Breaktru Forum
eCigarette Forum => Modding => Topic started by: dc99 on December 09, 2014, 08:39:50 PM
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I have heard there were issues using battery fuses with this board. Has anyone tried it before I ruin a board? I know there there for reverse polarity protection but is there any reason they shouldn't be used. Duel 18650
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For dual batteries fuses are a good idea to prevent disaster when one battery is inserted backwards. Otherwise, they aren't needed. Just make sure that your fuses can take the 20Amps that the DNA40 can take. 3 x 7amp hold fuses in parallel would work. Look at Mamu's dual dna30 design.
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For the DNA40, I was using 1x 7A fuse on each batt for dual parallel batts and had no issues, but some people are having weak batt message from the fuses going into a pre-trip state during TP preheat, so are using 2 x 7A fuses in parallel for each batt. That's how I am currently doing the build too - 2x 7A fuses parallel per batt for dual parallel batts.
http://www.digikey.com/product-detail/en/2920L700SLPR/F6137CT-ND/4147147 (http://www.digikey.com/product-detail/en/2920L700SLPR/F6137CT-ND/4147147)
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Is anyone still having issues with the newest releases of the DNA 40 and re-settable fuses?
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Is anyone still having issues with the newest releases of the DNA 40 and re-settable fuses?
What issue are you having T?
I'm still using the first 2 beta boards with no issues. They are both wired to PTC fuses.
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What issue are you having T?
I'm still using the first 2 beta boards with no issues. They are both wired to PTC fuses.
What fuses are you using and how many fuses on each batt?
I planned on using the 2920L700SL again, 2 in parallel....but it's still not clear if I should use 2 on each cell?
2 of these in parallel would work too, right?
http://www.ebay.com/itm/10-PCS-30V-8A-RUEF800-PolySwitch-Resettable-Fuse-/371082808972?pt=LH_DefaultDomain_0&hash=item5666424e8c
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The fuses that mamu mentioned work fine. 4 fuses total. 2 parallel for each battery.
For the DNA40, I was using 1x 7A fuse on each batt for dual parallel batts and had no issues, but some people are having weak batt message from the fuses going into a pre-trip state during TP preheat, so are using 2 x 7A fuses in parallel for each batt. That's how I am currently doing the build too - 2x 7A fuses parallel per batt for dual parallel batts.
http://www.digikey.com/product-detail/en/2920L700SLPR/F6137CT-ND/4147147 (http://www.digikey.com/product-detail/en/2920L700SLPR/F6137CT-ND/4147147)
The SMD 7A fuses have a much lower resistance than your ebay RUEF800 plus they are physically a lot smaller.
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Also, if you're looking to the fuses for reverse polarity protection, the RUEF series of fuses do not provide reverse battery damage.
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Also, if you're looking to the fuses for reverse polarity protection, the RUEF series of fuses do not provide reverse battery damage.
Oh that's definitely interesting!
How did you discover that mamu?
But more importantly...why doesn't it?
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I tested an assorted lot of fuses a while back for reverse polarity protection. I can't tell you why some do, some don't. Composition of the fuse itself I reckon.
PTC fuses are a curious lot. With regards to reverse polarity protection - some don't protect at all, some will protect if using single but will not protect if using 2x in parallel, and some will protect no matter if single or 2x in parallel.
The 7A Littlefuse will protect if using single on a single batt setup, but will not protect if using 2x in parallel on a single batt setup. It will protect no matter if using single or 2x in parallel on each batt in a parallel batt setup.
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It depends on the current draw under a reverse polarity condition. In some cases it's high enough to trip the fuse, in others it's not high enough to trip the fuse, but high enough to damage components. Unfortunately the only way to know for sure it to risk burning circuits which Mamu has done. If there's any doubt Mamu has posted a reverse polarity protection circuit with a MOSFET that will provide assurance of no damage to electronics. It's very simple and for use with a complete controller board that provides short circuit protection, it's all that's really needed. However it's never a bad idea to add fuses as a backup. Also some controller boards already have reverse polarity protection built into them.
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It will protect no matter if using single or 2x in parallel on each batt in a parallel batt setup.
Okay, so I'm assuming that you're using 2X for each batt on the 40, yes?
