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Battery Replacement on Lights with Internal Li-Ion Batteries



 
 
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  #1  
Old February 6th 18, 07:52 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default Battery Replacement on Lights with Internal Li-Ion Batteries

My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon. These lights don't have user-replaceable
batteries, but by removing two screws I was able to open it, and the
battery pack does have a connector on it so at least they didn't solder
it directly to the printed circuit board.

It's a 2 cell 18650 pack with the batteries in parallel, and a
protection circuit board shared between the two cells. The cells are
allegedly 2800mAH, for a total of 5600mAH. The closest I could find
on-line was a 2x2600mAH parallel pack
https://www.amazon.com/dp/product/B003SH4BV6.

I moved the connector from the old pack to the new pack, plugged it in,
and closed it up. Seems to work fine now.
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  #2  
Old February 6th 18, 10:07 PM posted to rec.bicycles.tech
Ian Field
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Posts: 250
Default Battery Replacement on Lights with Internal Li-Ion Batteries



"sms" wrote in message
news
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon. These lights don't have user-replaceable
batteries, but by removing two screws I was able to open it, and the
battery pack does have a connector on it so at least they didn't solder it
directly to the printed circuit board.

It's a 2 cell 18650 pack with the batteries in parallel, and a protection
circuit board shared between the two cells. The cells are allegedly
2800mAH, for a total of 5600mAH. The closest I could find on-line was a
2x2600mAH parallel pack https://www.amazon.com/dp/product/B003SH4BV6.

I moved the connector from the old pack to the new pack, plugged it in,
and closed it up. Seems to work fine now.


My favourite is recycle bin rescues - with a £0 price tag; life expectancy
isn't something to get traumatised about.

Most laptop packs are 2 or 3P-3S, you can split them up as series or
parallel pairs A/R.

  #3  
Old February 6th 18, 10:16 PM posted to rec.bicycles.tech
Joerg[_2_]
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Posts: 6,016
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On 2018-02-06 13:07, Ian Field wrote:


"sms" wrote in message
news
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking
it apart, I saw that the batteries were made in July 2015. Not too
good for it to stop working that soon. These lights don't have
user-replaceable batteries, but by removing two screws I was able to
open it, and the battery pack does have a connector on it so at least
they didn't solder it directly to the printed circuit board.

It's a 2 cell 18650 pack with the batteries in parallel, and a
protection circuit board shared between the two cells. The cells are
allegedly 2800mAH, for a total of 5600mAH. The closest I could find
on-line was a 2x2600mAH parallel pack
https://www.amazon.com/dp/product/B003SH4BV6.

I moved the connector from the old pack to the new pack, plugged it
in, and closed it up. Seems to work fine now.


My favourite is recycle bin rescues - with a £0 price tag; life
expectancy isn't something to get traumatised about.

Most laptop packs are 2 or 3P-3S, you can split them up as series or
parallel pairs A/R.



In many areas they won't let you dive into recycling bins. You'd almost
have to lie in wait, dart out and yell "Yo, don't hand over that laptop
just yet!". Otherwise when it's in there it's in there and not coming
back out.

--
Regards, Joerg

http://www.analogconsultants.com/
  #4  
Old February 7th 18, 03:56 AM posted to rec.bicycles.tech
Frank Krygowski[_4_]
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Posts: 10,538
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On 2/6/2018 1:52 PM, sms wrote:
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon.


Some of my bikes have dynamos that are 30 years old. They just keep
going and going and going...

--
- Frank Krygowski
  #5  
Old February 7th 18, 04:16 AM posted to rec.bicycles.tech
John B.[_3_]
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Posts: 5,697
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On Tue, 6 Feb 2018 21:56:16 -0500, Frank Krygowski
wrote:

On 2/6/2018 1:52 PM, sms wrote:
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon.


Some of my bikes have dynamos that are 30 years old. They just keep
going and going and going...


And I doubt that your generators cost $150 ($180 with a box) either
:-)

--
Cheers,

John B.

  #6  
Old February 7th 18, 05:48 AM posted to rec.bicycles.tech
Jeff Liebermann
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Posts: 4,018
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On Tue, 6 Feb 2018 10:52:50 -0800, sms
wrote:

My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon. These lights don't have user-replaceable
batteries, but by removing two screws I was able to open it, and the
battery pack does have a connector on it so at least they didn't solder
it directly to the printed circuit board.


I don't see a problem. If your wife used the light every day for
about 2 years, that would be 730 charge cycles. That's about the
correct lifetime for a 60% DoD (depth of discharge). See table 2:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries

Charging the batteries in parallel with a 2A USB charger is also about
right. For two alleged 2800mA-hr cells in parallel, that would be
about 0.35C charge which is quite safe.

I've found that the cells that die quickly are usually helped along by
a charge circuit that overcharges the battery. 4.2v should be the
absolute maximum. LiIon loses about 10% of it's capacity during the
initial rapid discharge from 4.2 to 4.0V. While I don't like losing
the 10%, the battery will last much longer if only charged to 4.0v.
Charging to 3.92v yields the best compromise between two failure
mechanisms (electrolyte oxidation and growing crud on the anode). See
"summary" section:
http://batteryuniversity.com/learn/article/bu_808b_what_causes_li_ion_to_die

It's a 2 cell 18650 pack with the batteries in parallel, and a
protection circuit board shared between the two cells. The cells are
allegedly 2800mAH, for a total of 5600mAH.


