Building a light system with remote battery & power switch

Flashlight Modding and DIY Parts
2

I’d avoid using 2 lights, simply because you’ll end up being mistaken for a car by most drivers.

The easiest solution is a Magicshine front light (or equivalent, there are a bunch out there) and Magicshine rear light, plus a Y cord to run both off a single battery. There are a bunch of different MS clones out there so you should be able to find one that has the UI/ modes that you’re after.

Neat bike though, should be able to carry a whole load of stuff in the front, as long as you can still turn the cranks. Can a full sized adult sit in there? I just hope it has decent brakes :slight_smile:

3

The problem is that there isn’t a very good place to mount a single headlight. It can’t go on the handlebars, as the rain cover will block it. It can’t go on either side of the box, because it won’t be visible on the other side of the box. And if it goes on the very front of the box, it would be prone to knocking into things and being damaged.

Also, the stock lights (terrible little button battery things) mount on the fenders and there are two. So the manufacturer doesn’t seem particularly concerned about this problem.

Also, is it really such a problem to be mistaken for a car? If someone thinks they’re seeing a slow-moving car, what exactly might they do that would be dangerous? I will most likely also be adding some reflective tape on the front, which would not look like a car.

I’ve only found a few variations with 3-4 modes. I’ve never seen a single mode version, and I’ve spent hours looking. The MS tail light has only one version, and it has that goofy twist switch with several modes. I really want no UI at all. I want it to be, well, like a car! One switch, in the cockpit. Simple and elegant.

Not comfortably, but yes:

It can carry up to 200 pounds in the box.

It’s better for carrying kids and groceries, which is our plan for it:

4

After more searching and reading, it seems that direct drive from Li-ion batteries probably won’t work — there will be too much current.

The most obvious next step would be to use an LED driver, either a single mode one, or one where you can set the mode once and it’ll remember it. I’m not a big fan of the cost or extra complexity.

Another idea I came across is to use lifepo batteries, which provide a lower voltage that can be directly run through the LED. What I haven’t been able to find is just how much current draw this will result in.

5

There are a bunch of single mode drivers out there for not much money, so I wouldn’t let that stop you. Try kaidomain, fasttech, or maybe international outdoor.

Edit: didn’t read lifepo properly… ignore the following…
You might consider the inherent danger of a lipo battery, if it’s not in a very sturdy case. That, and the expense of a hobby charger plus possibly fire safety equipment. (Youtube lipo fire — ignore the liposuction ads.)

6

These overseas electronics websites are driving me crazy! It’s really hard to find what I’m looking for. And then I have to wait weeks to get it.

Couldn’t I just take 8 7135 chips and solder them together myself, if I don’t want all the extra multi-mode stuff? The chips are 50 cents, and available in the US with like $2 shipping from illuminationsupply.com. I haven’t found any directions on making your own circuit for them, but they look really straightforward. I think you basically just wire 8 of them in parallel. But then, a lifepo battery wouldn’t work, because its voltage isn’t greater than the LED, and any lifepo packs wired in series will exceed the 6v limit of the 7135. And that’s too bad, because I like the safety of lifepos.

edit: Looks like maybe I can use this “poorman” 7315 trick — put the 7135 driver in between the two LEDs, in series, so that the first LED causes a ~3.3v voltage drop, which would leave the driver at 2.7-3.9 volts (depending on battery charge. lifepo being 3.0-3.6v, times two batteries, minus the 3.3v drop), which is perfectly within its range. At least, I think that’s how it works… it’s not very clear to me. Poorman Mutli-Lux setup method | Candle Power Flashlight Forum

7

my comment was more from the perspective that car drivers expect certain things from objects with lights at night; one light,moving fast = motorcycle; one light, moving slow = bicycle; two lights, moving fast = car. I can’t speak for the average bike ignorant car driver, but I’d imagine that if he/ she saw a slow or (in their eyes) stationary set of 2 lights, they’ll pull out of their junction as they would expect that it’s a stopped car. That might then lead to someone pulling out on you from a side junction. Not saying it’s guaranteed to happen, but I personally wouldn’t go the twin head light route.

However, if you do, I’m struggling a bit to think of a decent set up. Running linear drivers (those AMC7135 chips you’re talking about) off one switch would require far too long of a cable run as the switch has to be in line with the battery and you’d need a driver in each light. Even with a relatively sane current, say 1 to 1.5A per emitter, that’s still going to be several amps travelling several meters. Buck drivers in each light would be a better option (lower current draw from the battery, might be able to use a low current momentary switch) and there are plenty of simple one mode buck drivers for single LEDs available.

The rear light is going to be by far the hardest one and it’ll be easiest to just make your own. Red LEDs (XP-Es) would be the best, but you have to take care matching the LED Vf (~2.2V) with the driver and battery. A buck driver driving 2 or 3 XP-Es from a 2S pack would make a hell of a bright light even at 350mA drive current.

