Go Back  Bike Forums > Bike Forums > Commuting
Reload this Page >

Rechargable Battery 101

Notices
Commuting Bicycle commuting is easier than you think, before you know it, you'll be hooked. Learn the tips, hints, equipment, safety requirements for safely riding your bike to work.

Rechargable Battery 101

Old 12-19-09, 11:10 AM
  #1  
Senior Member
Thread Starter
 
Grim's Avatar
 
Join Date: Jun 2008
Location: Atlanta
Posts: 2,978

Bikes: Cannondale T700s and a few others

Likes: 0
Liked 2 Times in 2 Posts
Rechargable Battery 101

I posted this in a thread but thought some others might get some good info that would relate to some of the products we use commuting.

My background is I am a certified bench tech for cell phones. Over the 25 years I have been in this business I have accumulated enough repair certification from Nokia, Motorola, Mitsubishi, Audivox, HP, Wavetek and a few others to wallpaper about 10ft of wall. I also hold a FCC GROL. I currently handle network repair and return for large wireless telecom.

When I ran a consumer repair facility one of the biggest complaints had to do with batteries. Every training course I took for every product covered battery complaints. Here is some info that relates to the lighting we are using.

Here is a little info that hopefully wil help you get the most out of your rechargeable lights.

Battery 101

I have a bunch of cordless Makita Drills from my days as a Cell phone installer/repair dating back to the late 80's that still work.
Rechargeable (not lead acid) Batteries are best rated in charge cycles. Every time you charge a battery you use up a charge cycle. The best way to maximize the life of a battery is to run it fully dead before charging.

Ni Cads actually have one of the best charge cycle ratings of any modern rechargable battery. Thats what the 20 year old Mikita batteries are I still use regularly.

NiMh came about as a battery less susceptible to what is often referred to as "Memory".

Memory is a result of repetitive charging practices. The worst of these practices is putting a battery on charge every day when you get home from work regardless if it needs it. You will train that battery to need a charge every 24 hours.

Edit: let me clear up what I mean by "train" as somebody is picking hairs in the thread I originally posted this in. Repetitive Short charging like I described will cause the battery to develop a voltage drop that in a smart device like a cellphone and some higher end lighting will cause it to trip low battery. Most people call this "Memory". A good bit of it is the battery and the device it is used in loosing sync. Some batteries have a chip in them that retain its charge state. More complete discharges between charges is what is going to be the best at preventing this from happening and getting the best longevity out of the product.


The MiMh was a lot better then the NiCad at resisting "memory" but it is still possible have have what most people call memory happen. To get that better resistance came at a overall loss of charge cycles over a NiCad. A Nicad may have a rating of 1200 charge cycles where a NiMh might have a 800. The difference was perception. On Cellphones where I learned this people are very bad about being worried they will not have enough battery to make the day so they would charge nightly or even worse in the car every time they get in. The perception of the NiMh was better because it resisted having a "memory" much better so as a result even though it had less over all charge cycles available they would feel it was a better battery because it resisted their bad practices better.

Memory can be reversed in a NiCad. They actually sell fancy chargers that "Condition" a battery. it does this by running the battery through a few deep charge and full discharge cycles to get the chemicals in the battery warmed up. The point the average person was thinking their NiCad was bad they were tossing them 95% of the time that battery could be recovered. The NiMh on the other hand the recovery rate was more like 65%. Most of this because they used up the majority of the charge cycles the battery had in it. The perception being that NiMh was better but the reality was a properly treated NiCad actually has a longer lifespan.

Most rechargeable devices are now favoring LiIon for weight savings. LiIon does not have a memory BUT it has far less charge cycles then a NiCad.

Best way to treat any common rechargeable (except lead acid) is a full discharge before recharging.

The first few charges on any of the above batteries is the most important. You want to give it a good full charge and a full discharge to optimize the battery.

Resist short charging batteries if you can. My last cell phone was 7 years old and on its second battery. That second battery would still go 3-4 days where new it would go 7. This iPhone I just got pisses me off with only going 2 days if I limit the data use. It promotes bad charge practices and if you search iphone complaints battery issues is right up at the top of the complaint list and now you know why.

Lead Acid (what cars have for starting batteries) are best kept charged. Topping them off daily is actually good as long as you don't bake them out. Charge them use them regularly and recharge them as soon as you can. Leaving a lead acid discharged will sulfate the plates and they will stop holding a charge.

