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

[SL4P]

Maybe we're all missing the point.  Bob certainly thinks we have been.

This gadget is a shiny, hard object that will keep cats entertained for hours as it clatters across a hard timber or tiled floor.

For $2.50, that probably about right.  With apologies to someone... The Catteriser

[Howardlong]

I am milling the traces.

Without wishing to go to off topic, what milling machine are you using? That DFN is 0.45mm pitch.

The inductor is 3mm x 3mm  2.2uH at 1.4A

Which manufacturer/series is that? I have some Wuerth WE-TPC recommended in the DS but they're a bit bigger. Is the one you're using shielded?

[EEVblog]

The layout of the PCB is fairly well known. The protruding top contact should work, if the battery compartment can accommodate the extra battery length.

That's what Jay_Diddy_B was pointing out.  Adding the top contact is not the issue, physically fitting the cell-PCB combination in the slot meant to accommodate just the cell is.

Simply, use a 0.3mm PCB or some such. The Batteriser as shown should fit reasonably well in the cases shown. There will be fit/contact issues of course, maybe lots of them, but I don't think it's that bad. Using a 0.8mm example is not representative.

[Jay_Diddy_B]

I am milling the traces.

Without wishing to go to off topic, what milling machine are you using? That DFN is 0.45mm pitch.

The inductor is 3mm x 3mm  2.2uH at 1.4A

Which manufacturer/series is that? I have some Wuerth WE-TPC recommended in the DS but they're a bit bigger. Is the one you're using shielded?

I am using an LPKF Protomat C60. The cutters are from www.precisebits.com part number EM2E8-0625-90V.



The inductor is Wurth from MAPI 3010 series. They are shielded. 3mm square or 1212.

Link: http://katalog.we-online.com/en/pbs/WE-MAPI?sid=9e363cc1eb#vs_t1:c2_ct:1

This is the part: http://katalog.we-online.com/pbs/datasheet/74438333022.pdf

They have smaller ones, but I don't want have too much DCR.

Regards,

Jay_Diddy_B

[Jay_Diddy_B]

The layout of the PCB is fairly well known. The protruding top contact should work, if the battery compartment can accommodate the extra battery length.

That's what Jay_Diddy_B was pointing out.  Adding the top contact is not the issue, physically fitting the cell-PCB combination in the slot meant to accommodate just the cell is.

Simply, use a 0.3mm PCB or some such. The Batteriser as shown should fit reasonably well in the cases shown. There will be fit/contact issues of course, maybe lots of them, but I don't think it's that bad. Using a 0.8mm example is not representative.

I don't really know about this one. The batteries that I used for the test measured 50.0 and 50.2mm long. They are within the specifications published by Panasonic and Duracell.





It seems that you need a button that extends 1mm from top of the battery that is nominally 5mm in diameter.

It looks like you need to add 1mm to the length plus the thickness of the PCB.

I don't have any 0.4mm material. Itead can do 0.4mm boards but there is a $100.00 USD premium.

I am milling the boards with a 90 degree V cutter. To get 8 mil isolation I am cutting about 6 mil deep. The board might be too fragile for milling.

Jay_Diddy_B

[drussell]

It seems that you need a button that extends 1mm from top of the battery that is nominally 5mm in diameter.

Yeah, it's that 1mm+ around the button that kills you more than the board thickness.  If one could find really thin components and/or cut them into the board AND do a hole or recess for the button and connect to it in there and then isolate your contact terminal on the topside the length would be minimized as much as possible but that would be a pain and you'd still be adding some length but would fit most devices possible...  Still adding more than 1mm though...

It doesn't look like batteroo does a hole for the button in their design, so they're adding at least that button shoulder depth to the total length.

[rich]

really nice boards, loving your work Jay_Diddy_B 

The top contact on the batteriser is made from sprung loaded fingers (say 0.05mm thick?); board 0.3 or less and 0.1mm for the neg term sleeve. So their total additional length will be of the order 0.4 max.

As you mentioned, you are going to have a weak board after isolation milling, but perhaps potting the component side after assembly would make it more robust? In batterisers deign I guess the sleeve adds a little rigidity to the board also.

[Jay_Diddy_B]

The top contact on the batteriser is made from sprung loaded fingers (say 0.05mm thick?); board 0.3 or less and 0.1mm for the neg term sleeve. So their total additional length will be of the order 0.4 max.

As you mentioned, you are going to have a weak board after isolation milling, but perhaps potting the component side after assembly would make it more robust? In batterisers deign I guess the sleeve adds a little rigidity to the board also.

I think the spring fingers is something that got right. They will extend when you need them, at the positive end, and compress when they are not needed, for example between two cells. It would be hard for me to make something similar

I am not sure how they would mate with the spring contacts in the fluke 337 clamp meter.



I think that potting the electronics is a good idea. It is not something that I can do.

I am just doing this my (our) entertainment. It is the smallest board that I have ever worked on. There are some challenges making boards for 0.45mm pitch DFNs and soldering them.

By doing it, I am exploring some of difficulties that the Batteroo team might have.

I think that it is feasible to build one for an AA battery that can deliver about 500mA.

