EEVblog #751 - How To Debunk A Product (The Batteriser)

[chris_leyson]

Hi guys, finally got around to building an LTC3539 boost converter, the chip has been sitting on the bench for months  . Boost a chemical battery, I don't know, let's go for it, give it a shot, nice idea, build it and then "to measure is to know". Classic science.

So I built an LTC3539 boost converter, same as Jay_Diddy_B's design, 1MHz, burst mode with 2x10uF on input and output, it works well, nice one Linear Tech . Not trying to build it small I used a relatively huge inductor, best I could do for a prototype.

Inductor is 8 turns 0.5mm diameter copper onto a Ferroxcube TN14/9/5 4C65, Al is 50nH to 55nH per turn squared (deliberately wrote squared there). Overkill and probably 3u3, peak flux density using volt time product is B = V*t/N*Ae, units are B=Tesla, V=Volts, t = us, Ae = mm² and N = number of turns. V = 1.5 (V), t = 0.5 (us)  (assuming 50% duty cycle), N = 8 (Should have been 7 to get 2u2), Ae = 12.3 (mm²) and then B = 7.6 mT or not very much at all. At least I can justify my inductor choice. That's going to be linear BH loop and almost lossless. Next thing is switching losses...

Nice to see independant engineers choose the same chip, I chose startup voltage, peak current and operating frequency as my parameters. Just thinking out loud.

Going to test two Energizer Max Alkaline batteries with and with out boost converter at 150mA load, seems a good place to start.

[Cyberdragon]

Wait...this thread is STILL ALIVE?! And people are...trying to build replicas?
I think the only boost converter here is a defibrillator on this topic...

[Godzil]

Wait...this thread is STILL ALIVE?! And people are...trying to build replicas?
I think the only boost converter here is a defibrillator on this topic...

Yes still alive, you've got 800% more replies!

[AmmoJammo]

Uhh, no...  You need to re-think that

Adding anything more than an ultra-thin tab for connection to the bottom of the battery is going to increase the total length.  The only place that any circuitry can possibly go to minimize the added length is around the button at the top.

I actually was considering this the other day, and in my mind, it makes no difference....

If you add, say, 1mm worth of PCB and components to the top of the battery, around the nipple, you still have to add the nipple on top of this, to make contact with the battery holder terminal, this nipple needs to extend the same height off the PCB as the original did off the battery, or you're guaranteeing it won't even make contact in a lot of battery holders...

The end result is no different to adding a 1mm thick PCB to the bottom of the battery....

[Brumby]

If you add, say, 1mm worth of PCB and components to the top of the battery, around the nipple, you still have to add the nipple on top of this, to make contact with the battery holder terminal, this nipple needs to extend the same height off the PCB as the original did off the battery, or you're guaranteeing it won't even make contact in a lot of battery holders...

The end result is no different to adding a 1mm thick PCB to the bottom of the battery....

There is a difference.

Not all battery holders have a space restriction around the positive cap and for those, this is available space.  On the other hand,  the negative end has no such space and anything placed there will affect every battery compartment.

[AmmoJammo]

If you add, say, 1mm worth of PCB and components to the top of the battery, around the nipple, you still have to add the nipple on top of this, to make contact with the battery holder terminal, this nipple needs to extend the same height off the PCB as the original did off the battery, or you're guaranteeing it won't even make contact in a lot of battery holders...

The end result is no different to adding a 1mm thick PCB to the bottom of the battery....

There is a difference.

Not all battery holders have a space restriction around the positive cap and for those, this is available space.  On the other hand,  the negative end has no such space and anything placed there will affect every battery compartment.

No, there's no difference, unless you're designing a batteriser that only fits in 1 in 100 devices.

In fact, by putting it on the nipple end, you're creating empty space under the new positive terminal, as it has to be raised off the board.

[Brumby]

On reflecting on the free space around a battery - I was wondering how many battery compartments have you come across that do or do not have space down the side of the battery?  You know - the cross sectional view of a round battery in a square(ish) hole.

I know this gets right away from the purist geometry and cylindrical products like torches could get left out in the cold, but I just checked a couple of items on my desk (such as my cordless mouse) and there was plenty of space for some SMD magic.


Just throwing some thoughts out of the box here.........

[Brumby]

In fact, by putting it on the nipple end, you're creating empty space under the new positive terminal, as it has to be raised off the board.