I've been using the 2920L700SL (2X parallel) in prior 30 builds for single battery mods, but I'm working on a project that will need 2 - 4 batts in parallel.
So I'm assuming that 2X for each batt is what I want....or can I use 2X for each pack?
More specifically, for the 4 batts, (2) 50W iStick dual 18650 lipo's....in parallel.
These:
http://msnikita.com/2015/02/eleaf-istick-50w-disassembled/ (http://msnikita.com/2015/02/eleaf-istick-50w-disassembled/) (scroll down a bit to see the image gallery)
I have several of these packs that can be used for modding, but I'll be using brand new packs for the 2-pack design.
Need to know though if I would have to use 2X for each batt, or could I use 2X for each pack?
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Yes, I'm using 2x 7A fuses wired to each batt in a dual parallel batt configuration for the 40. The DNA40 can pull up to 16A input current and up to 23A instantaneous peak for output. 1x 7A fuse on each batt in a dual batt configuration for a total Ihold of 14A is not high enough of a hold current to not trip the fuses if the user maxes the current during a vape. This is the problem some users were having with 1x 7A fuse on each batt - tripping the fuses and getting the weak batt message when maxing the current. 2x 7A fuses on each batt solves that issue and still protects if the user should accidentally put a batt in backwards.
If you're using lipo batts as in that iStick, there's no worry about protecting for reverse polarity. Just need to know max input current and use a total number of fuses divided among the total number of batts that at least meets that max current.
If you're using quad parallel batt configuration - 1x fuse on each batt would be sufficient. You could look for fuses with a lower Ihold with a 4 batt configuration if you're not needing a fuse that will also protect from reverse polarity damage.
It's best to protect each batt with its own independent fuse. If one batt goes bad or wonky or dumps its current, not only will the circuit be protected but each batt will be protected from that bad batt by its fuse.
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Yes, I'm using 2x 7A fuses wired to each batt in a dual parallel batt configuration for the 40. The DNA40 can pull up to 16A input current and up to 23A instantaneous peak for output. 1x 7A fuse on each batt in a dual batt configuration for a total Ihold of 14A is not high enough of a hold current to not trip the fuses if the user maxes the current during a vape. This is the problem some users were having with 1x 7A fuse on each batt - tripping the fuses and getting the weak batt message when maxing the current. 2x 7A fuses on each batt solves that issue and still protects if the user should accidentally put a batt in backwards.
If you're using lipo batts as in that iStick, there's no worry about protecting for reverse polarity. Just need to know max input current and use a total number of fuses divided among the total number of batts that at least meets that max current.
If you're using quad parallel batt configuration - 1x fuse on each batt would be sufficient. You could look for fuses with a lower Ihold with a 4 batt configuration if you're not needing a fuse that will also protect from reverse polarity damage.
It's best to protect each batt with its own independent fuse. If one batt goes bad or wonky or dumps its current, not only will the circuit be protected but each batt will be protected from that bad batt by its fuse.
I don't want to mess with the pack since they're already wired in parallel and they only have 2 leads....so should I still use 2 fuses for the pack?
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Has anyone tested these yet?
http://www.mouser.com/ProductDetail/TE-Connectivity/MHP-TA15-9-77/?qs=/ha2pyFaduiTqFbpUcg4SopNyIqIYHZs0LSfhNjcIvFspgovy6/gFw== (http://www.mouser.com/ProductDetail/TE-Connectivity/MHP-TA15-9-77/?qs=/ha2pyFaduiTqFbpUcg4SopNyIqIYHZs0LSfhNjcIvFspgovy6/gFw==)
(http://s12.postimg.org/5da0566cd/Fuse_size.jpg)
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Those little 15a strap fuses are the bee's knees! :thumbsup: Haven't used them with DNA mods although they would certainly be suitable.
Made a little pcb to house two in parallel recently (board looks the same on the back)
(http://i.imgur.com/IPEYwzA.png)
Will share (Oshpark) if they work out alright after getting them. :D
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https://oshpark.com/shared_projects/rAqdqkGV
(http://i.imgur.com/dzH55Oy.png)
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I've used those too and I concur about their excellence.
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(http://i.imgur.com/i98J7p6.png)
https://oshpark.com/shared_projects/7VLeAfXV