Seems rather high. Note that batteries are tested at a 0.2C
discharge, which yields larger numbers than the usual headlight
discharge rate. The Lezyne Deca 1500XXL claims 1500 lumens, which
also seems a bit high. Assuming 120 lumens/watt at a nominal
3.7V/battery, that's:
1500 / 120 / 3.7 = 3.4A
to run the headlight at full brightness, or 1.7A per cell.
Meanwhile, the cell capacity is tested at:
0.2 * 2800 = 0.56A

The closest I could find
on-line was a 2x2600mAH parallel pack
https://www.amazon.com/dp/product/B003SH4BV6.


Notice that his version:
https://www.amazon.com/Tenergy-Li-ion-2200mAh-Rechargeable-Battery/dp/B002Y2LJW0/
is series connected, but claims only 2200ma-hr. Kinda looks like the
same cells, but wired differently. Looks like the one you purchased
might be lying about the battery capacity. You'll find out soon
enough if the battery is discharged faster than expected.

Ready to buy a battery discharge tester
http://www.westmountainradio.com/cba.php
and a lux meter?
https://www.ebay.com/itm/391973339920
https://www.ebay.com/itm/401324425264

I moved the connector from the old pack to the new pack, plugged it in,
and closed it up. Seems to work fine now.


Yeah, for how long will it work? Dig out your digital volts-guesser
and measure the EoC (end of charge) voltage. If it's over 4.2v, that
may be why it died early. Also, see how long it will run. You don't
want it going out prematurely on the initial test run. Maybe carry a
2nd headlight for the initial testing.

--
Jeff Liebermann
150 Felker St #D
http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558
  #7  
Old February 7th 18, 07:06 AM posted to rec.bicycles.tech
Tosspot[_3_]
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Posts: 1,563
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On 07/02/18 03:56, Frank Krygowski wrote:
On 2/6/2018 1:52 PM, sms wrote:
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking
it apart, I saw that the batteries were made in July 2015. Not too
good for it to stop working that soon.


Some of my bikes have dynamos that are 30 years old. They just keep
going and going and going...


I bet the lights don't, as he peers at a collection of CYOs[1] and a
recently defunct Flat-S. Tbf the Flat S is around 7 years old.

[1] Not one lasted 18 months, they simply aren't waterproof imho.
  #8  
Old February 7th 18, 03:38 PM posted to rec.bicycles.tech
SMS
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Posts: 9,477
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On 2/6/2018 8:48 PM, Jeff Liebermann wrote:

Notice that his version:
https://www.amazon.com/Tenergy-Li-ion-2200mAh-Rechargeable-Battery/dp/B002Y2LJW0/
is series connected, but claims only 2200ma-hr. Kinda looks like the
same cells, but wired differently. Looks like the one you purchased
might be lying about the battery capacity. You'll find out soon
enough if the battery is discharged faster than expected.


Tenergy has several different 18650 cells at different capacities.

I guess I should have gotten these 9800maH 18650 cells:
https://www.walmart.com/ip/8-pcs-Universal-18650-3-7V-9800-mAh-Rechargeable-Lithium-Batteries-Tip-Main-Batery-Cell-For-Flashlight-Torch-Camera/866646151.
9800mAH and only $1 each. But I'm waiting for the new 10,000 mAH cells.
  #9  
Old February 7th 18, 04:01 PM posted to rec.bicycles.tech
AMuzi
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Posts: 13,447
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On 2/7/2018 12:06 AM, Tosspot wrote:
On 07/02/18 03:56, Frank Krygowski wrote:
On 2/6/2018 1:52 PM, sms wrote:
My wife's Lezyne Deca 1500XXL stopped taking a charge, at
all. Taking it apart, I saw that the batteries were made
in July 2015. Not too good for it to stop working that soon.


Some of my bikes have dynamos that are 30 years old. They
just keep going and going and going...


I bet the lights don't, as he peers at a collection of
CYOs[1] and a recently defunct Flat-S. Tbf the Flat S is
around 7 years old.

[1] Not one lasted 18 months, they simply aren't waterproof
imho.


My regular glass bulb lamps go 6~8 years between bulb
failure in daily use. YMMV

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971


  #10  
Old February 7th 18, 04:22 PM posted to rec.bicycles.tech
JBeattie
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Posts: 5,870
Default Battery Replacement on Lights with Internal Li-Ion Batteries

On Tuesday, February 6, 2018 at 7:16:12 PM UTC-8, John B. wrote:
On Tue, 6 Feb 2018 21:56:16 -0500, Frank Krygowski
wrote:

On 2/6/2018 1:52 PM, sms wrote:
My wife's Lezyne Deca 1500XXL stopped taking a charge, at all. Taking it
apart, I saw that the batteries were made in July 2015. Not too good for
it to stop working that soon.


Some of my bikes have dynamos that are 30 years old. They just keep
going and going and going...


And I doubt that your generators cost $150 ($180 with a box) either
:-)


My generator and light cost almost five times the price of my little L&M Urban 800 all-in-one, which produces more light. Hub was $110 on sale at Western Bikeworks (SP PD8), and the Luxos B was around $120 OTC from Clever Cycles in Portland. Throw in time for building front wheel. I got the all in one on sale for around $45.

Now, the battery life on the Urban sucks, and forgetting to charge is a reality -- so it's not as convenient as a dyno light, but I can switch it around between bikes. I've been switching between two bikes for commuting lately due to mechanical issues. One bike has a through-axle and the other doesn't, so switching dyno lights would be impossible. I'd need a dyno hub with 15mm through axle which, on its own, can cost as much as $200. I would also have to get a handlebar mount since there is no through hole on the crown of either of my disc bikes. I miss that and once I get a bar mount, I'll go back to using my Luxos B on the commuter, but I'll also use my little flea-watt back up blinky on the bar. I think low watt flashers or pulsing (rather than bursting flash-bulb) flashers are good in urban bicycle and car traffic.



-- Jay Beattie.







 




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