HELP;- Can cheap batteries reduce the current draw?

I have puchased an ultrafire 502b torch with an xml-T6 led and am running it from an unprotected ultrafire 18650 2400mAh battery (blue). My initial tailcap readings on high were 0.98Amps and the light was not a bright as expected. I was advised to purchase a AMC7135*8+MCU 2800mAh 5-Mode Circuit Board and I have now soldered it in but am only getting 1.4A. I would like to drive the led at somewhere near 3A but where do I go from here. Is it possible that the batteries are not delivering the amperage required. Last night I was experimenting and I held a second battery behind the first for a few seconds and what a difference it was so bright and drew 4.6A. any help would be very much appreciated.

Get better batteries like the trustfire flame

Cheap batteries do not reduce the current, they cannot provide it.

I recommend any battery based on the Sanyo and the Panasonic cells, or the unprotected cells themselves from these companies.

You should never get more than a 2.8 amps draw with that driver. I would double check your DMM and definitely get some better batteries and don't feed that driver more than 6 volts or you will fry it.

Its a combination of driver / LED / and battery ..

All 3 affect performance ...

A bad LED , Driver or Battery can lower current / performance ...

And as for good batteries , that's very subjective [ as to whats a good battery ]

Some trustfire flames do well . some don't , having just one Good battery so you have something to go by , [ The Sanyo 2600 - is abundant and cheap enough ] , will help .

Also the MM , if its a cheaper model , cheap test leads can be inaccurate over 1A of current

To verify if it is the DMM+leads resistance which limits the current, try this.

Put the light over the bottom of a large upturned glass or glass bowl to better see its output. While you measure the current, slowly tip the minus probe (without losing contact) as far down as to make a short between battery end and tube. If the problem lies within the DMM and leads (rather than the battery, driver or LED), the brightness will increase considerably when connection is shorted.

Thanks for that tip, I have done as you said and there was no difference in the brightness when I shorted it out. Therefore we can presume that there is no current loss on the MM and leads.

Is it possible without doing any damage to connect the battery direct to the + and - terminals on the led hence cutting out the driver......if I then drew more amps, would that tell me that the driver is restricting the current drawn?

Cheap batteries can also increase current draw I’ve noticed right or wrong

If that was 2*18650's (i.e. around 8.4v) at 4.6A that's equal to one at 9.2A. You must have read it wrong.

I’m not sure i know the answer to that question …i just wanted to repost it so someone smarter could answer that question … you’re talking about bypassing the driver and directly giving the emitter voltage ?.

my advice on a previous question you asked is very much like old 4570's get at least one good battery and then you can judge everything else against that ...

lets ask the tuff questions .. did you get the blue batteries off ebay or in a set with a charger ? if yes than my guess after going this far into it is they are junk ..

where are you located ?...EDIT ?? oops answered my own question england ,mmmm.

If it were me i'd be taking the 6$ dino direct trustfire chance that they will send you protected

Maybe thermal runaway ?

Cheap batteries more than likely are cheap cells that are either old or just not that good to start with, and they most likely suffer from a high internal resistance.

Internal resistance is the biggest determining factor for the performance of a battery, and most of the problems that you get with batteries can be attributed to this.

Think of it as having a resistor in series with the battery. The resistor simply wastes energy as heat, and causes the voltage output to fall, proportional to current draw. So when you try to draw higher currents, the voltage drops.

In the context of a DirectDrive setup, Voltage is key in determining current draw, so if the voltage falls below the minimum voltage needed by the emitter, then the emitter itself won't draw as much current from the battery.

When you talk about current draw in general, there are MANY factors that determine the current draw, most significantly is the type of driver. Direct drive, linear regulators, or switch mode drivers all behave very differently.

Your one is a Linear regulated driver, and your observed problems do sound like a problem with a battery with too high an internal resistance.

The difference can be HUGE between good cells and cheap nasty cells. My pulled 18650s have an internal resistance of 1000-1500mOhms, the XTAR 2600mA have around 200-250mOhms, and my 2200mA flight packs have around 10mOhm resistance!

So with the cheap pulled cells, I get a voltage drop of 1-1.5V at 1A draw!! so a 4.20V fully charged cell will drop to 3.2-2.7V which is seriously low. (i.e. it can't really deliver 1A)

The XTAR at 1A draw will only drop 0.20V = so it will only drop to 4.0v. Practically in your context, this means that this cell will happily deliver your 2.8A, and only see a 0.6v drop, so a fully charged cell will be able to maintain 3.6V

And my flight packs, will only drop 0.01v at 1A draw. Infact, a 70A draw will only result in a 0.7V drop, which is confirmed in real world testing.

Should I get protected batteries or non protected, and what is the difference. Looked at various makes here in the UK and they are much more expensive than China, Japan, or USA. Does anyone know a reputable supplier in the UK?

Should I get protected batteries or non protected, and what is the difference. Looked at various makes here in the UK and they are much more expensive than China, Japan, or USA. Does anyone know a reputable supplier in the UK?

Protected batteries are much safer they shut off if you overcharge or overload them so they are much less likely to blow up. No clue on a UK source.

they also cut out if you try to over discharge them. thats the biggest reason they are what i went for

Get Panasonic batteries..

Sorry, gordy-s, can't help with a UK supplier. Anyway they'd be at least twice as expensive here so I always get mine from Kaidomain or Manafont. NEVER from ebay unless someone posts here regards a truly trustworthy ebay supplier and batch.

Are protected Panasonic 18650 batteries available at all?

Hiya all who have advised me on this forum. I have borrowed an ultrafire 3000mAh (red) an put in my 502b, I got 2.4A at the tail end and now am convinced that the battery was my problem. Thanks again for all your help. cant wait to get my batteries now.