Planing to use e-bike battery to power head/tail light. Any concerns?
11-15-15, 12:06 PM
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Planing to use e-bike battery to power head/tail light. Any concerns?
I realize this is e-bike related; however, it is headlight related.
I have a 36V bottle battery for my ebike. I also have a Magic Shine clone and and a 3V (PDW Danger zone) tail light.
Instead of having several batteries on my bike, all with different chargers, I want to power the other two light from the "main" battery.
My plan is to solder leads from the Bottle Battery case, after the main on/off switch, but before the e-bike controller. Those leads would then go to a pair of voltage regulators, one for the headlight and the other to the tail light (I need two of them because they operate at different voltages).
Does this seem sane? Any concerns (I am an Amateur Extra, I know which end of a soldering iron to hold)?
The Bottle Battery
The voltage regulator
I have a 36V bottle battery for my ebike. I also have a Magic Shine clone and and a 3V (PDW Danger zone) tail light.
Instead of having several batteries on my bike, all with different chargers, I want to power the other two light from the "main" battery.
My plan is to solder leads from the Bottle Battery case, after the main on/off switch, but before the e-bike controller. Those leads would then go to a pair of voltage regulators, one for the headlight and the other to the tail light (I need two of them because they operate at different voltages).
Does this seem sane? Any concerns (I am an Amateur Extra, I know which end of a soldering iron to hold)?
The Bottle Battery
The voltage regulator
- Non-synchronous rectification non-isolated Buck (SEPIC) module.
- Input Voltage: DC 4.5-55V; Output Voltage: DC 1.25-30V Adjustable.
- Output Current: Rated 2A, Max.3A(need heat sink). If output power is more than 15W, please install heat sink.
- Short Circuit Protection: current limiting, since the recovery.
- Application: DIY Adjustable Power Supply, DIY Universal Charger, Power supply for electronic equipment etc.
11-16-15, 09:27 AM
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Do yourself a favor and use an efficient switching regulator. (I can't tell from what you posted if it is a switching regulator or not.) The front and rear light may be able to run off of the same voltage, check the specs of the lights you have. (Just because the light generally runs on X volts doesn't mean it won't accept anywhere from Y-Z volts, it just may get a little warmer.) (For example, my fenix BT-10 generally runs on 4 AAs, but has a max input voltage of 12V. I run it on ~10V just fine.) You could also put two rear lights in series so you don't have to bother with multiple regulators. In fact, two of your taillights would need 6V, which is only slightly below the 7-8 V your magicshine clone needs, you'd be fine doing that.
You don't need an adjustable regulator, a single output (7-7.5V perhaps) switching voltage regulator would be more simple. If you use a switching regulator you may be able to get away with not needing a heat sink, if you use a linear regulator you'll definitely need a head sink. Also a switching regulator will give you much longer battery life.
You don't need an adjustable regulator, a single output (7-7.5V perhaps) switching voltage regulator would be more simple. If you use a switching regulator you may be able to get away with not needing a heat sink, if you use a linear regulator you'll definitely need a head sink. Also a switching regulator will give you much longer battery life.
Last edited by corrado33; 11-16-15 at 09:32 AM.
11-16-15, 12:42 PM
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I think that plan makes sense. What voltage does the MS run off of?
a buck regulator is a switching regulator topology.
a buck regulator is a switching regulator topology.
11-16-15, 02:44 PM
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You could also put two rear lights in series so you don't have to bother with multiple regulators. In fact, two of your taillights would need 6V, which is only slightly below the 7-8 V your magicshine clone needs, you'd be fine doing that.
You don't need an adjustable regulator, a single output (7-7.5V perhaps) switching voltage regulator would be more simple. If you use a switching regulator you may be able to get away with not needing a heat sink, if you use a linear regulator you'll definitely need a head sink. Also a switching regulator will give you much longer battery life.
You don't need an adjustable regulator, a single output (7-7.5V perhaps) switching voltage regulator would be more simple. If you use a switching regulator you may be able to get away with not needing a heat sink, if you use a linear regulator you'll definitely need a head sink. Also a switching regulator will give you much longer battery life.
My reason for ordering adjustable regulators, instead of, simpler, fixed regulators, is that it is easier to find adjustable than fixed regulators that meet my needs.
The Magic Shine clone seems to run on 7.8VDC
11-16-15, 03:08 PM
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I considered the idea of two taillights in series, as you mention. My concern is that if I forget to turn them both on I would be running way too much past the other and could cause damage.
My reason for ordering adjustable regulators, instead of, simpler, fixed regulators, is that it is easier to find adjustable than fixed regulators that meet my needs.
My reason for ordering adjustable regulators, instead of, simpler, fixed regulators, is that it is easier to find adjustable than fixed regulators that meet my needs.
I've essentially made the exact same thing you are, except I used a 12V lead acid battery (not the best idea.) I also used adjustable regulators (because it's what I had laying around.)
11-17-15, 04:01 PM
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I considered the idea of two taillights in series, as you mention. My concern is that if I forget to turn them both on I would be running way too much past the other and could cause damage.
My reason for ordering adjustable regulators, instead of, simpler, fixed regulators, is that it is easier to find adjustable than fixed regulators that meet my needs.
The Magic Shine clone seems to run on 7.8VDC
My reason for ordering adjustable regulators, instead of, simpler, fixed regulators, is that it is easier to find adjustable than fixed regulators that meet my needs.
The Magic Shine clone seems to run on 7.8VDC
11-18-15, 03:12 AM
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I put DC-DC converter inside the water bottle battery holder base, (many of them has space for adding a mini motor controller board).
11-23-15, 03:49 PM
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I got around to wiring in the regulator this weekend. I already like only having to plug in one thing when I get home. I realize it seems like a little thing; but it feels like significantly less hassle.
I have not noticed any significant change in range.
I have not noticed any significant change in range.
11-23-15, 04:50 PM
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I wouldn't expect there to be a big difference in range, if any. Do you know how much power the bike motor uses?
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11-23-15, 06:47 PM
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According to the display that came with it, I normally am pulling from about 20-50W. However, a couple of days ago I was commuting into a 32mph headwind. At that point it was pulling close to, and sometimes just over, 200W.
11-23-15, 07:33 PM
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Well, there you go. 3w to power your lights isn't much to add to the load. Good idea and well done. Got pictures or schematics?
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