Hohmtech Slice

[Tpat591]

So basically yeah it'll be an easy test to run.
I have to hook up both channels of my oscilloscope to the mod, one to the input form the batteries and one to the output of the board. take the readings a divide output by input to get the efficiency rating. fairly simple test. so for instance if it draws 5 volts from the battery to put out 4.5 volts at the 510 pin it would be 4.5/5 * 100 = 90% efficient. so when i get a chance probably this weekend I'll take it apart and run some tests to find the efficiency

Just read this again and I now realize you are talking strictly voltage here. I sure hope you will be determining amp draw in relation to voltage from the battery on that oscilloscope when you are doing this test or your just spinning your wheels.

Efficiency is not [voltage at 510] / [voltage draw from battery]. [volts] x [amps] = [watts].

Efficiency is [watts at 510] / [watts drawn from battery].

I'm guessing you know that & just said it wrong in a speed error but feel compelled to point that out.

No offense intended & please don't take this the wrong way.

 

[Anthony_Vapes]

Just read this again and I now realize you are talking strictly voltage here. I sure hope you will be determining amp draw in relation to voltage from the battery on that oscilloscope when you are doing this test or your just spinning your wheels.

Efficiency is not [voltage at 510] / [voltage draw from battery]. [volts] x [amps] = [watts].

Efficiency is [watts at 510] / [watts drawn from battery].

I'm guessing you know that & just said it wrong in a speed error but feel compelled to point that out.

No offense intended & please don't take this the wrong way.

No offense at all.

You don't actually measure wattage you measure voltage and calculate the wattage. That's how it's done even with DJLsb reviews. The oscilloscope records voltage then u calculate the wattage. Math is cool like that

Either way sight unseen I'm willing to bet it comes out the same since ohms law and all but I'll calculate both out and double check since it my first efficiency test. Wanna make sure I get it right or what's the point

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[Tpat591]

No offense at all.

You don't actually measure wattage you measure voltage and calculate the wattage. That's how it's done even with DJLsb reviews. The oscilloscope records voltage then u calculate the wattage. Math is cool like that

Either way sight unseen I'm willing to bet it comes out the same since ohms law and all but I'll calculate both out and double check since it my first efficiency test. Wanna make sure I get it right or what's the point

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How are you measuring amps draw at battery? Without that how do you calculate watts?

You need an in-line ammeter to do this.

 

[Anthony_Vapes]

How are you measuring amps draw at battery? Without that how do you calculate watts?

You need an in-line ammeter to do this.

Amp draw is calculated as watt/voltage so at 150 watts output of the chip take they and divide by the battery voltage which I can hook a multimeter to and that gives me the amp draw of the battery.

Everything is relative with electricity you really only need 2 values to find the rest

If my mod puts out 4 volts at .15 resistance it's outputting 106.67 watts. If my batteries are at 4.2 volts each aka 8.4 In series then 106.67/8.4 = 12.7 amps at the battery.



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[mjag]

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[52anddone]

 

[mjag]

During normal use I feel the battery life is better with the battlestar than my DNA75. With my VT75 the battery life is terrible unless I use a .35 ohm build on it. Hard to judge with my SMY SDNA 75, single 18650 but it seems to do OK, I don't have any other single 18650 mods I still use to compare it too.

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[Tpat591]

Amp draw is calculated as watt/voltage so at 150 watts output of the chip take they and divide by the battery voltage which I can hook a multimeter to and that gives me the amp draw of the battery.

Everything is relative with electricity you really only need 2 values to find the rest

If my mod puts out 4 volts at .15 resistance it's outputting 106.67 watts. If my batteries are at 4.2 volts each aka 8.4 In series then 106.67/8.4 = 12.7 amps at the battery.



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The above is true in a perfect world. In reality:

• Battery series voltage will actually be 8.4v - voltage drop caused by resistance of second battery in series (but your oscilloscope will show you that so that is not the issue).
• You are trying to solve for mod efficiency which is the loss of power in the chip/mod while operating.
  
• Your example above assumes ZERO loss of power due to mod inefficiency so it is useless to determine that very inefficiency.
  
• You cannot determine the loss due to board/mod inefficiency unless you have a known input wattage determined by voltage of battery series and the amp draw from battery series multiplied together compared to a known output wattage at the atty as just like ohms law you need 2 known values to determine the third so at very least you need an in-line (or inductance) ammeter between sled & chip.
  
• You are also technically making the mistake of believing that the ammeter/wattmeter on the mod is actually correct and the chip is properly calibrated. In an ideal world this would be case. It may not be however as we often see in review testings by DJlsb & Busardo showing mod delivering less or more than calculated.
  
• To properly test efficiency the ammeter should be employed between 510 & atty to verify chip output calibration to atty is correct (noting any differential), then be shifted to be between Sled & chip.

The nature of the test is why you don't see DJlsb & Busardo perform it in their reviews. Your example therefore changes to:

4v @ 0.15ohm = 106.67 * 0.15 = 16.0005w loss on 85% efficiency board needs 122.6705w total
122.6705w @ 8.4v - BatRes = 8.35v which calculates to 15.03a battery Draw rather than the 12.7a your example shows. That is a significant difference.​

 

[Tpat591]

During normal use I feel the battery life is better with the battlestar than my DNA75. With my VT75 the battery life is terrible unless I use a .35 ohm build on it. Hard to judge with my SMY SDNA 75, single 18650 but it seems to do OK, I don't have any other single 18650 mods I still use to compare it too.

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SDNA75 is single battery 1s config. Battlestar is dual battery series 2s config which should last at least twice as long. Since it is usually more energy efficient to Buck voltage than Boost it, Battlestar should last more than twice as long as SDNA75. Same should apply to a Cuboid as well.

