Led Lights 24v 36v 48v

[GM Canada]

I would like to order the led lights for my 48v system. There is no option but to add a 36v light set to my cart. Is the 36v light system good for 48v as well?

[rolf_w]

hi, I had the same questions - was ordering 48V LED lights and was told by GM that currently only 36V LEDs are available. Following a copy of my changed order:

"...I confirm after our skype conversation the following changes in our order:

1) the front and back lights are the same for all voltages, thus we still order them as foreseen
2) as the LED lamps for the lights are currently only available in a 36V version, we order for all lights 36V LED lamps
3) as 36V LED lamps have a shorter life when used with a 48V battery, we would receive replacement 48V lamps as soon as available with the next shipment

best regards

PS: to be precise - the 'light' is the entire component including fixture, reflector, cable, etc. - the 'lamp' is the LED replacement for the traditional screw type bulb.

[GM Canada]

OK, If I understand corectly you order a 36v system and somehow notify them you actually want to use it for 48v. They ship you 36v system you use that then they ship you 48v leds whent they receive them. Do they automaticaly ship the 48v leds when they get them. Is there an extra charge for the 48v leds when they come?

Gary

[rolf_w]

hi Gary, the system (battery, controller, ... and lights) we ordered was for 48V. The 'LED-bulbs' are currently available only for 36V. It is possible to use these LEDs in a 48V system, however at a reduced life time (probably, due to the higher current - maybe they are brighter though?). As we order frequently with GM we asked to ship replacement LEDs as soon as available - I don't know if they will charge any extra for LED-bulbs, these are shown on their website though without any price indication. r

[ccbreder]

maybe you can replace the LED bulbs with 48V from radio shat

[Gregte]

All you need to do to use 36 volt LED light fixtures in a 48 volt system is to put a resistor in series with the light fixture. Put in the amount of resistance required till there is a maximum of 42 volts (the voltage of a fully charged 36v battery) as measured across the light fixture. The cost for the resistor(s) is next to nothing.

Measure the current or read it in the specs and use a resistor that can handle that current. For instance, if the LED fixture draws 50ma at 36v then the watts going thru it are 1.8. This means a 2watt or higher resistor would do the job. Four quarter watt resistors in parallel equals 1 watt capability etc.

I would find burning out LEDs due to overpowering them unacceptable.

[Gregte]

maybe you can replace the LED bulbs with 48V from radio shat

All LEDs are low voltage. White LEDs are usually about 4 volts. Any more will burn them out due to too much current flow. Red LEDs are closer to 2 volts. No such thing as a 48v LED.

You put LEDs in series to increase their voltage capacity or you put in voltage regulation (current limiting) of some type.

[Jazzjerry]

Did anybody try the 36v ledlights on their 48V system yet?

I have the 36v lamps and am going to install them on my 48v system soon.
Hope somebody has some experiance to share.

Took the backlight bulb out. Only says -36v-

No watts specs found yet.

Will have to wait a bit before I receive the battery to be able to test that.

Anybody know which and how many resistors to use yet?

Best regards,

Jeroen

[Bikemad]

No watts specs found yet.
Anybody know which and how many resistors to use yet?

GM quote less than 2W operating power for both lights.

As LEDs usually require approximately 20mA (0.020Amp) of current, I would suggest using a single 680 Ohm 1/2 Watt resistor (or two 330 Ohm 1/4 watt resistors wired in series) for each of the two lamp units.

This should effectively reduce the 48V supply voltage (and also limit the current) to a safe level, suitable for the 36V LED lamps.

Alan
 

[GM Canada]

Did anybody try the 36v ledlights on their 48V system yet?

I use 36v lights on my Hybrid 48 volt bike. Three months so far no problem. I asume they will not last as long as if they were on a 36 volt system but they seem to be working fine.

Gary

[Jazzjerry]

Hello Gary,

I think I will go with your solution. Please keep me updated on when your bulbs blow or not at all.
I will keep you updated as well. Can always ad some resistors but when it seems to work fine why alter.

Best regards,

Jeroen

www.beeldhout.nl

[Leslie]

Ive tried a few things.  Resistors get too hot and so do linear regulators and need a big heat sink.

At one stage I used 3 lm317t chips to bump the voltage down to 12v the efficiency was really bad.

http://goldenmotor.com/SMF/index.php?PHPSESSID=63448252dcf451bd7f5405a6a4fff502&topic=1566.0


Design based on the LM2576HV.

Components.

LM2576HV 5 pin simple switcher IC. Data sheet<<<<
Hand wound 1650uh inductor.

1,2k series metal resistors feedback divider from ground.

10.54k series metal resistors, in series with 5k variable resistor with 1.4k parallel resistor = 1.2k. 10.54k to 11.7k total feedback divider from output.

100uf input filter capacitor

25v 2200uf capacitor output filter capacitor.

Heatsink.

Hand drawn diy etched circuit board.





Specs:
Input:  Tested on  48v 36v and 24v packs.  OK

Output:12v to 13.2v adjustable.

500ma to 750ma efficient regulation.

75% to 85% efficiency.  Unconfirmed but it runs very cool.  Just above ambient temperatures.

Switching speed 52khz

I can make these regulate 60v to 3v however I want to run these on 12v auto leds and any and all 12v products, If you rewind the inductor with heavier gauge enamel copper and less turns you can draw 3 amps out of the lm2976hv chip.  I wanted efficiency in the 500ma range.

These chips can also be used as drivers for fets for higher voltages and much higher currents.


Above is a link and post is the best solution I could find.  I can make these DC converters over the afternoon.

This one is designed to do led's at 12v and could easily be modded to run a 36v output from a 60v max with great efficiency with up to 3amps current.

The above has been tested on 24v, 36v and a 48v input.  Though it best efficient at 48v input with 12v~13v output. For 37v around at 500ma use a largish yellow iron powdered inductor rated at 50khz with about 1200uh of turns on it with .5mm copper magnet wire.

R1 can be between 1 k and 5k. At 36v Id look at around 3k.  So R2 would be around 80k.

Here is the data sheet for the lm2576hv.

http://www.jaycar.com.au/images_uploaded/LM2576.PDF

If you decide to do this I will discuss more and give you some suggestions on how to wind the inductor.

[Leslie]

Here is a schematic to guide you along the way.

These can be done on a proto board too.

[muzza.au]

G'day Leslie,

I would be interested in building this kit of yours for myself to be run off anywhere from 24v to 60v. I'm considering putting one of a pair of LED car driving lights onto my bike for its brightness and look. See attached picture. Could you give a list of components needed and how to build and tune it.

Muzza

[Rafa]

you can use a Dc-DC converter, switch technology, pin out compatible with LM78xx and efficience up to 98%

Visit: http://www.recom-international.com/pages/listSeries.php?line=INNO&productfamily=Switching+Regulators+R-78

It is a good product.