Battery charging, how often

Greenpotterer

Finding my (electric) wheels
Mar 29, 2011
12
16
Advice please. How often should I charge my battery? It's a new bike and at present I'm charging it when I return from a ride. The battery is about half full or a little more. I tried searching but there are many posts with the words battery and charging
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
820
785
Surrey
Charging your battery to full at the end of a ride is OK if you plan to use your bike soon afterwards.

However it is best practice not to store these batteries fully charged and unused for too long.

Storing your battery with a charge remaining of anywhere from around 50% to 70%% is much kinder.

You can leave a battery like this for a number of weeks.

Then charge it to full as close to the start of your ride as possible.

I keep my battery in doors but another poster pointed out the hopefully remote fire risk these batteries might pose.
 
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Greenpotterer

Finding my (electric) wheels
Mar 29, 2011
12
16
Charging your battery to full at the end of a ride is OK if you plan to use your bike soon afterwards.

However it is best practice not to store these batteries fully charges and unused for too long.

Storing your battery with a charge remaining of anywhere from around 50% to 70%% is much kinder.

You can leave a battery like this for a number of weeks.

Then charge it to full as close to the start of your ride as possible.

I keep my battery in doors but another poster pointed out the hopefully remote fire risk these batteries might pose.
Thanks for this. I'm hoping to use it a least several times a week. Like I said I'm new to this and suffering from range anxiety. I would be stuffed if the battery went as all roads to home are uphill and my knees are shot.
 

georgehenry

Esteemed Pedelecer
Nov 7, 2015
820
785
Surrey
If you are commuting to work then charging it when you get home ready to use the next day should be OK.

My battery will actually get me to work and back (24 miles) without a top up, but because I can, I charge my battery back to full at work for my ride home.
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
4,742
1,678
Basildon
The advice above is good, though nothing to panic about. Do what's most convenient for you. Just never leave your battery empty for any prolonged period, like several days or more. Another guideline is that you should aim to charge to full, but again it's nothing to panic about. If you haven't got time to charge it right up, it doesn't matter as long as you don't do it every day.
 

PP100

Pedelecer
Feb 28, 2020
135
72
What if you had to leave your battery for a long period of non use (say you could not ride your bike due to illness) eg for several weeks or even months? Any way to reduce long term deterioration?
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
4,742
1,678
Basildon
Ideal
What if you had to leave your battery for a long period of non use (say you could not ride your bike due to illness) eg for several weeks or even months? Any way to reduce long term deterioration?
Ideal is to store it about half-full in a cool place or somewhere where it doesn't get warm, but I never bother. It's all theoretical. maybe you can extend your battery life by 20% if you do everything right, but for most people, that'll be the difference between 4 years and 5 years, but by then, there'll be much better batteries so you'll be looking to get rid of it anyway.
 

Greenpotterer

Finding my (electric) wheels
Mar 29, 2011
12
16
Thanks for the advice most reassuring, I suppose if I got caught short so to speak while out and about. As of tomorrow of course I could always call for lunch or the pub for a couple of hours and charge up.
 

Ocsid

Pedelecer
Aug 2, 2017
199
134
77
Hampshire
On "range anxiety" I made use of the "remaining range" featured on our bike which I suspect most bikes feature, to develop a trustworthy understanding of what I could actually achieve. Probably other makes are different, but ours when understood instils confidence.

Range varies quite noticeably with the effort involved, but you soon get to understand the amount you need, as in our case the haul uphill home takes. Thus, quite quickly, at least over a known route you gain confidence in the actual reserves you have.

The battery technology we have appears well able to work effectively right to low charge levels, support does not go into a petering out mode as other battery types can.
 
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PP100

Pedelecer
Feb 28, 2020
135
72
Ideal

Ideal is to store it about half-full in a cool place or somewhere where it doesn't get warm, but I never bother. It's all theoretical. maybe you can extend your battery life by 20% if you do everything right, but for most people, that'll be the difference between 4 years and 5 years, but by then, there'll be much better batteries so you'll be looking to get rid of it anyway.
I would guess if it needed charging up a bit that is easier and even if you couldn't ride the bike out for some reason, maybe to discharge if required you could simply mount the bike on a stand and turn the pedals by hand on full assist - would also give some exercise...
 

sjpt

Esteemed Pedelecer
Jun 8, 2018
1,679
1,116
On "range anxiety" I made use of the "remaining range" featured on our bike which I suspect most bikes feature, to develop a trustworthy understanding of what I could actually achieve. Probably other makes are different, but ours when understood instils confidence.

Range varies quite noticeably with the effort involved, but you soon get to understand the amount you need, as in our case the haul uphill home takes. Thus, quite quickly, at least over a known route you gain confidence in the actual reserves you have.