Last edited by Grim; 12-19-09 at 11:48 PM.
Grim is offline  
Old 12-19-09, 11:31 AM
  #2  
aka Phil Jungels
 
Wanderer's Avatar
 
Join Date: Apr 2005
Location: North Aurora, IL
Posts: 8,234

Bikes: 08 Specialized Crosstrail Sport, 05 Sirrus Comp

Liked 86 Times in 60 Posts
Good info - Thanks for taking the time.
Wanderer is offline  
Old 12-19-09, 01:01 PM
  #3  
6 miles per taco, w00t!
 
HappyStuffing's Avatar
 
Join Date: Oct 2009
Posts: 255
Likes: 0
Liked 0 Times in 0 Posts
Fantastic article. I use all li-on rechargeable in my lights. My P7 from Deal Extreme and a Fenix light. Wondering if i should switch to NiCad now because of their excellent recharge cycles?
HappyStuffing is offline  
Old 12-19-09, 02:34 PM
  #4  
Senior Member
 
Join Date: May 2009
Location: Boston
Posts: 145

Bikes: Trek 2.3, Trek FX-7.3

Likes: 0
Liked 0 Times in 0 Posts
The reason that manufacturers have switched to Li batteries (from NiCads) is because a NiCad of the same capacity (and therefore running time) would be considerably larger and heavier, perhaps as much as twice the weight.

Also, the voltages are different. NiCads are 1.2 volts per cell and Li-ion batteries are 3.7 volts per cell. If you have typical 7.4 volt setup (2 cell Li-ion battery), this would require 6 Nicad cells (7.2 volts nominal) to achieve similar voltage.

Of course, these are nominal voltages. The actual voltage varies over the discharge cycle. Most LEDs are not very sensitive to voltage variations, but some other types of equipment are.
mr_antares is offline  
Old 12-19-09, 02:37 PM
  #5  
Senior Member
 
MNBikeguy's Avatar
 
Join Date: Mar 2007
Location: Minneapolis, MN
Posts: 1,834

Bikes: 05 Trek 5200, 07 Trek 520, 99 GT Karakoram, 08 Surly 1X1

Likes: 0
Liked 0 Times in 0 Posts
Good stuff.
I find a wide difference in battery life, probably due to my charging habits.
I was told we don't have to worry about "charging memory" anymore.
I'm inclined to believe you over these yay-hoos at the cell phone kiosks.
Thanks for posting.
MNBikeguy is offline  
Old 12-19-09, 03:03 PM
  #6  
Senior Member
 
Join Date: May 2009
Location: Boston
Posts: 145

Bikes: Trek 2.3, Trek FX-7.3

Likes: 0
Liked 0 Times in 0 Posts
While Li-ion batteries don't have "memory" the way that NiCads do, the life expectancy of all rechargeable batteries is measured in "discharge cycles". The more often you discharge and recharge them, the sooner they will lose the capacity to hold a charge.

So it's still a good idea to charge your batteries only when they need it. This may not always be practical, but it's the best way to extend battery life.
mr_antares is offline  
Old 12-19-09, 10:46 PM
  #7  
Senior Member
 
Join Date: Aug 2006
Posts: 1,952
Likes: 0
Liked 2 Times in 2 Posts
I admit I short charge my lights all the time. But there's no way around it - if I have a detour or decide to do an extra training ride, I simply can't get caught out in the dark without lights. Same with the cell phone - you'll find yourself batteryless when you need it most.

For sure, I'll try and deep discharge as much as I can , but it's too impractical for my critical items like hi-lumen lights (and phones).
agarose2000 is offline  
Old 12-19-09, 11:15 PM
  #8  
6 miles per taco, w00t!
 
HappyStuffing's Avatar
 
Join Date: Oct 2009
Posts: 255
Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by agarose2000
I admit I short charge my lights all the time. But there's no way around it - if I have a detour or decide to do an extra training ride, I simply can't get caught out in the dark without lights. Same with the cell phone - you'll find yourself batteryless when you need it most.

For sure, I'll try and deep discharge as much as I can , but it's too impractical for my critical items like hi-lumen lights (and phones).
I agree with you.

Though i don't race, i do commute in the dark a lot. Much of those commutes i don't use the full capacity of the battery but the next day i might need to. Thus, i just charge it up anyway. I just go by the theory of charge it when you need it regardless of how drained it is. Yes, it may shorten the life and i should probably do this before that, but only under these circumstances. . blah . . blah. . snort . .

