When 4.25 volts is not the same as 4.25 volts

[proax9]

I built a mod using TI's 04050C booster.
I found that regular 3.7v 14650 protected batts could not supply enough power (would cut off at or before 3 seconds).
I am now using only IMR 14650 3.7 batts. (No cut off issues).

The mod is set to deliver 4.25 volts. (Metered at 510 connection)
What I noticed was the hits seemed to be weakening after an hour or two, as you would expect from a non regulated mod.
BUT when I metered the voltage at the 510 connection, it was still 4.25 volts, BUT a weak hit.

I put in a freshly charged batt (same make, model, type) and what a difference in the hit!!

So why is 4.25 volts not hitting the same as 4.25 volts?????

 

[martinc]

Its ability to withstand amp draw is lessened over time...nor mal for all batteries that dont have an alternator.


mmmm....here's an idea...PV with an alternator....

 

[slimest]

proax9, you'd better begin from the law of energy conservation
Then you will come to proper batteries for loaded boosters.

 

[asdaq]

BUT when I metered the voltage at the 510 connection, it was still 4.25 volts, BUT a weak hit.

One more BUT, you aren't checking loaded voltage, are you? Your meter alone will put no strain on the circuit. Strange that it is weakening, are you using AW IMR's?

 

[proax9]

No, not AWs: I started with a not so standard size (14650 from an e-power), I do not think AW has a 14650.
But I am working on a smaller mod that will take my AW IMR 14500's.

Thanks all for your comments / observations.

 

[jhonutz]

a good question for you: what atty did you use? .Very important. for both booster and simple batt it`s not relevant to measure voltage in air, you must measure on resistive load.. Booster works better than batt with atty/carto 2 ohm or higher. At LR will be the same or booster will work worst than batt

 

[shortyjacobs]

Like others have said, it's volts UNDER LOAD that counts. A voltmeter draws only milliamps...any power source can supply that amperage, so the voltage is basically the "theoretical max" for that power source in that configuration at that moment in time.

When you drop an atty onto the batt, it starts sucking serious amps when you push the button. If the battery can't supply all the amperage that the circuit is asking for, then problems start. The voltage that the battery can put out will drop as you try to suck more amperage out of it. A fresh batt is also capable of pushing more amps than a half dead batt.

This becomes very obvious to me if I take a hit off of my 4xNiMH rig, which meters at around 5.4 volts, vs my VV regulated Lithium Ion mod, which I meter at 5V, versus my USB passthrough, (with 2 amp power supply), which also reads out at 5 volts.

In terms of "hit", the USB PT is a monster, as it has plenty of amperage to spare. The lithium ion comes in second, and the NiMH is a distant third, in spit of the fact that the NiMH meters highest when unloaded.

To test out the LOADED voltage, you can make a little test rig if you are handy. Take an atty/carto connector, (cut one out of an old dead atty), and a 510 connector, and connect the atty connector to the 510 connector with ~2" of wire, so you can screw the atty connector into your mod and your atty/carto onto the 510 connector. Strip a bit of wire from the center of each wire, and attach your voltmeter there. Now you can fire the atty/carto and look at the REAL voltage it's getting.

 

[proax9]

To test out the LOADED voltage, you can make a little test rig if you are handy. Take an atty/carto connector, (cut one out of an old dead atty), and a 510 connector, and connect the atty connector to the 510 connector with ~2" of wire, so you can screw the atty connector into your mod and your atty/carto onto the 510 connector. Strip a bit of wire from the center of each wire, and attach your voltmeter there. Now you can fire the atty/carto and look at the REAL voltage it's getting.

I will try this out- as will be a handy device in the future as well.

So, I've seen many mods that claim to be Regulated and use a boost circuit and one battery. Is it safe to say that they too- will loose performance (hit) as they batteries are used. SO regulated does not mean 'contant performance'..I guess?
That's disappointing.

 

[jhonutz]

regulated means 2xbatt with step down convertor. it`s the best VV ever made this kind of regulator.
Booster work weel only with 2 ohm or higher atty.

 

[slimest]

I guess, regulated means just regulated, adjusted. Buck or boost - another stories

 

[shortyjacobs]

I will try this out- as will be a handy device in the future as well.

I should have attributed my source. Got the idea from one of my threads, here.. He has a pic, which makes it clear.

You don't need fancy.

This is what I've using for years.

I just clamp my meter leads onto the bare wire.



BTW here's what 4 AA NiMHs do with a 2.5Ω load. (5.5V no load)

 

[srolesen]

4.25V is very close to max charge of battery at 4.2V, you might want to meassure:

1. Voltage on battery terminals at fresh charge
2. voltage on atomizer at fresh charge
3. voltage on battery terminals when performans starts to sag
4. voltage on atomizer when performans starts to sag

all meassures is best to make with the same atomizer mounted on mod

 

[VpnDrgn]

My , You aren't using a big enough battery for a booster mod.

 

[proax9]

My , You aren't using a big enough battery for a booster mod.

I am thinking that is the real problem.

 

[proax9]

Just an update-
I finished my latest mod with the 4050c booster- that uses a single 14500 battery.
I am using AW IMR batts- and there is virtually no drop off from the first to the last vape.

So, maybe it is more the battery quality (AW vs 'off brand') rather than the battery size.

 

[Rocketman]

maybe just the right chemistry for the application

 

[CraigHB]

If the booster is working right, output power should not change at all over the acceptable operating range for input voltage. An IMR 14500 does have the necessary drain capability to drive the PTN04050C to its maxiumum output (12W). Minimum input voltage for the PTN04050C is 2.95V. For otuput to be affected, you'd need to disharge the cell fairly deep. There was probably something else going on there. Possibly a poor connection from the battery to the booster causing an abnormal voltage drop. A dirty battery contact could cause that. Another possible cause woud be if atomizer resistance is too low. That can cause a voltage drop when the booster goes into an overload condition.