The big LIGHTS thread 2011-2014

monkey_man_1

Hiya, just a quick question. Both my chargers only seem to charge my cells to 4.14v and not 4.2v is this an issue? Ive read it's just the chargers issue? Also at what voltage should you aim to recharge the cells? After around 1hr on high on a 502b I was left with 3.55v is this ok or can I squeeze some longer run time out of it.

Many thanks

night_porter

monkey_man_1 wrote:

Hiya, just a quick question. Both my chargers only seem to charge my cells to 4.14v and not 4.2v is this an issue? Ive read it's just the chargers issue? Also at what voltage should you aim to recharge the cells? After around 1hr on high on a 502b I was left with 3.55v is this ok or can I squeeze some longer run time out of it.

Many thanks

Lots of people recommend only charging up to that amount to preserve the life of your batteries. My charger cuts out at 4.22v (measured with a Fluke so very accurate).

I have been using the same pair of Trustfire 2500mAh cells for nearly 3 years and because I work nights they only get time off when I go on holiday, no problems at all.

Protected cells will only cut off at 2.75v so as long as you are using protected cells then feel free to keep going but always keep a charged spare cell in your pocket in case it switches off completely.

If you are using unprotected cells it might be best not to run below 3.0v but in any case you should be able to run them a little longer than you currently do.

101_North

night_porter wrote:

101_North wrote:

I've a question regarding charging which I'm hoping someone might know the answer 2.

I have a hobby charger which can charge at up to 5A. I've been charging my single cells at 1A. I've read plenty online and many 18650 manufactures state that you can charge an 18650 up to 0.8C i.e. battery capacity/0.8c = charge rate. All makes sense - however! I've also got a 1S4P pack with a total capacity of around 10,000mAh. Using the previous formula that would work out at a charge rate of 9A or something! The charger obviously won't do this but would I be safe enough charging this pack at 2.5/3A? I'm assuming the charging current would be split across the 4 cells?

Any thought appreciated :-)

101

If you could actually guarantee that the current was split equally over all 4 cells then charging with a higher current would be okay. However, if any of the cells has been discharged more it will try and draw more current so it could exceed the 0.8c rate of the individual cell, which must be 2500mAh. To be safe I would not exceed 2A just in case 1 cell is drawing all of the current.

If there is a balance circuit on the battery pack then it should negate all I have just said but I would still err on the side of caution.

You must get a phenominal run time with that battery pack though? How long?

I have thought about making a pack like that but to eradicate the problems of charging I would use removeable cells and charge them indivually.

Cheers for the info. The cells charge fine in the pack as they will self balance as they are in parallel. They also discharge evenly. I cycled the pack a few times to check this is the case. The problem is that charging at 1A is slow. I want to keep the cells in the pack as I can waterproof it then and it saves the hassle of individual cells. From what you've said I should be fine at a higher current.

The run times are impressive but I'm running 2 XM-L torches from the one pack so the times are effectively halved. The 2 lights though allow me to run them in medium mode (with high an option if needed) most of the time which preserves run times. Only diy'd this setup a few weeks ago so I'm still getting an idea of run times - so far so good.

Cheers for the info

101

diy

@night_porter and 101_North, balance wire is the only way to do this safely for 2+S, most decent hobby chargers have a balance circuit.. but a 4P1S is balanced anyway. However the problem you get is different stages of charge which could over charge a stage 2 cell. Really only safe to do this with protected cells.

@monkey_man_1 are you sure your test meter is accurate? compare a couple of AA's to see.

101_North

diy wrote:

@night_porter and 101_North, balance wire is the only way to do this safely for 2+S, most decent hobby chargers have a balance circuit.. but a 4P1S is balanced anyway. However the problem you get is different stages of charge which could over charge a stage 2 cell. Really only safe to do this with protected cells.

@monkey_man_1 are you sure your test meter is accurate? compare a couple of AA's to see.

Cheers DIY. The 18650 holder has a built in protection circuit so I reckon it's OK. I can't fit protected cells in it anyway. Charged it a few times and it seems OK. I'll gradually up the charging current and see how it goes - maybe 0.5A at a time.

