regulated vs unregulated power supplies for "log vapes"

ubw, I can see the problem is that the output socket is soldered directly to the regulator board, so putting diodes in there is not a straightforward mod. It seems that if we want to maintain an accurate voltage display then some major surgery will be required. Another option is to replace the pot. From the LM317 circuits I have seen, it seems that the output voltage increases with increasing resistance in the pot, so theoretically using a lower value pot should limit the maximum voltage. We would need to know the resistance of the existing pot and take a guess at a suitable replacement value.

I've been working on a variable power supply design but making something that is efficient and cost effective is more difficult than it first appears. Funnily enough it is the housing, sockets, switches and other hardware that start to bump up the cost... the kinds of things that the Chinese can do for next to nothing.

u bwade wunner , just looking at the pics you posted and my power supply they are very similar , the circuit boards are identical but the housing and the way boards are mounted is slightly different, the regulator chip in mine has square edges on metal part where yours looks rounded edges, the transformer looks slightly different as well.

I've been considering trying to work out making something like the meters they show on this thread:
http://fuckcombustion.com/threads/worlds-smallest-510-voltmeter.6746/
--but with sockets to match what is used on log vapes. I think that something very small and contained/enclosed like some of the meters in that thread might be ideal for use with a log and a power supply with no display.

I guess this is the closest thing we have to an exclusive VVPS thread, so here's this weird new problem that just started ocurring with my Hildbrandt Spartan VVPS

Without a log vape plugged in, the LED will read 13.4 volts.
As soon as the log vape's port makes a connection with the VVPS, the voltage will drop down to 13.2
The problem is, I don't know if its still putting out the 13.4 and its just saying 13.2. As you VVPS people know, 0.2 voltage can definitely make a big difference.

I know for sure it isn't the log vape itself, the same thing happens with both the underdog & the rockzap.

Anyone have any ideas? Maybe its just the cable itself?

Odd, & you're sure it didn't always do that? I'd try another cable if you can easily make one, I have seen weird things happens just because a cable was starting to break/breaking.

If that doesn't change I can only think something is off on the inside. You do have warranty on these don't you, or is that suppose to go via Rick..?

Maybe if I made the first cable I could manage a second pretty easy, but mine came pre-assembled from Rick. It seems to be putting out the 13.2 volts not 13.4, so as far as my perceptions go its not functioning any differently.

Still, sent Rick a message to see how its warranty situation would play out if it got worse.

delta 9: The first thing I would check is the voltage coming from the switchmode board. That is the board that takes the mains power and steps it down to a DC voltage that the regulator can handle. You will see that there is a red and a black wire coming from that board and going into the regulator board. If you measure the voltage across those wires you should get about 20V. This should help you isolate the problem.
Warning: you will need to do this measurement while the power supply is switched on. There is the potential for electrocution if you don't know what you are doing. I accept no responsibility for any injury or damage caused by following the advice given in this thread. Cheers!

placetime: I saw that thread too and that voltmeter looks really cute. I'd love to play around with something like that but I'm a bit busy at the moment. A problem I have found with these digital voltmeters is that they sometimes won't work with some PWM controllers, so I don't see them as a universal solution. They work great with batteries though.

SD_haze: I think the voltage drop is normal. You will always get a different reading when measuring the open circuit voltage compared to when it is under load. It's not something that will get worse. FWIW my tattoo power supply is a cheap Chinese model and does exactly the same thing.

Thanks for the input hazy. Some more questions for hazy or anyone else who understands this stuff:

So, do those tattoo power supplies, like SD_haze's Spartan, have PWM controllers?

Those "standard" unregulated power supplies traditionally included with log vapes do not have PWM controllers, but regulated power supplies, such as the ones used with a wireless router or cell phone chargers do have PWM controllers, right?

I'm guessing that the no-display variable supply that can be purchased with a HI also has a PWM?

What about those LED dimmers that some people use? If I'm remembering correctly, those reduce amps, not volts, right? So one of those tiny voltmeters wouldn't help in that situation either, right?

The tattoo power supplies use a switching section to step down the mains voltage to about 20V, then a linear regulator handles the voltage reduction from there. Switching power supplies use PWM (Pulse Width Modulation) to achieve this. An unregulated power supply is just a transformer in a box. It's a lump of iron with wire wrapped around it. You can tell that a power supply is a switched-mode type (and therefore using PWM) because they are significantly smaller and lighter. I don't know anything about the HI power supplies, but if they are small and light then they will be switching power supplies.

According to Ohm's law the voltage will vary with current, so even though you may be limiting the current, the voltage will be lower as well, so you can use a voltmeter as an indicator of the overall power available from the supply. The opposite is also true, ie if you lower the voltage then the current will be lower as well.

Different PWM controllers work at different switching frequencies depending on their application. Many power supplies use a high frequency in the kHz range (thousands of times a second) but some LED dimmers operate at around 100Hz. This is where the problem occurs because the low switching frequency interferes with the sampling frequency of the digital voltmeter. Also the digital voltmeter derives its operating power from the circuit it is measuring, and instability of the power source caused by the low switching frequency can add to these problems.

I only found out all this stuff recently while experimenting with the dimmers.

