scooby

Common ground

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Bill, when I build a mod I am a firm believer that "bigger is better".  I always use the maximum wire sizes from the spec sheet, even though I rarely, if ever, go over 50 watts even with a DNA200.  My theory being that minimizing loss, and lowering impedance at the same time, can't hurt anything and may help.  We're dealing with very low resistances at firly high power/current and every little bit shaved can make a significant difference, at both the supply and output sides.  Just my semi-educmacated, (im)practical experiences anyway.  I just wish I had a meter that resolved down to .0001, or lower, ohms so I could see the fruits of my efforts.

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You mean like this one?

micro-ohm_meter_001.jpg 

They only cost like 65 bucks on eBay (shipped from China). I had one, but it disappeared. Maybe someone decided they needed it more than I did. Anyway getting down to 10 micro-ohms things really does get hairy.

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Yeah, then you need to worry about the quality of the connections as well.  Maybe I'll look on Fleabay.  Back in "ancient times" I used to have access to stuff like that and it was all traceable to NBS and sure didn't come from China.

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ChunkyButt200 said:

the output gnd and battery gnd are interconnected. so it shouldn't make a difference which pad the battery neg is soldered to. the battery neg is not being soldered to the box. what hotcig did and what this person is trying to do are two different things. 510 gnd stability is not in question, an alternative to where to solder the batt neg is. he wants to ADD the batt neg to his 510 gnd wire going to the board.



That's right. Here's a pic of what I'm planing. There's no reliance on the enclosure although the 2 screws do clamp the retaining/solder ring to secure the connector to it. (sled is just to indicate what I plan, not the one I'm using)

Normally the wire path would be down to the bottom of the enclosure to the B- pad, this way is a much shorter path.

It's been interesting reading this thread, not that I totally understand it all, thanks.



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scooby said:



That's right. Here's a pic of what I'm planing. There's no reliance on the enclosure although the 2 screws do clamp the retaining/solder ring to secure the connector to it. (sled is just to indicate what I plan, not the one I'm using)

Normally the wire path would be down to the bottom of the enclosure to the B- pad, this way is a much shorter path.

It's been interesting reading this thread, not that I totally understand it all, thanks.



looks good to me. i have to ask, is there something preventing you from running a proper gnd wire to the correct pad or you're just experimenting? please post back with your results. 

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ChunkyButt200 said:

looks good to me. i have to ask, is there something preventing you from running a proper gnd wire to the correct pad or you're just experimenting? please post back with your results. 



Well I just looked at the layout and thought - battery at the top, + battery at bottom so what's the neatest way to run the wires. 

Late last night my thoughts turned to a modified FD brass battery tube, in which case both wires will be from the bottom, the shortest path and of equal length so will satisfy my desire for neatness ;)

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Your wiring plan is fine scooby, short is good but no need for the power wires to be equal lengths I think the confusion comes from the balance wiring where you don't want them to vary much in resistance or it will affect the readings.  I would change those battery terminals though a couple of brass pan head screws ground flat with a spring behind the negative one work well.

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awsum140 said:

I guess you'll be mounting the tube "upside down", screw cap on the top of the mod then.



Yep, slice it open so the battery can just drop in and devise a way of doing a 1/4-1/2 turn to 'lock' the battery. Just thoughts right now until it arrives and I can have a look at it.



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VapingBad said:

Your wiring plan is fine scooby, short is good but no need for the power wires to be equal lengths I think the confusion comes from the balance wiring where you don't want them to vary much in resistance or it will affect the readings.  I would change those battery terminals though a couple of brass pan head screws ground flat with a spring behind the negative one work well.





Cheers Jon. Wouldn't use that sled, just an illustration of what I was thinking regarding the wiring.

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I wanted to follow up in this post. I pretty much have the same question and wanted to know how this ended up working.

I was thinking of making a rectangular brass or copper plate with a hole for the 510 to go through on one side and a  negative contact dimple on the other side, and then the 510 nut would secure it in place.

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jesseseetai said:

I wanted to follow up in this post. I pretty much have the same question and wanted to know how this ended up working.

I was thinking of making a rectangular brass or copper plate with a hole for the 510 to go through on one side and a  negative contact dimple on the other side, and then the 510 nut would secure it in place.

i understand what you're trying to do, that should work fine.

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jesseseetai said:

I wanted to follow up in this post. I pretty much have the same question and wanted to know how this ended up working.

I was thinking of making a rectangular brass or copper plate with a hole for the 510 to go through on one side and a  negative contact dimple on the other side, and then the 510 nut would secure it in place.





Yep, can confirm it works perfectly.

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