Finally..

[vereybowring]

I'm also not trying to say any battery is better or worse.
Using them safely is the main concern with batteries of any type.

Your work is very interesting and I applaud you for it.
I got a similar circuit a while back but haven't got round to making a mod with it yet.

Incidentally Garry's videos should be watched by all e cig users really.
They show you just how safe batteries are in general (unless of course he just happens to be monumentally lucky).

[maccafan]

Of course not Verey..

You are an experienced mod maker and it's very educational for me to get your point of view. I really don't know if it will work and if the 9v cells will supply the required current. They are after all AAA or slightly smaller NiMh batteries in series packaged in a tin box. And there is no data to suggest they will or they won't.

I do know that they are safer than Li-Ion and don't need any special balancing and safety circuitry when putting them together. Of course we are talking worst case scenarios here which I am sure as a person with H&S background you can appreciate. I am really uncomfortable with working with Li-Ion batteries. It's a very personal feeling shaped by experience with what happened to an electronics workshop technician at work a couple of years ago.

I am not making this mod for any commercial reasons. It's going to be for my personal use only and I want to be holding something that I am comfortable with. I am also thinking of putting a dc power jack in so I can switch to mains supply through an adapter and use the circuitry to give me the voltages I want.

[vereybowring]

Yeah the circuitry in question is very versatile.

I was thinking of getting a mains supply and use multiples of the the circuit (and other power regulators) to built a three way variable voltage E-Hookah.

Then again I've been thinking that for a few months and still haven't got round to it.

[maccafan]

I would be very interested if you could share some regulation circuitry with parts sourced locally..

[vereybowring]

Mar 29, 2012 15:10:48 GMT maccafan said:

I would be very interested if you could share some regulation circuitry with parts sourced locally..

I tend to get most of my parts from china courtesy of ebay.

I have looked around european sites and some parts can be got from them although you have lots of searching around and data sheets to look at to find what you want.
RS online, Proto-Pic, Rapid Electronics, and Mikroelectronika.

That's a selection of companies but like I said it takes some searching to find what you want.

I have made a few VV devices using the TI04050 chips which can be got from texas instruments as free samples. A circuit diagram for wiring those can be found in this thread.
I have also used LM350T regulators bought from ebay but since they require stacked cells I've not really trusted it safety wise but many others use this for VV. They might suit for what you are doing with the 9V NiMh batteries here's the data sheet. Look up poorvari on the ECF website to find out about wiring the LM350T. In fact a limiter circuit made with these takes up very little space but it does need a heat sink for prolonged use.

[maccafan]

Mar 29, 2012 15:37:37 GMT vereybowring said:

Mar 29, 2012 15:10:48 GMT maccafan said:

I would be very interested if you could share some regulation circuitry with parts sourced locally..

I tend to get most of my parts from china courtesy of ebay.

I have looked around european sites and some parts can be got from them although you have lots of searching around and data sheets to look at to find what you want.
RS online, Proto-Pic, Rapid Electronics, and Mikroelectronika.

That's a selection of companies but like I said it takes some searching to find what you want.

I have made a few VV devices using the TI04050 chips which can be got from texas instruments as free samples. A circuit diagram for wiring those can be found in this thread.
I have also used LM350T regulators bought from ebay but since they require stacked cells I've not really trusted it safety wise but many others use this for VV. They might suit for what you are doing with the 9V NiMh batteries here's the data sheet. Look up poorvari on the ECF website to find out about wiring the LM350T. In fact a limiter circuit made with these takes up very little space but it does need a heat sink for prolonged use.

Many thanks Verey..

I shall follow those links with interest and see f I can regulate the output..I am setting up a test bench to see how these 9v batteries perform under intermittent 2 amp load and will try and report the results.

[maccafan]

Ok test bench set up and running with a 3.2 ohm coil from a dead cart and continuous current:

These batteries defo don't like 2.3 amp output at (err. edit) 7.4 volts ie, 15 watts..Batteries went from 8.4 volts under load to 7.2 volts in about 2 minutes.. The voltage drain is almost like watching a stop watch.

One good sign is batteries barely warm to the touch.



Tried it at 5.2 volts ie., 1.625 amps ie., 8.45 watts. Better, much better:



Output is stable for about 14 minutes before a gradual drain over a period of 25 minutes till batteries reach 4.8 volts and output reaches 3.3 volts. Anything below this is pretty useless for vaping.

Batteries are now at 4.5 volts each.. Have redone the coil to my preferred 2.5 ohm and waiting for batteries to charge and will run again tomorrow at 4.4 volts and report back whilst I am waiting for the rest of the bits.

[maccafan]

Batteries freshly charged and the coil was redone to 2.5 ohm. Set at 4.7 volts output to demand 1.88 amps ie., 8.83 watts continuous.

Started test at 1738 hrs and piccy taken at 1800 hrs:



Batteries only slightly warm after 22 minutes.Looks good to go at 4.7 volts for another 30 minutes at the very least.

I will be making my own 7.2 v battery pack from 6 x AAA with 1100 mAh rechargeable batteries with a PP3 connector to extend the life even more and also to be able to charge the pack from a normal NiMh charger.The size will be slightly smaller than 2 x PP3 batteries making the mod slightly smaller provided I can get the right box for it.