power from battery to front light

Boomer

Finding my (electric) wheels
Nov 10, 2009
10
0
Hi

I have just ordered a electric kit for my bike, and while waiting I wonder if it will be possible to get power from the Li-Ion battery to the front light??

I have so far used a son hub dynamo with a B&M Lumotec Plus Oval light, and been very happy with it. My new kit comes with the motor on the front wheel, so I have to give up the hub dynamo:( Any smart solutions??:)

Best regards
Boomer
 
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flecc

Member
Oct 25, 2006
53,521
30,822
Let us know what voltage your new battery will be and someone may know of a suitable X volt to 6 volt converter. The only thing with that type of solution is that conversion has some loss so that plus the lights drain will reduce the range a bit.

Commercially I've seen two low current solutions. eZee have a set comprising a 7 series-linked LED headlamp "bulb" in series with one or two rear lamp LEDS, the 8 or 9 LEDs directly fed by the bike's 36 volt battery.

The new Panasonic unit's lighting supply circuit chops the 26 volt battery supply at high frequency with an uneven mark-space ratio, the minority "on" pulses averaging 6 volts when fed to the resistance of the filament 6 volt bulbs.
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Boomer

Finding my (electric) wheels
Nov 10, 2009
10
0
Let us know what voltage your new battery will be and someone may know of a suitable X volt to 6 volt converter. The only thing with that type of solution is that conversion has some loss so that plus the lights drain will reduce the range a bit.

.

It´s a 9.6Ah Li-Ion battery, that’s all I know:( I know minus about electric stuff, but had the thought that because the son hub produces much more than 6 v when going fast without popping the bulb, there must be some reduction built in the B&M lights.

Once a guy measured the output to 25 v when pulling the tire fast around by hand, and on a downhill surely the V most go higher. I have in 7 years never popped a bulb when going fast downhill. Anyway, I could just try and connect it and see what happens, or what:rolleyes:
 

emissions-free

Pedelecer
Oct 24, 2009
176
0
Shanghai
Boomer,

Alien Ocean do a light kit that connects directly to a 36V supply. As long as your battery is 36V it should work just fine. If the battery voltage is not marked on it, the charger should give you some clues. The charger voltage will be a bit higher than th batteries nominal voltage. Off the top of my head about 40V charger for a 36V battery and about 29V for a 24V battery.

Here's a link to the 36V lighting kit that Alien Ocean offer:
- Accessories

Thay may well have a 24V lighting kit also. As a matter of fact it should be fairly straighforward to convert to a 24V battery as it will likely just require a resistor change.

A DC-DC converter is also an option, as Flecc suggested and this would be useful if you have several parts that you wish to run but unless you're fairly handy with a soldering iron and have at least a basic knowledge of electronics, I'd stick with the drop in kit above.

The kit uses LEDs and will use very little power, much better than a filament lamp.

Hope he can hook you up :)
 

flecc

Member
Oct 25, 2006
53,521
30,822
It´s a 9.6Ah Li-Ion battery, that’s all I know:( I know minus about electric stuff, but had the thought that because the son hub produces much more than 6 v when going fast without popping the bulb, there must be some reduction built in the B&M lights.

Once a guy measured the output to 25 v when pulling the tire fast around by hand, and on a downhill surely the V most go higher. I have in 7 years never popped a bulb when going fast downhill. Anyway, I could just try and connect it and see what happens, or what:rolleyes:
Although higher voltages can be measured from dynamos, the resistance of the filament bulbs can reduce that dramatically if the current delivery level is very low, as it will be. Your battery is a different case, it won't have the slightest difficulty in delivering high current as well as it's much higher voltage and that will probably be instantly lethal to the bulbs.

The Alien kit that emissions-free mentions is a much better solution, if your battery is 36 volts.
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jerrysimon

Esteemed Pedelecer
Aug 27, 2009
3,292
112
Cambridge, UK
Yes I saw that a while back. Quite a nifty little kit if you want a simple solution to power it off your existing 36v battery.

Regards

Jerry
 

Boomer

Finding my (electric) wheels
Nov 10, 2009
10
0
Thanks guys!

I am (almost) sure its a 36v battery, so the alian ocean lights is the way I will go, and it´s not that expensive either.

Thanks again:)

Best regards
boomer