Battery ageing question.

[Hightechpete]

The 36v 11Ah battery on my 'winter bike' was charged to 38v before being laid up. From time to time I check that there are 2 of the 3 indicator lights still illuminated . This week only the red indicator lit up, so I gave it a charge. It will now only charge to 38v, the charger output is good at 42v.

The battery is 18 months old and has been charged about 30 times in total. Is this a sign that the battery is ageing or could there be another problem?.

Pete.

 

[Nealh]

38v is low so there is an issue with the battery, a cell group/s may have drained a bit low and now won't balance though 6v is a very large discrepancy
Ageing shouldn't be an issue on a 18 mth old battery.

 

[vfr400]

It's gone out of balance. Best would be to open it and balance it manually.

 

[Hightechpete]

It's gone out of balance. Best would be to open it and balance it manually.

Thanks for the replies, I'll do a search for manual balancing and report back.

 

[JuicyBike]

Fully discharging and fully charging should help. Possibly several times. Batteries like to be used...

 

[Woosh]

I keep telling my customers to ride their bikes as often as possible It's a case of usse it or lose it.
If you can't use your bike as often as you wish, do not store the battery in a full or nearly flat state.
Batteries are actually mechanical devices and will break down over time. I still remember my first lesson in Physics, we were learning about the pendulum and my Physics teacher (a very beautiful lady, no wonder I remember the lesson well) told us that it will stop after a while.
The mechanism is intercalation. Lithium ions move from one electrode to the other when charging, the opposite direction when discharging.
The destination electrode swells with the Lithium and degrades faster than the other electrode. If you store your battery for months, leave it between 50%-70% full (3 bars out of 5 on the LCD's battery indicator) and never expose your battery to heat or humidity unnecessarily.
Modern BMS will keep your battery alive for at least 2 years without recharging. You certainly do not want to top up charge your battery whie it is wintering!
One last comment, batteries do not last forever, the small risk of fire increases over time, especially if you don't use your battery much. You need to recycle your battery every 5-6 years.
Like with computers or mobile phones, the improvement over that period of time is considerable and make the new purchase worthwhile.

 

[Hightechpete]

Modern BMS will keep your battery alive for at least 2 years without recharging. You certainly do not want to top up charge your battery whie it is wintering!

Thanks for the explanation, but now I'm confused. The battery in question has a label which clearly states 'If the battery is to be stored it should be charged for 2 hours every 3 months.'

Anyway, it's been used and recharged and now its up to 40v, so thanks Juicy, it appears to be working.

It seems like a lot of trouble to manually balance the cells, specialist equipment which may or not work on other batteries without modification. If it needs doing regularly, and the equipment would work on any battery, then I would consider it. Any tips on which one to get would be appreciated.

 

[vfr400]

If you simply leave it on the charger, the balancing system will most likely charge at a rate of about 30 - 100mA instead of the normal 2A. If it's now at 40V, you have something like 3Ah to go, which would be about 30 to 100 hours of continuous charging.

 

[Hightechpete]

Thanks, I'll give that a try. From now on, I'll try to use all my my bikes regularly. I'm thinking that the best long term solution would be to get one good quality battery and swap it between the bikes, I'm assuming that spare battery holders are available?.

 

[Ajax]

I keep telling my customers to ride their bikes as often as possible It's a case of usse it or lose it.
If you can't use your bike as often as you wish, do not store the battery in a full or nearly flat state.
Batteries are actually mechanical devices and will break down over time. I still remember my first lesson in Physics, we were learning about the pendulum and my Physics teacher (a very beautiful lady, no wonder I remember the lesson well) told us that it will stop after a while.
The mechanism is intercalation. Lithium ions move from one electrode to the other when charging, the opposite direction when discharging.
The destination electrode swells with the Lithium and degrades faster than the other electrode. If you store your battery for months, leave it between 50%-70% full (3 bars out of 5 on the LCD's battery indicator) and never expose your battery to heat or humidity unnecessarily.
Modern BMS will keep your battery alive for at least 2 years without recharging. You certainly do not want to top up charge your battery whie it is wintering!
One last comment, batteries do not last forever, the small risk of fire increases over time, especially if you don't use your battery much. You need to recycle your battery every 5-6 years.
Like with computers or mobile phones, the improvement over that period of time is considerable and make the new purchase worthwhile.

Hi, Have you any suggestions on how i would go about recycling my batteries.
Clearly i can't simply dispose of the old batteries. But i wondered if anyone knows
on local council policies for disposing of, or recycling old Li batteries.

 

[anotherkiwi]

Hi, Have you any suggestions on how i would go about recycling my batteries.
Clearly i can't simply dispose of the old batteries. But i wondered if anyone knows
on local council policies for disposing of, or recycling old Li batteries.

Most supermarkets in France have a used cell collecting box, all of my Li-Ion batteries go in there and off they go for recycling.

I took my LiPo bricks to the local recycling place (déchetterie) and told the man they were charged to 3.8v/cell so quite dangerous. He said "Ok I'll not chuck them in the barrel of brine solution where I put the Li-Ion batteries then, I'll find a solution". I sleep sounder knowing I didn't chuck them off a cliff into the ocean...

 

[wheeliepete]

Hi, Have you any suggestions on how i would go about recycling my batteries.
Clearly i can't simply dispose of the old batteries. But i wondered if anyone knows
on local council policies for disposing of, or recycling old Li batteries.

Your local recycling centre in the UK will take your old battery packs, or if you put your location on your profile, someone here may come and collect them from you.

 

[Tarka]

It's a problem that the electric car industry doesn't like to talk about.
Zoe's are getting to the age where you don't get many miles to a charge any more, and the car is effectively worthless.

Lithium is a valuable and scarce resource yet no-one seems to want to re-cycle the batteries. Labour costs and fire risk puts them off.

 

[Woosh]

Thanks for the explanation, but now I'm confused. The battery in question has a label which clearly states 'If the battery is to be stored it should be charged for 2 hours every 3 months.'

Anyway, it's been used and recharged and now its up to 40v, so thanks Juicy, it appears to be working.

long time ago, batteries used to lose their charge so quickly that you had to top up charge them every few months.
How old is your battery?
Next time you want to store it for a month or more, write down the voltage before and after storage, see how much it has gone down. Batteries work between 41.5V (full) and 31.5V (flat). You can deduce how long before the voltage drops to 33V.
My batteries lose about 1.5V after 6 months.

 

[Woosh]

Hi, Have you any suggestions on how i would go about recycling my batteries.
Clearly i can't simply dispose of the old batteries. But i wondered if anyone knows
on local council policies for disposing of, or recycling old Li batteries.

They take Lithium batteries at Southend Councils refuse tips.
There is no dangerous substance in the cells but there is a bit in the solder.

 

[anotherkiwi]

It's a problem that the electric car industry doesn't like to talk about.
Zoe's are getting to the age where you don't get many miles to a charge any more, and the car is effectively worthless.

Lithium is a valuable and scarce resource yet no-one seems to want to re-cycle the batteries. Labour costs and fire risk puts them off.

No longer the case, this was true a couple of years ago:

At the moment there is a glut of Lithium. A process to extract it from sea water isn't too far away as well.

There is a Canadian company with a process that recovers most of the recyclable content of a Li-Ion battery. Last I heard they were setting up a partner in the EU.