The experiments that I documented in this post:

https://www.eevblog.com/forum/blog/eevblog-751-how-to-debunk-a-product-(the-batteriser)/msg809012/#msg809012

is the most significant result. It shows the maximum power that can be extracted from AA cell as it is discharged. This is governed by the maximum power theorem and the ESR of the cell. The inductor will add about 100m Ohm to the cell's ESR. This shows that it can not work at the high currents that they are promising.

It is going to be interesting how this plays out.

Regards,

Jay_Diddy_B

[SL4P]

AMUSING that the current (no pun intended) conversation is interesting - because now the group have roundly nailed the coffin shut for the proposed Batteriser technology.  And Batteroo are themselves in the BatterPoo with Energiser.

In the absence of further entertainment from the Batterooparvar brothers - the combined skills of the forum (with significant input from Jay_Diddy_B) have now focused on whether the mechanical assembly is possible - and viable in most applications.

It seem that with more engineering than expected - the mechanical aspects of assembly are possible for the low-current version, but whether it would actually fit and work as advertised in most applications is highly dubious.

As for delivering the suggested 5x battery life - no thanks.
Myth BUSTED.

[Mr.B]

If the board was made out of flatflex and if it was possible to manufacture a flatflex with a dimple in it to accept the positive terminal of the battery, then you would only be at the mercy of the thickness of the components sitting on the shoulder of the battery.

Seems too hard to me... Too many "if" statements.

[Brumby]

Too many "if" statements.

Time for a "Case" statement?

[amyk]

Suggestion: put the inductor under the positive cap, mill out the PCB on the other side for the original positive cap to fit into, then mill out the space under the DFN and mount it upside-down. Like this:



It's funny that we're now doing more engineering than Batteroo and cloning the Batteriser before it comes out, sort of like the Chinese. I mean that in the most positive way, of course.

[Brumby]

It's funny that we're now doing more engineering than Batteroo and cloning the Batteriser before it comes out,

Funny - yes - and absolutely hysterical if EEVblog members come up with a marketable solution ... not that I expect anyone here would really bother trying to promote it.

[AmmoJammo]

...someone should start a kickstarter campaign...

The "Eeveready!"

 

[EEVblog]

Funny - yes - and absolutely hysterical if EEVblog members come up with a marketable solution ... not that I expect anyone here would really bother trying to promote it.

They can't sue, their patent has all but failed 

[timb]

Too many "if" statements.

Time for a "Case" statement?

Can't. The "switch" isn't small enough to fit on the PCB!

[Karlcloudy]

Too many "if" statements.

Time for a "Case" statement?

Can't. The "switch" isn't small enough to fit on the PCB!

Better "return" to the drawing board then  O0

[Brumby]

 

[timb]

Too many "if" statements.

Time for a "Case" statement?

Can't. The "switch" isn't small enough to fit on the PCB!

Better "return" to the drawing board then  O0

I "C" what you did there!

(I'm soooo sorry! I just...can't stop myself...)

[g.lewarne]

Seems the tide on indegogo is really turning from eternal optimism to heavy rage.  Also, 2 less backers than yesterday?

[rrinker]

 You know their next excuse is going to be that they are making even further engineering improvements to bring you only the best Batteriser possible. And you know where they will be getting those ideas....

[Jay_Diddy_B]

Suggestion: put the inductor under the positive cap, mill out the PCB on the other side for the original positive cap to fit into, then mill out the space under the DFN and mount it upside-down. Like this:

I have kind of been that direction. The first board I made had a hole for the positive battery terminal. There are pictures of the board in this message:

https://www.eevblog.com/forum/blog/eevblog-751-how-to-debunk-a-product-(the-batteriser)/msg849196/#msg849196

These are the most important pictures:



In this view you can see that an insulator is needed to prevent the components shorting to the top of the cell. The entire surface of the cell is metal and connected to the positive terminal.



I would need to add a contact to make the connection from the positive terminal, in the hole to the board. I would then need add spring contact over the hole to connect the output to the device.

When I built the second one, I removed the hole. It is a much simpler construction.

Anybody got any ideas on how to do the AAA?

This photo gives you an idea. There is about 1/2 of the area available, 10mm versus 14mm diameter.





Regards,

Jay_Diddy_B

[g.lewarne]

Anybody got any ideas on how to do the AAA?

I was just thinking you could solve some of the positive "nub" size issues and perhaps even theAAA problem by putting some of the circuitry at the other end of the sleeve ?  I mean you have to have some way of connecting it to both sides of the battery so may as well use the extra flexibility the battery springs give you on the other end as well

[drussell]

I was just thinking you could solve some of the positive "nub" size issues and perhaps even theAAA problem by putting some of the circuitry at the other end of the sleeve ?  I mean you have to have some way of connecting it to both sides of the battery so may as well use the extra flexibility the battery springs give you on the other end as well

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.

That's the problem that was pointed out by Jay_Diddy_B in the previous sections, though, with some battery holders being designed to need that space around the button to be free when it is now not available with the components being in that space.  Adding anything to the bottom is just going to make the problem worse.

[MLXXXp]

At least they publically said you should be able to get a refund when it doesn't work in your product.  That could get interesting! 

No, that shouldn't be a problem for them. The just need to follow the somewhat standard policy:
"If you're not completely satisfied with your Batteriser product, return it, postage paid, for a full refund. Allow 6 to 8 weeks after we receive your shipment, to process your refund and mail you a check."

Requiring the customer to pay for return shipping will reduce refund requests significantly.