Hazy, i checked voltage from transformer board and there is 21 volts goin to reg board all wires are black , i had take boards out to see which wires go where and i noticed that the reg chip is beat up looking and bent along heat sink mount , i straitened the chip so it would have more contact with the housing and the heat sink but it made no difference to operation, i have another power supply coming to replace this one so hopefully it works . I just seen you seed pod log vape and it looks great would love to try it out some time.

Just checking in to let everyone know about a relatively cheap power supply for logs that that will max out @15V which is encouraging and may save youre log and youre Skin for that matter.

N.B
Ok I am reading different Mains Voltage specs on different websites so i would contact the seller like this one and enquire if these units will work on worldwide mains voltage before you buy.
These supplies will require banana plugs instead of the microphone jack we are using on current tattoo supplies.A small price to pay for a safer experience.

Link here stay Safe Everyone

isn't that the same one dave used to sell?

Yes.

delta 9, seems like the the power going into the regulator board is ok, so considering the condition of the regulator, perhaps that is the culprit. If you don't mind doing some desoldering then you could try replacing it. They're quite cheap so it might be worth having a go just for fun. It's probably easiest to snip off the old regulator so that you can easily desolder the pins one by one

Here is a cheap 6 step PS - Power Supply Regulated 3-12 VDC 2A 6-Way $19.40 + $11 shipping

Power Supply Regulated 3-12 VDC 2A 6-Way
This compact sized regulated power supply is ideal for all devices drawing up to 2 amps of current. It is fully regulated ensuring constant, accurate DC power to any type of electronic device. The rotary selector can switch between six popular voltages (3-4.5-6-7.5-9-12V DC). The color coded binding posts make connections easy. This unit works well with the detachable plug kit 120_537 by supplying an easy termination for the popular DC plugs on the market today. Dimensions: 2.5" H x 4" W x 5.25" D.

Has pretty good reviews
http://www.parts-express.com/pe/showdetl.cfm?partnumber=120-536
or from their Amazon storefront:
http://www.amazon.com/Power-Supply-Regulated-3-12-6-Way/dp/B0002MQGI6/ref=cm_cr_pr_sims_t

hazy , local electronics shop did not have a suitable replacement regulator so i could not change it to see if it could solve the problem, I did get a replacement power supply for the faulty one and it does work for the log vape but is very hard to adjust the voltage as it jumps up a volt or 2 with the slightest movement of the pot.

You should be able to get a cheap regulator off ebay eg:
http://www.ebay.com.au/itm/10pcs-LM...Electrical_Test_Equipment&hash=item1e7205c096
They even give you 10 of them

Perhaps you could try repairing the old unit and then play around with pot values to see if you can get a more restricted voltage range, therefore making it less sensitive. You might end up with a few pots you won't use but they're not too expensive, and you might end up with a great vaporizer power supply as well! If you are successful you can then do the same mod on the second unit

The only useable voltage is 12V, so it could only be considered a fixed voltage power supply for vaporizer purposes.

Just received another tattoo power supply that I bought on ebay. The seller sent me the wrong one initially but they let me keep it and sent me the right one after I contacted them about it. For a total cost of $13, I'm not going to complain . Here's a link to the ebay listing.



This is the best power supply I've seen so far. It's much smaller and lighter than my other one. It gets warm but not hot like the others. I think I can safely conclude that this power supply uses PWM so it should be very efficient. The only disadvantage with it is that it delivers up to 19V which is way too much for a log vape. However, the voltage adjustment knob is very stiff so there is no chance of accidentally bumping it and inadvertently changing the voltage. The other great thing about this power supply is that it only has one socket, so no need for any "dummy plug" to make it work

Who's got two thumbs and just ordered one on eBay too?

This Guy

Woot, great find Hazy!

I just ordered one too, lol.

I'm looking forward to have a portable PSU with a display so I won't have to bring my multimeter every time

ps: if you check out the ebay seller's products you can find them in different colors too!

pps: does it matter if I use a stereo or mono plug with it?

And this guy! Thanks for the post Hazy!

UD-Dave recently said he was going to put power cords on his website for tattoo power supplies as soon as he gets around to it (not sure when that'll be). You might want to shoot him a message if you don't have a solder iron or a handy friend.

Omg... I've looked at and wanted to buy that damn PS forever! But was positive it was a "get what you pay for".

There's about a billion of the exact same one on Amazon in multiple listings and colors. Now I'm going to have to get one. Have you measured with a meter for display voltage vs actual?

EDIT: Correction... this is indeed a different, yet similar looking PS. I could only find 1 seller on Amazon and they're almost out of stock and it $20.

The voltmeter on the power supply is showing half a volt higher than what I measured with one of my other voltmeters. I don't know how accurate my voltmeter is however, and my multimeter died last week so I can't test it with that. Found out the hard way that the polarity is reversed coming out of the power supply... killed one of my voltmeters. Not having a good run with meters lately So the long shaft of the plug is connected to positive, and the tip is connected to negative. Please keep that in mind if you're going to test your own unit.

I've had the power supply running for about five days straight. The first couple of days I had it sitting on a metal surface and it was only a little warm. After moving it to a more insulative surface I noticed it get a lot warmer. Not exactly hot, but very warm. Also I could hear a faint whine coming from it, which decreased in volume after putting it back onto the metal surface. Seems like it's probably a good idea to try to keep temperatures down to maximise the lifespan of the power supply.