Running additional circuits off main battery

[103Alex1]

Diodes are cheap.. nothing else needed apart from your chosen switch, don't have to bother with China

I'll do you a little circuit diagram as soon as I go to the pub and get a beer mat

Its possible to use even cheaper 3A ones but here is something suitable

Great - am starting to learn lots here now

 

[Old_Dave]

Got a feeling if you go and push 36v at a T6 LED

That wasn't what was meant ...lol, read the post again

If I can be arsed... tonight I'll do a side by side test with photo of the £6.99 lamp Vs a T6 torch

 

[103Alex1]

Then the tech in me thinks an auto on light switch activated by reduced light level.

. I have one with that auto-function on my Kalkhoff - it's one of these ...

B + M Lumotec IQ Cyo RT senso plus 40 lux at a low price in the online bike shop www.rosebikes.com

... but it's for dynamo powered lighting and the main LED isn't a patch on a CREE.

 

[103Alex1]

Oh I SEE .... (I think ! lol) ... i.e. put one of these :

http://www.el34world.com/Misc/bike/images/Img_6710.jpg

in one of these housings :

Waterproof 3W 1000~1300lm LED White Light Motorcycle Headlamp - Black (12~80V)

... and then nick the 3W driver to put in a Marwi housing with heatskins etc. if the driver actually works the T6 ?

 

[Old_Dave]

Almost

Get one of the first item and stick it in the second item... done, sorted, move on

Or even simpler .. just use a few of the second item and spend time saved to drink beer

 

[103Alex1]

Almost

Get one of the first item and stick it in the second item... done, sorted, move on

Or even simpler .. just use a few of the second item and spend time saved to drink beer

Mutter mutter ... T6 heatsink and melting housings ? ... what what ... hmmmm ... where's that beer ?

PS - here is what has come back from the Marwi light guy :

Sounds like a one-stop shop after all potentially :

Marwi Bullet - XML - 2800ma Multi Mode driver - Page 2

So I can just pre-set T6 current near-as by leaving on as many of the chips as I want in 350ma modules. I can't understand what he means by "limiting 350ma current" - does that mean one chip blocks 350ma current against the total maximum current serving the unit, or allows only that much current through and blocks the rest ?

... just looked at this ... doesn't look THAT bright even at 2.8A !!!

Marwi Bullet - XML - 2800ma Multi Mode driver - Page 2

... I need to go ride my bike to clear head. Confucious say confusion besets the man who thinks too much.

 

[Old_Dave]

So I can just pre-set T6 current near-as

Then just go for the simple resistor current limiting method rather than chips ...... use resistors to T6 pcb and adjust your variable 36v to XXv so that the voltage on the pcb is 3.3v (or what ever its supposed to be)

doesn't look THAT bright even at 2.8A

But thats only one lamp... your having a bar full (collective noun = candelabra)

 

[Scimitar]

PS - here is what has come back from the Marwi light guy :

Sounds like a one-stop shop after all potentially :

Marwi Bullet - XML - 2800ma Multi Mode driver - Page 2

So I can just pre-set T6 current near-as by leaving on as many of the chips as I want in 350ma modules. I can't understand what he means by "limiting 350ma current" - does that mean one chip blocks 350ma current against the total maximum current serving the unit, or allows only that much current through and blocks the rest ?

Looks like that's the answer - you can leave all four chips in place for 1.4A per head, or disable one or two for a lower output per head.
Much better than a simple resistor, as all a resistor does is dump valuable battery energy as heat, to no good useful purpose. Unless you position the resistors under the saddle and warm your donkey.
I wouldn't pay too much attention to the apparent brightness of the photos, it's all dependent on the exposure values and a photo session is only of any value if the exposure settings are exactly the same for all the lights being tested.

 

[Old_Dave]

all a resistor does is dump valuable battery energy as heat, to no good useful purpose.

What you say is of course correct..

But p)

If the intended purpose was to drop many volts then it would indeed be a waste, however using the adjustable output of the power supply to take care of the voltage then the resistors function would be that of 'current limiting' and the heat wastage would / should be minimal

 

[103Alex1]

What you say is of course correct..

