Chief Salty

Rebel 250c squonk mod battery sag when firing

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Hello!  Back in April I ordered a Rebel dual 18650 squonk mod from eSauce.  It arrived in May and I was ecstatic!  This was my first venture into the worlds of both squonking and DNA chips, and I couldn't wait!  I opened it, threw in a brand new pair of freshly charged Samsung 25Rs, filled the squonk bottle with my favorite juice, threw my Dead Rabbit RDA on, and nothing.  It wasn't firing at all.  After a bit of searching, I connected it to EScribe and found the chip to be programmed for a 4s LiPo battery vice dual 18650 batteries.  This was super confusing, especially considering that "Each unit is hand finished and tested using extensive quality control techniques."  I guess putting batteries in and a mod on top, then pressing the fire button doesn't fall into these "extensive quality control techniques."

Anyway, I changed that and all was good, or so I thought.  My battery life has always seemed extremely short to me.  I finally sought assistance from the Electronic_Cigarette subreddit (https://www.reddit.com/r/electronic_cigarette/comments/abc1a8/dna_250c_weak_batterymassive_drain_on_dual_18650s/) and was reminded of this forum, along with getting some solid advice from u/Wayne0.

I don't vape indoors, so I threw a build in an RDA that I wasn't using and dry fired it at the same settings I usually use while monitoring in Device Monitor.  I have to admit, I was pretty surprised when I saw that I was consistently getting a 0.8 V sag, no matter the batteries I was using.  I tried four different mated pairs, all while firing a 0.116 Ohm build at 90 W.  At that resistance, there should be nowhere near that level of sagging.  I cleaned all battery contacts and battery ends with isopropyl alcohol with absolutely no change.  I cleaned the 510, as well.  Still nothing.  One screenshot from Device Monitor is attached, but I'm happy to provide more if interested.

Great, not I get to take it apart and find the bad solder joints.  After I got the board out, there was a weird rubber(?) coating covering all of the soldered connections.  I can only guess this is to help with shorts, but it seemed excessive to me.  Admittedly, I was (and still am) probably still just irritated at the whole situation and overreacting.  Either way, once I got the coating off, I was pretty surprised by the solder job.  I used my ceramic tweezers and very carefully removed the coating to ensure I didn't damage the board or the contacts at all, so what you see in the pictures is exactly how it left eSauce, sans a little rubber.

While I can see what they were trying to do with the battery connections, it looks like they just pooled a bunch of solder around a few extra strands of wires to connect the sensing points.  I get it, but it looks sloppy and lazy.  This may be fine, and the resistance between the battery contacts and the back side of each corresponding contact on the board is 0.2 Ohm, so I guess it's functional.  The biggest thing that caught my attention was where they soldered the 510 wires.  Not only do the solder points look dry, but it looks like they burned the board.  There is room in the mod for them to have soldered the wires going up, away from the board, instead of down and over the board, soldering at a weird and awkward downward angle to avoid interference.

Now that the back story and rant is done, I think it's about time to begin desoldering, cleaning, and soldering in new wires in an attempt to fix my initial problem of having a 0.8 V sag when firing.  I'll update with more pictures and results as I go.

If you have any recommendations, complaints, or criticisms, I'm more than open to them.  If I'm being stupid about any or all of this, also let me know.  If you've had a similar experience, please feel free to vent.  Looking around a little bit, mine is far from an isolated incident, but I didn't see any specific examples, just people alluding to others' experience with poor quality control with Rebel mods.  I did consider sending it back to eSauce, but being in the US, I really don't feel like waiting for shipping to and from the UK.

Thank you!

 

Battery connections 1.JPG

Battery connections 2.JPG

510 connections 1.JPG

510 connections 2.JPG

3.80V.jpg

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More likely than not your battery sag is from the sled contacts....contact to cells is poor.

What's with the extra long bare end of T1 wire?

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24 minutes ago, dwcraig1 said:

More likely than not your battery sag is from the sled contacts....contact to cells is poor.

Hmm.  Good call.  I'll check that when I put it all back together and make sure there's not alignment issues causing poor contact due to the battery wrap.  Thanks!

27 minutes ago, dwcraig1 said:

What's with the extra long bare end of T1 wire?

Oof.  I really wish I knew.  I'm going to take care of that when I require this thing.  It doesn't make any sense to me at all.

I wish I knew what was going through their heads when the put these things together, and again when they "quality check" them.  "Extensively," no less.

😔

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1 hour ago, Chief Salty said:

Hmm.  Good call.  I'll check that when I put it all back together and make sure there's not alignment issues causing poor contact due to the battery wrap.  Thanks!

Oof.  I really wish I knew.  I'm going to take care of that when I require this thing.  It doesn't make any sense to me at all.