The battery technology we have appears well able to work effectively right to low charge levels, support does not go into a petering out mode as other battery types can.
On our 2016 Bosch system the remaining range is very erratic, based on the terrain over the last mile or so, rather than the last 20 miles or so. This makes it very erratic; slightly useful with very careful interpretation.

eg we live near the bottom of a not particularly big hill. Typically remaining range is higher when we get home than it was half way through a ride.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
1,425
278
73
Advice please. How often should I charge my battery? It's a new bike and at present I'm charging it when I return from a ride. The battery is about half full or a little more. I tried searching but there are many posts with the words battery and charging
Good and very important question, that is apparently not fully understood by many on the e-bike scene IMO, which is why I would recommend reading at the online "Battery University", as they seldom get things wrong!
There are other good sources, but that is a reasonable starting point.
If you treat your batteries well, they will give a very long and extended service life.
Too many people only get 2 to 3 years (but they accept that!), some even less, simply through ignorance.....
To get the best life IMHO, (this will cause some here to loudly disagree!) you do need to fully or almost fully discharge before recharging, and then charge back up to close to full or full,.
The BMS in the battery sets the lower limit of available charge.
And if you are riding a lot, the only way to do that in my view, is to own two batteries (one can be smaller and cheaper in most cases), and when the capacity of the one in use is below that needed for the rest of the ride, either pedal a lot, or swap the battery out for a full one, right where you are.
But that is a personal choice, either way.
Sadly, I am told (and I believe them!), swapping a battery while "on the road", is not quite so easy with some models of E-Bikes.
Never leave a charger connected to a battery, once full charge is reached, NO MATTER WHAT ANYONE ELSE TELLS YOU DIFFERENTLY, that is the reason so many batteries have very shortened lives......
Only some VERY expensive chargers FULLY remove power from the battery, BUT THEY ALL RESTART CHARGING AGAIN IF THE BATTERY VOLTAGE DROPS BELOW A CERTAIN LEVEL!
My saying this here, will probably cause some "nay sayers" to start posting the opposite, simply do not believe them!
Even if your charger is one that removes all power to the battery (a green charge LED is NOT an indication of this as some believe!), it needs a proper set up testing system to prove that either way, which as good as no one has at their disposal!
Its ALWAYS the safest option, if you are not 200% sure, is to completely remove mains from the charger when the battery is full, or close to....
I myself use a simple cheap 24 hour timer like this one:-
24 hour timer.jpg
which has a simple internal modification to it, that when it switches off the mains to the charger, after the time has I have set runs out, it actually also switches "itself" off as well.
Just one wire to the tiny synchronous motor inside, needs to moved from the mains plug" power in" (best is the wire that has the phase on it, not the neutral), to the output socket phase connection. There should be a 13 amp fuse in a UK timer, that is the phase "side".
Ones with an LCD or those that time for 7 days, will not usually work correctly in this application
If you are not "au fait" with MAINS voltage wiring, get an electrician with a soldering iron to do this, its at most a 5 minute job IF you picked a timer with normal screws holding it together, not safety screws, that is! They need special tools.
You just need to learn roughly how long a full charge is for your Battery/Charger combination, and then set the timer to say 10-15 minutes less, so that it is generally still charging when the mains is removed, or shortly after, the charge LED goes green.
I use the midnight position as 0 and say set it to 04:00, for a 4 hour charge.....your battery may need more or less time, depending upon its capacity and the "speed" of the charger.
Fast chargers also reduce the life span of the battery, albeit slowly, in comparison to a "slow/normal" charger.
On safety, these batteries if treated badly in some way, can possibly catch fire, and usually the only way to put it out completely, is to throw the whole bike in a small pond or similar, for around an hour at least.
If that is not possible, and you are unable to safely remove the burning battery in a tub of water,, you will need to say use a garden hose to keep the battery cooled as far as possibly to keep the fire "small", but it will only actually stop burning when all combustible components are used up.
This may take a hour or so, but guessing only, it may take even longer.....I have never had "the pleasure!"
Never let children or amateurs (wives!) touch your batteries or charger for any reason whatsoever.
Never charge where a fire may endanger life or property.
Recommended is to charge outside, away from strong sunlight, as the battery gets slightly warm from charging alone, and strong sunlight may warm it too much, further reducing the working life unnecessarily.
I do not 100% know what this Guy on the following video was actually doing wrong, but as you can see, he was probably doing something bad with two batteries (one can be seen on the rear carrier with a mess of wiring), and bottle type battery on the front down tube.
Maybe he got the polarity wrong, or they were just too vastly different in voltage/charge, but he also apparently did not use a big fuse somewhere as a safety device, I really don't know for certain (I don't think even the bike owner knows for certain !):-
Your Battery, if used properly and treated carefully with respect, then this will never ever happen to you!
Regards and I wish you and your bike batteries a long, safe and useful life together!
Remember, never believe anything from anyone, unless the same information can be gleaned from a reputable online source, or other reputable documentation....Do a lot of reading and be careful!
Andy
PS. I almost forgot (how could I?), that some of the "Nay-Sayers" I previously mentioned, will shortly start "picking" at anything that I have written here is wrong!
I always stay on the "safe side", but they simply want to start an argument......any argument is their idea of FUN!
It's your final choice who and what to believe on this forum of course, but a lack of valid links supporting their theories, is often a useful indication of invalidity and guesswork, which might help you further to decide what to believe!24 hour timer.jpg
 
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Ocsid

Pedelecer
Aug 2, 2017
199
134
77
Hampshire
To get the best life IMHO, (this will cause some here to loudly disagree!) you do need to fully or almost fully discharge before recharging, and then charge back up to close to full or full,.
Andy, could you direct us to where this claim is supported in your "Battery University" link?