That positive contact needs only be thick enough to carry the required current - and to have a thickness of insulation between it and the battery cap sufficient to isolate.  That will be able to be rather thin.  Mechanical strength will come from the surrounding board.

At the negative end, the bottom of the battery occupies the entire area, so any circuitry must have a clearly larger impact on overall length.


Would it be out of line to point out that the Batteriser - after so much 'development' - has a design which follows this logic?

[LabSpokane]

Folks, you're all missing the point.  With the stackup problems caused by the Batteriser, it's a perfect time for Bros. Roohparvar to upsell a shorter AA battery.

[AmmoJammo]

In fact, by putting it on the nipple end, you're creating empty space under the new positive terminal, as it has to be raised off the board.

That positive contact needs only be thick enough to carry the required current - and to have a thickness of insulation between it and the battery cap sufficient to isolate.  That will be able to be rather thin.  Mechanical strength will come from the surrounding board.

At the negative end, the bottom of the battery occupies the entire area, so any circuitry must have a clearly larger impact on overall length.


Would it be out of line to point out that the Batteriser - after so much 'development' - has a design which follows this logic?

no, its THE SAME!

If you put the board at the top, indicated in orange, you still have to extend the terminal 1mm above the height of this board, indicated in red, so that it actually makes contact in 90% of devices! (7 out of 8 I looked at need the 1mm high positive terminal)... doesn't matter if the total board thickness is 0.5mm or 1mm... the board is going to be the same thickness whether its at the positive or negative terminal....

Stick the same thickness board at the negative terminal, and you end up with the same overall length! just with less area for the PCB, as it needs the hole for the extended positive terminal....

Doesn't matter if the board is only 0.5mm thick, and the original terminal extends through it by 0.5mm, it still needs to be extended 1mm above the PCB surface, or it won't make contact in 90% of devices!

[Ian.M]

Alkaline cells generally have the seal at the base so a base mounted boost board wouldn't need a sleeve to connect to the other terminal of the cell, it would just need the user to notch the cell jacket where it covers the bottom corner so the board could contact the cathode terminal. 
Also the terminals are generally plated steel so the boost board could be held in place magnetically.

[AmmoJammo]

Alkaline cells generally have the seal at the base so a base mounted boost board wouldn't need a sleeve to connect to the other terminal of the cell, it would just need the user to notch the cell jacket where it covers the bottom corner so the board could contact the cathode terminal. 
Also the terminals are generally plated steel so the boost board could be held in place magnetically.

Indeed, and you don't have to stuff around with a crappy positive terminal, and shitty stainless steel sleeve, that won't fit in a lot of battery holders.....

*cough* "EEVeready Battery Booster!"

[Brumby]

OK - let me just clarify the differentiation I was trying to make....

In regards to this statement:

or it won't make contact in 90% of devices!

Don't know about 90% - but I'll use that figure....

If 90% have a space problem at the positive terminal, 100% will have a space problem at the negative.  So there is a difference.  Whether that difference translates into any material issue is another question - and one that Batteroo can have.


FWIW my mouse has a space problem with both.

[Brumby]

Alkaline cells generally have the seal at the base so a base mounted boost board wouldn't need a sleeve to connect to the other terminal of the cell, it would just need the user to notch the cell jacket where it covers the bottom corner so the board could contact the cathode terminal. 
Also the terminals are generally plated steel so the boost board could be held in place magnetically.

I like the idea - but aside from the question of space, there are some issues one could encounter in the consumer world.
1. Polarity.  The natural form factor of such a solution will be a disc that will have no inherent mechanical means to ensure correct polarity upon installation.  Perhaps something could be engineered.
2. Series connection.  Someone might see two cells in series with two discs and decide to stack the discs together rather than at the base of each cell.
3. Positive connection.  The positive casing is almost always wrapped by an insulating cover - which would need to be pierced or partly removed for contact.
4. Too small.  Difficult to handle if there are any dexterity issues.  Also, easily lost.  Would recommend the form factor is not completely circular, so if it fell onto the floor it would not roll 5m away.
5. Nowhere to put a brand - certainly not as prominent as the batteriser.


But, be these things as they may - Bob and Co have already done this homework ... haven't they?

[Ian.M]

I think you'll find more devices with a recessed +ve contact to prevent a reversed cell connecting, that simply wont work with a booster that has a lower profile +ve terminal than the original cell, than you will find devices that don't have enough -ve contact spring compliance to accept the extra thickness of a slimline boost board.

[AmmoJammo]

OK - let me just clarify the differentiation I was trying to make....