I wish I knew what was going through their heads when the put these things together, and again when they "quality check" them.  "Extensively," no less.

😔

Make the contacts hit the cell flat like not on the peak.

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Chief, pretty sure @AMDtrucking also has one and has ripped his apart. Hopefully if you undertake this mission you have proper electronics flux and solder. 🖐️

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I thought my soldering skills were weak! 

I almost ordered one of these when they first came out. Looking at the images you've posted, I'm so glad I didn't. 

Sorry about your luck on this but, thanks for showing the rest of us the poor quality of these mods.... For what these mods retail for, they really should be ashamed.... 

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4 hours ago, Wayneo said:

Chief, pretty sure @AMDtrucking also has one and has ripped his apart. Hopefully if you undertake this mission you have proper electronics flux and solder.

Certainly. More then one. But I only replaced leaky 510 connector with MM510 and defective boards. 

Rebel.png

REBEL is the easiest mod to work on. Lost Vape Drone BF, for example, is whole lot more complicated.

 

Parts.png

Edited by AMDtrucking
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10 hours ago, dwcraig1 said:

Make the contacts hit the cell flat like not on the peak.

Good call!  I'll check the alignment when I put it all back together.  I'll trim down the keystone contacts if they don't line up.  I didn't even think to look at that part, as I got a little pre-occupied with the weird, lazy soldering.

Thank you!

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Use the search feature of this forum, there are quite a few posts similar to your problem a while back on the Boxer mod, they use the same style sled contacts.

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4 hours ago, Chief Salty said:

Good call!  I'll check the alignment when I put it all back together.  I'll trim down the keystone contacts if they don't line up.  I didn't even think to look at that part, as I got a little pre-occupied with the weird, lazy soldering.

These contacts are very important. For example: SXK Boxer clone, uses similar contacts, but they are made out of nickel plated carbon steel. As the result, every once in a while, the mod refuses to power up. I got tired of it and replaced them with gold plated beryllium copper contacts, that I pulled out of KeyStone 1048 model They are much better.

 

Boxer KeyStone ContactsS.png

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After replacing all of the Rebel wiring and checking the keystone connector placement, I'm still getting about a 0.6 to 0.7 V sag when firing at .14 Ohm at 90W.

Any recommendations for what to check next?

After repairs.jpg

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Do you have a volt meter?  Measure the voltage on the ends of the cells when firing, then measure from the sled contacts and compare.  Measure at B+ and B- if necessary.

This will also tell whether the cells are at fault.  (if you get that big drop when measuring at the cells)

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So I brought out my Hcigar Vt133 with it's 2 25r's @4.1 volts each.  Fired at 90 watts, here is the result:

I have put a couple of brand new Samsung 20S' in the charger, will check again with those tomorrow when charged. It looks to me that the cell are at fault, at least with mine, will know better tomorrow.

VT133 at 90 watts.JPG

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7.6 to 6.3 from B+ to B- and 3.8 to 3.2 across each cell.

These results are similar with 4 different pairs of Samsung 25Rs and a pair of LG Browns.

I did order new batteries from IMR Batteries, so I can wait until they show up and see how that goes.

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Nice.  I ordered a couple pairs of Sony VTC5As to see how they compare to the Samsung 25Rs I got from Amazon.

I also have a new DNA 250C board on its way for a 4s LiPo mod I'm printing.

Hopefully it works out better than this Rebel has, but we'll see.

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I threw in a brand new, fully charged pair of Sony VTC5s from IMR batteries and still got about .4 VDC sag (4.19 down to 3.79 VDC).  I'll check all the solder points again, and I'll take a look at replacing the keystone contacts as recommended by @AMDtrucking

It is far better than before I started, but I feel like this is still a little bit much.

VTC5-1.jpg

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45 minutes ago, dwcraig1 said:

A Sony VTC5 is a 20 amp battery,  I don't think they are dropping more than expected.

A Sony VTC5A is a 25 amp battery, which ones do you have?

Sorry, I have VTC5-A batteries.

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A few days back my "lost in the mail" Vapecige 250C squonk finally made it to me, here it is firing at 90 watts with two Samsung 20S cells. Starting cell voltage was 4.10 volts and dropped to 3.86 volts. 

Vapecige 250C 2 Samsung 20S @ 90 watts.JPG

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I got the new keystone contacts in the mail and put them in to replace the ones that came installed.

With my 2 VTC5As at 4.15 VDC, they each dropped to 3.80 VDC.  I'm satisfied with that, especially considering I started out with a 0.8 VDC drop.  After one full day of vaping on this pair, I'm at 80%.  Far better than having to have replaced them halfway through yesterday.

I'll make note of when I get the low battery warning now, as well.

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