Need schooling on choosing fuses

[Skyfntm]

What I'm trying to learn is how I choose a fuse for the battery I'm using. I have been looking and have not been able to find anything that helps.

If someone could give me a quick lesson on fuses I would greatly appreciate it.

 

[retird]

https://www.youtube.com/watch?v=SwsdznUiHuA (video...one of many)

 

[Skyfntm]

https://www.youtube.com/watch?v=SwsdznUiHuA (video...one of many)

Thanks a bunch retird! The video wasn't much more than a tutorial on the websight. But the PDF was very informative!

Just need a slight bit of clarification. Say I have a 10amp battery, I would need a fuse rated at 10amps or 15amps? According to the PDF you multiply the amps buy 130% to get the required fuse.

Also for batteries in series, does the amps increase like the voltage does? If so would that mean I would need a fuse rated for 30amps?

 

[breaktru]

Here are some interesting facts on determining fuse size: PTC Fuses

 

[Skyfntm]

Here are some interesting facts on determining fuse size: PTC Fuses

Thanks a bunch for that link breaktru! My head is spinning trying to grasp everything lol.

Been reading everything over and over again for the past hour or so and just realized I have vaped 6ml in that time. Lol.
Taking a break now but I'm sure I will have more questions.

Thanks again retird and breaktru!

 

[breaktru]

Thanks a bunch for that link breaktru! My head is spinning trying to grasp everything lol.

Been reading everything over and over again for the past hour or so and just realized I have vaped 6ml in that time. Lol.
Taking a break now but I'm sure I will have more questions.

Thanks again retird and breaktru!

Using CraigHB's example for a 30W dna 30 with minimum battery input voltage of 3.2v and an efficiency loss of 20%, we have:

(20% x 30w) = 6w
6w + 30w = 36w
36w / 3.2v = 11.25A (3.2v is the min input voltage and 11.25A is the fuse rating or for practical sense 12A)

P.S.
If you look at the DNA 30 datasheet the Max Input Amperage is 12A

 

[Skyfntm]

Using CraigHB's example for a 30W DNA 30 with minimum battery input voltage of 3.2v and an efficiency loss of 20%, we have:

(20% x 30w) = 6w
6w + 30w = 36w
36w / 3.2v = 11.25A (3.2v is the min input voltage and 11.25A is the fuse rating or for practical sense 12A)

P.S.
If you look at the DNA 30 datasheet the Max Input Amperage is 12A

Ok so if I'm using duel 10A batteries in series I wouldn't really need a fuse for a DNA 30 or should I use a 10A fuse or a smaller Amp fuse? I'm sorry I'm still trying to learn all of this information in regards to what the input amperage is. Does the DNA protect itself in that sense?

 

[retird]

You cannot use batteries in series with the dna30.....and the dna30 requires a minimum battery of 12 amps.....you might want to read the datasheet on the dna30d....

Now I'm confused...what type mod are you wanting to build? I thought you were gonna build a mod with the dna30, but now I am wondering...

 

[Skyfntm]

I'm sorry retird I meant to say in parallel for the dna30. I know the DNA is a 3.7v not a 7.4v

But the 12a on the dna30 is for running at 30w correct? So if I don't go above 20w then the 10a batteries in parallel should be ok.

Edit- doesn't 2x 10A batteries in parallel make it 20A? So I would need fuse protection. And if the dna30 is 12a max then I would need 10a fuses on each battery. Now if I was using 30A batteries would I also use 10a fuse or go for 12a fuse?

Edit 2- I'm sorry for asking these questions. Not really but I'm sorry for confusion. I could just follow what everyone else is doing and do it to, but I want to know why it's done that way. That way if when I decide to do something creative I don't do it wrong. I want to know what I'm doing as all of you guys do. Ok I'm off my soap box. Thanks!

 

[retird]

No, 2 batteries in parallel does not mean 20 amps of continuous discharge.....each battery rated at 10 amps continuous discharge means that is the amount of amps that can be safely continuously discharged from that battery. And should one battery become disconnected for any reason then the good battery will still go 10 amps.

I can't stress enough that you should follow the recommended battery specs according to the data sheet, which is a minimum of 12 amps (most modders use batteries with higher than 12 amp CDR). Agree that the input amps may vary depending on the wattage setting but the specs are there for a reason....just as there is a reason to have a battery at 12 amps for input when the max output is only 10 amps.....the advantage to using 2 parallel batteries is for battery life (vape time between charges) and not for increasing amperage.

I appreciate your comment " I could just follow what everyone else is doing and do it to, but I want to know why it's done that way. That way if when I decide to do something creative I don't do it wrong. I want to know what I'm doing as all of you guys do."

To do it "right" requires a battery as required by the datasheet (manufacturers requirements)....hope this helps...

Hope you are successful in your mod project.....make sure and post pictures and info about it.....

 

[been there]

Thanks Skyfntm for asking this question , this is information I needed and thanks retird for the pdf needed that to, like you I want to know why something is done and how.

 

[Skyfntm]

No, 2 batteries in parallel does not mean 20 amps of continuous discharge.....each battery rated at 10 amps continuous discharge means that is the amount of amps that can be safely continuously discharged from that battery. And should one battery become disconnected for any reason then the good battery will still go 10 amps.

I can't stress enough that you should follow the recommended battery specs according to the data sheet, which is a minimum of 12 amps (most modders use batteries with higher than 12 amp CDR). Agree that the input amps may vary depending on the wattage setting but the specs are there for a reason....just as there is a reason to have a battery at 12 amps for input when the max output is only 10 amps.....the advantage to using 2 parallel batteries is for battery life (vape time between charges) and not for increasing amperage.

I appreciate your comment " I could just follow what everyone else is doing and do it to, but I want to know why it's done that way. That way if when I decide to do something creative I don't do it wrong. I want to know what I'm doing as all of you guys do."

To do it "right" requires a battery as required by the datasheet (manufacturers requirements)....hope this helps...

Hope you are successful in your mod project.....make sure and post pictures and info about it.....

Ok so this is what I'm understanding so far-

For the dna30 with a max input of 12a I would need a battery with an amp of 12 or more. With that being said, say I have a 30a battery then I would need to make sure that there is fuse protection to prevent a load of more than 12 amps. So I have 2x 30a batteries in parallel, off the positive of each battery is fuse protection. Now would I use 12a fuses off each battery to prevent over current above the max for the dna30? Or would I want more of a buffer and say 10a fuses?

 

[Skyfntm]

Thanks Skyfntm for asking this question , this is information I needed and thanks retird for the pdf needed that to, like you I want to know why something is done and how.

Anyone can follow step by step instructions to make something. But if you don't know "why" you are doing it this way then what if something happens? If you don't know why it was built that way you don't know where to start the trouble shooting. Or in my case, build different style mods.

 

[retird]

MAMU posted a great post about fuses in a new thread on ECF...it is worth copy/paste here:


http://www.e-cigarette-forum.com/fo...fuses-choosing-appropriate-fuse-your-mod.html