I'll come to that bridge when i come to it. Until then, i'll just continue to carry spares like i always do anyway. Problem solved
HappyStuffing is offline  
Old 12-19-09, 11:57 PM
  #9  
noob
 
habals's Avatar
 
Join Date: Oct 2009
Location: Cupertino, CA
Posts: 115

Bikes: Cyclocross 5

Likes: 0
Liked 0 Times in 0 Posts
Do NOT spread a MYTH!
(Sorry to the OP, but I just wanted other members to make decisions correctly based on facts)

Li-Ion should never be fully discharge. That only degrade the battery life.
Also, battery charge cycle is NOT the number of times you actually charged.
It is the usage of battery of the full amount of its capacity.
Please refer to these articles.

https://en.wikipedia.org/wiki/Lithium-ion_battery
Guidelines for prolonging lithium-ion battery life

  • Lithium-ion batteries should never be depleted below their minimum voltage (2.4 to 2.8 V/cell, depending on chemistry). If a lithium-ion battery is stored with too low a charge, there is a risk that the charge will drop below the low-voltage threshold, resulting in an unrecoverable dead battery.[citation needed] Usually this does not instantly damage the battery itself but a charger or device which uses that battery will refuse to charge a dead battery. The battery appears to be dead or not existent because the protection circuit disables further discharging and there is zero voltage on the battery terminals.
  • Lithium-ion batteries should be kept cool. Ideally they are stored in a refrigerator.[citation needed]
  • Aging will take its toll much faster at high temperatures.[38]
https://www.batteryuniversity.com/parttwo-34.htm
Simple Guidelines

Avoid frequent full discharges because this puts additional strain on the battery. Several partial discharges with frequent recharges are better for lithium-ion than one deep one. Recharging a partially charged lithium-ion does not cause harm because there is no memory. (In this respect, lithium-ion differs from nickel-based batteries.) Short battery life in a laptop is mainly cause by heat rather than charge / discharge patterns.
https://www.apple.com/batteries/
A charge cycle means using all of the battery’s power, but that doesn’t necessarily mean a single charge. For instance, you could listen to your iPod for a few hours one day, using half its power, and then recharge it fully. If you did the same thing the next day, it would count as one charge cycle, not two, so you may take several days to complete a cycle. Each time you complete a charge cycle, it diminishes battery capacity slightly, but you can put notebook, iPod, and iPhone batteries through many charge cycles before they will only hold 80% of original battery capacity. As with other rechargeable batteries, you may eventually need to replace your battery.

Last edited by habals; 12-20-09 at 12:01 AM. Reason: typo
habals is offline  
Old 12-20-09, 09:06 AM
  #10  
Senior Member
Thread Starter
 
Grim's Avatar
 
Join Date: Jun 2008
Location: Atlanta
Posts: 2,978

Bikes: Cannondale T700s and a few others

Likes: 0
Liked 2 Times in 2 Posts
Really I tried to keep this simple but here we are in a pissing match.

What you are failing to mention on Li Ion powered devices is that most smart devices take into consideration that a Li Ion should not have a full discharge and their charge circuit will shut them down above the point the battery will be damaged.

There is a lot of contraivercy on LiIon. If you read the links above that were posted if they are worth a crap they will talk about damage from heat. The Apple one doesn't have it at all. Course if you need a battery in 1.5 years instead of 3 that's just more money in their pocket so why would they.

Here is where the controversy comes in.

Batteries heat when charging.

If you look you should find charts showing that the amount of heat the battery is generating for a 30-70% charge is pretty flat but once you hit about 70% the internal temp of the battery starts raising because the internal resistance start raising as you approach a full charge. It starts to heat at an exponential rate and has to slow the charging to prevent overheating.

From one of the above links.
The speed by which lithium-ion ages is governed by temperature and state-of-charge.
It glosses over the fact that they create heat when charging. Anybody that has ever picked up their phone as it is charging will notice the battery is warm sometimes hot. It is being warmed from the inside out. This is detrimental to the battery as well.


Time wise the time it takes to charge a battery from 20-80% is about the same time it takes to charge from 80-100% because the internal resistance increases so much as the battery comes up to full capacity.

When LiIon came out there were all these instances of products melting or catching fire from crappie desgned charger set ups. Union carbide even managed to burn down their factory in India screwing up with Li based batteries they were producing and some reports say they killed 8,000 (no typo) in the process. https://epoch-archive.com/a1/en/us/ny...0091204_NY.pdf

Back to the point or the argument that this has become: Why subject that battery to that heat daily when it has the capacity to go two days before it needs it?

Yes there is a thermo protection device in the battery that will shut down charging if the temp gets too high but still if you think of the logic "topping off" when that 70-100% part of the charge cycle is where the battery runs the hottest. So is the 40-100% charge habit every 2-3 days less detrimental or is the charge 75-100% every niight? Thats the argument.

