http://citycyclingedinburgh.info/bbpress/ CityCyclingEdinburgh Forum » Topic: CR-V3 Battery. Possible Steveo-bait en Wed, 13 May 2026 03:27:56 +0000 http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-48217 Sun, 27 Nov 2011 21:35:41 +0000 steveo 48217@http://citycyclingedinburgh.info/bbpress/ <p>If you can get a 2xAA battery holder in there I've got a small 750ma driver that's only about the size of penny that'll probably fit, glue to the batter holder. Then you just need to work on the emitter.</p> <p>All this talk of "upgrading" old style lights has made me want to have a go... I'll add it to the list of stuff to do. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-48127 Sat, 26 Nov 2011 19:27:06 +0000 Uberuce 48127@http://citycyclingedinburgh.info/bbpress/ <p>Ah, I forgot about this thread. Proposed location is the shell of this bike's light...</p> <p><img src="http://farm7.static.flickr.com/6058/6303554785_13ddecf555_m.jpg"> </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46958 Thu, 17 Nov 2011 12:12:43 +0000 steveo 46958@http://citycyclingedinburgh.info/bbpress/ <p>I defy you to get a 317 circuit into the battery box of a aa light ;)</p> <p>Besides by the time you burn the over voltage off the efficiency would be terrible. You would need to drop about 1.5v at probably about 100ma for a blinky, that's about 0.15w before the losses in the regulator. The power being delivered to the blinky is only about .25w assuming 2.4v at 100ma. Given the only reason to use this battery over a pair of nimh batteries would be increased run time loosing nearly 40% of the power as heat is far from ideal. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46956 Thu, 17 Nov 2011 11:55:40 +0000 DaveC 46956@http://citycyclingedinburgh.info/bbpress/ <p>@ Steve, not a reguator kit but 3 discrete components. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46955 Thu, 17 Nov 2011 11:54:46 +0000 DaveC 46955@http://citycyclingedinburgh.info/bbpress/ <p><img src="http://i126.photobucket.com/albums/p86/Dave_Crampton/reg_cct.jpg"></p> <p>Maplins:<br /> Regulator LM317<br /> R1: Variable Resistor 500k N44BR<br /> R2: Rixed Resistor 560K M560K</p> <p>Connect up with a little veroboard (JP54J) and a soldering Iron, and then connect to battery and multimetre and adjust the Variable Res with a terminal screwdriver until the output is what you require. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46953 Thu, 17 Nov 2011 11:41:15 +0000 steveo 46953@http://citycyclingedinburgh.info/bbpress/ <p>Yeah but you wouldn't get it to fit in the battery box </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46951 Thu, 17 Nov 2011 11:29:56 +0000 DaveC 46951@http://citycyclingedinburgh.info/bbpress/ <p>You can buy a 3volt regulator from maplins, at the power you need. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46942 Thu, 17 Nov 2011 11:00:34 +0000 steveo 46942@http://citycyclingedinburgh.info/bbpress/ <p>Yeah digital cameras will have a converter to keep the voltage at what ever constant voltage they need.</p> <p>What you could do is get a 2aa battery holder from maplin and a power led of your favourite colour. I've got a couple of spare drivers that will work with that voltage range you could have. Soldering it together is simple the fun bit is deciding on the body of the light. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46896 Wed, 16 Nov 2011 22:56:18 +0000 Uberuce 46896@http://citycyclingedinburgh.info/bbpress/ <p>Ah, I guess digital cameras also have djinns inside to cope with the initial voltage... </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46849 Wed, 16 Nov 2011 15:03:36 +0000 DaveC 46849@http://citycyclingedinburgh.info/bbpress/ <p>Wiki says it may be possible, depending on exactly which battery model you have.</p> <p><a href="http://en.wikipedia.org/wiki/CR-V3_battery" rel="nofollow">http://en.wikipedia.org/wiki/CR-V3_battery</a></p> <p>CR-3V 3 volts</p> <p>RCR-3V 3.7 volts </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46846 Wed, 16 Nov 2011 14:56:58 +0000 steveo 46846@http://citycyclingedinburgh.info/bbpress/ <p>The fully charge voltage of a pair of AA's is about 2.6v the full charged voltage of the lithium battery is about 4.2v. In a front light there will be witch craft to step the voltage up to about 3.3v that the led needs. In a back light there is usually a small resistor to limit the current plus a circuit to make it flash because red leds work between about 2-2.5v. </p> <p>I suspect any "off the shelf" light will release its magic smoke if you put that battery in, its voltage is probably too far out of range for the circuitry. </p> <p>However it could be fairly simple to replace the driver and emitters in an existing light. </p> http://citycyclingedinburgh.info/bbpress/topic.php?id=4436#post-46842 Wed, 16 Nov 2011 14:36:37 +0000 Uberuce 46842@http://citycyclingedinburgh.info/bbpress/ <p>As the title suggests, I've got a rechargeable CR-V3 battery leftover from an old digital camera, and since I recall it being splendidly beefy I'd rather see it used. By me.</p> <p>Does anyone know off the top of their heads if there's lights that would take one? </p> <p>CR-V3's are the ones that are the exact same size and shape as two AA batteries if you'd wrapped them in clingfilm, and have the connections in the same place as if they were nose to tail, so they'll go in a 2xAA space if it's perfectly smooth inside. Digital cameras are made this way for that very reason, but I don't know about bike lights.</p> <p>If that's a non-starter, and this is where the steveo part comes in: how would I best go a-bodging? </p>