DNA 20d fuse/protection
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Huh...I was just wondering the same thing. Mamu has a tutorial and uses a couple of 16v 3A resettable fuses. Part # 16r300gu
Mamu uses lipo bateries, so I wondering if the same fuses will make a difference or be the same result as using two 18650 batteries?
I'm new to modding so IDK. Maybe someone else can help us out?
Mamu uses lipo bateries, so I wondering if the same fuses will make a difference or be the same result as using two 18650 batteries?
I'm new to modding so IDK. Maybe someone else can help us out?
Click this link and in post #1 there is a link to a pdf file tutorial........will answer many questions http://www.e-cigarette-forum.com/forum/battery-mods/366666-milo-dna20d-mod-step-step-how.html
I've seen that tutorial but that's just one modder's way (albeit a prolific modder!) I've seen others using automotive fuses, etc. so I was hoping to see some variety.
I was actually also hoping to see some of the math behind multiple batteries and multiple fuses.
I was actually also hoping to see some of the math behind multiple batteries and multiple fuses.
I have typically used a 7.5a low profile mini blade fuse, but the PTC resettable is a very good way to go especially if you can handle soldering the SMT ones (very small).
I believe it was breaktru who introduced using two PTC's and there are several write ups out there, but basically it halfs the resistance of the PTC's in the circuit.
Yep, you can't beat the specs of a couple SMT PTCs in parallel. Super low resistance, great hold current, decent speed and tiny form factor. And the 1812 size or bigger are not even that hard to solder. 0805 and smaller can be a total PITA, but they look great inside a piece of heat shrink soldered in line with the power wire. You can barely tell they're there.
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My build is going to consist of two 18650 batteries. And this will be my first experience building the DNA20.
The DNA20 Data Sheet says:
INPUT CURRENT: Minimum-1.5 / Average-4.0 / Max-7.0 AMPS
OUTPUT CURRENT: 6.0 AMPS
So if I use a 3 AMP fuse, will I be putting more limits on the DNA20 itself?
I have limited experience so I'm trying to figure this all out, while still trying to be on the safe side. I wish someone who knows more could just say 'use this fuse....if your using 18650 batteries' but I don't know if the answer is that simple. I want to be safe but I also want to have the DNA20 operating at it's full potential.
So if the DNA20's output is 6 AMPS then I can use a 6 AMP limit fuse...correct? Is that safe? That would leave +1 AMP to still be on the safe side if something goes haywire, since the datasheet says 7 AMPS max input.
I hope my way of thinking on this is correct. I could be completely wrong. This is why I'm asking.
The DNA20 Data Sheet says:
INPUT CURRENT: Minimum-1.5 / Average-4.0 / Max-7.0 AMPS
OUTPUT CURRENT: 6.0 AMPS
So if I use a 3 AMP fuse, will I be putting more limits on the DNA20 itself?
I have limited experience so I'm trying to figure this all out, while still trying to be on the safe side. I wish someone who knows more could just say 'use this fuse....if your using 18650 batteries' but I don't know if the answer is that simple. I want to be safe but I also want to have the DNA20 operating at it's full potential.
So if the DNA20's output is 6 AMPS then I can use a 6 AMP limit fuse...correct? Is that safe? That would leave +1 AMP to still be on the safe side if something goes haywire, since the datasheet says 7 AMPS max input.
I hope my way of thinking on this is correct. I could be completely wrong. This is why I'm asking.
The fuse or fuses aren't really intended to protect your batteries from the DNA. Under normal operating if proper batteries are used, the DNA shouldn't hurt your batteries. The fuse is more of a fail safe incase something goes wrong with your mod, DNA, etc. like a dead short that could lead to a dangerous battery venting situation.
If you use two 3amp PTC fuses like a lot are doing then you have a 6 amp fuse.
The input current is always going to be higher than the output and that will change as the battery voltage drops. The lower the voltage the more amps will be drawn to achive the constant supply of power.
If you use two 3amp PTC fuses like a lot are doing then you have a 6 amp fuse.
The input current is always going to be higher than the output and that will change as the battery voltage drops. The lower the voltage the more amps will be drawn to achive the constant supply of power.
PTC fuses are slow. Their triggering time is often 3-5sec. So you could pull short bursts of 7A on a 6A hold PTC quite comfortably without it interfering with vaping.
Thanks for clearing that up Bapgood. I'm just gonna use a couple of 3A resettable fuses together, and call it a day.
Thanks, I looked exhaustively through mouser for a better option as far as size and performance, but these really are pretty much the best choice. they don't really stock anything better.
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Those are the ones I use in my mods. I solder two in parallel (one on top of the other) and then to the wire ends, then shrink wrap them on the positive wire of the battery.
Yes, put them back to back, hold them with a clip or tweezers, apply some flux and solder. Don't overheat these, they really don't like that: the more heat, the more their resistance increases.
Would you be able to post a pic of what you mean? I'm having a little trouble imagining it, I'm not that familiar with SMT stuff. Exactly where are the solder points on these? Just the pads or the whole sides?
How would you test to see if it survived the soldering?
How would you test to see if it survived the soldering?
Mouser and farnell want £20 postage.
RS-online want only £5 or free if order is over £20.
So will these be fine as an alternative? Buy Resettable Wire Ended Fuses Fuse, PTC, resettable, radial, 3A TE Connectivity AHEF300 online from RS for next day delivery.
Specifications
Body Height 15.5mm
Body Length 10.2mm
Body Width 3.8mm
Hold Current 3A
Maximum Current 100 A
Maximum Resistance 0.11Ω
Minimum Resistance 0.035Ω
Power Dissipation 3.2W
Time to Trip 5s
Trip Current 6A
Voltage Rating 32 V dc
So in parallel, will they be - 6A Hold Current, 12A Trip Current (5s trip time) and 0.055Ω Maximum Resistance?
RS-online want only £5 or free if order is over £20.
So will these be fine as an alternative? Buy Resettable Wire Ended Fuses Fuse, PTC, resettable, radial, 3A TE Connectivity AHEF300 online from RS for next day delivery.
Specifications
Body Height 15.5mm
Body Length 10.2mm
Body Width 3.8mm
Hold Current 3A
Maximum Current 100 A
Maximum Resistance 0.11Ω
Minimum Resistance 0.035Ω
Power Dissipation 3.2W
Time to Trip 5s
Trip Current 6A
Voltage Rating 32 V dc
So in parallel, will they be - 6A Hold Current, 12A Trip Current (5s trip time) and 0.055Ω Maximum Resistance?
I believe these are the direct comparables. No need for the higher voltage handling since it should not be seeing more than 8ish. The smaller size is a plus. Buy Resettable Wire Ended Fuses Polyswitch,resettable fuse,RGE 3A TE Connectivity RGEF300 online from RS for next day delivery.
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