101

bartimaeus

Result! Two packages from DX in the post this morning... an XM-L drop-in to replace a dead XP-G, and two new XM-L 501b's (1.4a). Not sure exactly when I ordered but I think this is 5-6 weeks, so on the slow side! The XM-L is noticeably brighter than the XP-G. Next night ride will show how much different 2 x XM-L is from my older P7.

leaflite

Just ordered one of these to go on the bars:
http://www.lightmalls.com/trustfire-tr-3t6-cree-xm-l-3-t6-3800lm-high-brightness-led-flashlight-3-18650

From the reviews on budget light forums etc, it seems to have decent build quality, uses a screw in rather than a drop in for better heat management and has a fairly good driver in it. It has apparently been measured at 1600 otf lumens, which should be bright enough, if a little short of the 3800 lumen claimed output! The reviews all seem to state that it gives off huge flood but not much throw, so it seems that it will be perfect, when paired with a 501b or similar headtorch, for mtbing.

diy

my only observation is its going to be a foot long

leaflite

diy wrote:

my only observation is its going to be a foot long

It should be around 20cm in 2 cell mode, a similar length to a 501d

allthegearnoidea

isnt that the one that supers just got????

supersonic

Yep, I have the Fandyfire branded version. It throws alright, the sheer power sees to that. It has a very hot middle spot, and a wide flood, but is not an even graduation. Will get beam shots tonight, and compare to a SSC P7 torch and the MS XML clone.

supersonic

Some beam shots in my storm battered back garden, and inside - not the best, but you get a good idea. Top set are 0.5s exposure, F/2.8, ISO-200. Bottom set the same, but 1/20 of a second.

Ultrafire 501b, with SSC P7 driven at claimed 2.5A:


___________________
Magicshine clone with XML-T6, high.


___________________
FandyFire triple XML, hi (2.6A to each LED)


___________________

And in the same order, indoors:







______________________________________________

Notes: The MS clone with XML-T6 had a very pronounced dual beam - a tight central hot spot, then wide spill, with no graduation between. Then a halo, and artefacts from the crown. Needs a diffuser or modding, but some may like it this way.

The FF triple XML-T6 was similar, but a better graduation from the centre spot. Astonishing amount of light! Is bulky on the bars though.

The UF 501bP7 had the lowest output, but a better beam pattern IMHO, good flood and graduation from the centre. Seems easier on the eye, if not as bright as the MS clone.

Runtimes: TBD. Cells used were Ultrafire 2500mah protected. MS clone the 4 cell pack as provided.


To summarise: The MS Clone is going to a friend. The FF will be used for when I just must have the most light out there lol, but for me two P7 on the bars (and/or one on the hat) is the best bet for overall performance here.

diy

Super I think you'll find the ay-up is better

Tripple XML looks excellent. Perfect base to create a stubby with an external battery. Are you able to check/test the DC Amps on your P7s?

leaflite

diy wrote:

Tripple XML looks excellent. Perfect base to create a stubby with an external battery.

Sounds like a good idea. Might give it a go when it arrives. What would you need/how would you go about doing this modification?

thanks

allthegearnoidea

has anyone used a RC car 7.2v battery pack for powering lights??
only reason i ask is that ive a Load in the shed from running my elecy Truck for a few years, could be a good spare battery pack perhaps??

Northwind

Supersonic, are those all with the 2 cells in? How does it work with one? I've got an old P7 torch modded with a battery pack but it's 3.7V and I did such a good job of waterproofing and reinforcing the cables I don't think I can rewire it :oops:

supersonic

Northwind wrote:

Supersonic, are those all with the 2 cells in? How does it work with one? I've got an old P7 torch modded with a battery pack but it's 3.7V and I did such a good job of waterproofing and reinforcing the cables I don't think I can rewire it :oops:

The FF XMLx3 was with the two cell tube. The 501b P7 as is. No mods here: the MS Clone, with its own pack.

I think I will mod the FF: the head unscrews, so need to cap it and solder in a lead, but with a 2s3p cell would make a fantastic light.

Northwind

Am I right that the FF will run with just one? If so, could you do me a big favour and give it a crack?

night_porter

allthegearnoidea wrote:

has anyone used a RC car 7.2v battery pack for powering lights??
only reason i ask is that ive a Load in the shed from running my elecy Truck for a few years, could be a good spare battery pack perhaps??

In theory any DC power source that has sufficient voltage and current output will be suitable for running LED lights.

