Hi All,
Noticed the range is getting less and less on my USB Lezyne 400 lumin headlight.
I plug her in to charge at work at start of day, in the PC, and pull out when I got home from work in the evening
Am I overcharging her?
The (lack of) documentation says nothing about this, just the MINIMUM time to charge to max.
Hope you can advise
Regards
Martin
PS
The LED charging light goes out on my "Specialised STIX rear light."
I'm assuming it has some kind of "Chargind cut off" function?
can one overcharge USB bike lights?
Re: can one overcharge USB bike lights?
From Lezyne I'd expect it to have overcharging protection, although this isn't mentioned in the manual. The manual says the light has a Li-Po battery.
Any battery has a limited lifespan in terms of charging cycles and can be expected to suffer a drop off in capacity over it's life. A bit of googling suggests 300-500 charge cycles is not an uncommon useful lifespan for Li-Po.
The warranty against manufacturing faults on a Lezyne battery is six months, perhaps in an effort to eliminate erroneous warranty claims in situations that reflect fair wear and tear.
Any battery has a limited lifespan in terms of charging cycles and can be expected to suffer a drop off in capacity over it's life. A bit of googling suggests 300-500 charge cycles is not an uncommon useful lifespan for Li-Po.
The warranty against manufacturing faults on a Lezyne battery is six months, perhaps in an effort to eliminate erroneous warranty claims in situations that reflect fair wear and tear.
Re: can one overcharge USB bike lights?
Li-ion/Li-po batteries are generally happiest kept between around 40 and 70% charge.
Firstly Li-ion batteries degrade as they are charged and discharged. Charging and discharging further away from the optimum voltage reduces their total capacity more quickly. Rapid charge and discharge may also do so, though the extent to which it does has been subject of some debate recently.
Secondly they degrade simply as a matter of existing. This degradation happens quicker at higher temperatures and higher charge levels. (e.g. a battery at 25C and 100% charge will lose about 20% of it's total capacity over a year, at 40% charge it would only lose 4-5%)
Given that, no it generally isn't a good idea to leave them plugged into stuff when charged. Whilst they do have a protection circuit built in to stop overcharging, discharging or other issues (ALL li-ion batteries have this as they tend to undergo a runaway thermal reaction when outside certain operating parameters, plenty of vids on youtube) you will still be unnecessarily shortening the battery life as:
-you're operating it mostly at at the top end of the charge (unless you drain it in one commute, in which case you have no choice)
-I find, even with charging cut offs, plugged in stuff tends to get warmer than it needs to, which will shorten the life.
Usually there's some kind of indication if it's charged?
Li-ions do not really suffer from any memory affects so there's no need to go to 100% or 0%. Also do you actually use all 400 lumens? If so do you need to?
Firstly Li-ion batteries degrade as they are charged and discharged. Charging and discharging further away from the optimum voltage reduces their total capacity more quickly. Rapid charge and discharge may also do so, though the extent to which it does has been subject of some debate recently.
Secondly they degrade simply as a matter of existing. This degradation happens quicker at higher temperatures and higher charge levels. (e.g. a battery at 25C and 100% charge will lose about 20% of it's total capacity over a year, at 40% charge it would only lose 4-5%)
Given that, no it generally isn't a good idea to leave them plugged into stuff when charged. Whilst they do have a protection circuit built in to stop overcharging, discharging or other issues (ALL li-ion batteries have this as they tend to undergo a runaway thermal reaction when outside certain operating parameters, plenty of vids on youtube) you will still be unnecessarily shortening the battery life as:
-you're operating it mostly at at the top end of the charge (unless you drain it in one commute, in which case you have no choice)
-I find, even with charging cut offs, plugged in stuff tends to get warmer than it needs to, which will shorten the life.
Usually there's some kind of indication if it's charged?
Li-ions do not really suffer from any memory affects so there's no need to go to 100% or 0%. Also do you actually use all 400 lumens? If so do you need to?
The contents of this post, unless otherwise stated, are opinions of the author and may actually be complete codswallop
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RideToWorky
- Posts: 218
- Joined: 23 Oct 2015, 1:14pm
Re: can one overcharge USB bike lights?
Hi Steve
Many thanks for the informative reply!
I do use the full 400 lm. It is dark the country roads I'm right home in.
Have checked the instructions next step down is free hundred lumens, but that only give me one hour 20, as opposed to 1 hour.
Good point about overcharging shortening the battery life life.
What I'll do is probably just charge for three hours each day when I get home, and also at work.
Come summer, probably won't use it at all!
Cheers
Martin
Many thanks for the informative reply!
I do use the full 400 lm. It is dark the country roads I'm right home in.
Have checked the instructions next step down is free hundred lumens, but that only give me one hour 20, as opposed to 1 hour.
Good point about overcharging shortening the battery life life.
What I'll do is probably just charge for three hours each day when I get home, and also at work.
Come summer, probably won't use it at all!
Cheers
Martin