Help! Battery Recharge Intervals

Paul265

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Apr 9, 2020
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Can someone please clarify best practice for battery recharge. I have Bosch a 400Wh Battery and over winter when not in use I kept it indoors at about 60% charge. Recently I've been doing short daily rides only burning about 15%. Should I always top it back up to 100% before next day or let it go down lower before recharge to 100%. Thanks.
 

Nealh

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If only doing short rides and using only 15% no harm in leaving it as is and going for another short ride before fully charging again.
 
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Paul265

Finding my (electric) wheels
Apr 9, 2020
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If only doing short rides and using only 15% no harm in leaving it as is and going for another short ride before fully charging again.
Thanks, but is it OK to say do 4 days at 15% each then when it's then down to 40% fully recharge i.e is there a minimum that is good practice not to go below. This assumes I know my rides are only gonna take 15% cus I'm sticking to a similar route each day.
 

Fishy

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Nov 16, 2018
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I have a 500 Wh Bosch battery.
If I know I'm going to be using it regularly, (every day at the moment), I charge to 100%, then just ride until it's down to between 20 and 30%, then fully charge again.
If It's not going to be used for a long time, I store it between 30 and 60%.
 

Paul265

Finding my (electric) wheels
Apr 9, 2020
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I have a 500 Wh Bosch battery.
If I know I'm going to be using it regularly, (every day at the moment), I charge to 100%, then just ride until it's down to between 20 and 30%, then fully charge again.
If It's not going to be used for a long time, I store it between 30 and 60%.
Thanks
 

Nealh

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Thanks, but is it OK to say do 4 days at 15% each then when it's then down to 40% fully recharge i.e is there a minimum that is good practice not to go below. This assumes I know my rides are only gonna take 15% cus I'm sticking to a similar route each day.
Yes no real issue with doing so for short runs.
Minimum value is 32v/33v about 10/15% and a get home value in low pas if needed, I usually cease discharge at about 35v so about 30%.
 
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BazP

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Oct 8, 2017
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I have a 500 Wh Bosch battery.
If I know I'm going to be using it regularly, (every day at the moment), I charge to 100%, then just ride until it's down to between 20 and 30%, then fully charge again.
If It's not going to be used for a long time, I store it between 30 and 60%.
I have a 500Wh Bosch battery but the only indication of state of charge is 5 led’s. That’s 20% between each led, so how do you know it’s at 30%?
Do some batteries have built in voltmeters or do people carry one on rides.
Nealh, how do you know when you are down to 35v on a ride?
 

Nealh

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Aug 7, 2014
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I have a 500Wh Bosch battery but the only indication of state of charge is 5 led’s. That’s 20% between each led, so how do you know it’s at 30%?
Do some batteries have built in voltmeters or do people carry one on rides.
Nealh, how do you know when you are down to 35v on a ride?
Either I use an lcd3 with voltage reading or on my home built packs I wire in a separate meter on the exterior of the pack, the addition of a volt meter is easy and even a locked in system should be possible.
On my commute/town bike I know the voltage quite accurately by mileage or by the lcd battery bar, the lcd2 is quite basic with no thrills.

The Swizzbee has no oem display led or lcd so I have wired in a Coulombe meter to the battery box and added the watt meter lcd to the stem, this givse me the info supplied of wh, ah, current, voltage etc etc.
 
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Fishy

Pedelecer
Nov 16, 2018
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I have a 500Wh Bosch battery but the only indication of state of charge is 5 led’s. That’s 20% between each led, so how do you know it’s at 30%?
Do some batteries have built in voltmeters or do people carry one on rides.
Nealh, how do you know when you are down to 35v on a ride?
I have the Kiox display, shows battery in actual percentage.
 

Andy-Mat

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Oct 26, 2018
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I have a 500Wh Bosch battery but the only indication of state of charge is 5 led’s. That’s 20% between each led, so how do you know it’s at 30%?
Do some batteries have built in voltmeters or do people carry one on rides.
Nealh, how do you know when you are down to 35v on a ride?
Having your own volt meter is not a requirement, but a damn good idea.
Reasonably accurate ones are under 20 UK pounds on ebay.
Obviously, check its accuracy against a known good one if possible.
On my bikes, I generally ride till the BMS cuts off power, unless I was going for a very long ride and then I recharged with probably up to 20% of capacity remaining.
It was for two reasons:- 1) laziness 2) saving on charges, as all battery chemistries have a limited number of charges they can accept before the battery starts to age.
One should only charge when needed.
Also, not ignore the battery for long periods, as they self discharge slowly....
Never leave a battery on charge once full charge has been achieved.
Andy
 
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D C

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Apr 25, 2013
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I read somewhere , can't remember where, that checking a Bosch or Yamaha battery with a voltmeter can cause problems afterwards, could this be correct?
Dave.
 