I’ve made a lot of lights and do a lot of commuting miles at night and my personal favourites are all-in-one USB rechargeable lights that I can click onto the bike in seconds.

8

Firstly - Nice Bike!

A couple of observations.

I disagree with Matt on the two lights issue. I think it would help to define the width of the bike and also give you a nice wide low beam which should work well in an urban environment. I would actually wonder about a pod on either side of the cargo bay. White front with red read in the same unit (I’ve seen them in auto supply), this would also stop people passing to close. I’ve had my bars clipped by a wing mirror before now when some numpty thought I was on a 2D bike. People seeing a single flashy rear will think bike, give you no room and possibly clip wheels etc, the red lights either side would help with this.

The MS rear is crud. Friend of mine killed his in less than a week and that was just commuting on his fixie, nothing off road. Personally I like having a rear light that is totally independent. That way if the battery pack goes down I can at least crawl home, I won’t ride on roads at night without a working rear light. The Smart Rapid lights work well and I get about 15hrs before I notice enough dimming to justify charging it. I could go longer and still have useful output.

9

Illumination supply has the 3A 105C driver and is located in Ca. They also have bare 7135 chips and there are threads on doing that. :bigsmile: You definitely need current control for a bike light to dictate run time. A separate switch for the tail would ease the current load on a single switch(maybe under the seat).I like using Vistalight nightstick sets as a basis for bike mods but there are others like Marwi than can be had for cheap.

10

I think you are over-thinking this a bit, Mackstann. I sent you a PM. I ride a funny bike all over Portland and have great respect for very bright redundant front and rear lights for daytime use. On top of that, I also have lights for night.

The Magicshine clones do not carry current on their switch. They simply trigger the MP on the driver to change modes. They run on standby current as long as they are plugged in. This means you can go light gauge wire to a remote switch with little trouble.

I do not prefer wired batteries but for the main seeing lights I will make an exception. The clones are also good about putting out a lot of light and you can get them cheap these day. And I mean CHEAP! My last set was $21 delivered.

For daytime running lights I choose small zoomies with aspheric lenses. If you want to be a hobbyist, I have some recommendations, and if you want off the shelf, I have a couple of considerations.

The rest is math to calculate runtime and brightness levels. Knowing what you have for batteries is probably more important than anything else. Fortunately you landed in a forum with Kumabear which has some of the top of the line cells available from KeepPower. XTAR also has a great reputation for chargers in case you are looking for some.

Welcome to the forum.

11

Thanks. I do agree that I’m probably over-thinking it. I’m really frustrated that what seems to me like a simple, convenient light system for a city bike doesn’t seem to exist, but I’m not content to just let it go. Everyone wants to pop their lights off and have batteries in the lights… I don’t get that. No one wants to do that on a motorcycle or car… why on a bike? I’d rather have one battery to charge (even this I’m not exactly excited about), one switch to mess with, and nothing to remove from the bike regularly. As close to zero maintenance/hassle as possible. The fact that I’m doing this on a tadpole trike makes it a bit weird, but still, nothing like this seems to exist for 2-wheeled bikes.

The closest thing is a dynamo-powered light system, which is actually what I would prefer (and have on my city bike) — there’s ZERO batteries or switches to ever think about, but putting a dynamo light system on this trike has its own serious problems. I even looked into lights powered by magnets on the spokes (Reelights), but again, they have some unresolved issues on the trike that I’m not really confident about, and their brightness is unspecified (unbelievable!).

I could keep it cheap and simple and just use MagicShines and switch them all individually, cycling through high, low, flash, on three different lights, every time I want to turn them on or off. That would be the path of least resistance upfront. But it’s inelegant and it’s going to bother me over time. Then again, is this annoyance worth spending possibly a couple hundred extra bucks to prevent? I’m not sure.

12

sounds like you have exactly what you have in mind mackstann so go for it and make your own, then come back and let us know what you did. Suggesting other options seems pretty pointless based on your replies so far. Good luck.

13

I go through the ritual every time I ride and I will agree with you. One of the prices we pay for modes is that they need controls for each light (sort of) to keep them in sync. However, the Magicshine clone can be run in pairs off a single battery with a Y cable. Again, you can then hardwire the switches on the light remote (they are only momentary interupts on the driver) and maintain the original switch in the lights. This gets you the front lights run off one cell. Depending on runtime, you can buy 2S3P packs if you need the extended runtime. With the included battery charger, these charge very quickly for some reason. But I don’t know the charge rate. The stock batteries are not the best in the world, but again, if runtime is of a premium, high quality cells can be configured for the stock 7.2V used by the lights.

