then feed it into V=IR to find out how many amps they would draw from a battery. This means you'd shuffle this formula to I = V/R. So say for instance you'd made a coil that measures at 0.8 ohms. That's the "R" part. Keep that number in your head. For the "V" bit, you always assume that your batteries will be fully charged. The number is always 4.2. So, I = 4.2/0.8. The result is 5.25 amps. That's the "I" part.
• So, now you know that your 0.8 ohm coil will pull 5.25 amps out of your battery when it's fully charged.
• Most batteries are rated at between 10 and 30 amps but this can vary depending on what you bought. 5.25 amps is pretty safe at this range so you're good to go. The lower your resistance goes though, the more amps you'll pull and you need to be comfortable with that number when you put it against your battery's draw limit. There comes a point when you need to blend knowledge with experience and a wee bit of bravery to come up with a decision.

Hope that helps. Sincere apologies if I'm teaching your granny to suck eggs.

It does help, because every time I hear it phrased a slightly different way it makes slightly more sense. Kinda gradually fills the blanks in my head if that makes sense. I am pretty sure I am safe at the moment because knowing that I don't know what I am doing I have been working belt and braces to be on the safe side. I am running VTC5 and my day to day coils are 1-1.2ohms. I did build a 0.4 yesterday for giggles, but that was strictly limited use to try and blow a cloud. When I bought my batteries I went for the best I could find from a reputable UK dealer, I might not need the oomph but with battery safety I would rather err on the side of caution.

 

[xibxang]

You made the best choice with with Sony VTC5. Your 0.4ohm coil would pull 10.5 amps (4.2 divided by 0.4) so you're well within the safe limits. Don't be scared to make that your daily vape coil if you fancy it.

 

[Diche]

You made the best choice with with Sony VTC5. Your 0.4ohm coil would pull 10.5 amps (4.2 divided by 0.4) so you're well within the safe limits. Don't be scared to make that your daily vape coil if you fancy it.

Thank you THAT is really helpful, I was pretty sure I was running something safe because I knew I had over specced on the batteries, but knowing I can experiment a little more is really, really helpful. I am planning on branching out in the coming weeks and I will just keep plugging the numbers into the coil calculator until they start to stick. If I remember rightly the VTC5 is a 30amp continuous with a higher pulse rating, and the general rule of thumb is staying inside the continuous is reasonably safe and playing with the pulse rating is somewhat stupid.

 

[xibxang]

Just be mindful that once you start getting to 0.15 ohms and lower, you're knocking on the 30amp continuous limit (I think it's 28amps if I remember correctly). The 60amp pulse limit starts to come into play and many people consider this to be unsafe. Saying that, you get many, many cloud chasers going to 0.05 ohm coil builds and lower (0.05 is 84 amps!) and yet they're still alive and well. So you pays your money and takes your choice at that level. It's all down to you personally.

The important part is that you keep plugging the numbers like you say and start to get a feel for them. At the end of the day they're only numbers but they'll give you the power to know when you're getting beyond your comfort zone. For the record, a battery can't physically supply 60 amps; what you're banking on at that level is that it'll give you what it has and not rupture itself in the process. It's all theoretical past a certain point but again, having a feel for the numbers will help you feel comfortable. And don't worry, it'll all become more familiar the more you play with them.


flying over your house,
a guy called xib

 

[Jonshaw78]

OK, so in layman's terms you need to know:

• The safe amp draw limit for the batteries you're using. If you're unsure, tell us here in this thread what make and model they are and someone can look it up for you and report back.
• This is the important bit. Measure the resistance of your coils then feed it into V=IR to find out how many amps they would draw from a battery. This means you'd shuffle this formula to I = V/R. So say for instance you'd made a coil that measures at 0.8 ohms. That's the "R" part. Keep that number in your head. For the "V" bit, you always assume that your batteries will be fully charged. The number is always 4.2. So, I = 4.2/0.8. The result is 5.25 amps. That's the "I" part.
• So, now you know that your 0.8 ohm coil will pull 5.25 amps out of your battery when it's fully charged.
• Most batteries are rated at between 10 and 30 amps but this can vary depending on what you bought. 5.25 amps is pretty safe at this range so you're good to go. The lower your resistance goes though, the more amps you'll pull and you need to be comfortable with that number when you put it against your battery's draw limit. There comes a point when your coil resistance gets down to 0.2 ohms and under, and you need to blend knowledge with experience and a wee bit of bravery to come up with a decision.

Hope that helps. Sincere apologies if I'm teaching your granny to suck eggs.

No that actually makes sense for once , cheers manna