Preliminary testing with the DNA30

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retird

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What mamu said..... break the positive battery connector (contact) so each battery will have it's own output wire on the battery holder....add a wire to the connector that now has no output wire, add fuses to each holder positive output wire in parallel with output from fuse connected back together to the input positive of the dna...pardon my poor drawing....

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Skyfntm

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Split the positive connection on the holder so each batt will have its own fuse shut down. That way if one batt goes ballistic, the other batt won't see the backlash.

If you don't split the positive connection on the holder, you will have one common fuse - if you happen to put one batt in backwards and the other batt in correctly - you'll have a batt meltdown. That's why each batt needs its own independent fuse to protect that batt in situations of extreme current dump that happens with short circuit or reverse polarity.

Batt1 + > 2x fuses in parallel > common wire
Batt2 + > 2x fuses in parallel > common wire
Common wire > dna + input

Another alternative since your goal is to simply lower the resistance of the fuse when using parallel fuses, is to use a single fuse on each batt that has the same hold current as the 2x fuses in parallel. With a single fuse on each batt, you will still have parallel fuses when you connect the common wire so the combined resistance of the fuses will be lower.

For example, if you have a fuse with a 5A hold current and you put 2x in parallel, you now have a 10A fuse. Use a single fuse with a 10A hold current on each batt.

Batt1 + > single fuse > common wire
Batt2 + > single fuse > common wire
Common wire > dna + input

The problem is though the higher the hold current, the larger the fuse is in size - so you may not have space inside the mod for the larger fuse. And you can't find surface mount fuses higher than 4.5A hold current - at least that's what I've found with my search for one.

Another thing is that since current is shared with parallel batts, you can use a lower hold current fuse on each batt and still safely protect each batt and the circuit. However, you don't want the fuse to trip during normal operating mode and you don't want it to trip from simple internal or external heat - so you need to choose a hold/trip current high enough that will prevent inadvertent tripping but not too high that it won't trip to protect the batt and circuit.

Choose whichever method works best for you and the space you have inside the case. Your goal is to protect each batt as well as the circuit.

Thank you mamu. I will look and see what I have space wise when I get everything.


What mamu said..... break the positive battery connector (contact) so each battery will have it's own output wire on the battery holder....add a wire to the connector that now has no output wire, add fuses to each holder positive output wire in parallel with output from fuse connected back together to the input positive of the dna...pardon my poor drawing....

View attachment 296339

That is a great drawing retird! Thanks!
 

684Alpha

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Hey guys, just wondering if anybody has tested these 3 7V 3400mAh 18650 NCR18650B Rechargeable LI ION Battery NCR18650B FOR Panasonic | eBay. They are Panasonic 3400mAh High Drain 18650. Was hoping Mamu and or bap could chime in. I guess only being 10a they would not be appropriate for the DNA30, but they should be good for the DNA20. or am I way off base?. Just thinking 3400mAh would be nice in a single battery set up.

Features
  • Made in Japan NNP battery cells
  • Uses newest and best LiNiCoAlO2 chemistry
  • 304 Stainless steel button top
  • IC protected against short, over-discharge, over-charge
  • Measures only 68mm in height
  • Button top design
  • Steel plate reinfocred bottom
  • Ultra high capacity and high voltage even under heavy loading
  • Satety vent with thermal cut-off protection

Specifications

  • Voltage: Typical 3.6V (4.2V when fully charged)
  • Capacity: 3400mAh (discharged at 0.2C)
  • Dimensions: 18.6mm x 68mm (+/-0.1mm)
  • Current over-flow protection: 5A+
  • Weight: 50gram





Cheers
 
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mamu

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Keep in mind that the DNA30 has a max input current of 12A - you really need to choose batts that have a discharge rating at least that, more preferably higher though so the batt is not stressed under load when running the DNA30 at higher watts.

I really like the LG 30A 18650 batt and the Sony 30A 18650 batt. If you're going to use a single 18650 batt for the DNA30, either one of those two batts would be my choice. They're still my choice when using dual parallel 18650 batts.
 

mamu

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Hey mamu, I saw that you were looking at fuses for an OKR T10 over on breakthru. If you could message me I would like to show you a wiring schematic and a couple questions about the chip.

I don't do PMs here.

If you have the link to breaktru's forum for the OKR thread, just post your schematic and questions there.
 

bapgood

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I am finding that I can not go over 20 watts without the board resetting using sony 30a c4 tried with multiple resistance build varying from .5 to 1.8 ohms same issue.. Any ideas what this could be?

Probably the battery contacts and/or wiring. What mod is it?

I have used a single 2100mah sony 30a to go to 30 watts using a 0.5 ohm and 2.8 ohm coil. However I couldn't with one battery holder I tried.
 

mamu

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If there is any issue with the batt not handling the load at any given power setting, the DNA will reset itself. This is a great safety feature with the DNA.

from Evolv's datasheet on the DNA30:
Device resets: If the battery is not able to power the device at the desired setting, or the battery is excessively discharged, the device may go immediately into a low voltage shutdown. If firing the device causes the screen to blank out and then display the welcome screen, you should charge, replace or upgrade your battery. This is especially common at power settings above 20 watts.
 

bapgood

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brand new purchased today and fully charged at .25a trickle charge as well to make sure it was good to go

Yep that would qualify as fairly new :lol:

Do you have a hot spring from a mechanical mod or something? If you do try putting it over the existing spring and make sure it's contacting the battery and the existing spring plate.

I did this on a Reo and it worked much better, then I swapped out the existing spring with one from the top of Sigelei 19 mechanical mod.
 

mamu

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If the batt is ok and a 30A Sony 18650 would be more than ok for 30W, then the most common issue causing the problem would be, as bap said, the batt contacts or the wiring, with the batt contacts usually being the culprit.

I had the DNA30 running at 30W with a 0.8 ohm coil using a single 30A 18650 Sony and using a Memory brand dual 18650 batt holder and the DNA fired aok.

I can't tell what batt contacts are in the mod or the brand, but that could be causing be the issue.

Unfortunately, underrated batt contacts or batt contacts with high contact resistance is going to be a huge issue when running the DNA30 >20W, even if it is a 30A batt.
 
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