An additional Y cable can be run to rear lights. once can modify almost any flashlight head to run wired rather than calls. Just remove the body, connect the wires, and pot the driver. I would suggest finding a way to use the same remote switch (or a second one) to simply switch modes. Standby is not a common feature of the stock drivers, however. So it may be best to use the very same lights in the back as you chose for the fronts. So, for under $100, you can have 4 very bright lights on all 4 corners of the bike.

As for red tail lights, this is probably the easiest thing in the world to do. Remember Rubylith? It is available in sheets on ebay and works excellent in bike lights. Since you are in my neighborhood, I can make you some red filters if you need.

So the only thing left is a good battery pack. You have choices. You could go with Li-Ion by ganging together several of these:

they come in 1, 2, 3, and 4 cell configurations and they are internally wired and protected in a variety of configurations. The 2SnP configurations can be charged using the chargers provided with the lights.
Alternatively, you could opt for hobby cells (LiPo). These have some good properties including high discharge rates. They may be heavier and are still very expensive.
If you are planning to run the lights at their full 10W capability, you might have to consider a separate circuit or consider IMR cells rated for higher discharge rates. Then again, if you use flash modes for the rear, the light only has a 50% duty cycle, roughly.

For your power requirements, you need to think about your use case. Many of your decisions will come from that.

Have you thought about how you plan to mount these things?
Would pluggin in 2 chargers at the end of that day be just as easy as 1 (and get twice the charge rate)?
Will the stock 2S2P (4400mah) cells be sufficient for a pair of lights… 8800mah by paralleling 2 stock cells for the front and another 2 for the rear?

Having said all that, I love my 7135 drivers with their limitations being full current switching and input voltage limitation to 4.2V (5V). Short of using voltage converters (buck driver), this means high current in the lines and the switch. The plusses include current control for all your lights and there are some really nice mode options out there, up to and including custom programming for cycling. I run 17 mode drivers which provide more options for runtime and alternates for traffic patterns. I will also say that the Be-Seen modes do not require 1000 lumens. there is very little difference in being noticed at 400lm and 1000lm. The biggest difference is night riding, when you want to be able to switch your front lights to 1000lm to see the street and combat night blindness from oncoming cars.

I will also reitterate the need for different lensing for be-seen lights over seeing lights. You want a wide beam dispersion for be-seen lights. Two advantages to this is that one, you can be seen easily from people pulling out of side streets. This applies to front and rear lights… and it also removes that dangerous blinding focused beam when someone ends up aligned with the beam. A well dispersed even beam is a lot easier for drivers to tolerate.

Therefore, my setup is 2x2 be-seen lights. Modified Zoom lights at wide dispersal using aspheric lenses. The emitter is very close to the lens so they are also very efficient. The I have a light on the bow for seeing. One of the clones I spoke of, and I have a normal flashlight velcro’d to my helmet; 1000lm to draw immediate attention to whatevere I happen to look at (night rides). Now you see whay I opened this thread the way I did… charging cells has become a ritual. And yes, with a little effort, it can easily be simplified.

14

NightSpy, I think you and I are converging on a workable, Goldilocks plan. I’m realizing I should make my modifications incrementally, or otherwise risk having a grand failure that holds the bike hostage from being used at night.

I’m thinking it’ll go like this:

At first, I just buy the two MagicShine headlights and one MagicShine tail light. The headlights each come with a battery.

I can start off with zero modifications. We can just use a single battery pack. It might not last very long with three lights, but this is not a long haul bike. It’s a school and grocery store bike (both of which are close). The second battery could be used as backup. And the modes could be nice after all — at the very least, the flashing mode could be useful in the daytime.

I might need to make my own Y connector to carry the extra current of three lights. I’ll see whether the stock one gets hot or not. This would be simple.

Then, I can wire in a master power switch. It won’t be that useful at this point, but I’m trying to think of easy, incremental steps that won’t leave the bike out of commission for long. It is the family bike, after all, not just my toy.

Then, I can wire a single 2-pole remote momentary button to both headlights’s buttons (one pole per light). This will flip through their modes in unison, from the handlebar (or other convenient-while-seated position). Since each headlight has its own internal state, it is possible that they could get out of sync somehow, but I think that is unlikely to happen in normal usage.

I discovered that the MS tail light conveniently has a mode memory, simply due to the way its rotating mode switch works. So the master power switch can be used to power everything on, and the tail light will immediately go back to doing whatever it was doing the last time it was used. The unified headlight mode button can then be used to put both headlights into the desired mode. This is a pretty decent setup already, and all I did was add two switches.