I find it hard to believe you would go through two fresh batteries in SDNA75 before the battery dies in Battlestar w/ identical attys. With Cuboid I found it would die when I went through 1.5 18650 in SDNA75 if vaped side by side with identical tanks & I get impression from use that Battlestar might fall in near 1.75. That is a wild guess as I haven't even run my batteries down to dead much less done this test with Battlestar.

What is your experience?

 

[mjag]

I don't use the sdna75 that much, I really like it but my vaping habits have changed so I tend to need more power. I like it a lot more than my VT75. It is a 26650 but the battery life sucks compared to all my other 26650 mods. It can also get hot when vaping over 60 watts. I know I am not alone with the troubles with the VT75, others have said the same thing.

We all know the DNA 75 board is not as efficient as the DNA 200/250. In real world use I can confirm that.

I have been changing the batteries on the battlestar everyday. That's usually not normal for most of my dual 18650 mods. I have been using it a lot though, it is my road mod right now. On the road I don't vape at high watts, I like to see where I am going. That is why it has surprised me a little, I usually get better battery life with my other dual battery road mods. I have been using with my Tornado 150 in TC on the road though and lately my merlin mini in single coil mode. Could be these tanks are using up more power, never used them on the road with my other mods as they are new.

Really it was just an observation, I noticed I was changing the batteries everyday with the battlestar. That's not normal for me as I use a lot of different mods throughout the day.

Just in my short time with the battlestar I would guess it is the same efficiency as the dna75. Neither one is as efficient as a dna200/250 or FSK chip.

Not really going to test this theory, not that interested. I am sure Anthony and you will get to the bottom of it, I am just going to sit back and steal some popcorn from @52anddone

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[Tpat591]

I don't use the sdna75 that much, I really like it but my vaping habits have changed so I tend to need more power. I like it a lot more than my VT75. It is a 26650 but the battery life sucks compared to all my other 26650 mods. It can also get hot when vaping over 60 watts. I know I am not alone with the troubles with the VT75, others have said the same thing.

We all know the DNA 75 board is not as efficient as the DNA 200/250. In real world use I can confirm that.

I have been changing the batteries on the battlestar everyday. That's usually not normal for most of my dual 18650 mods. I have been using it a lot though, it is my road mod right now. On the road I don't vape at high watts, I like to see where I am going. That is why it has surprised me a little, I usually get better battery life with my other dual battery road mods. I have been using with my Tornado 150 in TC on the road though and lately my merlin mini in single coil mode. Could be these tanks are using up more power, never used them on the road with my other mods as they are new.

Really it was just an observation, I noticed I was changing the batteries everyday with the battlestar. That's not normal for me as I use a lot of different mods throughout the day.

Just in my short time with the battlestar I would guess it is the same efficiency as the dna75. Neither one is as efficient as a dna200/250 or FSK chip.

Not really going to test this theory, not that interested. I am sure Anthony and you will get to the bottom of it, I am just going to sit back and steal some popcorn from @52anddone


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Can't blame you a bit.

DNA 200/250 - 95% Efficiency published by Evolv
G2 - 95% Efficiency published by Hohmtech
DNA75/60 - 85% Efficiency published by Evolv
Slice - Efficiency unknown
Battlestar - Efficiency unknown

 

[KenD]

Isn't the chip efficiency different at different power levels? I'd think that more than one reading would be needed to get the average.

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[Tpat591]

Isn't the chip efficiency different at different power levels? I'd think that more than one reading would be needed to get the average.

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Agreed. I have only seen it published as a single value and would think it more likely to be a range of values over different settings because life never seems that clean. We are probably given average or best case scenarios.

Didn't you do a lot of testing on Cuboid efficiency back in the day when they first hit? Seem to remember that you posted a lot of things about Cubiod having an efficiency issue where you weren't getting the battery life you expected from a series mod. It was those posts that intrigued me about the concept IIRC.

I'm actually pretty interested in where the Slice falls efficiency wise since Hohmtech never published the rating for the Slice and I've seen a few people make complaints about the battery life it has.

Any testing methodology suggestions?

 

[KenD]

Didn't you do a lot of testing on Cuboid efficiency back in the day when they first hit? Seem to remember that you posted a lot of things about Cubiod having an efficiency issue where you weren't getting the battery life you expected from a series mod. It was those posts that intrigued me about the concept IIRC.

That wasn't me, but I was involved in the discussion, mainly pointing out that the iStick tc100w isn't more efficient because it's parallel. It has better battery life than the Cuboid, but series/parallel isn't the factor.

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[Anthony_Vapes]

Isn't the chip efficiency different at different power levels? I'd think that more than one reading would be needed to get the average.

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that would be wise for sure. I'm thinking of testing at 50 watts, 100 watts and 150 watts

 

[KenD]

that would be wise for sure. I'm thinking of testing at 50 watts, 100 watts and 150 watts

Adding 20 or 25w would be good as well, though it would increase the work of course.

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[Anthony_Vapes]

Also just to point out this will be my first time testing for efficiency so I'm open to suggestions as well as doing my own research in the meantime

 

[Anthony_Vapes]

Adding 20 or 25w would be good as well, though it would increase the work of course.

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it's actually not much more. much easier to test then watts since with watts i need to use different builds on different attys. for efficient i can use 1 build on 1 atty. i could add in a 25 watts step as well easily

 

[Tpat591]

It is new ground as no reviewer has ever even bothered with baseline efficiency rating across different mods & manufacturers. It is possible that different build resistances would place vastly different loads on the chip.

Interesting stuff though.

 

[Anthony_Vapes]

It is new ground as no reviewer has ever even bothered with baseline efficiency rating across different mods & manufacturers. It is possible that different build resistances would place vastly different loads on the chip.

Interesting though.

sadly this is true. I never even heard it mentioned