Battery 60-80%

If I'm only doing short rides during winter, is it OK to just keep topping the battery up to 60-80% as I don't go out every week and I don't want to leave it at 100% for too long. Does the battery need charging to 100% occasionally or doesn't it matter? Thanks

From my experience, I used to charge my last battery to 100% after every ride, and I personally think that's what caused it to degrade fairly quickly. It could be left anywhere between 1 day to 2 weeks between rides.

 

My latest battery I charge to 100%, but only before I go out for a ride. When I return, I don't charge it and leave it in a state of discharge anywhere from 40% - 60%. I have found my latest battery is faring far better than the last.

Balancing only happens at the top of the charge cycle (100%). It works on the basis of a little and often, so an occasional 100% charge is not enough to keep your battery balanced.

 

The problem is that you'd never know how much balancing is needed. Some don't need much and others need a lot.

 

You can get an idea of how much out of balance your battery is by measuring the voltage as soon as you get the green light. The further it is from 42.0 v for a 36v battery, the more unbalanced it is.

Vfr400 is correct, but be aware some packs balance at less than 100%. It will all depend on the BMS that your battery pack has.

 

Mine balances from 50% plus, so I never need to charge to 100% to activate the balancing feature.

Edited November 26, 20205 yr by Fordulike

Interesting what you say Fordulike as my Yamaha Battery is lasting incredibly well and I take it indoors after my ride 10 mile ride home from work and leave like that at about 60% charge until I next need to use the bike and then charged up close to setting off.

 

It does get charged back to full at work before I ride it home but the gap between being fully charged and used again is just the length of my shift at work.

 

It will be 6 years old in March 21 and has carried me 12,746 miles, and still seems to have around the range it had when new. Due to the way patterns of work can vary and holidays etc it can be left for 6 weeks sometimes before it is used again.

So many different opinions.

As I said before our bikes were off the road for the 30 months Stormont played with themselves.

Not knowing any different I simply topped the batteries up to full every few months during that time and when we got them going again we are still getting the distance and performance we got before the enforced "shut down".

Anyone prepared to offer storage advice as they will be away this weekend because we are just too cold.

I always keep my batteries fully charged.

They seem to last well.

Anyway, what exactly is fully charged?

We know that even when the charger goes green that the cells are not actually at 100%

Degradation of a battery will be much less noticeable, if it is not used in a power hungry fashion. The majority of EN 15194 bikes are unlikely to drain their battery pack beyond a rate of 1C. Whereas, a bike with a BBS02 or BBSHD fitted, can easily require discharges of 2C-3C from the pack.

 

It's at these higher drain levels, where battery sag is most noticeable on an aging or degraded pack.

 

Obviously, the quality of cells in a pack play a part too, on how long it lasts and how much abuse it can take.

Edited November 27, 20205 yr by Fordulike

I rarely charge mine after rides; usually only charge when the battery indicator has reduced by 1 bar and I've had this battery for 8-years

About 90% max charge for all of mine a few hours before use, other wise they are left in discharged state above 40%. It depends on how active you are at checking voltage and knowing your battery 's mileage with usage, noticing changes in its range and how or if the battery sags more then usual are indicators of cell imbalance.

Not much wrong with 100% charging but do it a few hours before use and not always if the bike is not going to be used.

If I'm only doing short rides during winter, is it OK to just keep topping the battery up to 60-80% as I don't go out every week and I don't want to leave it at 100% for too long. Does the battery need charging to 100% occasionally or doesn't it matter? Thanks

 

Topping up to 60 - 80% is ideal for storage, for use set the charger to 90% or still to 100% but carry out the final 20% balance charge a few hours before use is required. Depending on usage one might not need to charge every day and may be able to get away with a few days or weekly.

Topping up to 60 - 80% is ideal for storage, for use set the charger to 90% or still to 100% but carry out the final 20% balance charge a few hours before use is required. Depending on usage one might not need to charge every day and may be able to get away with a few days or weekly.

No way to adjust our chargers or set them other than go from green lights going out when the charger decides.

Don't know how to test the capacity of either battery because my comprehensive multi meter isn't interested in giving a plausible reading.

Topping up to 60 - 80% is ideal for storage, for use set the charger to 90% or still to 100% but carry out the final 20% balance charge a few hours before use is required. Depending on usage one might not need to charge every day and may be able to get away with a few days or weekly.

Thanks, but should I also do the final charge to 90-100% or can I just use it as is between 60-80% ? Then say burn 20-30% on a short ride then top it back to 60-80% cus I might not go out again for a week.

Thanks, but should I also do the final charge to 90-100% or can I just use it as is between 60-80% ? Then say burn 20-30% on a short ride then top it back to 60-80% cus I might not go out again for a week.

 

Its not that difficult:

 

Fully charge the battery to 100% before you intend to ride it (the night/day before is fine).

Ride your bike. Don't recharge it after the ride *

Repeat.

 

 

* Unless you've discharged it to a really low level, like 10% or so, and/or you don't intend to ride it again for a long period ,in which case its safer to get it more around the 50-70% before you leave it.

One can argue about the exact percentages for optimum life/safety, but the general principles are sound.

If you're not that organised and never know when you might want to ride your bike at the drop of a hat, then charge it up to 100% after every ride and just live with the (probably very slight) reduced battery life. Just keep the battery cool in storage.

I think the most important thing with lithium batteries, is not to leave them in such a state of discharge for a long period of time, that the voltage of the cells dips below a recoverable state.

 

A battery pack that is fully charged to 100% and left for long periods of time, may at worst, have less useable service life.