Then I can move on to the battery. I could get a larger battery pack if called for (I’m still not sure what kind of runtime I will get in typical usage). I’ll play this by ear. A larger pack with more cells in parallel would be a straightforward upgrade. The old packs could still be backups. I still want to have a single battery pack. Running some heavier gauge wire isn’t that big of a deal. It’s not a racing bike. Also, I still am thinking about lifepo. I like the extra safety. It seems that the MagicShine will work on them, but the battery life indicator will be rendered meaningless (which is probably not a big deal).

Down the road, I could maybe hack the modes in the MS headlights, if I don’t like the stock ones. I can buy a third one to use as a guinea pig; if I fail, then I can maybe repurpose it for my mountain bike (which needs a better headlight anyway).

I don’t really like the idea of using a headlight or flashlight as a tail light, because they’re opaque on the sides. I think it’s important that the tail light should be visible from the side, like the MS tail light is (its lens is convex, instead of being recessed like a headlight/flashlight).

I also think it might be good to have some amber or red side “be seen” lights on the front wheels (or sides of the front box), but I will leave this idea on the table for now. I do plan on adding reflective tape to the front wheel fenders, which should be helpful in making them visible to cars from the side/rear.

I do plan on using the wide/elliptical lenses on the headlights, which seem to be better for city use.

I have thought about mounting but I don’t have solid plans yet because I’ve been hung up on the electronics. I think mounting will be easier. I’m not really worried about it.

Questions:

If the stock 2S2P pack can’t supply enough current for these three lights, what will happen? Will I just get less light output and worse battery life? Or could it be dangerous (overheating batteries, fire, self-destruction, etc.)?

Running a pack with more cells in parallel should also increase the amount of current it can give, right?

15

A couple of things… you shouldn’t have issues with running lights in parallel. In full power mode, it is still only 3 amps or so not including the rear light. With the 2P arangement, that is only 1.5C per cell. Magicshine has become very good about telling you exactly what cells they use so you can do the math and calculate that. In general, the risk is battery life.

I do understand the side light advantage. I have a lot of area that my rear lights reflect off of. So I feel that I do get an advantage there at night. Duringg the day, nothing short of a full burst “in your face” will wake up the sleep deprived Portlandians. Side visibility becomes my least concern specially since they see me coming …and going a mile away. My light cone angle is 90 degrees without reflections. And since sidelights are primarily a nightime advantage, this is the purpose for the helmet light… I can truly get anyone’s attention just by looking at them, very quickly and urgently if needed. the heavy frame pillars in today’s cars are the primary problem with being noticed by side traffic.

And yes, newer underestimate the usefulness of reflective surfaces. They are typically the go-to solution for real nightime visibility. I run tires with reflective sidewalls exclusively for this reason. The only limitation to this is the fact you actually need light to activate the reflective properties… d’uh!

I forgot to mention that I do also have a Mars 3.0 blinky on the back of the helmet too.

I would like to play with one of the magicshine tail lights. It is not the brightest thing in LEDs and the side lights are only a few 5mm basic leds. Nothing spectacular. There really are some much better solutions in the realm of 180 degree visibility on the rear. None are as cheap, however.

And there is a lens at Amazon you might be interested in… I have one and it does work:
http://www.amazon.com/Angle-MagicShine-Gemini-Lights-Headlight/dp/B004WLCLQY/ref=sr_1_7?ie=UTF8&qid=1357851720&sr=8-7&keywords=magicshine

Also, if your headlights go out of sync, with a 2-pole mode remote switch, you can always use the switch at each light to re-sync them. No need to remove the stock switch.

16

Yep, I have it on my wish list!

Yeah, or I could cycle the main power. I imagine it would be a rare event (probably mostly triggered by the kids playing around).

Thanks for all the help.

17

Instead of using more small cells in parallel, which can mess up the balance of the cells over time, is there any reason not to just use two of those really giant cells (D, M, 26650) to get the desired Wh at 7.2v?

18

18650 is the cell that most manufacturers of computers are interested in so people like Sanyo and Panasonic, the leaders int he industry, are going to put effort in. At 3400mah capability in the Panasonic 18650, it is hard to beat that kind of power density in other formfactors at this time. that is not to say it may not serve you better, but you will be hard pressed to gain 25% on a much larger cell.

Balancing Li-Ion is not an issue if you start out with quality cells with similar useage. Mixing and matching cells after a year’s unrelated use, then maybe you should use caution. This is only an issue in series; not so much parallel.

You will find the capacity correlations here in Kumabear’s battery listings. It is a good quide for understanding today’s tech.

19

I see. I just realized that IMR batteries have similar safety characteristics of LiFePo but have the usual 3.7 voltage — those could be a winner. It looks like the MNKE 26650 IMR batteries could be a good option. I’m not too concerned about physical size, really, as long as it’s not absurd. It’ll just be mounted in some kind of box on the bike frame, out of the way.

20

Sounds like you’re set :cowboy_hat_face:

21

They must stay dry. Protect them from rain and spray.