In regards to this statement:

or it won't make contact in 90% of devices!

Don't know about 90% - but I'll use that figure....

If 90% have a space problem at the positive terminal, 100% will have a space problem at the negative.  So there is a difference.  Whether that difference translates into any material issue is another question - and one that Batteroo can have.


FWIW my mouse has a space problem with both.

What are you even trying to argue?

The battery will be extended by the same amount, no matter what end you put the PCB on, because the positive terminal STILL has to be 1mm higher than the surface its protruding from, whether it be the battery itself, or the PCB.

Are you assuming that the positive terminal won't extend higher than the original battery length? so it doesn't even make contact in 90% of devices?

It really seems you enjoy arguing, but I'm not sure you're actually putting any thought whatsoever into your argument!

Edit: if the battery compartment will accommodate the extra length at the positive terminal, you're not extending the battery length any more than this by having the PCB on the negative terminal!

[Brumby]

What are you even trying to argue?

Since words aren't adequate, I've made a picture...

The battery will be extended by the same amount, no matter what end you put the PCB on, because the positive terminal STILL has to be 1mm higher than the surface its protruding from, whether it be the battery itself, or the PCB.

That is an assumption - which is not always true and when it's not true, there is a difference (the point I have been trying to make.)

Edit: if the battery compartment will accommodate the extra length at the positive terminal, you're not extending the battery length any more than this by having the PCB on the negative terminal!

Again - not always true.


Take this example:



The bulk of the space available for this particular battery compartment is the green area.  The orange area will contain a top (+ve output) and bottom (+ve input) conductive layer separated by a layer of insulation.  The orange area represents the increase in overall length.

I do not, nor have I ever said, that this is the case for all situations with the PCB at the positive end.

What are you even trying to argue?

The difference lies in (to use your figures) the 10% that you are ignoring.

If it escapes your understanding at this point, then I give up.




As for the real world ... 

I think you'll find more devices with a recessed +ve contact to prevent a reversed cell connecting, that simply wont work with a booster that has a lower profile +ve terminal than the original cell, than you will find devices that don't have enough -ve contact spring compliance to accept the extra thickness of a slimline boost board.

[AmmoJammo]

very few devices have a battery holder like that, so if thats what you're basing it on, you're more of an idiot than batteriser.

[miguelvp]

Again - not always true.


Take this example:



The bulk of the space available for this particular battery compartment is the green area.  The orange area will contain a top (+ve output) and bottom (+ve input) conductive layer separated by a layer of insulation.  The orange area represents the increase in overall length.

I do not, nor have I ever said, that this is the case for all situations with the PCB at the positive end.

That might be true, IF you ignore the large negative spring that will allow you to accommodate a taller circuitry.
 

[Brumby]

very few devices have a battery holder like that, so if thats what you're basing it on, you're more of an idiot than batteriser.

Insults aside.

You made a point that there is no difference.  I showed you a case where there is.  When you make absolute statements, be prepared to be challenged.  When shown to be wrong, it does you no credit to spit the dummy.

It was a point of principle - not practicality.



Enough of this.

Let's just get back to the Batteroo show.....

[AmmoJammo]

very few devices have a battery holder like that, so if thats what you're basing it on, you're more of an idiot than batteriser.

Insults aside.

You made a point that there is no difference.  I showed you a case where there is.  When you make absolute statements, be prepared to be challenged.  When shown to be wrong, it does you no credit to spit the dummy.

It was a point of principle - not practicality.



Enough of this.

Let's just get back to the Batteroo show.....

you mean when you're an idiot and make a device that physically won't make electrical contact in 90% of battery holders?

that isn't a difference, that's stupid!

[Brumby]

Now you've forgotten your original claim.   

[AmmoJammo]

Now you've forgotten your original claim.   

I haven't forgotten anything.

My original claim, was that a "batteriser" that can be guaranteed to physically make electrical contact in a device, would be the same physical dimensions, regardless of whether the PCB is on the positive, or negative terminal... whether or not its too long to fit in the battery holder isn't changed, unless you make a "batteriser" that will only make electrical contact in 10% of devices!

[Brumby]

You have changed your use of the word 'guarantee'.

Your original use may not be what you meant, but that's what I picked up on.

[AmmoJammo]

You have changed your use of the word 'guarantee'.

Your original use may not be what you meant, but that's what I picked up on.

I didn't realise it was a requirement to specify that the device actually make electrical contact in its intended application