 

A battery pack that is left in a very low discharge state for a long period of time, can drop to an unrecoverable state. Think of the old phone or iPod that you drag out of the junk drawer after many years of unuse, and no matter what you do, it just won't switch on.

 

Dead battery vs shortened life battery, I know which one I'd prefer.

Edited November 28, 20205 yr by Fordulike

Using a timer plug it is with a little trail and error very easy to partially charge your battery to somewhere in the 50% to 70% range if you have depleted most of it on your ride.

 

Bring your battery in the house, connect it to your charger with a timer plug to limit the time of the charge to what you need and that's that.

 

Then charge it to full before your ride.

 

I have two older rear hub bikes with silver fish batteries that sit behind the seat tube and they don.t get brought into the house, simply charged in the garage to full or almost full after returning home, so they are ready to use whenever I need to.

 

The last battery I bought for one of these bikes was under £200 including a charger and will be three years old at the beginning of April next year and is holding up well.

 

I look after the Yamaha battery so carefully because it costs a lot to replace. The Yamaha battery is also very easy to remove and bring in the house.

 

I wonder about how easy it is to remove the batteries that are now prevalent and hidden in the down tube of those lovely crank drive mountain bikes.

 

Being able to remove a battery easily for me is a very practical attribute and means you are likely to do so even when you are tired etc. For me it is just part of my routine when I get back from work.

 

I do now use one of my rear hub bikes to share the ride to work and back miles I do, and have to remove the battery at work to charge it away from the bike. At first I was worried this would be arduous but in reality with a quick release seat post it is very easy.

 

So the real reason I don't do it at home is probably A. Because I am too lazy and B. Because the batteries are relatively cheap. C. These bikes get used all the time at short notice and it is more convenient to just be able to jump on them and go.

 

A cheap battery is an abused battery.

Thanks, but should I also do the final charge to 90-100% or can I just use it as is between 60-80% ? Then say burn 20-30% on a short ride then top it back to 60-80% cus I might not go out again for a week.

 

Charge to full (100%) a few hours before use ride it and leave it, if you discharge 20 - 30% then it will be at 70 - 80%. A good SOC to leave the battery resting at.

Balancing only happens at the top of the charge cycle (100%). It works on the basis of a little and often, so an occasional 100% charge is not enough to keep your battery balanced.

 

The problem is that you'd never know how much balancing is needed. Some don't need much and others need a lot.

 

You can get an idea of how much out of balance your battery is by measuring the voltage as soon as you get the green light. The further it is from 42.0 v for a 36v battery, the more unbalanced it is.

 

That's interesting to know, my 10 day old Woosh Rambletta has just had it's battery charged for the 3rd time since new, the measured voltage was 41.8v across the battery terminals so presume thats very good.

In their manual for the bike it stated that the very first charge to leave the battery connected to the charger a further 2 hours after the green light on the charger illuminates to 'fully tune the battery, there is no need to do this again in the future'.

Leaving it on to tune it !!! My ones don't play notes or tunes .

The extra time on charge is to ensure cell groups are balanced as close as possible.

So far my 6 y/o 29E celled batteries are staying nicely balanced, only charging to 90%.

That's interesting to know, my 10 day old Woosh Rambletta has just had it's battery charged for the 3rd time since new, the measured voltage was 41.8v across the battery terminals so presume thats very good.

In their manual for the bike it stated that the very first charge to leave the battery connected to the charger a further 2 hours after the green light on the charger illuminates to 'fully tune the battery, there is no need to do this again in the future'.

If you check the voltage from time to time, any reduction from that 41.8v will show how much imbalance there is. You only need to leave it on charge for a long time after the green light if the battery is unbalanced.

If you check the voltage from time to time, any reduction from that 41.8v will show how much imbalance there is. You only need to leave it on charge for a long time after the green light if the battery is unbalanced.

 

One thing to bear in mind is that some chargers, eg Yose Power, only output 41.7 V, so the pack will not get above that voltage.

No way to adjust our chargers or set them other than go from green lights going out when the charger decides.

Don't know how to test the capacity of either battery because my comprehensive multi meter isn't interested in giving a plausible reading.

 

The charger does not decide when to display the green light. That happens in the BMS. When the input current drops below a set level, the BMS disconnects the charging circuit until the pack is used again and it's voltage drops.

One way to ensure charging to less than 100% is to open up the charger and see if there is a potentiometer controlling the output voltage. Then you can tune the output to what you want. If not, what you could do is to put one or more ordinary 5A silicon diodes in series with the output. These induce a voltage drop of about 0.5V per diode, so if you want 41V from a 42V charger, just use two diodes in series.

If you check the voltage from time to time, any reduction from that 41.8v will show how much imbalance there is. You only need to leave it on charge for a long time after the green light if the battery is unbalanced.

 

Once the green light comes on, no more current flows into the battery, it is no longer balancing. The BMS disconnects the charger from the battery, hence the green light.

The thing that worries me from what you say is that the battery is supposed to be new, when it aught to be delivering its best performance.

 

I would consider trying to get it replaced from where you bought it.

 

The last silver fish battery I bought was quite cheap off ebay (under £200 including a charger), so I was not expecting anything spectacular, but it can still power a heavy me and two panniers 10 miles to work at an average speed over 18 mph on my 2011 rear hub cadence sensor bike and will be 3 years old at the end of March 21.

 

It does sag quite badly on hills ( dropping to 1 bar showing on the display before recovering after the hill) but does not cut out.

 

I start my journeys with a fully charged battery and am sure it would not take me much further than 10 miles on full assist, but I don't need it to, and can re charge it at work.

 

Interestingly I re charge my battery in a over heated room and the battery performs better on my journey home.