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  1. #1
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    Convert Philips SafeRide for use with external USB power source ?

    so SafeRide runs on 1.2V 2,600 mah batteries x 4. so it runs on 4.8V x 2,600 mah and it runs for 2 hours. which means it draws about 1,300 ma @ 4.8 V.

    USB power is 5V and up to 2A. seems like a perfect match.

    this product:

    Anker 2nd Gen. Astro2 9000mAh Portable Double-USB Port External Battery Charger

    would run the SafeRide for 7 hours on high and then recharge from flat in about 10 hours using any standard USB charger designed for tablets. in practice it would recharge much faster because you wouldn't ride for 7 hours.

    this product:

    Anker 2nd Gen. Astro3 12000mAh External Battery

    would run TWO SafeRides for 4.5 hours, and also recharge from flat in about 10 hours over USB.

    and by taking out the batteries from the main SafeRide unit it would become lighter thus reducing any kind of light mount chatter and slip which are huge problems on this light.

    i will add that i already own a similar Anker product but mine is small and only rated for 1A output which probably isn't enough. the ones i linked are rated at 3A and 4A output.

    what do you think ? would it work ? how foolproof would that project be ? is there a better way ? could it be done in a reversible way so i could then convert it back for use with internal batteries ( if i want to give it to my mom for example ).

    could there be a problem with power quality from the Anker since it probably includes some kind of electronics to convert lithium voltage to 5V. maybe the SafeRide will not be able to cope with anything other than clean DC if i simply tap into its battery contacts ?

    what if i use a small 4.8V Ni-Mh battery in parallel with the anker - will it smooth the power output of the Anker ? or will my Ni-Mh battery get destroyed by overcharging ? would there be any kind of simple solution to clean up the USB power if necessary ?

    by the way i just tried turning on the SafeRide while it is charging over USB - it won't let me do that. i have to unplug USB charger from the back of it before it will let me turn itself on. that's a real shame. it would be nice if i could simply use it without mods while plugged into portable USB power ...

    there is a Philips ActiveRide light that already has an external lithium battery, but its beam pattern isn't as optimal as SafeRide, and it costs about $100 more than SafeRide whereas the Anker is only $40.

    also as a side note, is it possible to get a new 3D mount for my old SafeRide ?

  2. #2
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    Forum user Pethelman converted a Saferide to external power and replaced the LEDs with XMLs and a new driver on a thread here a year or so ago. While that is quite different than your question it helps show something of what the Saferide platform is capable of.

  3. #3
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    Quote Originally Posted by Vancbiker View Post
    Forum user Pethelman converted a Saferide to external power and replaced the LEDs with XMLs and a new driver on a thread here a year or so ago. While that is quite different than your question it helps show something of what the Saferide platform is capable of.
    yes i know what he did. he even previously pitched that idea to me personally but i told him that project is too advanced for me. if he made a conversion kit and offered it for sale i would buy it. better yet i would send him my SafeRide with some money to have him convert it for me. but to do the whole project by myself is too much.

    what i hope to accomplish here should be comparatively very easy, and while it would not result in any extra output it would lower the weight of the light head significantly, improving its stability, and extend battery life from a very limiting 2 hours to pretty much anything you like.

    of course the simplest way to do this would be to simply use a large Ni-Mh external 4.8 battery, but how do you charge it ? the reason i'm looking at the Anker is because it recharges over standard USB power.

  4. #4
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    Quote Originally Posted by Vancbiker View Post
    Forum user Pethelman converted a Saferide to external power and replaced the LEDs with XMLs and a new driver on a thread here a year or so ago. While that is quite different than your question it helps show something of what the Saferide platform is capable of.
    i will say however if i could get that 3D mount for the saferide ( with the mount i have i can't fit two of them on my bar ) and mod the saferide with XML2s and then put two of them on the bar, i would be in heaven !

    on the road that is, let's be clear ...

  5. #5
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    Forget those battery banks. What they are doing is they are stepping up 4.2V from lion to a higher voltage and then regulate the output to 5V, which means wasting lots of energy for nothing. If you want to power up your light, just attach 1SxP 18650 pack to it and you're good to go.

  6. #6
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    Quote Originally Posted by Toaster79 View Post
    Forget those battery banks. What they are doing is they are stepping up 4.2V from lion to a higher voltage and then regulate the output to 5V, which means wasting lots of energy for nothing. If you want to power up your light, just attach 1SxP 18650 pack to it and you're good to go.
    i don't know what 1SxP is but isn't the voltage from a single lithium cell going to be too low ?

