DNA 20 PSB

[WillBlack]

This would be a better choice for a DNA20.

http://www.fasttech.com/products/0/10003906/1279300-218650-serialparallel-battery-holder-case

The PCM equipped one will cripple the DNA.

• Maximal continuous Discharging current 5A

When boosting, the batteries have to provide significantly more current than a simple check at the atty would show. And as the voltage of the batteries drop the current draw has to keep increasing to maintain regulation.

[Proetus]

Thanks for the alternative! However the battery holder listed works fine, it's been used previously and has no issues. It also has the bonus of if you put the batteries in backwards, they do not make contact. Impossible to put reverse voltage on the board that way.

[WillBlack]

Thanks for the alternative! However the battery holder listed works fine, it's been used previously and has no issues. It also has the bonus of if you put the batteries in backwards, they do not make contact. Impossible to put reverse voltage on the board that way.

You are using it with the DNA20?

[Proetus]

I am not, but I will be. However Mikepetro is. Certainly feel free to check it out Proof is in the pudding!

[WillBlack]

The DNA like many of today's devices already has it's own protection built in.

...It features controlled power from 7 to 20 watts, runs from a single lithium cell and includes protective features such as overcurrent, over and undervoltage protection and a thermal shutdown.

Adding another layer to the battery itself often confuses this built-in protection and is neither needed nor good practice. And this holder's PCM circuit will in fact be chewing up some current and impact actual mAh. It's a fact of life that anything in the path will do this.

Here's an example, of the battery he uses (a poor choice BTW), naked Panasonic vs a PCM protected one.

I imagine he thinks he will be gaining additional runtime with this 3400mAh cell, he will not. He can expect an early end to his vapetime as this under powered cell has excessive sag under load. Even with it reading 3.5V (unloaded), once the button is pressed it will probably sag/drop below the DNA20's threshold/cut off. This has been reported on one of the UK forums by many non high drain battery users.

Here's a view at some of the stuff in the path of an add on PCM circuit.

I'm always leery of new modders (Feb 2013) posts as rarely have they tested it fully or are honest in any shortcomings. Many of his statements show he has not done his homework.

Here's one.

I figure that I can get a full 20w down to about 3.6v on the batteries and still only pull 5.5a

That is incorrect and shows that he doesn't understand the current demands of batteries when used in a boost type of circuit. He has figured the current at the atty, obviously there is a lot of stuff, circuits, wires, his added PCM etc on the way to the atty. Nor is 20W some sort of constant, the amp draw will vary quite a bit depending on the ohms of the load. The question is what does a boosted cell need to provide over the range of it's voltage to maintain regulation. And as the voltage drops the current needs to steadily increase.

My advice would be to bypass the holder's PCM, the wires also look a bit thin (24GA, 26GA?) I'd opt for Evolv's recomended 20GA and use a proper high drain cell rated at a minimum of 10A.

That said here's a 10A comparing my fav high mAh cell vs. the Panasonic high drain 10A offering.

Just something to think about. Good luck.

[Proetus]

Did you read the whole thread? It doesn't seem so, as he is on his third set of different batteries. The third set providing no issues. I have no issues trusting the individuals in that thread as they are known to me. Not saying you aren't knowledgable in the subject, as it seems you are. I see no issues with that build. Is the additional PCM needed on the battery holder? Probably not but it also doesn't seem to be hurting anything.

[WillBlack]

LOL, I give up.

Probably not but it also doesn't seem to be hurting anything.

I thought I thoroughly explained the reasoning with examples and charts to boot. Of course it hurts. As does Ignoring common, correct practice and ignoring the manufacturer's recommendations and specs.

Did you read the whole thread?

Why would I? So many glaring mistakes and incorrect assumptions, I saw more than enough to know hack modding when I see it.

It's your choice, doing it right cost no more money, actually sometimes less, and takes no more time.

I guess It just depends what group you want to be a part of, the elite or.... ?.

CYA...