Lets bring it back up when somebody fry's their iPhone battery. I continue to wait till I get down around 30-40% of charge before recharging as Motorola, Nokia and the rest of the manufactures that I have had repair classes from advise to do.
Grim is offline  
Old 12-20-09, 12:33 PM
  #11  
Senior Member
 
Join Date: May 2009
Location: Boston
Posts: 145

Bikes: Trek 2.3, Trek FX-7.3

Likes: 0
Liked 0 Times in 0 Posts
Originally Posted by Grim
Really I tried to keep this simple but here we are in a pissing match.
I don't think we've quite sunk to that level yet. This stuff is confusing, in large part because Li Ion batteries are different from NiCad and NiMH batteries, and some old "urban legends" are being applied to Li Ion batteries.

What should be stated clearly (and we don't disagree on) is that Li Ion batteries don't have memory issues, and that their primary enemies are heat and time. Not much we can do about time (except don't stockpile batteries), but plenty we can do to subject our batteries to as little heat as possible.

Originally Posted by Grim
Batteries heat when charging.

If you look you should find charts showing that the amount of heat the battery is generating for a 30-70% charge is pretty flat but once you hit about 70% the internal temp of the battery starts raising because the internal resistance start raising as you approach a full charge. It starts to heat at an exponential rate and has to slow the charging to prevent overheating.
This is a very good point.

Originally Posted by Grim
Back to the point or the argument that this has become: Why subject that battery to that heat daily when it has the capacity to go two days before it needs it?

Yes there is a thermo protection device in the battery that will shut down charging if the temp gets too high but still if you think of the logic "topping off" when that 70-100% part of the charge cycle is where the battery runs the hottest. So is the 40-100% charge habit every 2-3 days less detrimental or is the charge 75-100% every night? Thats the argument.
I think that if you know that the battery will last 2 days, then your approach is a good one. However, those of us who are on the road for longer still have a problem. (My commute is about 2:30 round trip).

In the absence of a good "fuel gauge" (and typical voltage monitoring isn't an adequate for these batteries, as it would be for Lead Acid batteries), there's no way to know if your battery will last another trip or not.

I suppose one other approach would be to have 2 batteries. Run on Battery A until the "shutdown point" and then swap to Battery B. Battery A goes on the charger and only returns to service when Battery B is fully discharged.

The problem here is that both Battery A and Battery B are "aging" simultaneously, and we're only using one of them at any given time. I'm not sure that any life extension from infrequent charging would be enough to be worth paying for 2 batteries.
mr_antares is offline  
Old 12-21-09, 12:50 AM
  #12  
6 miles per taco, w00t!
 
HappyStuffing's Avatar
 
Join Date: Oct 2009
Posts: 255
Likes: 0
Liked 0 Times in 0 Posts
*sits back to watch the flame war*

. . popcorn anyone?
HappyStuffing is offline  
Old 12-21-09, 09:39 AM
  #13  
Senior Member
 
Join Date: Jun 2005
Location: Iceland
Posts: 273
Likes: 0
Liked 0 Times in 0 Posts
Grim,
Thank you for this very informative post. This for sure will be of help for me to get the most out of my rechargeables.
But after reading this I do have two questions.

1) if 50 % of the heat is generated when charging 80-100%, heating increasing exponentially with charge and then again I would guess that the "aging" would be increased exponentially with absolute temperature (according to the Arrhenius equation), why wouldn't we just charge up to 80%? Wouldn't that triple (or more) the battery life? Of course it would decrease the "capacity of each charge" but for most of my batteries it is the life time that is a problem rather than the capacity of each charge.

2) I thought that the speed of charging (charging voltage) and discharging was also an important factor in battery life? Naturally the temperature of the battery is higher during fast charging than slow charging. E.g. I had two chargers that worked for my last mobile phone, one had a higher voltage, charging much faster, than the other. I have usually used the slower charger to safe battry life (but of course the phone died after 4 years with the original battery in fine condition).
__________________
My advice is free of charge and of respective quality.
1982 Miyata 912
1998 Wheeler 5900 with front and rear air cushion suspension
2015 Canyon Spectral 7.0 EX
j3ns is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Jewel
Electric Bikes
10
01-04-18 04:10 PM
gif4445
Electronics, Lighting, & Gadgets
10
02-09-17 07:55 PM
krobinson103
Electronics, Lighting, & Gadgets
3
09-29-12 10:39 AM
Lionheart
Commuting
10
12-20-09 12:55 AM

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Your Privacy Choices -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.