All I can read both in your link and their BU-808: How to Prolong Lithium-based Batteries, rather seems to completely contradict such a claim, and these both align with the advice I have been given;

I quote from your reference:
"Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge because a high voltage stresses the battery. "

And:
"Lithium-ion does not need to be fully charged; a partial charge is better."

Then, quoting from their BU-808 "Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. "
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
1,425
278
73
Andy, could you direct us to where this claim is supported in your "Battery University" link?

All I can read both in your link and their BU-808: How to Prolong Lithium-based Batteries, rather seems to completely contradict such a claim, and these both align with the advice I have been given;

I quote from your reference:
"Li-ion does not need to be fully charged as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge because a high voltage stresses the battery. "

And:
"Lithium-ion does not need to be fully charged; a partial charge is better."

Then, quoting from their BU-808 "Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. "
That is my own personal take on keeping Li-ion batteries working longer, after many years patrolling this globe with a Laptop, from the early 1980s, I do not remember exactly when the batteries became Li-ions, probably 10 years or so later..
Many of my colleagues were needing replacement batteries within one year, and I never ever had needed a replacement, I had about 10 different company Laptops over around 20 years.
Also other private ones over the last 14 years from Toshiba, since I retired, till I bought a desktop this year!
So the Company's Quality manager in the USA, saddled me (after we had touched on the subject at a meeting) with an investigation as to why I, and some other people, never needed battery replacements, but many others did.
For me it was initially a "Carry-Over" from my many years with earlier Laptops, but with different Battery Chemistry, as I just did the same!!
You are now the proud owner of something I found out over about 10 months of part time investigation, talking to probably at least half the people in a large American company, that carried company Laptops.
By the way, you would surely not consider such actions as being in any way detrimental to battery life, would you?
I assume that you would say no! So there is no harm to doing it, but with the possibility that your battery, if not already damaged, might live far longer that it would have done, otherwise!!
Remember, its YOUR BATTERY and your money for a replacement, you treat your battery any way you like, but don't try to kill the messenger!
And you will need a good many years of study to try and prove me wrong!!
You are not the first to ask that question, and probably not the last either....
Have a great weekend.
Andy
 

WheezyRider

Esteemed Pedelecer
Apr 20, 2020
367
144
Modern e-bike batteries come with a BMS that disconnects the charger once it is charged. So you really do not need to worry about having your charger connected to a timer unit.

It could even be detrimental, as you don't know how out of balance the banks of cells are in your pack and it could take several hours to achieve balance, which is done at the end of a cycle. Only charging for a fixed time could prevent adequate time for balancing as no two charging cycles are the same.

Completely discharging a pack was done in the days of NiCd cells that used to suffer the memory effect. Lithium cells don't have a memory effect problem and deep cycling is never good for battery life, so avoid it.
 
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WheezyRider

Esteemed Pedelecer
Apr 20, 2020
367
144
Please do not throw a burning lithium battery "in a pond" or even throw water on it. Lithium metal reacts vigorously with water to make hydrogen gas. Best to cover it in sand and stand well back.
 

Woosh

Trade Member
May 19, 2012
14,247
11,353
Southend on Sea
wooshbikes.co.uk
they do produce hydrogen gas but if your lithium battery is burning, I reckon the pond's water will stop the fire in its track.
 
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Trek

Finding my (electric) wheels
Jun 22, 2013
21
22
Hi, I have just read the latest edition of Shimano Steps manual and I quote:
Charging the battery can be carried out at any time regardless of the amount of charge remaining, but you should fully charge the battery at the following times: if the battery has become fully spent, charge it as soon as possible.if you leave the battery without charging it, it will cause the battery to deteriorate. If the cycle will not be ridden for a long period of time, store it away with approx 70% capacity remaining, in addition do not let the battery become completely empty by charging it every six months.
 
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GSV3MiaC

Pedelecer
Jun 6, 2020
43
16
Throwing water on it is a bad idea. Sinking it in a large amount of water (eg pond, sea, lake, ocean) will indeed stop it dead. Your Lithium battery should not have reached the metallic Lithium stage anyway, that is not the plan!

The problem with over discharge is that the Battery management system requires power to work, and if there is no power at all it usually defaults to 'this battery is dead / unsafe / missing, and I'm not going to put any power into it'.

Sometimes that is too clever by half, but battery builders would much rather have it fail safe than the alternative .. apart from the fact they can then sell you a new one.
 
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ChuckingFeet

Pedelecer
Dec 3, 2019
36
29
Derby
A li-on battery fire is basically chemical, the electrolyte is highly flammable , there is very little lithium metal actually present .The potential energy contained in a charged battery contributes lots to maintaining the heat . A large amount of water does work in extinguishing , also inert material like sand, the key is to take the heat away to prevent re-ignition .
 

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