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    1SxP is 1 series x parallel cells wired pack. So 1S4P would be 4 parallel wired cells. I doubt there is a buck driver in that light. I'm almost sure it's a linear type driver of somekind, so it's turning extra voltage into heat. 4 series NiMH cells would have 5.8V fresh of the charger, and drained to a safe level something under 4V, so there isn't enough ovrhead for the buck driver when the batteries are drained. Why would be 4.2V from the LiIon be insufficient? There would be less heat produced in the driver so the whole sistem would be more efficient and at the end of discharge curve the LEDs would be probably in direct drive. Which afterall isn't such a bad thing, since the light would start dimming slowly which you would notice and would know that batteries are depleted. But if there's some other type of driver in that light, than this probably won't work, but it's still worth to try. You could also ditch the original charger, get a cheap AMC7135 based driver. This way you're single LiIon ready assuming LEDs are wired parallel (if not, rewire them)

  8. #8
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    Quote Originally Posted by Toaster79 View Post
    1SxP is 1 series x parallel cells wired pack. So 1S4P would be 4 parallel wired cells. I doubt there is a buck driver in that light. I'm almost sure it's a linear type driver of somekind, so it's turning extra voltage into heat. 4 series NiMH cells would have 5.8V fresh of the charger, and drained to a safe level something under 4V, so there isn't enough ovrhead for the buck driver when the batteries are drained. Why would be 4.2V from the LiIon be insufficient? There would be less heat produced in the driver so the whole sistem would be more efficient and at the end of discharge curve the LEDs would be probably in direct drive. Which afterall isn't such a bad thing, since the light would start dimming slowly which you would notice and would know that batteries are depleted. But if there's some other type of driver in that light, than this probably won't work, but it's still worth to try. You could also ditch the original charger, get a cheap AMC7135 based driver. This way you're single LiIon ready assuming LEDs are wired parallel (if not, rewire them)
    tell me Toaster, if 1 cell is really enough, why do the vast majority of lithium powered lights work on 2SxP ? in fact my L&M Seca works on 3SNP but it has 6 LEDs and i'm guessing they're wired pairwise in series ?

    how much voltage does an LED need anyway ? 3.3V ? does this value depend on LED model much or is it more or less the same for all white LEDs ? if it is a linear driver as you say, is there some kind of minimum voltage drop across it even when it is wide open so to speak ?

    and isn't the Philips going to cut out at some point to prevent damage to the batteries ? i wonder at what level that would be - i doubt it will be much lower than 4V ?

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    And the vast majority of flashlights uses single cell setup! Also a lot of DIY single LED lights are being driven by a single cell and a linear type of driver (AMC7135, lflex, ...). Using multiple series cells setup benefits in eficiency when using a buck driver. Also multiple series wired LEDs can be driven with lower cell number than LED number when using a boost driver. So now we've got three types of different driver topology and there are also boost/buck drivers, which can boost lover voltage from a single NiMH cell to Vf of the LED and at the same time they can step down higher voltage of 2S LiIon cells to LED's Vf, It's all about efficiency.

    Typical forward voltage depends on LED type. Red LEDs have Vf ranging at around 2V, white/blue LEDs have Vf ranging at around 3V. But 3V is typical Vf for a certain type of LED at certain current. Vf can be as low as 2.5V or as high as 4V. Not only Vf changes with current but it also changes with junction temperature of the LED.

    Linear type of drivers usually don't have voltage drop since they are limiting the current and burning the excess voltage.

    Since I haven't had a look at the Philips driver and there isn't much info out there abou it, I cant tell you if it has a voltace cut-off or not. Empty NiMH cell is concidered when it's voltage drops to 0.8V, so that makes 3.2V for 4S setup. Empty LiIon is concidered when it reaches 3V. Some even deplet them to 3.2V for longer life time. Do the math.

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    Androgen, people who have done the mod (to pick one example) report that there is both a voltage cut-off (4v) and a timer cut-off (45-70 minutes) after which the light will drop to low output & cannot be switched back to high until the circuit detects the batteries have been charged or replaced.

    How do you plan to address the timer issue ?

  11. #11
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    Quote Originally Posted by Toaster79 View Post
    And the vast majority of flashlights uses single cell setup! Also a lot of DIY single LED lights are being driven by a single cell and a linear type of driver (AMC7135, lflex, ...). Using multiple series cells setup benefits in eficiency when using a buck driver. Also multiple series wired LEDs can be driven with lower cell number than LED number when using a boost driver. So now we've got three types of different driver topology and there are also boost/buck drivers, which can boost lover voltage from a single NiMH cell to Vf of the LED and at the same time they can step down higher voltage of 2S LiIon cells to LED's Vf, It's all about efficiency.

    Typical forward voltage depends on LED type. Red LEDs have Vf ranging at around 2V, white/blue LEDs have Vf ranging at around 3V. But 3V is typical Vf for a certain type of LED at certain current. Vf can be as low as 2.5V or as high as 4V. Not only Vf changes with current but it also changes with junction temperature of the LED.

    Linear type of drivers usually don't have voltage drop since they are limiting the current and burning the excess voltage.

    Since I haven't had a look at the Philips driver and there isn't much info out there abou it, I cant tell you if it has a voltace cut-off or not. Empty NiMH cell is concidered when it's voltage drops to 0.8V, so that makes 3.2V for 4S setup. Empty LiIon is concidered when it reaches 3V. Some even deplet them to 3.2V for longer life time. Do the math.
    i guess i could test it with my 18650 cell. it has built in PCB protection anyway so i guess i wouldn't harm it. i could recharge them with my intellicharger, but how would i make the holder from which i can remove individual cells for charging ? are there 18650 holders in which you could custom wire them in parallel and be able to remove individual cells to recharge ?

    a single 18650 cell would not give me any extra life over four Ni-Mh cells. i would need at least two in parallel. and if that plan succeeds i might get a second saferide in which case i would need 4 in parallel.

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