But p)

If the intended purpose was to drop many volts then it would indeed be a waste, however using the adjustable output of the power supply to take care of the voltage then the resistors function would be that of 'current limiting' and the heat wastage would / should be minimal

Okay ... what am I missing ? Does it make any difference whether I use chips (seems the boards come with 4 chips each limiting 350ma current and if you don't want to use all that or want to use the in-built current limiter chips then you actually have to take them off). Don't the chips and the resistor do exactly the same thing in the non-multimode version Marwi guy linked for me ?

I could actually vary the number of chips removed to make my highest powered lamp brighter than the rest by limiting less current than the others (and hence achieve my car with undipped headlights flasher-unit setting after all ?)

I still cannot work out what is best as far as supplying the voltage to the lights or how many step-down voltage reducers to use. Tillson has convinced me the one he recommended is good, has been bench tested and allows up to 3A total current draw... but it outputs a fixed 9V.

This one which arrived today, can output anything from 1.25v upwards but is only good for 1.5A-2A with the inbuilt heatsink, unless an additional heatsink is incorporated :

LM2596HV DCDC Step Down Converter Adjustable Heatsink | eBay

... and therefore I am guessing won't run say 3 CREE lights and a tail-light off the one converter without further mods (as they will together draw more than 2A probably). Does that make sense / have I understood right ?

I can limit to whatever voltage works with a DC-DC as long as it's the right converter and safe / efficient. I have no preference one way or the other which voltage or which converter, or at this stage whether it's £2 or £25, just that it works safely and well lol. If the current can be limited at the lights using chips which come already supplied with the driver board then my logic says just use them ... if I know what current to limit to and what effect that has on the light brighnesses.

 

[103Alex1]

Unless you position the resistors under the saddle and warm your donkey.

Now joking aside .... there's something of a guilty attraction to having a warmed up donkey on a cold Winter's day ... but not sure I'd want my bottom any hotter on a sweaty Spring ride (I say Spring because that's when we get our Summer if recent years are anything to go by )

 

[Old_Dave]

Im reserving any further comment until it's dark enough for a photo shoot of the T6 comparison


Sent from my iPhone using Tapatalk

 

[103Alex1]

Yippee ... look forward to seeing the results .

Just unpacked boxes from sorting office which arrived while I was away last week and D8veh's connectors and springless throttle have turned up ... so I am going to have plenty to keep me out of mischief for a bit now - from fitting that brake cutoff switch, to fitting a tyre and doing a road test (hallelujah - can it finally be in sight ) and building the cruise control.

Be good to decide on the lighting plan, get my orders for bits in and have them winging their merry way to me whilst I'm playing with motors and throttles. The waits don't seem so long when you're busy building the bits you've got. .

 

[Old_Dave]

Garden test shows that the T6 is brighter than the £6.99 lamp (with built in voltage reducer), or does it !! I'll tell you what it really proves after the pictures

Piccy 1
T6 beam on the right sharp focus



Piccy 2
T6 again on the right but De-focused to give approximately same beam size



Piccy 3
T6 again on the right De-focused to give approximate equal brightness



The bottom line... The led is of course a major factor, and the T6 is brighter, but the optics play a significant part in the illuminating experience, So a T6 without adjustable focus is a waste of £ compared to the all in one cheaper option.

I was going to convert one of the cheapies to T6.. but as its a plain glass lens I'll save my money.

 

[103Alex1]

When you say adjustable focus, Old_Dave do you mean a diffuser or a torch head that changes the spread as you turn it ?

I use diffuser lenses on both the little T6 lights I have - they're about £5 off e-bay if I remember right.

The magicshine clone T6 type lights everyone buys do not have a focus so far as I am aware, but are reckoned to be a world better than many lights costing 5 times as much by pretty much everyone I've read posting about them. Something ain't adding up for me now and confusion rears its head once again ....

Is this why some people keep recommending torches over fixed lights for mounting on bike handlebars ? The adjustable focus ? First time I've ever seen this point being raised.

