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Charging 8.4V Li-Ion packs for front lights



 
 
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  #11  
Old November 2nd 14, 03:54 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Charging 8.4V Li-Ion packs for front lights

Jeff Liebermann wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:

Amazon doesn't seem to have many 4.2V lights anymore.


Search Amazon, eBay, and DX.com for "18650 bicycle light". You should
find plenty. Amazon shows 2,629 hits of which 615 are bicycle
headlight specific.


Sure, but generally that's 8.4V lights these days AFAICS.


You need one of these. 4200 lumens:
http://www.amazon.com/SecurityIng%C2%AE-Waterproof-Temperature-Headlight-Rechargeable/dp/B00K7SRZ4Y


Amazing! I didn't want to illuminate a stadium though and this could
leave a major gash when turfing the MTB,

--
Regards, Joerg

http://www.analogconsultants.com/
Ads
  #12  
Old November 2nd 14, 04:03 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Charging 8.4V Li-Ion packs for front lights

somebody wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:


You can get a USB-to-8.4 converter from dx.com and charge it using a
normal 5 volt supply. I have one and it cost $3.

I don't need USB because the bikes stay in the garage. Well, at least
since I am married they do :-)


I bring the pack into the cube at work to top off the charge. Just
because I can.


Slightly off topic: Many of the newer Chinese lights run from 4.2
volts. I have one that uses 4 18650's in parallel. Much cheaper to
build and simpler charging.

Newer ones? I looked at some 4.2V solutions but it seems they are going
out of style. It sure would be simpler and I could easier splice in a
Portland 1/2W rear light that normally takes two AAs. The downside is
that when the Li-Ion is down to 3.5V or so the converter in the light
would need to draw around 3.5 amps to get it to run at full brightness.
That's a bit much for the cable and causes voltage drop.

Amazon doesn't seem to have many 4.2V lights anymore.


Both lights came from dx.com. I avoided the really cheap and really
expensive ones. Both worked out OK. The 8.4 volt pack runs a tail
light now.


If those are around 1000 lumesn or more, which ones at dx.com? Prices
for head lights seem to be higher there than Amazon.


It would be nice to have something that can put at least a little charge
back into a Li-Ion and a hub dynamo at a good speed could deliver 5W.
For example by switching to a very low power mode or strobe when the
charge level becomes iffy. But neither my road bike nor my MTB has that.
A roller dynamo would be nice because it can (sometimes) be retrofitted
without a major wheel rebuild.


It would be nice to try a hub dyno just to see it in action. Think of
it as a bucket list item.



Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.

--
Regards, Joerg

http://www.analogconsultants.com/
  #13  
Old November 2nd 14, 04:13 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default Charging 8.4V Li-Ion packs for front lights

On 11/1/2014 11:51 PM, Jeff Liebermann wrote:

You need one of these. 4200 lumens:
http://www.amazon.com/SecurityIng%C2%AE-Waterproof-Temperature-Headlight-Rechargeable/dp/B00K7SRZ4Y


Is that all?



--
- Frank Krygowski
  #14  
Old November 2nd 14, 04:35 PM posted to rec.bicycles.tech
Ralph Barone[_3_]
external usenet poster
 
Posts: 321
Default Charging 8.4V Li-Ion packs for front lights

Joerg wrote:
somebody wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:


You can get a USB-to-8.4 converter from dx.com and charge it using a
normal 5 volt supply. I have one and it cost $3.

I don't need USB because the bikes stay in the garage. Well, at least
since I am married they do :-)


I bring the pack into the cube at work to top off the charge. Just
because I can.


Slightly off topic: Many of the newer Chinese lights run from 4.2
volts. I have one that uses 4 18650's in parallel. Much cheaper to
build and simpler charging.

Newer ones? I looked at some 4.2V solutions but it seems they are going
out of style. It sure would be simpler and I could easier splice in a
Portland 1/2W rear light that normally takes two AAs. The downside is
that when the Li-Ion is down to 3.5V or so the converter in the light
would need to draw around 3.5 amps to get it to run at full brightness.
That's a bit much for the cable and causes voltage drop.

Amazon doesn't seem to have many 4.2V lights anymore.


Both lights came from dx.com. I avoided the really cheap and really
expensive ones. Both worked out OK. The 8.4 volt pack runs a tail
light now.


If those are around 1000 lumesn or more, which ones at dx.com? Prices
for head lights seem to be higher there than Amazon.


It would be nice to have something that can put at least a little charge
back into a Li-Ion and a hub dynamo at a good speed could deliver 5W.
For example by switching to a very low power mode or strobe when the
charge level becomes iffy. But neither my road bike nor my MTB has that.
A roller dynamo would be nice because it can (sometimes) be retrofitted
without a major wheel rebuild.


It would be nice to try a hub dyno just to see it in action. Think of
it as a bucket list item.



Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.



Joerg, I'm running rim brakes with my hub Dynamo.
  #15  
Old November 2nd 14, 04:44 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Charging 8.4V Li-Ion packs for front lights

Ralph Barone wrote:
Joerg wrote:
somebody wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:


[..]

It would be nice to have something that can put at least a little charge
back into a Li-Ion and a hub dynamo at a good speed could deliver 5W.
For example by switching to a very low power mode or strobe when the
charge level becomes iffy. But neither my road bike nor my MTB has that.
A roller dynamo would be nice because it can (sometimes) be retrofitted
without a major wheel rebuild.
It would be nice to try a hub dyno just to see it in action. Think of
it as a bucket list item.


Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.



Joerg, I'm running rim brakes with my hub Dynamo.



That would get you into serious "Oh dang!" situations out here. My old
MTB has rim brakes and I quickly learned that I don't want those. Plus
the rims wear down really fast.

Even 6" discs up front are marginal, has to be at least 7" for even some
of the local trails.

--
Regards, Joerg

http://www.analogconsultants.com/
  #16  
Old November 2nd 14, 04:54 PM posted to rec.bicycles.tech
Ralph Barone[_3_]
external usenet poster
 
Posts: 321
Default Charging 8.4V Li-Ion packs for front lights

Joerg wrote:
Ralph Barone wrote:
Joerg wrote:
somebody wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:


[..]

It would be nice to have something that can put at least a little charge
back into a Li-Ion and a hub dynamo at a good speed could deliver 5W.
For example by switching to a very low power mode or strobe when the
charge level becomes iffy. But neither my road bike nor my MTB has that.
A roller dynamo would be nice because it can (sometimes) be retrofitted
without a major wheel rebuild.
It would be nice to try a hub dyno just to see it in action. Think of
it as a bucket list item.

Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.



Joerg, I'm running rim brakes with my hub Dynamo.



That would get you into serious "Oh dang!" situations out here. My old
MTB has rim brakes and I quickly learned that I don't want those. Plus
the rims wear down really fast.

Even 6" discs up front are marginal, has to be at least 7" for even some
of the local trails.



Just saying that Hub dynos and disk brakes don't always have to go
together. Luckily, Hub dynos come in both flavours.
  #17  
Old November 2nd 14, 06:00 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Charging 8.4V Li-Ion packs for front lights

Ralph Barone wrote:
Joerg wrote:
Ralph Barone wrote:
Joerg wrote:
somebody wrote:
On Sat, 01 Nov 2014 17:34:05 -0700, Joerg
wrote:

[..]

It would be nice to have something that can put at least a little charge
back into a Li-Ion and a hub dynamo at a good speed could deliver 5W.
For example by switching to a very low power mode or strobe when the
charge level becomes iffy. But neither my road bike nor my MTB has that.
A roller dynamo would be nice because it can (sometimes) be retrofitted
without a major wheel rebuild.
It would be nice to try a hub dyno just to see it in action. Think of
it as a bucket list item.
Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.

Joerg, I'm running rim brakes with my hub Dynamo.


That would get you into serious "Oh dang!" situations out here. My old
MTB has rim brakes and I quickly learned that I don't want those. Plus
the rims wear down really fast.

Even 6" discs up front are marginal, has to be at least 7" for even some
of the local trails.



Just saying that Hub dynos and disk brakes don't always have to go
together. Luckily, Hub dynos come in both flavours.



Yes, but the disc flavor commands a three digit investment. A bit much.
Batteries are more economical.

--
Regards, Joerg

http://www.analogconsultants.com/
  #18  
Old November 2nd 14, 06:38 PM posted to rec.bicycles.tech
SMS
external usenet poster
 
Posts: 9,477
Default Charging 8.4V Li-Ion packs for front lights

On 11/2/2014 7:03 AM, Joerg wrote:

Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.


A dynamo makes little sense on a mountain bike no matter the price.

As I pointed out, suitable dynamo wheels for commute bicycles are
available for a pretty reasonable price. Decent rims and a decent hub
dyno, though probably not for randonneuring where you'd want high-end stuff.
  #19  
Old November 2nd 14, 06:48 PM posted to rec.bicycles.tech
Joerg[_2_]
external usenet poster
 
Posts: 6,016
Default Charging 8.4V Li-Ion packs for front lights

sms wrote:
On 11/2/2014 7:03 AM, Joerg wrote:

Not really. A hub dynamo is a major change on a bike. It has to have
disc brake mounts which puts it into the $100 category. Then new
spokes, wheel asembly. The latter I don't want to really do myself
anymore so that's going to cost as well.


A dynamo makes little sense on a mountain bike no matter the price.


It does if you use the MTB for longer trips. Except for errands and
commutes which are around an hour mine are mostly 3-5h, much of it in
the dark or where I prefer to ride with lights. That's something a
battery cannot stomach without at least some recharging.

[...]

--
Regards, Joerg

http://www.analogconsultants.com/
  #20  
Old November 2nd 14, 07:21 PM posted to rec.bicycles.tech
Jeff Liebermann
external usenet poster
 
Posts: 4,018
Default Charging 8.4V Li-Ion packs for front lights

On Sun, 02 Nov 2014 10:13:47 -0500, Frank Krygowski
wrote:

On 11/1/2014 11:51 PM, Jeff Liebermann wrote:

You need one of these. 4200 lumens:
http://www.amazon.com/SecurityIng%C2%AE-Waterproof-Temperature-Headlight-Rechargeable/dp/B00K7SRZ4Y


Is that all?


9600 lumens and climbing:
http://www.amazon.com/Totoab-Bicycle-9600lumen-9600mAh-Battery/dp/B00ORO72U6/
There are flashlights with more lumens, but this is the highest rating
claimed for a bicycle head light.

I was a somewhat off on my previous power consumption estimate. I
would guess(tm) about 5 watts per LED. With 8 LED's, that is 40 watts
for this head light. At 5 watts per bottle dynamo, it would take at
least 8 bottle dynamos to power it.


--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
 




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