I think your 7.2v packs are made from either NiMH or NiCad with multiple cells shrink wrapped together in a pack? They should be fine as long as your emitter isn't limited to 4.2v. Most of the XM-L's I see advertised are limited though.

I have some old camcorder Li-ion cells with a nominal 7.2v that I use to power up drop-ins and although they are rated at only 1350mAh they give a stronger light than 2 Surefire 2500's. I am guessing that this is the same reason why DIY uses old laptop batteries because they are better quality?

Because the technology is meant for general public use they are super protected and reasonably waterproof, so no charging fears with these. I have toyed with the idea of inserting them into an old water bottle to give super long run times for something like supersonics FandyFire head (which looks awesome) and as it comes with 2 18650 cells must be capable of taking the higher voltage. I just worry about the heat dissipation.

Of course I may be wrong but I am sure someone with more knowledge than I have will set me straight

allthegearnoidea

hmmmn, thanks for that fella, yeah they are niHM packs, have a load of GP cell'd 3300 packs that i ran in the truck (quad battery chassis for longer run times), so might do the old spare bottle holder and old bottle to make a decent long run time pack, knock up a lead to usewitht he light,
gotta be worth a shot!!

diy

A couple of points about batteries and drivers.

Drivers

The job of the driver is to regulate the current to the LED. For a given voltage it will output a set current. The current will go up or down with an increase or decrease in voltage. This is primarily why the Dx 1.4A XM-L (50x) drivers run at 1.7-1.8A They are 1.4A at 3.7v (nominal) at 4.2v they are. 1.8 or more. If you run a 7.2v pack you will "under current" the LED by about 15%. i.e. the output will drop. But this has to be balanced with the fact that ultra high current light will drop to this after about 20 mins anyway. So in short you will get lower but more consistent output.

Batteries

Laptop cells Ah are rated at 3.7v at 1-3A typically, depending on the age and cell config in the pack. They are designed to run at this voltage to increase the life of the cell. If you carefully juice up the cell to 4.2v, not only do you increase the brightness of your LED, but you also increase the Ah. The cost is significantly shorter life (roughly a 5th). Broadly speaking a 2400mAh, 3.7v 18650 found in a laptop will stretch to 2700mAh at 4.2v. Given its designed to run at 3-5A current, that equates to the top 20% of 18650 performers.

allthegearnoidea

thanks DIY, contemplating one as a back up pack!! but may get a 4 cell caddy type and use that instead?? (18650 one)

diy

Some drivers are designed to work at multiple steps in voltage though, which accounts for why lights can run at 4.2, 8.4 or 12.6v. I have some XPG's that will take 4.2-16.8V which lets you run 1,2,3 or 4S.

allthegearnoidea

this forum needs the 'thanks' button added!!!!
thanks for the info fella, much appreciated!

supersonic

The FF will not light with a single cell. Just can't provide the current needed.

Northwind

Well boo :x Suppose my 4-cell pack should have the amps for it but wee bit of a gamble for the voltages I guess. Thanks!

Coolnick

Does anyone have a link to a decent XML torch available from UK dealextreme warehouse please? Thanks, Nick

night_porter

Coolnick wrote:

Does anyone have a link to a decent XML torch available from UK dealextreme warehouse please? Thanks, Nick

UF WH-501b http://www.dealextreme.com/p/ultrafire- ... -904455241 website says £11.74 and should be delivered in less than a week.

Neal_

Coolnick wrote:

Does anyone have a link to a decent XML torch available from UK dealextreme warehouse please? Thanks, Nick

http://www.dealextreme.com/p/ultrafire- ... -904455241

EDIT: Bah, beaten to it

night_porter

diy wrote:

Some drivers are designed to work at multiple steps in voltage though, which accounts for why lights can run at 4.2, 8.4 or 12.6v. I have some XPG's that will take 4.2-16.8V which lets you run 1,2,3 or 4S.

This makes sense as I think I have the same XPG and it confused the hell out of me.

One thing still confuses me though is how do people know what current is being drawn if they are measuring at the tailcap?

Surely if the driver is controlling the current through the emitter the only way to know for real is to connect your multimeter by desoldering one of the legs? Is it purely maths based on the charge of the cell or am I being a numpty?