Panasonic battery life

[lemmy]

I checked the charge capacity of the battery for my Kalkhoff Tasman today, the original 10ah one that came with the bike. I bought it in November 2009 so the bike is going on 2 years old.

A long press on the button gave me all 5 lights coming up, suggesting that the battery capacity is not too far off what it was originally.

This surprises me because I have made no attempt to treat the battery well. I often charge it after 3 or 4 miles if I'm going on a longer ride, for example. In practise, I just charge it whenever I feel like it and when I do run the battery down to a flashing battery indicator it is only because I have ridden a long way, not a planned reconditioning discharge.

When new, on stop go London and fairly hilly going through Richmond Park I'd get 27-30 miles range on a full charge using medium power constantly on, before the the battery light went to slow flashing mode. Looking at my trip meter today, it's done 27.5 miles before the flashing light.

Maybe the battery will deteriorate rapidly from now on I don't know but even if it does it looks good for another year. Given that I do about 1500 miles per annum, that seems pretty reasonable overall.

Have I been particularly lucky, I wonder? Or does carelessness pay

 

[tillson]

My original Panasonic battery is about 31 months old. It still shows 5 LEDs on the capacity test and gives me about 25 miles range on Medium Power, 40+ on low power.

 

[lemmy]

That seems in line with mine, then. So a practical life might well be in the 4 year range.

I wonder if that's due to good battery management software or just the way it is with the Panasonic batteries?

 

[Scottyf]

A little bit of both I would assume. Also not stressing the cells creates for a longer life.

Given that it would be crank driven it would be more effcient.
I'm suprised by the use of battery still being that useful.


But then again I guess most people are quick to get a new battery when even after say 1000cycles you'd still have 80% of battery life. I don't know how far battery's then go down by or suffer alot of voltage sag.

But I think Lithium batteries can be useful after the 2 year block.


Either way its still cheaper than petrol ;-)

 

[flecc]

As Scotty said, I'm sure it's bit of both, but theres no doubt that very good management software is the biggest factor in getting long lithium battery life. I'm not at all surprised that these are lasting well and I'd expect a regularly used one to be useful for three years and maybe more.

 

[tillson]

I mainly use my bike in low power mode these days and have noticed that the range in low power mode is not far off what it was when the battery was new. The reduction in range is noticeable in medium power mode and decidedly noticeable in high power mode. The ageing battery seems to exhibit a deterioration in capacity when high demands are made of it, and exhibit hardly any deterioration under less demanding conditions.

As time progresses, I am becoming more impressed with the Panasonic battery. Initially I had my doubts about it's longevity, but those doubts have now disappeared and I am very pleased.

 

[Scottyf]

The higher C rate you deman the lower any batteries capacity is.
Hence what your finding more so on an aging battery.

This is why its good to overstate your battery when you first buy. The easier time you can give the cells for any application the longer they will last.

I think this is why the batteries on solar satalites are quite large and never use there full capacity at all. But only a few % to ensure battery life.