 

[Old_Dave]

I mean....For the brightest pool or spot of light at distance x then the beam needs to be focused at that distance...

Non focused / flood light just relying upon like for like reflector size...IMHO whilst the T6 Has greater lumens... It's not that much better than the 3W led in the cheap lamp.






Sent from my iPhone using Tapatalk

 

[103Alex1]

OK - understood. That's definitely something to think about when evaluating the costs and effort.

Going right back full circle to where I started a few days ago, my original thoughts were to run 2/3 of the cheap ones as "low beam" wide flood near distance lamps. Then have a beam-up switch to turn on the CREE(s) for longer throw and brightness. There could be one or two of these brought on by circuit settings 2 and 3 all as sequential additions leaving the others on.

It all got derailed when it appeared that the cheap lights and the CREEs were running at different voltages so couldn't be hooked up to the same buck converter ... and more so when it then appeared the CREEs had the multimode which was going to over-complicate rigging up to a handlebar switch.

So, where we now seem to have got to is that there's an easy workaround for the single LED CREEs simply by using an AM7135 board in place of the usual CREE driver boards... but I am told quite clearly that these driver boards mustn't be used at a voltage exceeding 5A. The housing complications can be got round by using Marwi housings instead of trying to modify the usual magicshine-style housings. So far so good.

I think the point I'm taking from your experiment is that (as I suspected), it's a waste of money using CREEs for near-distance flood lighting. That accords with my own thinking !!! It's the longer throw power lighting I originally wanted to use T6s for.

(Hesitates) ... it the answer really very simple then - just get 2 high-powered CREE T6s to run at 5V, set them so as not to overload the current capacity of the relevant buck converter, and add in 2 x cheapie front ones + 1 x rear light in series which can run at 5V and use the remaining available current capacity of the 5V buck ?

... or even simpler maybe ...

1) 2 front cheapies + 1 rear (with diode ) to come on when the bike's turned on (and always be on) ... via a 12V buck if needs be ... plus ...

2) 2 CREEs in parallel off a separate circuit run at 5V to come on via my handlebar switch as supplementary lights (Off - ONE - BOTH settings as needed). I can run them both at up to 1.4A each if the buck / DC-DC converter can run 3A with no additional resistors / no mods to the current limiter chips on the standard replacement boards. Just fit and connect. Or so it seems... ?

Has what was unfeasibly complicated this morning now become relatively straightforward with exploring all the options ? Or have I missed a problem in my ever so hopeful "summing up" ?

 

[Old_Dave]

And that M'lud concludes the case for the defence


Sent from my iPhone using Tapatalk

 

[103Alex1]

Lol. So ..... have I basically got it eek: ... after heaven knows how many attempts ) ... ? There will be more questions to come on "how to do it" (unfortunately) but at least if I can fix what it is I'm doing that'll be a big achievement (all things considered lol !!)

If so, I found this buck converter which claims to "do 5V max 3A" to use on the CREE circuit.

DC DC HRD Converter Regulator 12V 24V 36V Step Down to 5V 3A Buck Input 12 50V | eBay

But it's untested. And from Shanghai eek.... and no mention of heatsinks confused: - why ? should there be ?) and so I am worried. Should I be ?

I have one of these in me hand already too ...

LM2596HV DCDC Step Down Converter Adjustable Heatsink | eBay

... but rated for 1.5A unless there's another heatsink (and I've no idea how to adjust it or fit a heatsink !). Would it be easier / safer to use this and fit another heatsink ?

Bloomin 'eck - so many questions !!!

 

[Scimitar]

Right, here's something else to cloud the issue, but pick and choose to suit yourself.
I discovered these pages because I'm looking to re-life a pair of what were expensive yard torches, both running off 6V SLAs and was utterly fed up with the rate of bulb loss, so decided to bring them up to date with a nice T6 in them.
Firstly, the T6...
https://www.fasttech.com/products/1136804
Secondly, the current-limiting module that suits my application...
https://www.fasttech.com/products/1612/10001268/1105800

And the page those drive units come from...
https://www.fasttech.com/category/1612/diy-kits-parts-led-drivers