Andy-Mat

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Oct 26, 2018
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I read somewhere , can't remember where, that checking a Bosch or Yamaha battery with a voltmeter can cause problems afterwards, could this be correct?
Dave.
I have never had a Yamaha Battery, and I will never ever buy anything from Bosch.....so I cannot say either way. But someone here will know I am sure.
Andy
 

georgehenry

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Nov 7, 2015
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RE Yamaha Battery pedelec member chris_n commented
"
Whatever you do even if someone suggests otherwise do not go trying to do capacity tests with external loads and do not go sticking multimeters into battery terminals. If you try to do a load test you will kill the battery, if you go sticking a multimeter on it you will not get correct readings unless it is connected to the bike and turned on.
My advice is to go back to the dealer, no one in the UK that I know of is repairing these batteries. "

https://www.pedelecs.co.uk/forum/threads/haibike-2018-sduro-hardseven-1-0-problem.33301/#post-473225

Also with a lithium battery partial charges back to full are not harmful and it is better not to deeply discharge the battery too often if possible.

My Yamaha 400Wh battery is entering its 6th year and is performing seemingly exactly as it did when new. It has covered 11,900 miles.

I use my bike to commute to work and back.

I store my battery indoors at about 65% charged and charge it back to full prior to my off road 12/14 mile ride to work. I charge it back to full while at work after having used 25% to 30% of its capacity. I ride it 10 miles home on the road using higher assist levels to average around 20mph for the 10 mile journey. I then store the battery in the house at the above mentioned 60%/65% charge level.

I only charge it back to full when I next use the bike. This gap could be only until the next day or as much as six weeks.

Used in this way my 400Wh Yamaha battery seems to be lasting extremely well.
 
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Andy-Mat

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I read somewhere , can't remember where, that checking a Bosch or Yamaha battery with a voltmeter can cause problems afterwards, could this be correct?
Dave.
I can actually believe it of a Bosch, as it apparently has these "communications" between different components that someone else here wrote about, and disrupting the comms apparently can cause parts to go into a "sleep mode"... but I have no idea about the Yamaha batteries myself....
I hope this helps.
Andy
 

Paul265

Finding my (electric) wheels
Apr 9, 2020
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Having your own volt meter is not a requirement, but a damn good idea.
Reasonably accurate ones are under 20 UK pounds on ebay.
Obviously, check its accuracy against a known good one if possible.
On my bikes, I generally ride till the BMS cuts off power, unless I was going for a very long ride and then I recharged with probably up to 20% of capacity remaining.
It was for two reasons:- 1) laziness 2) saving on charges, as all battery chemistries have a limited number of charges they can accept before the battery starts to age.
One should only charge when needed.
Also, not ignore the battery for long periods, as they self discharge slowly....
Never leave a battery on charge once full charge has been achieved.
Andy
So just to clarify, whether you recharge a battery from say 80% or from BMS cut off (as you said) does that then class as a full recharge i.e if say the battery is capable of 3000 recharges, would either situation be one less recharge off the total?
 

Nealh

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So just to clarify, whether you recharge a battery from say 80% or from BMS cut off (as you said) does that then class as a full recharge i.e if say the battery is capable of 3000 recharges, would either situation be one less recharge off the total?
A partial charge doesn't count as one cyclic charge, it needs to be 100%, so 60% & 40% charge counts as one full cyclic charge and so on, etc, etc.
 
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Andy-Mat

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So just to clarify, whether you recharge a battery from say 80% or from BMS cut off (as you said) does that then class as a full recharge i.e if say the battery is capable of 3000 recharges, would either situation be one less recharge off the total?
Basically yes.
IMHO it does not matter how "long" or how much "capacity" is added, a charge is a charge. Whether seconds or hours. Some battery manufacturers mention this deep in their literature, but not all of them do this.
Battery manufacturers appear to want to try and get the guarantee finished, before anything nasty happens to the battery.
But maybe I am simply getting cynical in my old age!
I do believe sincerely, that this is what destructs batteries.
In articular, leaving them for long periods on the charger for no reason. As this apparently forms as a lot of tiny charges, especially with the cheaper chargers, IMHO.
A good charger (which I do not possess!), is one that not only stops charging, but also removes the mains connection, and the DC output connection as well, and needs a button resetting to reconnect and charge again..
Hopefully that makes sense to all here.
Regards
Andy
 
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georgehenry

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I agree with Nealth and disagree with Andy-Mat on this as my own battery has spent its whole life being partially charged back to full and as I said is has now entered its 6th year of service working like it did when it was new after covering 11,900 miles.
 
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Andy-Mat

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Oct 26, 2018
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I agree with Nealth and disagree with Andy-Mat on this as my own battery has spent its whole life being partially charged back to full and as I said is has now entered its 6th year of service working like it did when it was new after covering 11,900 miles.
How depleted was the battery generally, when you carried out a fresh charge?
How do you treat the battery when charging if I may ask, as that IMHO is the most important part.
I myself have a modified 24 hour timer to switch the mains off when I myself judge it to be fully charged, time wise. That way I cannot forget it.
My last e-bike I bought secondhand, probably about a year old, treated the battery the same and I gave it away after 6 years of usage, with no noticeable loss of capacity, though I did not do any testing in that area. If there was any loss, it had been gradual and not noticeable to me...I rode about 20,000 KMS on that bike....
I mostly did empty to (or close to) full charges....
Not leaving the battery on the charger after its full, is my personal thought that appears to be the single best practice to give the best long term life of the battery.
I will start planning the build of a charger this year to my own spec, to see if that helps in any way at all...Thats the type of project I love, especially the planning.
regards
Andy
 
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