Charging

[jellybeans]

Hi,

I recently bought a Volt Kensington electric bike which I'm very happy with
I was wondering if anyone offer some advice about the best way to charge it.

The bike shop seemed very knowledgeable and said to let the battery run down to one bar before charging, however the manual says to charge after every ride, hence I am confused about what to do!

Thanks for any advice on what is best to do for best battery life.

 

[RPe]

May I also ask the same question about my Gtech battery .... should I run it right down or recharge it for example when there’s 40% left.

 

[Benjahmin]

Use it - charge it. The more a battery is deep cycled the shorter it's life will be. Why go out with a partially charged battery and suffer range anxiety when you decide to go further than planned 'cos it's a nice day and the birds are singing?

 

[Nealh]

I use my batteries on a 60./70+ mile rides and sometimes means down to lvc (3.3 - 3.4v) to get the range. Locally I ride using the odo and know the voltage they sit at, often I will ride down to 3.6 - 3.7v (about 30 - 40%).
Generally charge after each use but quite pointless if l only a few miles done.
Using down to lvc won't hurt every now an then, doing so you will find out range possible and how much the battery may be depleted. If for instance range is 40 miles and you ride 10 miles, you will know battery is at approx. 75% charge. The best advice is use and charge if your daily mileage is more then 20/25% of the charge, if not charge it every two or three rides.
Batteries lose life if left at full charge to long/often or too low, 3.7 - 3.9v is a healthy non use level.
New cells for battery building often come delivered at 3.6 - 3.8v and all will be at the same give or take 0.01v.

 

[Nealh]

May I also ask the same question about my Gtech battery .... should I run it right down or recharge it for example when there’s 40% left.

I would recharge, esp with low ah batteries as you will be stressing the cells more unless of course you have top 15/20a rated cells.

 

[Nealh]

Use it - charge it. The more a battery is deep cycled the shorter it's life will be. Why go out with a partially charged battery and suffer range anxiety when you decide to go further than planned 'cos it's a nice day and the birds are singing?

I agree if going out for an amble or no where in particular but just to go and ride.
For local use or commute use, usage is different, depends how far you cycle. If it's only 10/15 mins a day pointless recharging, in which case every few days will suffice.

 

[Nealh]

Deep discharging is typically below 3.3v down to 2.8v to get the full quoted ah out of a cell depending on the amp daw , however most battery bms will cease discharge at 3.3v - 3.4v and the lvc will come in to play. Below 3.3v there is little capacity left and cells will crash quite quickly below this level in a matter of yds.

 

[Deleted member 4366]

The higher the state of charge of the battery, the higher the voltage, so the higher the power you can get from the motor. The power will be 33% more when the battery is full compared with when empty.

 

[RPe]

Am I right in thinking re chargeable batteries are more efficient if they are recharged from a low level or was that the case years ago ?

 

[Nealh]

Am I right in thinking re chargeable batteries are more efficient if they are recharged from a low level or was that the case years ago ?

It was the case with Nimh cells as they had a memory effect, Lithium doesn't suffer that issue.

 

[Danidl]

Am I right in thinking re chargeable batteries are more efficient if they are recharged from a low level or was that the case years ago ?

No.. old thinking . the current battery technology prefers a little and often . Older nickel based batteries had a problem that little and often encouraged the growth of internal crystal spikes which ruptured the cells and made short circuits.
Lithium ion prefers to be brought close to full charge and not fully discharged. Every full cycle causes a little damage to the rigid matrix holding the ions. The charge discharge cycle causes swelling shrinking so keeping the dimension stable lenghtens life.

 

[Olis4]

From my understanding running modern batteries very low is the biggest no no. They do protect again this, for example the Bosch system shuts down and still has enough power to power the lights for 2 hours.

On most of my rides I return with around 40% which is a good state of charge for the battery to be left in (30 - 60% is ideal) so I leave it and charge it the night before I ride so it only sits with full charge for max 18 hours.

I could have an opportunity to ride and not be charged up but that is a risk i'll take to protect a £600+ battery